Ultrafast electron microscope rod for transmitting nanosecond pulse electric signals

Abstract

The utility model discloses an ultrafast electron microscope rod for transmitting nanosecond pulse electric signals in the field of electron microscopes, which comprises a sample rod, a filter circuit module is arranged in the sample rod, and the input end of the filter circuit module is connected with a waveform generator through a coaxial line; the sample table comprises a bottom plate and a sample bearing structure arranged on the bottom plate, the input end of the sample table is also connected with the output end of the filter circuit module through a coaxial line, and the coaxial line is sequentially connected with the waveform generator, the filter circuit module and the sample table in the signal transmission direction; the utility model has the beneficial effects that nanosecond pulse voltage signals can be transmitted to a sample end in a high-fidelity manner, the requirements of an ultrafast experiment on short pulse signals with different frequencies are met, welding or conductive adhesive fixation is not needed during sample replacement, and the sample replacement steps are simplified.

Description

Technical Field

[0001] The utility model relates to the field of electron microscopes, in particular to an ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals. Background Art

[0002] As an imaging tool with atomic-level resolution, transmission electron microscopy (TEM) can detect the structure of material systems from multiple angles, including diffraction, real-space imaging, and energy-space imaging. It is a powerful means to study the origins of novel physical structures. However, with the increasing demand for physical property control, the study of static structures can no longer meet the needs of further exploration of the evolution of physical properties. Therefore, time-resolved transmission electron microscopy based on pump-probe has emerged. In this technology, light, electricity, or pressure are used as pump signals to excite the sample into a non-equilibrium state, and a pulsed electron beam is used as a detection signal to detect the structure of the non-equilibrium state. In devices using electrical signals as pump signals, the electrical signals are transmitted to the sample in the form of electrical pulses of different frequencies, driving changes in related physical parameters. In order to obtain higher time resolution, the pulse width of the electrical pulse signal is mostly in the nanosecond range.

[0003] However, the transmission of nanosecond pulsed electrical signals can cause some distortion in the time domain due to the presence of transmission line impedance and capacitance. Since the functionality of a time-resolved transmission electron microscope (TEM) relies on the stability of the electrical signal in the time domain, this distortion limits the responsiveness of the results obtained from time-resolved experiments to the actual physical process, severely hindering the proper performance of electrical pumping experiments. Furthermore, sample preparation is generally difficult in TEM electrical pumping experiments. How to quickly and easily transfer the sample to the sample holder and achieve good contact with the electrodes is a key technical challenge that needs to be addressed.

[0004] In summary, how to transmit nanosecond short pulse signals of different frequencies to the sample end with high fidelity and how to place the sample in the electron microscope sample holder conveniently and efficiently are key technical issues that need to be solved in electrically pumped time-resolved transmission electron microscopy.

[0005] To this end, we propose an ultrafast electron microscope rod that transmits nanosecond pulsed electrical signals. Summary of the Invention

[0006] In view of the above-mentioned deficiencies in the prior art, the utility model provides an ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals.

[0007] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present utility model is:

[0008] An ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals comprises: a sample rod, which is internally provided with a filter circuit module, the input end of the filter circuit module being connected to a waveform generator via a coaxial line; a sample stage, which comprises a base plate and a sample supporting structure provided on the base plate, the input end of the sample stage also being connected to the output end of the filter circuit module via a coaxial line, and the coaxial line sequentially connecting the waveform generator, the filter circuit module and the sample stage according to the signal transmission direction.

[0009] It is further defined that the sample supporting structure includes a leaf spring, which is V-shaped and arranged on the bottom plate through an insulating layer. A rectangular pressing plate is provided at the open bottom of the leaf spring, and a through hole is opened on the pressing plate for the electron beam to pass through.

[0010] It is further defined that the sample stage also includes a coplanar waveguide structure, which includes a central conductor, side conductors and a dielectric substrate. The dielectric substrate is laid on the bottom plate, and the central conductor and the side conductors are both horizontally arranged on the dielectric substrate. The side conductors are in an "E" shape, and the central conductor is arranged in the opening of the side conductor.

[0011] It is further defined that the coaxial line includes an input axis and an output axis, the input axis is connected to the waveform generator, the input port, the filter circuit module, the bottom end and the top end of the center conductor on one side, and the end of one side of the leaf spring in sequence according to the signal transmission direction, and the output axis is connected to the other end of the leaf spring, the top end and the bottom end of the center conductor on the other side, and the output port in sequence according to the signal transmission direction.

[0012] It is further specified that the center conductor and the side conductors are both made of copper.

[0013] It is further specified that the dielectric substrate is made of silicon.

[0014] It is further defined that the filter circuit module includes a capacitor C1, a capacitor C2, a capacitor C3, a transistor Q1, a transistor Q2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7; one end of the capacitor C1 is connected to the signal input end, and the other end is respectively connected to the resistor R1, the resistor R2 and the transistor Q1, the other end of the resistor R1 is respectively connected to the ground, the resistor R4, the resistor R7, the capacitor C2, the resistor R5, the other end of the resistor R5 is connected to the signal output end, the other end of the resistor R2 is respectively connected to the resistor R3 and the power supply, the other end of the resistor R3 is respectively connected to the transistor Q2 and the capacitor C3, the other end of the capacitor C3 is connected to the signal output end, the other end of the transistor Q2 is respectively connected to the transistor Q1, the resistor R7, the capacitor C2 and the resistor R6, the other end of the resistor R6 is connected to the power supply, the other end of the transistor Q1 is connected to the resistor R4, and an on-off switch is connected between the signal input end of the capacitor C1 and the signal output end of the capacitor C3.

[0015] The input signal vin is coupled to the base of transistor Q1 through capacitor C1. The function of capacitor C1 is to prevent the DC component from passing through and only allow the AC signal to enter the amplifier circuit; the electrical signal processed by the capacitor enters transistor Q1. Transistor Q1 serves as the first-stage amplifier, with its base receiving the input signal and the collector outputting the amplified signal; wherein, resistors R1 and R4 form a voltage divider bias network to provide a stable operating point for Q1, resistor R2 is the collector load resistor of transistor Q1, which determines the amplification factor, and capacitor C2 is used to bypass the AC component of resistor R5 to reduce the output impedance and improve the transmission efficiency of the AC signal; transistor Q2 serves as the second-stage amplifier, with its base receiving the signal from the collector of transistor Q1 and further amplifying the signal; resistor R3 is a three The collector load resistor of transistor Q2; resistors R6 and R7 form a voltage divider bias network to provide a stable operating point for transistor Q2; resistor R7 provides the base bias voltage for transistor Q2; finally, capacitor C3 couples the amplified signal to the signal output terminal Vout, while blocking the output of the DC component; among them, resistor R5 is the output load resistor and, together with C3, determines the output impedance. Through the bias of the transistor, the charge and discharge time constant of the capacitor, the current limiting effect of the resistor, and the feedback of the circuit, the pulse width is effectively shortened, and the response speed and performance of the circuit are improved. The combination of this multi-stage amplification circuit and the electron microscope sample holder enables high-fidelity transmission of nanosecond pulse voltage signals to the sample end in the transmission electron microscope, meeting the requirements of ultrafast experiments for short pulse signals of different frequencies.

[0016] It is further defined that the transistor in the filter circuit module is a high-frequency transistor, and the capacitor and resistor are chip capacitors and chip resistors respectively.

[0017] Beneficial effects of the utility model:

[0018] (1) The utility model combines the advantages of the common-emitter two-stage amplifier circuit through an innovative circuit module design, and sets a one-way switch on this basis. This design effectively improves the signal overshoot problem of the nanosecond pulse signal during transmission to the sample. Regardless of whether the one-way switch is closed or not, the signal transmission efficiency and stability can be significantly improved. This is particularly important for electric pumping experiments in time-resolved transmission electron microscopy technology, because it ensures that the nanosecond pulse signal can be transmitted to the sample end with high fidelity, thereby improving the accuracy and reliability of the experiment.

[0019] (2) The utility model performs well in the transmission of nanosecond pulse signals for single pulses. Its circuit module structure is simple and efficient, which not only reduces the cost of production and maintenance, but also improves the transmission efficiency of the signal. This design makes the transmission of nanosecond pulse signals more stable and reliable, providing strong support for the research of time-resolved transmission electron microscopy technology.

[0020] (3) Compared with the existing sample rod, the present invention is more convenient in sample replacement. It abandons the traditional connection methods such as welding or conductive glue, and fixes the sample by pressing and fixing it with a leaf spring and a pressing piece. This greatly simplifies the sample replacement steps, saves experimental time, and improves experimental efficiency. At the same time, this design also reduces the signal distortion problem caused by poor connection, further improving the accuracy of the experiment.

[0021] (4) When dealing with extremely small samples, traditional fixing methods such as welding or conductive adhesive bonding are very difficult, while fixing by pressing is very convenient. Even when changing samples, there is no need to remove the solder and conductive adhesive, and an almost stable electrical connection state can be maintained. This is particularly important for fine experiments in time-resolved transmission electron microscopy technology because it ensures that the sample can always maintain a stable electrical connection during the test, thereby improving the accuracy and repeatability of the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a perspective view of the present utility model;

[0023] Figure 2 Schematic diagram of the structure of the sample stage;

[0024] Figure 3 This is the circuit diagram of the filter circuit module;

[0025] Figure 4 A comparison diagram of the output signal of the utility model and the output signal of the wave source;

[0026] Figure 5 This is a comparison diagram of the output signal of the present invention, the output signal of the wave source, and the output signal of the existing coaxial line.

[0027] The symbols of the components are as follows:

[0028] Sample rod 1, sample stage 2, base plate 21, sample supporting structure 22, leaf spring 221, pressing piece 222, insulating layer 223, coplanar waveguide structure 23, center conductor 231, side conductor 232, dielectric substrate 233, coaxial line 3, input axis 31, output axis 32, filter circuit module 4, input port 5, output port 6. DETAILED DESCRIPTION

[0029] The specific implementation methods of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific implementation methods. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all utility model creations using the concept of the present invention are protected.

[0030] Example:

[0031] like Figures 1-3 As shown, an ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals includes a sample rod 1 and a sample stage 2; a filter circuit module 4 is provided inside the sample rod 1, the transistor in the filter circuit module 4 is a high-frequency transistor, the capacitor and resistor are chip capacitors and chip resistors respectively, and the input end of the filter circuit module 4 is connected to the waveform generator via a coaxial line 3; the sample stage 2 includes a base plate 21, a sample supporting structure 22 provided on the base plate 21, and a coplanar waveguide structure 23, the sample supporting structure 22 includes a leaf spring 221, the leaf spring 221 is V-shaped and is provided on the base plate 21 through an insulating layer 223, and a rectangular pressing piece 22 is provided at the bottom of the opening of the leaf spring 221. 2, a through hole is provided on the pressing plate 222 for the electron beam to pass through; the sample stage 2 also includes a coplanar waveguide structure 23, the coplanar waveguide structure 23 includes a central conductor 231, a side conductor 232 and a dielectric substrate 233, the dielectric substrate 233 is laid on the bottom plate 21, the central conductor 231 and the side conductor 232 are both horizontally arranged on the dielectric substrate 233, the side conductor 232 is in an "E" shape, the central conductor 231 is arranged in the opening of the side conductor 232, the central conductor 231 and the side conductor are both made of copper, and the dielectric substrate 233 is made of silicon; the coaxial line 3 includes an input axis 31 and an output axis 32, the input axis 31 is arranged according to the signal The waveform generator, input port 5, filter circuit module 4, the bottom and top ends of the central conductor 231 on one side, and one end of the leaf spring 221 are connected in sequence in the direction of signal transmission. The output axis 32 is connected in sequence to the other end of the leaf spring 221, the top and bottom ends of the central conductor 231 on the other side, and the output port 6 in the direction of signal transmission; the filter circuit module 4 includes capacitor C1, capacitor C2, capacitor C3, transistor Q1, transistor Q2, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6 and resistor R7; one end of capacitor C1 is connected to the signal input end, and the other end is connected to resistors R1 and R2 respectively. and transistor Q1. The other end of the resistor R1 is respectively connected to the ground wire, resistor R4, resistor R7, capacitor C2, and resistor R5. The other end of the resistor R5 is connected to the signal output end. The other end of the resistor R2 is respectively connected to resistor R3 and the power supply. The other end of the resistor R3 is respectively connected to the transistor Q2 and capacitor C3. The other end of the capacitor C3 is connected to the signal output end. The other end of the transistor Q2 is respectively connected to the transistor Q1, resistor R7, capacitor C2, and resistor R6. The other end of the resistor R6 is connected to the power supply. The other end of the transistor Q1 is connected to resistor R4. An on-off switch is connected between the signal input end of the capacitor C1 and the signal output end of the capacitor C3.

[0032] The input signal vin is coupled to the base of transistor Q1 through capacitor C1. The function of capacitor C1 is to prevent the DC component from passing through and only allow the AC signal to enter the amplifier circuit; the electrical signal processed by the capacitor enters transistor Q1. Transistor Q1 serves as the first-stage amplifier, with its base receiving the input signal and the collector outputting the amplified signal; wherein, resistors R1 and R4 form a voltage divider bias network to provide a stable operating point for Q1, resistor R2 is the collector load resistor of transistor Q1, which determines the amplification factor, and capacitor C2 is used to bypass the AC component of resistor R5 to reduce the output impedance and improve the transmission efficiency of the AC signal; transistor Q2 serves as the second-stage amplifier, with its base receiving the signal from the collector of transistor Q1 and further amplifying the signal; resistor R3 is a three The collector load resistor of transistor Q2; resistors R6 and R7 form a voltage divider bias network to provide a stable operating point for transistor Q2; resistor R7 provides the base bias voltage for transistor Q2; finally, capacitor C3 couples the amplified signal to the signal output terminal Vout, while blocking the output of the DC component; among them, resistor R5 is the output load resistor and, together with C3, determines the output impedance. Through the bias of the transistor, the charge and discharge time constant of the capacitor, the current limiting effect of the resistor, and the feedback of the circuit, the pulse width is effectively shortened, and the response speed and performance of the circuit are improved. The combination of this multi-stage amplification circuit and the electron microscope sample holder enables high-fidelity transmission of nanosecond pulse voltage signals to the sample end in the transmission electron microscope, meeting the requirements of ultrafast experiments for short pulse signals of different frequencies.

[0033] Figure 4 The signal output in is the output signal after the filter circuit module, and the wave source output signal is the signal sent by the waveform generator; Figure 5 The unfiltered output signal is the signal emitted from the waveform generator and output only after passing through the existing coaxial line. The signal emitted by the wave source is the signal emitted by the waveform generator. The filtered output signal is the output signal after passing through the filtering circuit module, and the signal voltage is a negative voltage with the same absolute value as the previous two.

[0034] Example 2:

[0035] The difference between Example 2 and Example 1 is that the dielectric substrate 233 is made of ceramic or quartz.

Claims

1. An ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals, characterized in that: include: A sample rod (1) is provided with a filter circuit module (4) therein, and an input end of the filter circuit module (4) is connected to a waveform generator via a coaxial line (3); A sample stage (2) includes a base plate (21) and a sample supporting structure (22) disposed on the base plate (21); an input end of the sample stage (2) is also connected to an output end of the filter circuit module (4) via a coaxial line (3); and the coaxial line (3) sequentially connects the waveform generator, the filter circuit module (4), and the sample stage (2) in a signal transmission direction; The filter circuit module (4) includes a capacitor C1, a capacitor C2, a capacitor C3, a transistor Q1, a transistor Q2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7; one end of the capacitor C1 is connected to the signal input end, and the other end is respectively connected to the resistor R1, the resistor R2 and the transistor Q1; the other end of the resistor R1 is respectively connected to the ground wire, the resistor R4, the resistor R7, the capacitor C2 and the resistor R5; the other end of the resistor R5 is connected to the signal output end; the other end of the resistor R2 is respectively connected to the resistor R3 and the power supply; the other end of the resistor R3 is respectively connected to the transistor Q2 and the capacitor C3; the other end of the capacitor C3 is connected to the signal output end; the other end of the transistor Q2 is respectively connected to the transistor Q1, the resistor R7, the capacitor C2 and the resistor R6; the other end of the resistor R6 is connected to the power supply; the other end of the transistor Q1 is connected to the resistor R4; an on-off switch is connected between the signal input end of the capacitor C1 and the signal output end of the capacitor C3.

2. The ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals according to claim 1, characterized in that: The sample supporting structure (22) includes a leaf spring (221), which is V-shaped and is arranged on the bottom plate (21) through an insulating layer (223). A rectangular pressing plate (222) is provided at the open bottom of the leaf spring (221), and a through hole for the electron beam to pass through is opened on the pressing plate (222).

3. The ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals according to claim 2, characterized in that: The sample stage (2) further includes a coplanar waveguide structure (23), the coplanar waveguide structure (23) including a central conductor (231), side conductors (232) and a dielectric substrate (233), the dielectric substrate (233) being laid on the bottom plate (21), the central conductor (231) and the side conductors (232) being both horizontally arranged on the dielectric substrate (233), the side conductors (232) being in an "E" shape, and the central conductor (231) being arranged in an opening of the side conductors (232).

4. The ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals according to claim 3, characterized in that: The coaxial line (3) comprises an input axis (31) and an output axis (32), wherein the input axis (31) is sequentially connected to a waveform generator, an input port (5), a filter circuit module (4), the bottom end and the top end of a central conductor (231) on one side, and an end of a leaf spring (221) in the direction of signal transmission, and the output axis (32) is sequentially connected to an end of the other side of the leaf spring (221), the top end and the bottom end of the central conductor (231) on the other side, and the output port (6) in the direction of signal transmission.

5. The ultrafast electron microscope rod for transmitting nanosecond pulsed electrical signals according to claim 4, characterized in that: The center conductor (231) and the side conductor (232) are both made of copper.

6. The ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals according to claim 4, characterized in that: The dielectric substrate (233) is made of silicon.

7. The ultrafast electron microscope rod for transmitting nanosecond pulse electrical signals according to claim 1, characterized in that: The transistor in the filter circuit module (4) is a high-frequency transistor, and the capacitor and resistor are chip capacitors and chip resistors respectively.

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