Temporal characterization of oscillator signals in charged particle microscopy

Abstract

A method for characterizing a light beam within a charged particle lens barrel, the method comprising: directing a light beam pulse towards a sample within the charged particle lens barrel; directing the charged particle beam pulse towards the sample; detecting charged particles that interact with the sample based at least in part on the beam pulse and the charged particle beam pulse; determining a time delay between the charged particle beam pulse and the beam pulse based at least in part on the charged particles; and determining at least one characteristic of the beam pulse based at least in part on the time delay.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 645,747, filed May 10, 2024, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] Embodiments of this disclosure relate to charged particle microscopy systems. More specifically, this disclosure describes beam synchronization techniques in charged particle microscopy. Background Technology

[0004] Charged particle microscopy can be used to study materials and structures with biological or inorganic properties. Scanning electron microscopy and transmission electron microscopy (SEM) / (TEM) image a target object, such as a protein or semiconductor wafer, by focusing a beam of electrons and / or photons onto it. Some particles may interact with the target object and transmit information about it to the microscope user. Some microscopy techniques can additionally combine laser-based techniques with charged particle beams. When using laser-based techniques, beam chopping is often used to address the relaxation time characteristics, saturation effects, and residual emissions of photoemitters. The use of a chopper / beam blanker in TEM implies active synchronization between two sources (pump and probe), which already have their own clocks. Synchronization on the picosecond timescale presents significant challenges. Summary of the Invention

[0005] According to some embodiments, a method for characterizing a beam within a charged particle microscope is provided, the method comprising: directing a beam pulse toward a sample within the charged particle microscope; directing a charged particle beam pulse toward the sample; detecting charged particles interacting with the sample based at least in part on the beam pulse and the charged particle beam pulse; determining a time delay between the charged particle beam pulse and the beam pulse based at least in part on the charged particles; and determining at least one characteristic of the beam pulse based at least in part on the time delay.

[0006] According to some embodiments, the charged particle beam is a charged particle beam pulse, wherein the beam is a beam pulse, and wherein determining the time delay further includes: synchronizing the charged particle beam pulse with the beam pulse; and determining a plurality of time steps, wherein one of the plurality of time steps represents a time offset of the charged particle beam pulse relative to the beam pulse.

[0007] According to some embodiments, the beam is a beam pulse, and determining the time delay further includes: synchronizing the charged particle beam pulse with the beam pulse; and determining a plurality of time steps, wherein one of the plurality of time steps represents a phase delay of the charged particle beam pulse relative to the beam pulse.

[0008] According to some embodiments, the beam is a beam pulse including a time pulse profile, and the method further includes: guiding a charged particle beam into an energy dispersive spectrometer configured to generate detector data describing the energy distribution of the charged particle beam; generating a detector dataset describing multiple energy distributions corresponding to multiple time steps; and using the detector dataset to generate profile data describing the time pulse profile.

[0009] According to some embodiments, generating the detector dataset may include sampling detector data generated simultaneously with the interaction period of the beam and the charged particle beam, wherein the detector data may be characterized in that the sampling period is about an order of magnitude smaller than the pulse duration described by at least one characteristic, the at least one characteristic being the time pulse profile of the beam intensity.

[0010] According to some embodiments, the charged particle beam is a charged particle beam pulse, and generating the detector dataset includes integrating the detector data using multiple charged particle pulses over a given time step.

[0011] According to some embodiments, an operating parameter scheme corresponding to the at least one characteristic is generated, the operating parameter scheme describing one or more operating parameters of the charged particle beam system, wherein the at least one characteristic includes the time pulse profile of the beam intensity.

[0012] According to some embodiments, determining at least one characteristic of the beam further includes measuring the effective pulse duration of the beam using photon-induced near-field electron microscopy (PINEM) spectroscopy.

[0013] According to some embodiments, the temporal intensity distribution of the beam is characterized at least in part based on the effective pulse duration.

[0014] One or more machine-readable storage media storing executable instructions that, when executed, cause a charged particle beam system to perform operations including: directing a beam pulse toward a sample within a charged particle microscope tube; directing a charged particle beam pulse toward the sample; detecting charged particles interacting with the sample, at least in part based on the beam pulse and the charged particle beam pulse; determining a time delay between the charged particle beam pulse and the beam pulse, at least in part based on the charged particles; and determining at least one characteristic of the beam pulse, at least in part based on the time delay.

[0015] According to some embodiments, the charged particle tube is a transmission electron microscope (TEM).

[0016] According to some embodiments, the charged particle mirror tube includes a radio frequency (RF) cavity configured to generate charged particle beam pulses.

[0017] According to some embodiments, the pulse frequency of the charged particle beam pulse is from about 25 MHz to about 100 MHz.

[0018] According to some embodiments, the operation further includes coupling the light beam into a light guide material.

[0019] According to some embodiments, the operation further includes: adjusting the delay of the beam pulse or charged particle beam pulse directed toward the sample, based at least in part on the determination of the at least one characteristic.

[0020] According to some embodiments, the operation further includes: adjusting the intensity, frequency, or phase delay of the beam pulse directed toward the sample, at least in part based on the determination of the at least one characteristic.

[0021] A charged particle beam device includes: one or more processors; and one or more machine-readable storage media operatively connected to a control circuitry system, the media storing executable instructions that, when executed, cause operations including: directing a beam pulse toward a sample within the charged particle beam device; directing a charged particle beam pulse toward the sample; detecting charged particles interacting with the sample, at least in part based on the beam pulse and the charged particle beam pulse; determining a time delay between the charged particle beam pulse and the beam pulse, at least in part based on the charged particles; and determining at least one characteristic of the beam pulse, at least in part based on the time delay.

[0022] According to some embodiments, at least one characteristic of the light beam includes a characterization of the time asymmetry of the light beam.

[0023] According to some embodiments, at least one characteristic of the light beam includes pulse duration or laser chirp.

[0024] According to some embodiments, the at least one characterization is used to characterize one or more optical modes in a microresonant cavity. Attached Figure Description

[0025] The foregoing aspects and many accompanying advantages of this disclosure will become more readily understood when taken in conjunction with the accompanying drawings and the following detailed description.

[0026] Figure 1 This is an exemplary schematic diagram illustrating an exemplary charged particle beam system according to some embodiments of the present disclosure.

[0027] Figure 2 This is an exemplary schematic diagram illustrating a system for controlling a pulsed light source and a pulsed charged particle source according to some embodiments of the present disclosure.

[0028] Figure 3This is an exemplary flowchart illustrating techniques for generating control signals in systems of pulsed light sources and pulsed charged particle sources according to some embodiments of the present disclosure.

[0029] Figure 4 This is an exemplary schematic diagram illustrating a technique for gating a pulsed charged particle source using a control signal from a light source according to embodiments of the present disclosure.

[0030] Figure 5 This is an exemplary composite diagram illustrating the periodic operation of a beam blanking device according to an embodiment of the present disclosure.

[0031] Figure 6 This is an exemplary schematic diagram illustrating a technique for interrogating a pulse beam using a charged particle beam pulse according to embodiments of the present disclosure.

[0032] Figure 7 This is an exemplary set of schematic diagrams illustrating exemplary data for different pulse beam profiles according to embodiments of the present disclosure.

[0033] Figure 8 This is an exemplary flowchart illustrating an exemplary process for synchronizing and interrogating charged particle beam pulses and pulsed beams according to embodiments of the present disclosure.

[0034] Figure 9 This is an exemplary flowchart illustrating an exemplary process for synchronizing and interrogating charged particle beam pulses and pulsed beams according to embodiments of the present disclosure.

[0035] Figure 10 This is an exemplary flowchart illustrating an exemplary process for synchronizing and interrogating charged particle beam pulses and pulsed beams according to embodiments of the present disclosure.

[0036] Figure 11 This is an exemplary flowchart illustrating an exemplary process for coarse and fine alignment of charged particle beams and pulsed beams according to embodiments of the present disclosure.

[0037] Figure 12 This is an exemplary flowchart illustrating an exemplary process of synchronizing a charged particle beam and an amplified pulse beam according to embodiments of the present disclosure.

[0038] Figure 13 This is an exemplary flowchart illustrating an exemplary process for characterizing a light beam according to embodiments of the present disclosure.

[0039] Figure 14 This is an exemplary system block diagram according to embodiments of the present disclosure.

[0040] In the accompanying drawings, unless otherwise specified, the same reference numerals denote the same parts in each view. Where appropriate, it is not necessary to label all instances of elements to reduce confusion in the drawings. The drawings are not necessarily drawn to scale, but rather focus on illustrating the principles described. Detailed Implementation

[0041] While illustrative embodiments have been described and illustrated, it should be understood that various changes may be made therein without departing from the spirit and scope of this disclosure. In the following paragraphs, embodiments of charged particle beam systems, components, and methods for synchronizing pulsed beams of photons and charged particles in systems including such subsystems are described. For simplicity, embodiments of this disclosure focus on transmission electron microscopy and related instruments. Therefore, the embodiments are not limited to such systems, but rather contemplate charged particle beam systems configured for “ultrafast” techniques to probe sample dynamics on relatively short timescales (e.g., picoseconds, femtoseconds, etc.). Advantageously, synchronization of the pulsed beam and charged particles can at least partially improve the performance of ultrafast microscopy techniques by decoupling the light source from the charged particle source (e.g., generating charged particle beam pulses using a radio frequency resonant cavity instead of an optically pumped photoelectric emitter). Furthermore, independent control of the pulsed beam and charged particle beam pulses allows the time delay to act as an independent variable in various techniques for optical interrogation of materials (e.g., micro-resonant cavities) and in the temporal characterization of the pulsed beam itself.

[0042] In charged particle microscopy, characterizing various parameters of a target object (e.g., circuits, wafers, biological samples, etc.) can involve interrogating the object using a beam of charged particles, such as an electron beam. Electrons can interact with the target and can be detected by a detector for analysis and examination. Typically, the process of characterizing a target object requires multiple cycles of pulsed electron beams to acquire images. Therefore, imaging in charged particle microscopy is usually based, at least in part, on the elastic interactions between electrons and the target object. These elastic interactions may not involve energy gain or loss and can provide information about the target object's structure and bonding. In contrast, inelastic interactions do involve energy loss due to electron excitation in the target object and are studied in electron energy loss spectroscopy (EELS).

[0043] In UTEM, a light beam (laser) is used to study what typically occurs in femtosecond (10⁻¹) wavelengths. 5Ultrafast dynamic processes on short timescales (in the range of femtoseconds) are captured by lasers. One function of lasers is to provide ultrafast excitation to samples. Synchronized electron pulses can be used for imaging during illumination, enabling real-time capture of transient states and how the sample evolves. Achieving synchronization between the laser and electron beams in UTEM presents technical challenges, particularly in the context of time-resolved EELS. Precise time alignment is required between the optical pulses used to excite the sample and the electron pulses used for spectral interrogation to resolve dynamic phenomena on femtosecond timescales. Synchronization deviations reduce temporal resolution and impair the ability to accurately capture transient states within the sample. Even minute fluctuations in the timing of optical excitation or electron pulse generation can lead to time mismatch, affecting the accuracy of EELS measurements and limiting the system's ability to resolve ultrafast dynamics.

[0044] Maintaining the stability and coherence of laser and electronic pulses further exacerbates this challenge. For time-resolved EELS spectroscopy, ultrafast lasers produce highly stable pulses on the femtosecond scale, while electronic pulses maintain a consistent energy distribution and shape. External factors such as thermal drift, mechanical vibration, and electronic noise can introduce jitter or time drift into the laser and / or electronic pulse sequences. This instability disrupts synchronization, reducing the reliability and precision of the spectral data.

[0045] Embodiments of this disclosure enable close synchronization of the arrival times of charged particles and laser pulses at the sample, with only sub-picosecond jitter, and the repetition rate can be varied to match the detected sample response.

[0046] According to the embodiments described herein, techniques for synchronizing various signals are provided. For example, a radio frequency (RF) cavity can generate charged particle pulses, and a laser oscillator can generate beam pulses that operate at approximately the same frequency. Synchronization of charged particle pulses and beam pulses includes ensuring that the charged particle pulses and beam pulses operate at exactly the same frequency, and controlling the phase and / or time delay between the charged particle pulses and beam pulses. Synchronization is achieved by mixing signals from an RF driver coupled to the RF cavity and an optical driver coupled to the light source to generate a “coarse” or “rough” difference frequency signal about the two signals. The mixed signal can be used as feedback to the optical driver to synchronize the optical driver with the RF cavity. Furthermore, “fine” or “precise” synchronization can be performed by switching the harmonic frequencies of the signals from the RF driver or the optical driver to minimize the time delay / phase delay between the two signals. In some embodiments, a beam blanker can receive signals from the optical driver to control blanking and / or can send signals to the optical driver based on signals from the RF driver.

[0047] According to the embodiments described herein, a pulse pickup technique for adjusting the repetition rate of a charged particle beam is provided. This adjustment can be performed after synchronization as described above. In this way, the light source can emit amplified beam pulses based on the response time of the beam blanker and / or the sample. A delay generator can receive a signal and trigger the beam blanker to rapidly unblank the charged particle beam, such that the charged particle beam pulses arrive at the sample only when the amplified beam pulses are emitted toward the sample. In this way, by receiving a signal from the optical driver, the beam blanker can operate with a fixed time delay relative to the RF cavity, wherein the trigger signal has an inverse time delay, such that the blanker blanks the charged particle beam when the light source is not emitting light, thus both the charged particle pulses and the beam pulses simultaneously interrogate the sample.

[0048] According to the embodiments described herein, temporal characterization of a light beam can be performed. For example, a charged particle pulse and a light beam pulse can interact at the sample, causing the energy distribution of the charged particles to split into multiple sidebands. The stronger the beam, the broader the energy spectrum may become. The time delay between the laser and the charged particle beam can then be measured to generate a temporal profile of the beam intensity. This output can reflect the true asymmetric temporal profile of the beam, whereas conventional devices can only provide a symmetric profile. These techniques are applicable not only to free space but can also be advantageously extended to light pulses within photonic nanostructures. Information obtained from the temporal characterization of the beam may help interpret probing experiments performed within charged particle microscopy.

[0049] Advantageously, embodiments of this disclosure allow the repetition rate of electronic pulses to be reduced to arbitrary frequencies (e.g., set by the laser system) while maintaining the pulse properties and timing accuracy of the pulses generated by the RF cavity. In contrast, the frequency of electronic pulses in ultrafast TEMs based on conventional photoelectron emission is determined by the pulse frequency of the laser beam sent to the photodiode. Such techniques are limited by optical delay line challenges, as described above.

[0050] I. Exemplary System a. Charged particle beam system

[0051] Figure 1This is a schematic diagram illustrating an exemplary charged particle beam system 100 according to some embodiments of the present disclosure. In the following description, for simplicity, details of the internal components and functions of the exemplary system 100 are omitted, and the description focuses on embodiments of the present disclosure. The exemplary system 100 includes a charged particle source section, a TEM tube (e.g., a charged particle tube), the TEM tube including a charged particle source section 105, a TEM tube 110, an objective section 115, and an imaging section 120 (e.g., equipped with an electron energy loss spectrometer 125). The exemplary system 100 includes one or more components for implementing “ultrafast” operation, such as a radio frequency (RF) cavity 130, a beam blanker 155, and one or more light sources 160. In the context of this disclosure, “ultrafast” operation refers to a TEM system configured, for example, to generate detector data on a picosecond timescale using stroboscopic analysis with a pulsed beam. Thus, the relative positions and order of the RF cavity 130 and the beam blanker 155 may vary in different embodiments of the present disclosure. For example, the RF cavity 130 may be located before the beam blanker 155, and these components may be placed in various ways at different locations in the exemplary system 100 to generate a pulsed electron beam.

[0052] The charged particle source section 105 may include electronic devices configured to power the charged particle source, which may include a high-voltage field emission source or other electron emission source to form an electron beam and conduct it through a vacuum into the TEM tube 110. The electron beam can be modulated using a beam blanker 155 to generate a pulse sequence. Pulses can be generated by repeatedly deflecting the beam according to a trigger signal provided to the beam blanker, as shown in the reference. Figure 2-8 As described in more detail. The beam blanker 155 can be an electrostatic element or an electromagnetic element. In some cases, the relaxation time of the magnetic field can limit the compatibility of electromagnetic elements operating at ultrafast speeds. For this purpose, embodiments of this disclosure may include an electrostatic beam blanker configured to periodically interrupt a continuous electron beam as a means of generating a pulse sequence characterized by frequencies from about one kilohertz (kHz) to about one hundred megahertz (MHz).

[0053] Downstream of the beam blanker 155, relative to the charged particle source section 105, an RF cavity 130 may be configured such that a pulse sequence passes through the body 135 of the RF cavity 130 via an aperture 140 defined in the body 135. The aperture 140 may be substantially centered on the beam axis of the exemplary system 100, with the components of the RF cavity 130 arranged generally symmetrically around this axis. The RF cavity 130 may include one or more antennas 150 disposed within the body 135. The antennas 150 may be electrically connected to RF power lines and used to drive the antennas 150 at one or more RF frequencies. The antennas 150 may be disposed in a dielectric or insulating insert 145, substantially concentric with the aperture 140. The behavior of the RF field in the aperture (e.g., the location of standing waves) may be at least partially based on various distances 137, 139, 141, and 151 of the RF cavity components. For example, where each antenna can be driven at the corresponding RF frequency, the distance 151 between the antennas 150 can affect the interaction of the two RF fields. The RF cavity 130 is described in more detail in U.S. Patent US11328892B2, European Patent EP3772745A3, Korean Patent KR102586724B1 and Korean Patent Application KR20230127968A, Japanese Patent JP7378366B2 (titled "Coating on dielectric insert of a resonant RF cavity") and Chinese Patent CN112349571B (titled "RF cavity, apparatus and system for charged particle microscope"), the disclosures of which are hereby incorporated by reference in their entirety.

[0054] RF cavity 130 can be configured as a "dual-mode" cavity to support two resonant modes at slightly offset field frequencies in the 1 to 5 GHz range (including portions, sub-ranges, and interpolations thereof). The difference between the frequencies can cause a deflection of charged particles at a relatively low frequency (e.g., about 75 MHz) in the downstream aperture. RF cavity 130 may include a pickup antenna such that a second frequency at a relatively low harmonic can be derived from a signal from the pickup antenna within the RF cavity. Advantageously, using a signal from the pickup antenna, at least in part based on a synchronization signal derived from the actual field within RF cavity 130, can reduce the effects of drift and instability in the RF cavity and associated drive circuitry. However, in some cases, an electrostatic beam blanker with a bandwidth in the GHz range can be used for a single-mode RF cavity operating at about 1 GHz to about 5 GHz (e.g., about 2.4 GHz). The beam blanker can directly modulate electronic pulses of a 2.4 GHz pulse sequence.

[0055] The TEM tube 110 includes components for beam formation, including electromagnetic and / or electrostatic lenses, and multiple apertures to control the properties of the electron beam. The TEM tube 110 components include a condenser lens, objective lens, projection lens, aberration corrector, deflector, astigmatism reducer, etc., and corresponding apertures. The objective lens section 115 accommodates a sample through which the electron beam can pass. The sample section may include one or more types of detectors, such as an X-ray detector, a secondary electron detector, etc.

[0056] Objective section 115 also includes an optical coupling 163 (e.g., via connector 161) to a light source 160, through which photons can be introduced into the vacuum environment of system 100 and directed toward the sample. In some cases, light source 160 includes a fiber laser. Light source 160 can be coupled to objective section 115 via an optical fiber. In some embodiments, light source 160 is optically coupled to objective section 115 via one or more optical elements (e.g., optical mirrors, lenses, apertures, filters, etc.). Similarly, embodiments of this disclosure include systems in which optical coupling 163 is included as part of or in a TEM barrel 110 other than objective section 115. Thus, exemplary system 100 may include one or more optical elements disposed within the system to direct and convert the light beam toward the sample.

[0057] The light source 160 may include a laser having an oscillator and an output stage. The oscillator may be configured to generate optical pulses at a given frequency (e.g., approximately 75 MHz), which is a characteristic of the oscillator design. The output stage may include an optical amplifier or other gain medium, and may also include a switch to determine which pulses are actually output from the oscillator (e.g., one out of every N pulses from the oscillator). In this way, the switch may act as a "pulse pickup," and the switch signal may act as a trigger signal, which can be used in the modulated beam blanking unit 155, as referenced. Figure 2-5 More details to follow.

[0058] A state-of-the-art TEM tube 110 can have up to four condenser lenses for flexible (e.g., stepwise or graded) reduction and focusing of the electron beam on the sample, and up to five projection lenses for flexible magnification of the electron beam downstream of the sample to the detector, as well as up to two aberration correctors. Since state-of-the-art aberration correctors can include additional lenses and several multipoles (e.g., four lenses and two to three or more multipoles), a modern TEM tube 110 can include up to approximately twenty lenses. The coordinated operation of the lenses and other optical elements results in a given reduction at the sample and a given magnification at the detector.

[0059] Imaging section 120 includes one or more types of detectors, sensors, screens, and / or optics configured to generate images, spectra, and other data for use in sample imaging and / or microanalysis. For example, the imaging section may include a scintillator screen, binoculars, a transmission electron microscopy (TEM) detector (e.g., a pixelated electron detector, a secondary electron detector, a camera), a segmented STEM detector, and an electron energy loss spectroscopy (EELS) spectrometer 125, etc. The EELS spectrometer 125 acts at least in part as an energy filter by focusing an electron beam onto an electrostatic or magnetic dispersive element (also called a "prism") that exerts a force on the electrons proportional to their velocity. In this way, electrons that have transferred energy to the sample (e.g., through elastic collisions) can be redirected through the magnetic dispersive element and toward the detector. The detector may include a pixelated detector (e.g., a CCD device configured to detect electrons) that generates one-dimensional or two-dimensional EELS data from which an EELS spectrum can be derived. In some embodiments, the EELS spectrometer 125 further includes one or more optical elements, such as electromagnetic or electrostatic lenses and / or multipole and / or accelerators, to modulate scattered electrons and / or focus scattered electrons onto a detector.

[0060] Embodiments of this disclosure relate to ultrafast electron microscopy in TEM systems, examples of which are described below. Figure 1 describe. Figure 2-10 The techniques involved relate to improving the performance of TEM systems in ultrafast mode, including the use of RF cavities (e.g., Figure 1 The RF cavity 130) electron beam pulse generator is synchronized to the laser system (e.g., Figure 1 The technology (160) is based on a light source in the TEM. The goal of this technology is to reliably phase-lock the laser signal and the electron beam signal. Another goal is to achieve a controllable time delay between the pump beam pulse guiding the sample into the TEM and the electron pulse probing the same sample.

[0061] In existing technologies, laser-based ultrafast TEM relies on photoelectron emitters. Synchronization between the pump and probe is achieved through an optical path that splits the beam pulse into a pump pulse and a probe pulse. One pulse directly illuminates the sample, while the other stimulates photoemission, generating synchronized electron pulses. Disadvantages of laser-based technologies include the relaxation time characteristics, saturation effects, and residual emission of the light emitter, typically addressed by beam chopping. Using a chopper / beam blanker in TEM implies active synchronization between two sources (pump and probe), each with its own clock. Synchronization on the picosecond timescale presents significant challenges.

[0062] The embodiments of this disclosure solve the synchronization problem in at least partly by means of the following: Figure 3 As shown, signals from two sources are mixed to derive a signal that varies with the time offset between the two signals, and the length of the laser oscillator is adjusted in a control loop (e.g., via one or more piezoelectric positioners) to eliminate the time offset.

[0063] b. Signal control components

[0064] Figure 2 This is an exemplary schematic diagram illustrating a system 200 for controlling a pulsed light source and a pulsed charged particle source according to some embodiments of the present disclosure. See reference... Figure 2 and Figure 8 Detailed examples of the technology described in this embodiment include using RF signals from an RF cavity module (e.g., RF driver 305) to derive output signals for at least two frequencies, wherein the first frequency ( Figure 3 The "F" in the text corresponds to the frequency of the light source 160, while the second frequency is a harmonic of the first frequency. Figure 3 (The “H” in the original text). Exemplary techniques include electronically mixing two signals with corresponding signals from a beam system (e.g., an optical driver 310), which may be a laser. Exemplary techniques include using a first (lower frequency) signal to define a coarse phase lock between the electronic signal and the laser signal.

[0065] Figure 3 This is an exemplary system block diagram 300 illustrating techniques for generating control signals in a system of pulsed light sources and pulsed charged particle sources according to some embodiments of the present disclosure. Figure 3 As shown, mixing two signals at a first frequency may include a vector product of the two signals to define an error signal upon which a feedback control scheme is based, the feedback control scheme including one or more parameters of the laser or reference signal 315 as control variables. Each vector multiplication symbol ⊗ illustrates the formation of the composite signal. In a non-limiting example, the error signal is Figure 3 One of the four computational signals shown.

[0066] The optimization of the error signal can be achieved through one or more control methods, such as a PID feedback control model using the error signal as the controlled variable and the characteristic length of the laser oscillator as the modulation variable, where, for example, the setpoint of the error signal is zero within an allowable tolerance. The optimization of the first error signal may correspond to a “coarse” synchronization of the laser and RF signals, after which the control technique transitions to a second frequency (H) signal for phase-locking. In some embodiments, an electronic time delay is applied to one of two higher frequency signals (e.g., an RF harmonic signal or a laser / optical harmonic signal). The error signal can be generated using two second frequency signals, one of which includes a time delay. The error signal can be used to generate a feedback signal to one or more piezoelectric elements in the laser oscillator, such that the oscillator output is locked to a reference signal 315. Figure 3 As shown, the reference signal can be mixed with a second frequency (H) signal. Advantageously, one of the reference signals carries an electronic time delay (e.g., delay circuit 320). The reference signal can have a frequency from about 1 MHz to about 100 MHz, including its subranges, fractions, and interpolations. In some examples, the default method for changing the time delay is to apply an electronic time delay to one of the frequency signals (e.g., the higher of the frequency signals). Alternatively, to achieve a relatively small time delay, the variation may involve adding a DC offset to the error signal. Adding a DC offset can be used to scan the time delay within a small range (±1 to 2 picoseconds (ps)) with high accuracy.

[0067] In some embodiments, the first frequency differs from the field frequency within the RF cavity and / or the frequency at which the cavity interacts with electrons. The first frequency can also be a divisor of either. For example, the first frequency can be equal to the laser oscillator frequency, but it can also be a multiple of the laser oscillator frequency (e.g., given the discussion above, where a fast beam blanking is used to achieve equivalence of the electron and optical pulse frequencies). In this case, the first frequency (F) can be a fraction of both the field frequency within the cavity and the frequency of the electron pulse generated by the cavity (e.g., approximately 75 MHz).

[0068] In practice, synchronization can be achieved using actuator control 330, at least in part by a) modifying signal generator 205 (e.g., RF driver) to provide an additional synchronization output of approximately 600MHz derived from the 2.4GHz master optical pulse signal in addition to the 75MHz synchronization signal; b) using a tunable pulsed laser module (e.g., light source 160), including the synchronization controller 220 electronics system; and c) connecting the RF synchronization output to the corresponding 75MHz and 600MHz synchronization inputs of the controller 220 of light source 160.

[0069] Advantageously, the technology disclosed herein avoids the need for optical delay lines in the laser path and provides nominally consistent beam pulse properties on the sample. Furthermore, implementation as... Figure 2 and Figure 3 The systems shown in Figures 200 and 300 have little to no impact on the performance of the RF subsystems due to phase-locked operation. Furthermore, the time delay can be electronically selected and / or defined, eliminating the physical limitations imposed on the time delay length by physical time-delay optics (e.g., allowing potentially infinite time delays without limitations on delay line length). Finally, the techniques disclosed herein allow for higher frequency locking for better accuracy, while also preventing phase ambiguity, which can lead to spurious convergence in systems with multiple stagnation points, by starting from the fundamental frequency of both systems.

[0070] While the general concept of RF-laser synchronization has been described, a significant limitation of existing methods is the time delay introduced by the use of optical delay lines. Therefore, the time delay is typically implemented in either branch (optical delay line or RF phase shifter). A drawback of optical delay lines is that altering the delay inevitably affects the laser beam's positioning and / or focusing on the sample, leading to alignment and optical stability challenges. Similarly, phase shifters in the RF signal path negatively impact the amplitude and / or phase stability of the RF signal, necessitating the recalibration of internal components of the TEM system. Another disadvantage of some systems is the need for deep integration between the laser system and the RF driver, limiting the flexibility of component selection and thus requiring dedicated TEM systems rather than flexible ultrafast modes.

[0071] To this end, embodiments of this disclosure include a "multimode" TEM system comprising using an ultrafast mode and a dual-mode cavity (e.g., generating a difference frequency within the typical laser oscillator range) of an RF cavity for beam chopping and / or using a pickup antenna within the RF cavity to generate a synchronization signal. In some embodiments, the pickup antenna within the RF cavity is used to directly generate the synchronization signal based on the actual standing wave of one of the cavity modes, thereby mitigating some sources of timing uncertainty in the RF module. This can be used for fine phase-locked loops (e.g., regarding...) Figure 3 The error signal can be enhanced by using a higher harmonic second frequency (e.g., above 600 MHz) of the mode selector 325. For example, using a harmonic frequency of 1.2 GHz can reduce the variance of the error signal as a complement and / or alternative to (e.g., using a more stable RF source) reducing both types of signal instability and laser beam pointing correction (before it falls on the photodiode). The error signal can also be used to estimate instability between RF and laser timing.

[0072] c. Charged particle beam control

[0073] Figures 4 to 5 This generally involves ultrafast TEM and specifically the use of RF cavity-based electron beam pulse generators combined with amplified laser systems, as referenced in [reference missing]. Figures 1 to 3 As described in more detail. In some cases, amplified laser systems will generate pulsed beams at a given pulse rate, where a subset of the pulses will be amplified. Therefore, embodiments of this disclosure enable pulsed particle beam systems to align the repetition rate of charged particle beam pulses with the amplified output of the pulsed laser system at any repetition rate.

[0074] Figure 4 This is an exemplary schematic diagram 400 illustrating a technique for gating a pulsed charged particle source using control signals from a light source according to embodiments of the present disclosure. A resonant RF cavity 401 operates at a substantially fixed frequency within a tuning range and can receive a charged particle beam 410. The RF cavity can be synchronized with a light source 160, as shown in reference... Figure 2-3 In more detail, and by applying a tunable amplifier (e.g., signal generator 205) to the pulsed laser system and a beam blanking device to the charged particle beam pulse 415, the electron pulse frequency and the beam pulse frequency can be synchronized to arbitrary pulse frequencies over a relatively wide frequency range, as described in the reference. Figure 1 More details to follow.

[0075] For this purpose, a plexiglass blanking device 420 can be used (e.g., Figure 1 The beam blanker 155 acts as a pulse pickup to sample a subset of the charged particle beam pulses 435 generated by the resonant RF cavity 401. The beam blanker 420 may include an electrode 425, a voltage source 430 coupled to the electrode 425 via a high-frequency switch 431 and / or via a common signal generator, wherein the high-frequency switch 431 may be coupled to an amplifier of the laser system, and the common signal generator is configured to generate a trigger signal to the laser amplifier and the switch 431. In this way, the beam blanker 420 may be synchronized with the laser amplifier or shutter, or both the pulse pickup and the laser amplifier or shutter may be synchronized to the common trigger signal.

[0076] Exemplary process (e.g., Figure 9 This includes generating charged particle beam pulses from a continuous electron beam using RF cavity 401 or another high-frequency beam modulator. An exemplary process also includes using a high-frequency beam blanker (e.g., an electrostatic beam blanker) or a second electron beam modulator as a "pulse pickup." In this context, a "pulse pickup" refers to the function of optical elements that, based on a trigger signal, periodically block the passage of an electron pulse by deflecting the pulse into a beam baffle, aperture 440, etc.

[0077] The exemplary process also includes synchronizing the RF cavity with the laser oscillator, as referenced above. Figure 2-3The RF cavity 401 can be configured to generate pulses at a repetition rate equal to or a multiple of the laser oscillator frequency. The pulses can be resampled by controlling a pulse pickup (e.g., beam blanker 420) to operate at the same repetition frequency as the amplified output of the laser (allowing one or more electronic pulses to pass through).

[0078] In a typical femtosecond pulsed laser design, the amplified laser output frequency is a precise divisor of the oscillator frequency, such that exactly one out of N pulses is amplified, where N is an integer greater than 1. In this way, the laser amplifier and pulse pickup can be synchronized with a common trigger signal, but the pulse pickup can also be synchronized with a signal from the laser. When the pulse pickup is synchronized with the laser, an inverse time delay variation can be applied to the pulse pickup to account for the time delay of the laser relative to the RF signal. Advantageously, the inverse time delay reduces or eliminates instabilities in pulse pickup.

[0079] Figure 5 This is an exemplary composite figure 500 illustrating the periodic operation of a beam blanker according to an embodiment of the present disclosure. The time-delayed output of the delay generator is configurable to trigger an electrostatic beam blanker (ESBB) driver. The trigger signal can be synchronized with the laser's amplifier and / or shutter, allowing the amplified output of the laser to be used at any approximate frequency. In some cases, such as when adapting to hardware response time constraints, the trigger signal can timely cancel the beam blanker for the next laser pulse, which occurs a known time period after the current laser pulse. A time delay of approximately ten nanoseconds (ns) to approximately five hundred ns can improve the time overlap between the "picked" electronic pulse and the beam pulse on the specimen, although this time delay depends on various experimental parameters. In some embodiments, the time delay can be approximately equal to the time between subsequent beam pulses (e.g., approximately 9.07 microseconds for a pulse frequency of approximately 110.3 kHz) plus a fixed offset from approximately -10 ns to approximately -1000 ns. This represents an "inverse time delay," where a positive delay is applied to the beam blanker but results in a negative time delay relative to the next laser pulse (e.g., the next photon beam pulse). For long scan time delays, the ESBB time delay can be adjusted accordingly because the RF pulse has a time delay relative to the beam pulse (e.g., a negative relative delay of the laser pulse).

[0080] In this way, the time delay between the RF and laser outputs can be delayed by a given value (e.g., a positive value), and an opposite (e.g., a negative value) time delay can be applied between the laser and the fast beam blanker, where the end result is to keep the RF beam pulse generator and the beam blanker synchronized while causing the electronic pulses and beam pulses to time-shift relative to each other. Within a relatively narrow time delay range between the pulsed beam and the electronic pulses, the time delay between the laser and charged particle beam system can be static. However, for larger time delays (e.g., approximately on the order of an oscillator period or longer), the pulse pickup time delay can be "scanned" relative to the laser signal to ensure that the RF beam pulse generator and the beam blanker remain synchronized.

[0081] d. Charged particle beam and beam technology

[0082] Figure 6 This is an exemplary schematic diagram 600 illustrating a technique for interrogating a pulsed beam using a charged particle beam pulse according to embodiments of the present disclosure. Figure 7 This is an exemplary schematic group 700 that shows exemplary data for different pulse beam profiles. Figure 6-7 This generally involves ultrafast TEM, and specifically, the use of RF cavity-based electron beam pulse generators in conjunction with a beam source (which may be an amplified beam source), as referenced. Figure 1-5 More details are provided. In some cases, the amplified laser system will generate pulses with a time pulse profile of 625 (and...). Figure 7 The pulsed beam (as shown in the example) can be controlled at least in part based on the operating parameters of the amplified light source. To this end, embodiments of this disclosure enable the charged particle beam pulse to interrogate the temporal profile of the pulse generated by the laser system.

[0083] Therefore, the process of beam pulses is inquired (e.g., Figure 13 This includes, for example, overlapping a charged particle beam pulse 601 with a beam pulse 605 on a sample 615 in a TEM configured for ultrafast operation. The electron beam generates a subset 610 of charged particles with altered energy levels through inelastic scattering by the beam pulse 605, which is then reflected in an EELS spectrometer 645 (which is related to...). Figure 1 The pulse profile is received in an example of an EELS spectrometer 125 and oriented (along B) toward a detector (not shown). The detector can be at least partially based on the principle of photon-induced near-field electron microscopy to scan a time delay over a set of time steps to sample the pulse profile, thereby detecting the pulse profile 630, 635 to be derived over multiple pulse measurements.

[0084] Photon-induced near-field electron microscopy (PINEM) allows for the interrogation of time-varying nanoscale electromagnetic fields within an electron microscope, achievable on a picosecond timescale using ultrafast TEM. For visible light, inelastic coupling between electrons and light is physically forbidden in free space, but can be achieved by confining near-field radiation to surfaces or nanostructures. In PINEM, confinement on sample 615 generates an evanescent confined near-field with a broad momentum distribution, reaching high intensity in the nanoscale confined space, thus also increasing the cross-section of electron-light coupling. Therefore, the method disclosed herein includes recording PINEM spectra and scanning the time delay between electrons and beam pulses to record one or more additional spectra. The PINEM spectra are used together to measure the effective pulse duration of the laser pulse and can be used to characterize the temporal intensity distribution of the pulsed laser. This method can comprehensively characterize the temporal profile of laser intensity.

[0085] Conventionally, autocorrelators are used to characterize ultrashort (e.g., picosecond to femtosecond scale) beam pulses. One drawback of autocorrelators is the lack of a "sign" in the time scale; the output is always symmetrical about the peak intensity (e.g., the maximum overlap time). This limitation affects the flexibility and robustness of ultrafast systems and can be addressed by cross-correlating the beam pulse signal with different signals (e.g., electron pulse signals).

[0086] For example, the amplified output of a pulsed laser can be used for PINEM experiments. With a pulse compressor built into the laser amplified output path, variations in the final pulse duration, ranging from approximately one hundred femtoseconds (fs) to approximately one hundred picoseconds (ps), can be applied. Using time-delay scans of the beam pulses at various compressor settings, PINEM spectra of different widths can be collected as a function of relative time, representing intensity variations during the laser pulse. In contrast, commercially available autocorrelators capable of characterizing the temporal profile of beam pulses always generate symmetrical outputs, providing no information about the temporal asymmetry of the laser pulse. Advantageously, information about beam pulse asymmetry can improve the accuracy and precision of microanalyses, including exposure to ultrafast beam pulses. To this end, the techniques of this disclosure include processes for deriving the temporal intensity distribution of one or more beam pulses, as well as the pulse duration and laser chirp. For example, laser chirp can be measured by varying the peak spacing in the PINEM spectrum according to the time delay. The techniques of this disclosure are extendable to applications in photonics and functional materials. In one illustrative example, the pulse beam technique can be used to interrogate optically active materials as a method for temporarily characterizing one or more optical modes in a microcavity. Optical modes include solitons or pulses that generate frequency combs. Measuring the temporal characteristics of optically active materials depends on the synchronization of the electronic pulses with the inquired microcavity modes, and can benefit from relatively shortened pulse durations to improve the temporal resolution of the mode shape.

[0087] II. Exemplary Process a. Signal synchronization process

[0088] Synchronizing beam pulses and charged particle beam pulses in transmission electron microscopy (TEM) is technically challenging. These challenges arise from the inherent differences in how beam pulses and charged particle beam pulses are generated, directed, and / or modulated. Beam pulses (e.g., generated by a laser oscillator) can operate at high frequencies with femtosecond precision, while charged particle beams (e.g., charged particle beam pulses) are limited by the charged particle beam source, beam blanking device, and switching electronics. Achieving synchronization requires a precise timing control system to align the beam pulses and charged particle beam pulses from both sources in terms of phase, duration, frequency, and time of arrival at the sample. Misalignment can occur due to jitter in the trigger signal, variations in beam path length, and / or differences in pulse duration.

[0089] When the beam pulse and the charged particle beam pulse are out of sync, it can affect the sample in several ways. For pump-probe experiments, synchronization ensures that the beam pulse excites the sample at essentially the same time relative to the arrival of the charged particle beam pulse, enabling real-time image and video capture. Without synchronization, the charged particle beam pulse may interrogate the sample before or after the beam pulse-induced excitation occurs, resulting in incomplete and / or misleading data about intermediate (e.g., transient) states of the sample. This can lead to misinterpretations of the sample's structure or thermal properties, either by the user or the machine. Furthermore, or alternatively, out-of-sync pulses can cause repetitive or uneven energy delivery to the sample, potentially damaging sensitive materials or introducing thermal effects that obscure the results.

[0090] The lack of synchronization also leads to significant time inefficiencies in experimental workflows. When a sample is excited by asynchronous pulses, it may not immediately return to equilibrium and requires a period of relaxation before the next pulse sequence can be applied. This waiting time increases during experiments, slowing data collection and reducing throughput, thus increasing production time and costs. Furthermore, repeated measurements to account for inaccuracies caused by pulse asynchrony can add additional time. The arrival of synchronized beam pulses and charged particle beam pulses can reduce the time spent on sample analysis, improve the quality of analysis, and reduce the processing power required for experiments.

[0091] Figure 8 This is an exemplary flowchart illustrating an exemplary process 800 for synchronizing and interrogating charged particle beam pulses and pulsed beams according to embodiments of the present disclosure. In some examples, process 800 may be implemented by some or all components of a system or apparatus, and / or include, for example, combinations of... Figure 1-7 and Figure 9-14 Those processes, methods, or techniques described herein. In some embodiments, process 800 may have a greater than Figure 8 The diagram illustrates a number of steps, either more or fewer. It should be understood that these steps can be performed in any suitable order. Process 800 begins at step 805, in which the pulsed electron beam is aligned and / or synchronized with a pulsed beam (e.g., a pulsed photon beam), as in combination. Figure 1-6 As shown. Process 800 may include a synchronization RF signal and an optical pulse signal. Process 800 may include generating a composite signal 810 using the RF signal, the optical pulse signal, and a reference signal. Process 800 may also include aligning and / or synchronizing the composite signal 815.

[0092] In some embodiments, the RF signal describes the frequency generated by the action of the RF cavity on the electron beam. The action of the RF cavity on the electron beam may include sweeping the electron beam 820 (e.g., a charged particle beam pulse) through an aperture placed in the electron beam path. The pulse frequency of the optical pulse signal (e.g., a pulsed beam) 825 may be from about 25 MHz to about 125 MHz.

[0093] In some embodiments, the RF signal and the optical pulse signal are frequency matched. The frequency-matched signal may correspond to a situation where the first harmonic frequency of the RF signal is substantially equal to the first harmonic frequency of the optical pulse signal.

[0094] In some embodiments, synchronizing the RF signal and the optical pulse signal includes generating an error signal using a first harmonic frequency component of the RF signal and a first harmonic frequency component of the optical pulse signal. The synchronizing RF signal and the optical pulse signal may also include modifying one or more parameters of the pulsed light source as part of error signal optimization. Generating the error signal may include generating a vector product of the RF signal and the optical pulse signal and filtering the vector product to remove high-frequency components. High-frequency components may include harmonic frequencies higher than the fundamental frequency component.

[0095] In some embodiments, the pulsed source is a pulsed laser source. One or more parameters may include the characteristic length of the laser oscillator of the pulsed laser source. The characteristic length describes the path length of the oscillator between two reflectors, wherein one or more reflectors may be movable relative to the gain medium.

[0096] In some embodiments, generating a composite signal includes generating an RF composite signal using the vector product of harmonic components of an RF signal and a reference signal, and generating an optical composite signal using the vector product of harmonic components of an optical pulse signal and a reference signal. The harmonic frequency may refer to a harmonic order higher than a first frequency or the fundamental frequency. Generating the optical composite signal includes adding a time delay to the vector product of the harmonic frequency components of the optical pulse signal and the reference signal. The time delay may be a variable time delay.

[0097] In some embodiments, the reference signal has a frequency from about 5 MHz to about 50 MHz. Optionally, the frequency may be about 20 MHz.

[0098] In some embodiments, the synchronous composite signal includes generating an error signal using the composite signal. The synchronous composite signal may also include modifying one or more parameters of the pulsed light source as part of error signal optimization. Generating the error signal may include generating a vector product of the RF composite signal and the optical composite signal, and filtering the vector product to remove frequency components outside the passband of the vector product, including harmonic frequency components of the optical pulse signal and the optical composite signal.

[0099] Figure 9 This is an exemplary flowchart illustrating an exemplary process 900 of synchronizing charged particle beam pulses and pulsed light beams according to embodiments of the present disclosure. In some examples, process 900 may be implemented by some or all components of a system or apparatus, and / or include, for example, Figure 1-8 and Figure 10-14 The processes, methods, or techniques shown. In some embodiments, process 900 may include those... Figure 9 The number of steps described may be greater or less. It should be understood that these steps can be performed in any suitable order. Depending on the signal processing implementation, some, specific, or all of the steps may be performed in the time domain or frequency domain as appropriate.

[0100] At 902, a light pulse signal can be generated from a light source that emits light pulses toward the sample. Figure 3 The optical driver 310 is used to generate or determine a first frequency (e.g., Figure 3 The first frequency "F" can be a fraction of the frequency of the field in the RF cavity and the frequency of the charged particle beam pulse generated by the cavity (e.g., charged particle beam pulse 415).

[0101] At 904, a radio frequency (RF) signal can be generated associated with the RF cavity that emits a charged particle beam pulse toward the sample (e.g., from information about...). Figure 3 (RF driver 305). For example, the association could be retrieving the RF signal directly from the RF driver that sends the RF signal to the RF cavity, or the association could be measuring the RF signal from the RF cavity (or a suitable equivalent) and then using it to generate a composite signal (such as...). Figure 3 (As described in the text). Therefore, in some examples, the RF signal can be used to control the RF cavity and to provide the RF signal for composite vector multiplication, or it may not be used to control the RF cavity. The RF signal can be provided by the RF cavity (e.g., regarding...). Figure 1 The RF cavity 130 receives the signal. The RF cavity may be a dual-mode cavity. As a supplement or alternative, the RF cavity may include a pickup antenna. In some examples, the RF signal used for synchronization may be derived directly from the RF signal (e.g., from the RF driver 305). Alternatively, the pickup antenna may be used to determine the RF signal. Thus, the RF signal used for synchronization (multiplied by the optical pulse signal vector to generate a composite signal) may be the same as the RF signal used to control the RF cavity, or it may be a result of the pickup antenna detecting the RF signal.

[0102] In some embodiments, coarse alignment of the RF signal and the optical pulse signal can be performed. For example, at 906, a composite signal can be generated using at least the RF signal and the optical pulse signal. The RF signal and the optical pulse signal can be mixed at a first frequency to generate the composite signal. As part of error signal optimization, generating the composite signal may involve generating an error signal using a first harmonic frequency component of the RF signal and a first harmonic frequency component of the optical pulse signal, and modifying one or more parameters of the light source. In some examples, generating the error signal includes generating a vector product of the RF signal and the optical pulse signal and filtering the vector product to remove high-frequency components. Additionally or alternatively, the high-frequency components may include harmonic frequencies higher than the fundamental frequency component.

[0103] In 908, the light source can be controlled (e.g., one or more light source parameters such as oscillator length) or at least partially based on a composite signal to control the RF cavity, such that the beam pulses and charged particle beam pulses are synchronized at the sample (e.g., as shown in the image). Figure 6 (As shown).

[0104] In some examples, the light source may be a pulsed laser source, and modifying one or more parameters may include modifying the characteristic length of the laser oscillator of the pulsed laser source. Alternatively, the characteristic length describes the oscillator path length between two reflectors, where one or more reflectors are movable relative to the gain medium (e.g., titanium-doped sapphire).

[0105] According to some embodiments, an RF composite signal is generated using the vector product of the harmonic frequency components of an RF signal and a reference signal. In this example, the optical composite signal can be generated using the vector product of the harmonic frequency components of a laser oscillator and a reference signal. Alternatively or additionally, the harmonic frequency components can be harmonic orders higher than the fundamental frequency.

[0106] In some examples, generating the RF composite signal may include using the harmonic frequency components of the RF signal and a reference signal between 5 MHz and 50 MHz, preferably about 20 MHz (e.g., regarding...). Figure 3 The vector product of the reference signal (315) and the optical composite signal may be used. Generating the optical composite signal may include using the vector product of the harmonic components of the oscillator and the reference signal, such that the harmonic frequency components can be one harmonic order higher than the fundamental frequency. Alternatively, generating the composite signal may include adding a time delay to the vector product of the harmonic frequency components of the optical pulse signal and the reference signal. The time delay may be a variable time delay.

[0107] In some embodiments, fine alignment of the RF signal and the oscillator can be performed. For example, returning to the discussion of 908, the harmonic signal can be generated at least partially based on a first frequency, and the error signal can be generated at least partially based on the composite signal. As part of error signal optimization, one or more parameters of the light source (e.g., intensity, frequency, phase, etc.) can be modified. In some examples, the error signal may include a vector product of the generated composite signal and filtering the vector product to remove frequency components outside the passband, including harmonic frequency components of the optical pulse signal and harmonic frequency components of the RF signal. According to some embodiments, the first frequency may be the fundamental frequency of the RF driver and / or optical driver, and fine alignment of the RF signal and the optical pulse signal may be performed in a mode selector (e.g., regarding...). Figure 3 The mode selector 325 switches from phase-locked at the first frequency to phase-locked at the harmonic frequency of the RF driver and / or optical driver.

[0108] In some embodiments, the composite signal may be mixed with a harmonic signal to generate a difference frequency signal. The difference frequency signal can define the feedback of a light source (e.g., a laser oscillator). The path length can be adjusted to maintain tight phase lock with the signal driving the RF cavity (e.g., less than 1 picosecond (ps) jitter). In some examples, the delay between beam pulses can be electronically adjusted without moving parts.

[0109] According to some embodiments, the optical driver can be phase-locked to the RF driver, at least in part, based on a difference frequency signal. The difference frequency signal can help control the time delay and / or phase between the optical driver and the RF driver. In examples where the optical driver and RF driver are matched, the result may include a DC error signal representing the time delay between pulses. To allow the light source to overlap with the charged particle beam source, the time delay can be guided towards zero.

[0110] b. Bundle blanking process

[0111] Synchronized light sources and blanking devices use a signal associated with the light source as a trigger signal, which the blanking device can use to blank a beam of charged particles. The blanking device can generate pulses by deflecting or blocking the charged particle beam at specific intervals using the trigger signal. Variations in the timing of the trigger signal from the light source can cause delays or inaccuracies in the blanking device's response. Furthermore, or alternatively, the mechanical and electronic components of the blanking device may introduce delays or jitter, making precise alignment with the light source signal more difficult.

[0112] Triggering a beam blanker based on a light source signal allows for controlled interaction between charged particle beam pulses and the sample over a specific time period. Synchronizing the beam blanker with the light source signal enables the charged particle beam pulses to be transmitted at desired intervals, thereby reducing unnecessary sample exposure and improving the quality of acquired data (e.g., images, videos, etc.). By synchronizing the beam blanker with the light source, the instantaneous state of the sample can be analyzed, allowing for the observation of ultrafast processes and dynamic changes in the sample's structure or properties.

[0113] Figure 10 This is a flowchart illustrating an exemplary process for triggering a beam blanking device. By aligning the time, frequency, and duration of the trigger signal with the beam pulse, the charged particle beam can be precisely blocked or unblocked synchronously with the light source. This can be used in pump-probe imaging, where the interaction between the charged particle beam and the beam pulse can be controlled to capture time-resolved data (e.g., images, video, etc.). Process 1000 can be implemented by some or all of the components of a system or device, and / or include, for example, combinations of... Figure 1-9 and Figure 11-14 The processes, methods, or techniques described above. In some embodiments, process 1000 may include... Figure 10 The number of steps described herein may be greater or less. It should be understood that these steps may be performed in any suitable order. Figure 10 This can occur after synchronization (e.g., phase-locked loop) has already taken place, such as in combination. Figure 8 and Figure 9 More details to follow.

[0114] At 1005, a trigger signal can be generated. The beam blanker can be triggered by the blanking signal and quickly switch between "on" and "off" states, thereby precisely controlling the exposure time of the charged particle beam on the sample. The trigger signal can be a voltage or a pulse, which is received by the beam blanker.

[0115] In 1010, a blanking signal is used in conjunction with a trigger signal. The trigger signal (e.g., a voltage pulse or digital input) can be received and processed by the beam blanker's control circuitry, which generates a corresponding blanking signal. This blanking signal controls the operation of the beam blanker by directing the deflection system to divert or block the charged particle beam. The characteristics of the blanking signal (including its amplitude, duration, and timing) can be derived from the parameters of the trigger signal to provide synchronization.

[0116] At 1015, the beam blanking can be modulated (e.g., regarding...). Figure 1 The beam blanker 155 can be modulated using a blanking signal. By modulating the timing, duration, and frequency of the trigger signal, the beam blanker can be controlled to achieve synchronous or periodic beam blocking, thereby enabling time-resolved imaging of the sample.

[0117] Figure 11This is an exemplary flowchart illustrating an exemplary process 1100 for synchronizing and interrogating charged particle beam pulses and pulsed beams according to embodiments of the present disclosure. Process 1100 can be implemented by some or all components of a system or apparatus, and / or includes, for example, Figure 1-10 and Figure 12-14 The processes, methods, or techniques shown. In some embodiments, process 1100 may include those... Figure 11 The number of steps described herein may be greater or less. It should be understood that these steps may be performed in any suitable order. Figure 11 This can occur after synchronization (e.g., phase-locked loop) has already taken place, such as in combination. Figure 8 and Figure 9 More details to follow.

[0118] At 1102, a first charged particle beam pulse and a second charged particle beam pulse can be generated and output from the RF cavity. A high-frequency switch (e.g., high-frequency switch 431) can receive the first charged particle beam pulse and the second charged particle beam pulse and perform fast blanking.

[0119] At 1104, the first charged particle beam pulse can be blanked at least partially based on the amplified beam pulse. In some embodiments, the amplified light pulse can be generated at a multiple of a first frequency. In some examples, the multiple of the first frequency is at least partially based on the response time of the sample. According to some embodiments, the high-frequency switch can be coupled to an amplifier of the laser system and / or via a common signal generator configured to generate trigger signals to the laser amplifier and the high-frequency switch. In this way, the beam blanker can be synchronized with the laser amplifier or shutter, or synchronize both the pulse pickup and the laser amplifier or shutter to a common trigger signal.

[0120] At 1106, the second charged particle beam pulse and the amplified beam pulse can be directed toward the sample. For example, at least a portion of the charged particle beam pulse can be blanked to generate a subset of the charged particle beam pulse at a multiple of the first frequency (e.g., Figure 4 435 in Figure 6 (601 in the middle). It can be made by a beam blanking device (e.g., Figure 1 The blanking device 155 performs blanking. The blanking device can operate with a fixed time delay relative to the RF cavity. The blanking device can be triggered by a signal from the light source, such that the amplified optical pulse has a time delay relative to the RF signal pulse, and the blanking device receives an inverse time delay. In this way, the timing of the blanking device can be a constant value relative to the pulse generated in the RF cavity. In some examples, the process can be performed in reverse, where the light source can be triggered by a signal from the blanking device, instead of the blanking device being triggered by the light source. For example, the shutter on the light source can be controlled by an inverse time delay triggered by the blanking device.

[0121] In some examples, the delay generator may generate a trigger signal at least partially based on a multiple of a first frequency and send the trigger signal to a beam blanker or optical driver to trigger at least one of the beam blanker or light source. Alternatively, transmitting a subset of charged particle beam pulses and amplified optical pulses may include an amplifier that may generate a delayed output from the delay generator to trigger the beam blanker or light source. In some examples, the delayed output may vary between generating a second charged particle beam pulse or amplified optical pulse while applying an inverse time delay to the light source or beam blanker; and the subset of charged particle beam pulses may be time-shifted relative to the amplified optical pulse to compensate for the time delay of the light source relative to the RF signal.

[0122] In some embodiments, generating a trigger signal includes transmitting a pulse signal from a pulse beam controller to a delay generator. Generating a trigger signal may include receiving a control signal that includes timing information for the beam blanker and the pulse beam controller. The modulated beam blanker may include temporarily quenching an electromagnetic field applied by the beam blanker, in the presence of which electrons are deflected away from the beam axis.

[0123] In some embodiments, generating a blanking signal includes combining a trigger signal with a delay offset. Generating a blanking signal may include receiving a delay offset from a control system. The delay offset may be an element in an offset dataset. Generating a blanking signal may include selecting a delay offset from the offset dataset according to a process used to interrogate the dynamic system.

[0124] In some embodiments, the trigger signal is characterized by a frequency of about 0.1 kHz to about 10 MHz. Process 1100 may include synchronizing the pulsed electron beam and the pulsed beam by: synchronizing the RF signal and the optical pulse signal, generating a composite signal using the RF signal, the optical pulse signal and the reference signal, and synchronizing the composite signal.

[0125] In some embodiments, the modulated beam blanker temporarily unlocks the pulsed electron beam, thereby allowing one or more electron pulses to pass through the beam blanker substantially without deflection.

[0126] In some embodiments, process 1100 includes generating a photon pulse using a pulsed photon source while generating a trigger signal. The pulsed beam may be a pulsed laser. The beam blanker may be an electrostatic beam blanker.

[0127] c. Bundle characterization process

[0128] Time-resolved imaging relies on capturing phenomena that may evolve on ultrafast timescales (picoseconds or femtoseconds). The temporal pulse profile of the beam provides information about the timing of the excitation event, enabling accurate measurement of the sample's dynamic response when paired with a pulse of charged particle beams. The beam intensity and pulse duration of the source can be adjusted to minimize sample damage caused by excessive energy delivery in sensitive materials. The temporal pulse profile of the beam can also influence how photons interact with the electrons, atoms, or molecules of the sample.

[0129] Furthermore, the temporal pulse profile aids in calibrating setups, including optical delay lines, trigger synchronization systems, and detectors. Once the temporal pulse profile of the beam is determined, it can be manipulated (e.g., through pulse shaping methods) to provide selective excitation of modes or maximize signal contrast. The temporal pulse profile defines the intensity variation of the beam over time, including pulse duration, rise and fall times, and peak intensity (e.g., pulse duration, rise and fall times, and peak intensity). Figure 7 (As shown). Temporal pulse profiles can be used to synchronize optical pulses with charged particle beam pulses, ensuring that the two beams interact with the sample at the desired temporal overlap. In pump-probe experiments, the beam's temporal profile determines how energy is delivered to the sample over time during interrogation. Understanding this temporal pulse profile helps optimize conditions, such as matching the beam's pulse duration to the characteristics of the charged particle beam used for energy transfer or dynamic imaging.

[0130] Figure 12 This is an exemplary flow diagram illustrating an exemplary process 1200 for synchronizing and interrogating charged particle beam pulses and pulsed light beams according to embodiments of the present disclosure. Process 1200 can be implemented by some or all components of a system or apparatus, and / or include, for example, Figure 1-11 , Figure 13 and Figure 14 The processes, methods, or techniques shown. In some embodiments, process 1200 may include those... Figure 12 The number of steps described herein may be greater or less. It should be understood that these steps may be performed in any suitable order. Process 1200 may include guiding the photon beam to intersect with the beam axis 1205 of the charged particle beam system. Process 1200 may include generating a charged particle beam 1210 substantially aligned with the beam axis. Process 1200 may include guiding the charged particle beam into an energy dispersive spectrometer 1215, the energy dispersive spectrometer being configured to generate detector data 1220 describing the energy distribution of the charged particle beam. Process 1200 may also include generating a detector dataset describing multiple energy distributions corresponding to multiple time steps.

[0131] In some embodiments, the charged particle beam is a pulsed beam, and the photon beam is a pulsed beam. Process 1200 may include synchronizing the charged particle beam with the photon beam. Process 1200 may also include defining a plurality of time steps, wherein one of the time steps describes a time offset or phase delay of the charged particle beam relative to the photon beam.

[0132] In some embodiments, the photon beam includes a photon pulse defining a time profile. The method may include generating profile data describing the time profile using a detector dataset. Generating the detector dataset may include sampling detector data generated simultaneously with the interaction period of the photon pulse and the charged particle beam. The detector data may be characterized in that the sampling period is approximately an order of magnitude smaller than the pulse duration described by the time profile. The method may include generating an operating parameter scheme corresponding to the time profile, the operating parameter scheme describing one or more operating parameters of the charged particle beam system.

[0133] In some embodiments, the charged particle beam comprises charged particle pulses. Generating the detector dataset may include integrating detector data using multiple charged particle pulses over a given time step. The charged particles may be electrons. Guiding the photon beam to intersect the beam axis may include coupling the photon beam to a light-guiding material that is at least partially transmissive to the charged particles. The material may be at least partially arranged on the beam axis. The light-guiding material may include photonic nanostructures, microcavities, or photonic metamaterials.

[0134] In some embodiments, the charged particle beam system is an electron microscope. The electron microscope may be a transmission electron microscope (TEM). The electron microscope may include a radio frequency (RF) cavity configured to generate a pulse beam of charged particles having a pulse frequency from about 25 MHz to about 100 MHz. Optionally, the pulse frequency may be about 75 MHz.

[0135] Figure 13 This is an exemplary flowchart illustrating an exemplary process 1000 for synchronizing and interrogating charged particle beam pulses and pulsed beams according to embodiments of the present disclosure. Process 1000 can be implemented by some or all components of a system or apparatus, and / or include, for example, Figure 1-9 , Figure 11 and Figure 14 The processes, methods, or techniques shown. In some embodiments, process 1000 may include those... Figure 10 The number of steps described herein may be greater or less. It should be understood that these steps may be performed in any suitable order. Figure 10 It can occur after phase-locked loop has already occurred, such as in combination. Figure 8 and Figure 9 More details to follow.

[0136] At 1302, the beam (e.g., Figure 6 The beam pulse 605) is directed toward the charged particle tube (e.g., Figure 1 Samples (e.g., within a charged particle system 100) Figure 6 The beam is guided by sample 615. In some examples, the beam is a pulsed beam. The beam may include a temporal profile (and a spatial profile).

[0137] At 1304, charged particle beams (e.g., Figure 4 A subset of charged particle beam pulses 415 or 435 can be directed toward the sample. In some instances, the charged particle beam is a charged particle beam pulse.

[0138] At 1306, charged particles interacting with the sample can be detected. EELS spectrometers (e.g., Figure 1 The EELS spectrometer 125 can receive charged particles (e.g., Figure 6 The charged particle beam pulse (610) is generated and its energy loss is analyzed. The relative time delay between the beam and the charged particle beam can be determined. Determining the time delay may include synchronizing the charged particle beam pulse with the pulse beam and determining multiple time steps. The time step may represent the time offset or phase delay of the charged particle beam pulse relative to the pulse beam.

[0139] According to some embodiments, determining the relative time delay may include guiding a charged particle beam into an energy-dispersive spectrometer (e.g., EELS spectrometer 125), which is configured to generate detector data describing the energy distribution of the charged particle beam and to generate detector datasets describing multiple energy distributions for corresponding multiple time steps (see [link to relevant documentation]). Figure 7 Generating the detector dataset may include sampling detector data generated simultaneously with the interaction period of the beam and the charged particle beam, such that the detector data is characterized in that the sampling period is about an order of magnitude smaller than the pulse duration described by at least one characteristic, said at least one characteristic being the temporal pulse profile of the beam pulse intensity. Generating the detector dataset may include integrating the detector data with respect to a given time step using multiple charged particle pulses. Alternatively or additionally, the detector dataset may be used to generate profile data describing the temporal pulse profile of the pulse beam (e.g., Figure 6 Time pulse profile 625).

[0140] At 1308, the time delay between the charged particle beam and the beam pulse can be determined, at least in part, based on the charged particles. The interaction between the beam pulse and the charged particle beam pulse on the sample may generate measurable signals (e.g., diffraction patterns or induced changes in sample dynamics). In some examples, the delay can be estimated using a computational model or algorithm that takes into account the beam pulse wavelength and / or the charged particle beam pulse duration. According to some embodiments, the source (e.g., a laser oscillator) and the charged particle beam pulse can be synchronized using trigger signals timed relative to each other or independent triggering. The timing of the trigger signal can be used to set a baseline for the arrival time at the sample.

[0141] At 1310, at least one characteristic of the beam can be determined at least in part based on the time delay. This at least one characteristic may include the time-pulse profile of the beam intensity. In some embodiments, determining the characteristic may include measuring the effective pulse duration of the beam using PINEM spectroscopy (reference...). Figure 6 (To be discussed in more detail). This characteristic may include, but is not limited to, the time asymmetry of the beam (e.g., Figure 7 (as shown), pulse duration, and / or laser chirp. This characterization can be used to characterize one or more optical modes in a microcavity.

[0142] II. Exemplary Control System

[0143] Figure 14 This is an exemplary block diagram 1400 of a controller 1401 for performing methods, processes, techniques, and the like for a microscope system, according to certain aspects of this disclosure. Examples of microscope systems (e.g., charged particle microscope tubes) may include... Figure 1-6 Some or all of the components of a microscope system. Examples of methods, processes, techniques, and operations may include... Figure 7-13 Some or all of the methods, processes, techniques, and operations. As shown, controller 1401 may include a control circuitry system including a processor 1402 communicatively coupled to memory 1404. Processor 1402 may include processing devices or multiple processing devices. Non-limiting examples of processor 1402 include field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), microprocessors, or any combination thereof. Processor 1402 may execute instructions 1410 stored in memory 1404 to perform operations, such as... Figure 1-13 The operation of microscopes, processes, scans, and methods. In some examples, instruction 1410 may include processor-specific instructions generated by a compiler or interpreter from code written in any suitable computer programming language, such as C, C++, C#, Python, or Java.

[0144] Memory 1404 may include one or more storage devices. Memory 1404 may be non-volatile and may include any type of storage device that retains stored information when power is lost. Non-limiting examples of memory 1404 include electrically erasable programmable read-only memory (EEPROM), flash memory, or any other type of non-volatile memory. At least some of memory 1404 may include non-transitory computer-readable media from which processor 1402 can read instructions 1410 via bus 1406. Bus 1406 may be a communication and / or power bus that enables processor 1402 to communicate with memory 1404. Non-transitory computer-readable media may include electronic storage devices, optical storage devices, magnetic storage devices, or other storage devices capable of providing instructions 1410 or other program code to processor 1402. Non-limiting examples of non-transitory computer-readable media include disks, memory chips, RAM, ASICs, or any other medium from which a computer processor can read instructions 1410.

[0145] The memory 1404 may also include operational information regarding parameters 1412 (e.g., calibration, image acquisition, detector sensitivity, power), the RF cavity chopper 1420 (e.g., frequency, synchronization, calibration), the image processor 1424 (e.g., dark field, bright field, calibration, intensity, synchronization), the light source 1426 (e.g., duty cycle, pulse frequency, synchronization, alignment, calibration), the beam blanker 1422 (e.g., frequency, synchronization, calibration), the energy filter settings 1428 (e.g., position, adjustment, calibration), and the target stage 1430 (e.g., position, orientation, translation). The controller 1401 can receive information about operational parameters from the microscope (e.g., TEM, SEM, or others). At least some information about any component of the controller 1401 may be pre-stored and may be associated with each scanning cycle (e.g., acquisition). Parameter 1412 may include operational parameters related to the electron microscope system, such as the required energy / primary energy of the electron beam, the energy spread of the energy loss spectrum, the locking mechanism, the feedback loop, etc. In some examples, parameter 1412 can be compared with a predetermined threshold (e.g., known arrangement, known sample type, etc.).

[0146] Detailed exemplary embodiments

[0147] Examples of the inventive subject matter according to this disclosure are described in the following paragraphs:

[0148] According to some embodiments, a method for synchronizing a mixed signal in a charged particle microscope tube is provided, the method comprising: generating an optical pulse signal from a light source that emits a beam pulse toward a sample within the charged particle microscope tube; generating an RF signal associated with a radio frequency (RF) cavity that emits a charged particle beam pulse toward the sample; generating a composite signal using at least the RF signal and the optical pulse signal; and controlling at least one of i) the light source or ii) the RF signal for the RF cavity, at least partially based on the composite signal, such that the beam pulse and the charged particle beam pulse are synchronized at the sample.

[0149] According to any of the foregoing examples, the method further includes generating a first charged particle beam pulse and a second charged particle beam pulse output from the RF cavity; blanking the first charged particle beam pulse by a beam blanker based at least in part on the amplified beam pulse; and guiding the second charged particle beam pulse and the amplified beam pulse toward the sample.

[0150] According to any of the foregoing examples, the light source emits amplified light pulses at a frequency that is at least partially based on the response time of the sample.

[0151] According to any of the foregoing examples, the method further includes generating a trigger signal by a delay generator at least partially based on a multiple of the frequency; and sending the trigger signal by the delay generator to trigger at least one of a beam blanker or a light source.

[0152] The method for generating the second charged particle beam pulse and the amplified optical pulse according to any of the foregoing examples further includes:

[0153] According to any of the foregoing examples, the method further includes an amplifier that generates a delayed output by a delay generator to trigger a beam blanker or a light source, wherein: the delayed output changes between the generation of a second charged particle beam pulse or an amplified optical pulse, while applying an inverse time delay to the light source or the beam blanker; and the second charged particle beam pulse is time-shifted relative to the amplified optical pulse to compensate for the time delay of the light source relative to the RF signal.

[0154] The method according to any of the foregoing examples further includes generating an error signal using harmonic frequency components of an RF signal or an optical pulse signal; and wherein the control further includes modifying one or more parameters of the RF cavity or light source as part of the error signal optimization.

[0155] According to any of the foregoing examples, generating an error signal includes: generating a vector product of an RF signal and an optical pulse signal; filtering the vector product to remove high-frequency components of the vector product, wherein the high-frequency components include harmonic frequencies higher than the fundamental frequency component of the RF signal or the optical pulse signal.

[0156] According to any of the foregoing examples, the light source is a pulsed laser source; and the one or more parameters include a characteristic length of the laser oscillator of the light source, which describes the path length of the laser oscillator between two reflectors, wherein one or more reflectors are movable relative to the gain medium.

[0157] According to any of the foregoing examples, generating a composite signal includes: generating an RF composite signal using the vector product of the harmonic frequency components of an RF signal and a reference signal; generating an optical composite signal using the vector product of the harmonic frequency components of a laser oscillator of a light source and a reference signal, wherein the harmonic frequency components are at least one harmonic order higher than the fundamental frequency of the RF signal or the optical pulse signal.

[0158] According to any of the foregoing examples, generating an optical composite signal involves adding a time delay to the vector product of the harmonic frequency components of the optical pulse signal and the reference signal.

[0159] According to the methods of any of the foregoing examples, the frequency of the reference signal ranges from about 5 MHz to about 50 MHz, and optionally, the frequency is about 20 MHz.

[0160] According to any of the foregoing examples, the step of controlling the optical pulse signal or the RF signal further includes: at the mode selector, switching from phase locking at a frequency associated with the optical pulse signal or the RF signal to phase locking at a harmonic frequency of the optical pulse signal or the RF signal.

[0161] According to any of the foregoing examples, the method further includes generating an error signal based at least in part on the composite signal; and modifying one or more parameters of the light source as part of error signal optimization.

[0162] According to any of the foregoing examples, generating an error signal includes: generating a vector product of the composite signal; and filtering the vector product to remove frequency components outside the passband, including harmonic frequency components of the optical pulse signal and harmonic frequency components of the RF signal.

[0163] According to certain embodiments, one or more machine-readable storage media store executable instructions that, when executed, cause a charged particle beam microscope to perform operations including: generating an optical pulse signal from a light source that emits a beam pulse toward a sample within the charged particle microscope; generating a radio frequency (RF) signal associated with an RF cavity that emits a charged particle beam pulse toward the sample; generating a composite signal using at least the RF signal and the optical pulse signal; and controlling at least one of i) the light source or ii) the RF signal, at least partially based on the composite signal, to control the RF cavity such that the beam pulse and the charged particle beam pulse are synchronized at the sample.

[0164] According to any of the machine-readable storage media or methods in the foregoing examples, the RF cavity is a dual-mode cavity.

[0165] According to any of the machine-readable storage media or methods in the foregoing examples, the operation further includes: generating an RF signal by using a pickup antenna that at least utilizes the RF cavity; or receiving an RF signal from an RF driver coupled to the RF cavity.

[0166] According to any of the machine-readable storage media or methods in the foregoing examples, the charged particle beam system is an electron microscope.

[0167] A charged particle microscope tube includes: one or more processors; and one or more machine-readable storage media operatively coupled to a control circuitry system, the media storing executable instructions that, when executed, cause operations including: generating an optical pulse signal from a light source that emits a beam pulse toward a sample within the charged particle microscope tube; generating a radio frequency (RF) signal associated with an RF cavity that emits charged particle beam pulses toward the sample; generating a composite signal using at least the RF signal and the optical pulse signal; and controlling at least one of i) the light source or ii) the RF signal, at least partially based on the composite signal, to control the RF cavity such that the beam pulses and the charged particle beam pulses are synchronized at the sample.

[0168] According to any of the foregoing examples, the machine-readable storage medium, method, or charged particle mirror tube further includes a delay generator; and a beam blanker coupled to the delay generator, wherein the delay generator is configured to trigger the beam blanker at least in part based on control of a light source or RF cavity.

[0169] A method for characterizing a beam within a charged particle microscope tube, the method comprising: directing a beam pulse toward a sample within the charged particle microscope tube; directing a charged particle beam pulse toward the sample; detecting charged particles interacting with the sample based at least in part on the beam pulse and the charged particle beam pulse; determining a time delay between the charged particle beam pulse and the beam pulse based at least in part on the charged particles; and determining at least one characteristic of the beam pulse based at least in part on the time delay.

[0170] According to any of the foregoing examples, the machine-readable storage medium, method, or charged particle lens, wherein the charged particle beam is a charged particle beam pulse, wherein the beam is a beam pulse, and wherein determining the time delay further includes: synchronizing the charged particle beam pulse with the beam pulse; and determining a plurality of time steps, wherein one of the plurality of time steps represents a time offset of the charged particle beam pulse relative to the beam pulse.

[0171] According to any of the foregoing examples, the machine-readable storage medium, method, or charged particle lens, wherein the charged particle beam is a charged particle beam pulse, wherein the beam is a beam pulse, and wherein determining the time delay further includes: synchronizing the charged particle beam pulse with the beam pulse; and determining a plurality of time steps, wherein one of the plurality of time steps represents a phase delay of the charged particle beam pulse relative to the beam pulse.

[0172] According to any of the foregoing examples, a machine-readable storage medium, method, or charged particle microscope tube, wherein the beam is a beam pulse including a time pulse profile, the method further includes: guiding the charged particle beam into an energy dispersive spectrometer configured to generate detector data describing the energy distribution of the charged particle beam; generating a detector dataset describing multiple energy distributions corresponding to multiple time steps; and using the detector dataset to generate profile data describing the time pulse profile.

[0173] According to any of the foregoing examples, the machine-readable storage medium, method, or charged particle tube, generating the detector dataset includes sampling detector data generated simultaneously during the period of interaction with the beam and the charged particle beam, wherein the detector data is characterized in that the sampling period is approximately an order of magnitude smaller than the pulse duration described by at least one characteristic, which is the temporal pulse profile of the beam intensity.

[0174] According to any of the foregoing examples, the machine-readable storage medium, method, or charged particle column, wherein the charged particle beam is a charged particle beam pulse, and wherein generating the detector dataset includes integrating the detector data using multiple charged particle pulses over a given time step.

[0175] Based on any of the machine-readable storage media, methods, or charged particle tubes of the foregoing examples, an operating parameter scheme corresponding to the at least one characteristic is generated, the operating parameter scheme describing one or more operating parameters of the charged particle beam system, wherein the at least one characteristic includes the time pulse profile of the beam intensity.

[0176] According to any of the foregoing examples, the machine-readable storage medium, method, or charged particle microscope tube, determining the at least one characteristic of the beam further includes measuring the effective pulse duration of the beam using photon-induced near-field electron microscopy (PINEM) spectroscopy.

[0177] The machine-readable storage medium, method, or charged particle tube according to any of the foregoing examples also includes characterizing the temporal intensity distribution of the beam at least in part based on the effective pulse duration.

[0178] One or more machine-readable storage media storing executable instructions that, when executed, cause a charged particle beam system to perform operations including: directing a beam pulse toward a sample within a charged particle microscope tube; directing a charged particle beam pulse toward the sample; detecting charged particles interacting with the sample, at least in part based on the beam pulse and the charged particle beam pulse; determining a time delay between the charged particle beam pulse and the beam pulse, at least in part based on the charged particles; and determining at least one characteristic of the beam pulse, at least in part based on the time delay.

[0179] Machine-readable storage medium, method, or charged particle microscope tube according to any of the foregoing examples, wherein the charged particle microscope tube is a transmission electron microscope (TEM).

[0180] Machine-readable storage medium, method, or charged particle mirror tube according to any of the foregoing examples, wherein the charged particle mirror tube includes a radio frequency (RF) cavity configured to generate charged particle beam pulses.

[0181] Machine-readable storage media, methods, or charged particle microscopes according to any of the foregoing examples, wherein the pulse frequency of the charged particle beam pulses is from about 25 MHz to about 100 MHz.

[0182] According to any of the machine-readable storage media, methods, or charged particle tubes in the foregoing examples, the operation further includes: coupling the light beam into a light-guiding material.

[0183] According to any of the machine-readable storage media, methods, or charged particle microscope tubes of the foregoing examples, the operation further includes: adjusting the delay of the beam pulse or charged particle beam pulse toward the sample, at least in part based on the determination of the at least one characteristic.

[0184] According to any of the machine-readable storage media, methods, or charged particle tubes of the foregoing examples, the operation further includes: adjusting the intensity, frequency, or phase delay of the beam pulse directed toward the sample, at least in part based on the determination of the at least one characteristic.

[0185] A charged particle beam device includes: one or more processors; and one or more machine-readable storage media operatively connected to a control circuitry system, the media storing executable instructions that, when executed, cause operations including: directing a beam pulse toward a sample within the charged particle beam device; directing a charged particle beam pulse toward the sample; detecting charged particles interacting with the sample, at least in part based on the beam pulse and the charged particle beam pulse; determining a time delay between the charged particle beam pulse and the beam pulse, at least in part based on the charged particles; and determining at least one characteristic of the beam pulse, at least in part based on the time delay.

[0186] According to any of the foregoing examples, in a machine-readable storage medium, method, or charged particle tube, at least one characteristic of the beam includes a characterization of the time asymmetry of the beam.

[0187] According to any of the machine-readable storage media, methods, charged particle beam devices, or charged particle mirror tubes of the foregoing examples, at least one characteristic of the beam includes pulse duration or laser chirp.

[0188] Machine-readable storage media, methods, charged particle beam devices, or charged particle mirror tubes according to any of the foregoing examples, wherein the at least one characterization is used to characterize one or more optical modes in a microresonant cavity.

[0189] A charged particle beam system may include a charged particle source, a charged particle beam mirror operatively coupled to the charged particle source and including a plurality of charged particle optical elements disposed along the beam axis, the charged particle optical elements including a radio frequency (RF) cavity. In some examples, the system may include a sample section operatively coupled to the charged particle beam mirror and defining a sample position on the beam axis; a light source optically coupled to the sample section and configured to guide the beam toward the sample position; a control circuitry system operatively coupled to the RF cavity and the light source; and one or more machine-readable storage media operatively coupled to the control circuitry system, the media storing executable instructions that, when executed, cause the system to perform operations, including operations of the methods or media described in the embodiments herein.

[0190] According to any of the foregoing examples, a method for synchronizing a charged particle beam pulse with a pulsed beam. The method may include synchronizing an RF signal and an optical pulse signal. The method may include generating a composite signal using the RF signal, the optical pulse signal, and a reference signal. The method may also include synchronizing the composite signal.

[0191] According to any of the foregoing examples, the RF signal describes a frequency generated by the action of the RF cavity on the electron beam. The action of the RF cavity on the electron beam may include sweeping the electron beam through an aperture placed in the electron beam path. The pulse frequency of the optical pulse signal can be from about 25 MHz to about 125 MHz.

[0192] According to any of the foregoing examples, the RF signal and the optical pulse signal are frequency-matched. A frequency-matched signal may correspond to a situation where the first harmonic frequency of the RF signal is substantially equal to the first harmonic frequency of the optical pulse signal.

[0193] The method according to any of the foregoing examples further includes synchronizing the RF signal and the optical pulse signal, including generating an error signal using a first harmonic frequency component of the RF signal and the first harmonic frequency component of the optical pulse signal. Synchronizing the RF signal and the optical pulse signal may also include modifying one or more parameters of the pulsed light source as part of error signal optimization. Generating the error signal may include generating a vector product of the RF signal and the optical pulse signal and filtering the vector product to remove high-frequency components. High-frequency components may include harmonic frequencies higher than the fundamental frequency component.

[0194] According to the method of any of the foregoing examples, the pulsed source is a pulsed laser source. One or more parameters may include the characteristic length of the laser oscillator of the pulsed laser source. The characteristic length may describe the path length of the oscillator between two reflectors, wherein one or more reflectors may be movable relative to the gain medium.

[0195] The method according to any of the foregoing examples also includes generating a composite signal, including generating an RF composite signal using the vector product of harmonic components of an RF signal and a reference signal, and generating an optical composite signal using the vector product of harmonic components of an optical pulse signal and a reference signal. The harmonic frequency may refer to a harmonic order higher than a first frequency or fundamental frequency. Generating the optical composite signal includes adding a time delay to the vector product of the optical pulse signal and the harmonic frequency components of the reference signal. The time delay may be a variable time delay.

[0196] According to the methods of any of the foregoing examples, the frequency of the reference signal ranges from about 5 MHz to about 50 MHz. Optionally, the frequency can be about 20 MHz.

[0197] The method according to any of the foregoing examples further includes, in which, synchronizing the composite signal includes generating an error signal using the composite signal. Synchronizing the composite signal may also include modifying one or more parameters of the pulsed light source as part of error signal optimization. Generating the error signal may include generating a vector product of the RF composite signal and the optical composite signal, and filtering the vector product to remove frequency components outside the passband of the vector product, including harmonic frequency components of the optical pulse signal and the optical composite signal.

[0198] One or more machine-readable storage media store executable instructions that, when executed, cause the machine to perform operations including those operations according to any of the foregoing examples.

[0199] A charged particle beam system includes a charged particle source. The system includes a charged particle beam mirror operatively coupled to the charged particle source and including a plurality of charged particle optical elements disposed along a beam axis, the charged particle optical elements including a radio frequency (RF) cavity. The system includes a sample section operatively coupled to the charged particle beam mirror and defining a sample position on the beam axis. The system includes a light source optically coupled to the sample section and configured to direct the beam toward the sample position. The system includes a control circuitry operatively coupled to the RF cavity and the light source. The system may also include one or more machine-readable storage media operatively coupled to the control circuitry and storing instructions that, when executed, cause the system to perform operations including those operations of the method of one or more embodiments of the first aspect.

[0200] According to any of the foregoing examples, the RF cavity is a dual-mode cavity. The RF cavity may include a pickup antenna. The charged particle beam system may include an electron microscope. The electron microscope may be a transmission electron microscope (TEM).

[0201] A method for synchronizing charged particle beam pulses and pulsed beams. The method may include generating a trigger signal. The method may include using the trigger signal to generate a blanking signal. The method may also include using the blanking signal to modulate a beam blanker.

[0202] The method according to any of the foregoing examples further includes, in which generating the trigger signal, transmitting a pulse signal from the pulse beam controller to the delay generator. Generating the trigger signal may include receiving a control signal that includes timing information for the beam blanker and the pulse beam controller. Modulating the beam blanker may include temporarily quenching the electromagnetic field applied by the beam blanker, in the presence of which electrons are deflected away from the beam axis.

[0203] The method according to any of the foregoing examples further includes generating a blanking signal by combining a trigger signal with a delay offset. Generating a blanking signal may include receiving a delay offset from a control system. The delay offset may be an element in an offset data set. Generating a blanking signal may include selecting a delay offset from the offset dataset according to a process used to interrogate the dynamic system.

[0204] According to any of the foregoing examples, the trigger signal is characterized by a frequency of about 0.1 kHz to about 10 MHz. The method may include synchronizing charged particle beam pulses and pulsed beams by: synchronizing an RF signal and an optical pulse signal, generating a composite signal using the RF signal, the optical pulse signal, and a reference signal, and synchronizing the composite signal.

[0205] According to any of the foregoing examples, the method wherein the beam blanker is modulated to temporarily release the blockade of the charged particle beam pulse, thereby allowing one or more electron pulses to pass through the beam blanker substantially without deflection.

[0206] The method according to any of the foregoing examples also includes generating photon pulses simultaneously with generating the trigger signal using a pulsed light source. The pulsed beam can be a pulsed laser. The beam blanker can be an electrostatic beam blanker.

[0207] One or more machine-readable storage media storing executable instructions that, when executed, cause the machine to perform operations including those according to any of the foregoing examples.

[0208] A charged particle beam system may include a charged particle source. The system includes a charged particle beam barrel operatively coupled to the charged particle source and including a plurality of charged particle optics disposed along the beam axis, the charged particle optics including a radio frequency (RF) cavity and a beam blanking device. The system includes a sample section operatively coupled to the charged particle beam barrel and defining a sample position on the beam axis. The system includes a light source optically coupled to the sample section and configured to direct the beam toward the sample position. The system includes a control circuitry operatively coupled to the RF cavity and the light source. The system may also include one or more machine-readable storage media operatively coupled to the control circuitry and storing executable instructions that, when executed, cause the system to perform operations including those of the methods of one or more embodiments of the fourth aspect.

[0209] According to any of the foregoing examples, the charged particle beam system is an electron microscope. The electron microscope can be a transmission electron microscope (TEM). The beam blanking device can be an electrostatic beam blanking device.

[0210] A method for sampling a pulsed beam includes guiding the beam to intersect with the beam axis of a charged particle beam system. The method may include generating a charged particle beam substantially aligned with the beam axis. The method may include guiding the charged particle beam into an energy-dispersive spectrometer configured to generate detector data describing the energy distribution of the charged particle beam. The method may also include generating a detector dataset describing multiple energy distributions corresponding to multiple time steps.

[0211] According to any of the foregoing examples, where the charged particle beam is a pulsed beam and the light beam is a pulsed beam, the method may include synchronizing the charged particle beam with the light beam. The method may also include defining multiple time steps, wherein one of the multiple time steps describes a time offset or phase delay of the charged particle beam relative to the light beam.

[0212] According to any of the foregoing examples, the beam comprises a photon pulse defining a time profile. The method may include generating profile data describing the time profile using the detector dataset. Generating the detector dataset may include sampling detector data generated simultaneously with the interaction period of the photon pulse and the charged particle beam. The detector data may be characterized in that the sampling period is approximately an order of magnitude smaller than the pulse duration described by the time profile. The method may include generating an operating parameter scheme corresponding to the time profile, the operating parameter scheme describing one or more operating parameters of the charged particle beam system.

[0213] According to any of the foregoing examples, the charged particle beam comprises charged particle pulses. Generating the detector dataset may include integrating the detector data using multiple charged particle pulses over a given time step. The charged particles may be electrons. Guiding the photon beam to intersect the beam axis may include coupling the beam into a light-guiding material that at least partially transmits the charged particles. The material may be at least partially arranged on the beam axis. The light-guiding material may include photonic nanostructures, microcavities, or photonic metamaterials.

[0214] According to any of the foregoing examples, the charged particle beam system is an electron microscope. The electron microscope may be a transmission electron microscope (TEM). The electron microscope may include a radio frequency (RF) cavity configured to generate a pulse beam of charged particles having a pulse frequency from about 25 MHz to about 100 MHz. Optionally, the pulse frequency may be about 75 MHz.

[0215] One or more machine-readable storage media store executable instructions that, when executed, cause the machine to perform operations including those operations according to any of the foregoing examples.

[0216] The charged particle beam system includes a charged particle source. The system includes a charged particle beam mirror operatively coupled to the charged particle source and including a plurality of charged particle optical elements disposed along the beam axis, the charged particle optical elements including a radio frequency (RF) cavity and a beam blanking device. The system includes a sample section operatively coupled to the charged particle beam mirror and defining a sample position on the beam axis. The system includes a light source optically coupled to the sample section and configured to direct the beam toward the sample position. The system includes a control circuitry operatively coupled to the RF cavity and the light source. The system may also include one or more machine-readable storage media operatively coupled to the control circuitry and storing executable instructions that, when executed, cause the system to perform operations including those of the methods of one or more embodiments of the seventh aspect.

[0217] Various embodiments have been described in the foregoing description. Specific configurations and details have been set forth for illustrative purposes to provide a thorough understanding of the embodiments. However, it will also be apparent to those skilled in the art that these embodiments can be practiced without these specific details. Furthermore, well-known features may have been omitted or simplified so as not to obscure the described embodiments. While the exemplary embodiments described herein focus on ultrafast charged particle beam systems, particularly ultrafast TEM (or UTEM) systems, these are non-limiting, illustrative embodiments. The embodiments of this disclosure are not limited to such embodiments, but are intended to address analytical instrument systems in which a wide array of material samples can be analyzed to determine chemical, biological, physical, structural, or other properties exhibiting time dynamics on submicrosecond timescales, including but not limited to chemical structure, trace elemental composition, etc.

[0218] Various embodiments have been described in the foregoing description. Specific configurations and details have been set forth for illustrative purposes to provide a thorough understanding of the embodiments. However, it will also be apparent to those skilled in the art that these embodiments can be practiced without these specific details. Furthermore, well-known features may have been omitted or simplified so as not to obscure the described embodiments. While the exemplary embodiments described herein focus on electron microscopy systems, these are non-limiting, illustrative embodiments. The embodiments of this disclosure are not limited to such materials but are intended to address the problems of electron beam systems, for which a range of particles can be used to image, microanalyze, and / or process materials at the atomic scale. Such particles may include, but are not limited to, electrons, ions, or photons in TEM systems, SEM systems, STEM systems, UFTEM systems, EFTEM systems, ion beam systems, and / or particle accelerator systems.

[0219] Some embodiments of this disclosure include systems having one or more data processors and / or logic circuitry. In some embodiments, the system includes a non-transitory computer-readable storage medium containing instructions, wherein, when executed on one or more data processors, the instructions cause the one or more data processors to perform part or all of the methods disclosed herein and / or part or all of one or more processes and workflows. Some embodiments of this disclosure include computer program products embodied in a non-transitory machine-readable storage medium, including instructions configured to cause one or more data processors to perform part or all and / or part or all of the methods disclosed herein, for example, including... Figures 8-13 The methods, operations, and processes.

[0220] The terms and expressions used herein are descriptive rather than restrictive, and their use is not intended to exclude any equivalents of the features shown and described or portions thereof, but rather to recognize that various modifications are possible within the scope of the claims. Therefore, it should be understood that while this disclosure includes specific embodiments and optional features, modifications and alterations to the concepts disclosed herein can be made by those skilled in the art, and such modifications and alterations are considered to be within the scope of the appended claims.

[0221] As used in this application and claims, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” include the plural forms. Additionally, the term “comprising” means “including.” Furthermore, the term “coupled” does not exclude the existence of intermediate elements between coupled items.

[0222] The systems, apparatuses, and methods described herein should not be construed as limiting in any way. Rather, this disclosure relates to all new and non-obvious features and aspects of the various disclosed embodiments, whether individually or in various combinations and sub-combinations. The disclosed systems, methods, and apparatuses are not limited to any particular aspect or feature or combination thereof, nor are they required to have any one or more specific advantages or to solve any one or more specific problems. Any operational theory should be readily applicable, but the disclosed systems, methods, and apparatuses are not limited to such operational theories.

[0223] Although some operations of the disclosed methods are described in a specific order for ease of presentation, it should be understood that this descriptive approach encompasses rearrangement unless the specific order is required by the language. For example, operations described sequentially may be rearranged or performed simultaneously in some cases. Furthermore, for the sake of brevity, the accompanying drawings may not show the various ways in which the systems, methods, and apparatuses disclosed herein can be used in conjunction with other systems, methods, and apparatuses. Additionally, the specification sometimes uses terms such as “produce” and “provide” to describe the disclosed methods. These terms are high-level abstractions of the actual operations performed. The actual operations corresponding to these terms will vary depending on the specific implementation and are readily apparent to those skilled in the art.

[0224] In some examples, values, programs, or devices are referred to as “lowest,” “best,” “smallest,” “greater than,” “less than,” “equal to,” etc. It should be understood that such descriptions are intended to indicate that there are many functional alternatives available, and that such a choice is not necessarily better, smaller, or preferred than other choices.

[0225] The term "image" is intended to include a two-dimensional grid, which may comprise at least one or more portions. Each portion is characterized by its coordinates and its values ​​(color and / or intensity). Thus, an image can refer to a visual representation of a sample in variations of grayscale and / or color and / or intensity. Furthermore, each portion in an image may correspond to a point (e.g., a location) on a target object or a sub-location on a target object, etc.

[0226] Some embodiments of this disclosure include systems having one or more data processors and / or logic circuits. In some embodiments, the system includes a non-transitory computer-readable storage medium containing instructions that, when executed on one or more data processors and / or logic circuits, cause the one or more data processors and / or logic circuits to perform part or all of the one or more methods disclosed herein and / or part or all of one or more processes and workflows. Some embodiments of this disclosure include a computer program product tangibly embodied in a non-transitory machine-readable storage medium, the computer program product including instructions configured to cause one or more data processors and / or logic circuits to perform part or all of the one or more methods disclosed herein and / or part or all of one or more processes.

[0227] The terms and expressions used herein are descriptive rather than restrictive, and their use is not intended to exclude any equivalents of the features shown and described or portions thereof, but rather to recognize that various modifications are possible within the scope of the claims. Therefore, it should be understood that while this disclosure includes specific embodiments and optional features, modifications and alterations to the concepts disclosed herein can be made by those skilled in the art, and such modifications and alterations are considered to be within the scope of the appended claims.

[0228] When a term is used without a clear definition, it should be understood that unless the term has a special and / or specific meaning in the field of charged particle microscopy systems or other related fields, it refers to the general meaning of the word. The terms “about” or “substantially” are used to indicate a deviation from the stated property, where the deviation has little or no effect on the corresponding function, property, or attribute of the described structure. In the example shown where a dimensional parameter is described as “substantially equal” to another dimensional parameter, the term “substantially” is intended to reflect that the two parameters being compared may be unequal within permissible limits (such as confidence intervals inherent in manufacturing tolerances or system operation). Similarly, where geometric parameters (such as alignment or angular orientation) are described as “approximately” perpendicular, “substantially” perpendicular, or “substantially” parallel, the terms “approximately” or “substantially” are intended to reflect that the alignment or angular orientation may differ from the precisely stated condition (e.g., not precisely perpendicular) within permissible limits. For numerical values ​​(such as diameter, length, width, etc.), the term “about” can be understood to describe a deviation of up to ±20% from the stated value. For example, the size "about 20mm" can describe sizes ranging from 15mm to 25mm.

[0229] This description provides exemplary embodiments and is not intended to limit the scope, applicability, or configuration of this disclosure. Rather, the following description of exemplary embodiments will provide those skilled in the art with an enabling description for implementing various embodiments. It should be understood that various changes may be made to the function and arrangement of elements without departing from the spirit and scope set forth in the appended claims. Specific details are set forth in the description to provide a thorough understanding of the embodiments. However, it should be understood that embodiments may be practiced without these specific details. For example, particular system components, systems, processes, and other elements of this disclosure may be shown schematically or omitted from the illustrations to avoid obscuring the embodiments with unnecessary detail. In other instances, well-known circuits, processes, components, structures, and / or techniques may be shown without unnecessary detail.

Claims

1. A method for characterizing a beam of light inside a charged particle microscope tube, the method comprising: The beam pulse is directed toward the sample in the charged particle mirror tube; Guide the charged particle beam pulse toward the sample; Charged particles interacting with the sample are detected, at least in part, based on the beam pulse and the charged particle beam pulse. The time delay between the charged particle beam and the beam pulse is determined at least in part based on the charged particles; and At least one characteristic of the beam pulse is determined based, at least in part, on the time delay.

2. The method of claim 1, wherein the charged particle beam is a charged particle beam pulse, wherein the light beam is a light beam pulse, and wherein determining the time delay further comprises: Synchronize the charged particle beam pulse with the beam pulse; as well as Multiple time steps are determined, wherein the time step represents the time offset of the charged particle beam pulse relative to the beam pulse.

3. The method of claim 1, wherein the charged particle beam is a charged particle beam pulse, wherein the light beam is a light beam pulse, and wherein determining the time delay further comprises: Synchronize the charged particle beam pulse with the beam pulse; as well as Multiple time steps are determined, wherein the time step in the multiple time steps represents the phase delay of the charged particle beam pulse relative to the beam pulse.

4. The method of claim 1, wherein the beam is a beam pulse including a time pulse profile, the method further comprising: The charged particle beam is guided into an energy dispersive spectrometer configured to generate detector data describing the energy distribution of the charged particle beam. Generate detector datasets describing multiple energy distributions corresponding to multiple time steps; The detector dataset is used to generate contour data describing the time pulse profile.

5. The method of claim 4, wherein generating the detector dataset comprises sampling detector data generated simultaneously with the interaction period of the beam and the charged particle beam, wherein the detector data is characterized in that the sampling period is about an order of magnitude smaller than the pulse duration described by at least one characteristic, the at least one characteristic being the temporal pulse profile of the beam intensity.

6. The method of claim 4, wherein the charged particle beam is a charged particle beam pulse, and wherein generating the detector dataset comprises integrating the detector data over a given time step using a plurality of charged particle pulses.

7. The method according to claim 1, further comprising: Generate an operating parameter scheme corresponding to the at least one characteristic, the operating parameter scheme describing the charged particle One or more operating parameters of the sub-beam system, wherein the at least one characteristic includes the time pulse of the beam intensity. contour.

8. The method of claim 1, wherein determining the at least one characteristic of the light beam further includes include: The effective pulse duration of the beam was measured using photon-induced near-field electron microscopy (PINEM).

9. The method of claim 8, further comprising: The temporal intensity distribution of the light beam is characterized at least in part based on the effective pulse duration.

10. One or more machine-readable storage media storing executable instructions that, when executed, cause a charged particle beam system to perform operations including: Guide the beam pulse toward the sample in the charged particle mirror tube; Guide the charged particle beam pulse toward the sample; Charged particles interacting with the sample are detected, at least in part, based on the beam pulse and the charged particle beam pulse. The time delay between the charged particle beam and the beam pulse is determined at least in part based on the charged particles; and At least one characteristic of the beam pulse is determined based, at least in part, on the time delay.

11. One or more machine-readable storage media according to claim 10, wherein the charged particle beam tube is a transmission electron microscope (TEM).

12. One or more machine-readable storage media according to claim 10, wherein the charged particle mirror tube includes a radio frequency (RF) cavity configured to generate charged particle beam pulses.

13. One or more machine-readable storage media according to claim 10, wherein the pulse frequency of the charged particle beam pulse is from about 25 MHz to about 100 MHz.

14. The operation further comprises: The light beam is coupled into the light guide material.

15. The operation further comprises: The delay of the beam pulse or charged particle beam pulse directed toward the sample is adjusted, at least in part based on the determination of the at least one characteristic.

16. The operation further comprises: The intensity, frequency, or phase delay of the beam pulse directed toward the sample is adjusted, at least in part, based on the determination of at least one of the aforementioned characteristics.

17. A charged particle beam device, comprising: One or more processors; as well as One or more machine-readable storage media operatively coupled to a control circuitry system, the media storing executable instructions that, when executed, cause operations including: The beam pulse is directed toward the sample in the charged particle beam device; Guide the charged particle beam pulse toward the sample; Charged particles interacting with the sample are detected, at least in part, based on the beam pulse and the charged particle beam pulse. The time delay between the charged particle beam and the beam pulse is determined at least in part based on the charged particles; and At least one characteristic of the beam pulse is determined based, at least in part, on the time delay.

18. The charged particle beam apparatus of claim 17, wherein the at least one characteristic of the beam includes a characterization of the time asymmetry of the beam.

19. The charged particle beam apparatus of claim 17, wherein the at least one characteristic of the beam includes pulse duration or laser chirp.

20. The charged particle beam device of claim 17, wherein the at least one characterization is used to characterize one or more optical modes in the microresonator.

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