Broadband radio frequency spectrum real-time monitor

Abstract

A sensor system includes a laser source that emits a pump beam at a first wavelength and a probe beam at a second wavelength; and an optical device for receiving the pump beam and the probe beam. The optical device is operable to produce a plurality of beams, each having a different frequency than the pump beam and the probe beam. One or more cells receive the beams from the optical device and allow the beams to pass therethrough, wherein the cells contain alkali atoms. A dichroic filter is configured to receive the beams from the cells. The dichroic filter separates pump beam light and probe beam light from the beams. A detector array receives the probe beam light from the dichroic filter. The detector array includes a two-dimensional array of light sensors that map out a transmission corresponding to a respective beam of the probe beam light that passed through the cells.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit and priority of U.S. Provisional Application 63 / 044,753, filed June 26, 2020, which is incorporated herein by reference. Background Technology

[0003] The core issue in electronic warfare is intercepting or detecting radio frequency (RF) signals transmitted by unfriendly operators. These operators may attempt to reduce the probability of interception by transmitting very weak signals, hopping between frequencies, or sending their signals over a wide bandwidth. Therefore, to detect these signals, it is necessary to monitor the RF spectrum across a wide (greater than 20 GHz) band in real time with high sensitivity, dynamic range, and frequency resolution.

[0004] Electronic warfare poses a growing threat not only to covert communications but also to navigation, with interference and deception of the Global Positioning System (GPS) and other navigation signals jeopardizing the freedom of movement of defense assets. Spectrum monitoring and analysis can be a crucial part of addressing GPS signal denial and degradation.

[0005] The extremely high sensitivity of Rydberg atoms to electric fields has sparked interest in using them as RF field sensors to replace antennas and front-ends in radio receivers. However, to date, the advantages of Rydberg electrometers have not translated into significant benefits due to accompanying challenges.

[0006] Specifically, there is a growing interest in using Rydberg electrometers in wide-bandwidth applications and leveraging their capabilities to address multiple Rydberg levels. If the discrete nature of frequency sensitivity can be overcome, these characteristics could be utilized for fast spectrum scanning and ultra-widebandwidth communications. Summary of the Invention

[0007] This invention discloses a sensor system comprising a laser source configured to emit a pump beam at a first wavelength and a probe beam at a second wavelength; and an optical device for receiving the pump beam and probe beam from the laser source. The optical device is operable to generate multiple beams, each beam having a different frequency than the pump beam and probe beam. One or more units are configured to receive one or more beams from the optical device and allow the one or more beams to pass through them, the one or more units containing multiple base atoms. A dichroic filter is configured to receive the one or more beams from the one or more units. The dichroic filter is operable to separate the pump beam and probe beam from the one or more beams. A detector array is configured to receive the probe beam from the dichroic filter. The detector array includes a two-dimensional array of optical sensors operable to map the transmission of a corresponding beam of probe beam passing through the one or more units. Attached Figure Description

[0008] The features of the invention will become apparent to those skilled in the art from the following description with reference to the accompanying drawings. It should be understood that the drawings illustrate only typical embodiments and are therefore not intended to limit the scope of the invention. The invention will be described with additional features and details using the drawings, wherein:

[0009] Figure 1A This is a schematic diagram of a sensor system based on one implementation scheme;

[0010] Figure 1B This is a schematic diagram of a sensor system based on an alternative implementation scheme;

[0011] Figure 2 This is a schematic diagram of a sensor system for a Rydberg spectrum analyzer, based on one implementation scheme.

[0012] Figure 3 This is an exemplary implementation of a sensor system for rapid spectrum scanning;

[0013] Figure 4 This is an exemplary implementation of a sensor system for rapid spectral scanning, according to another specific embodiment;

[0014] Figure 5 This is a schematic diagram of a portion of a photonic chip with multiple cascaded frequency shifters according to one embodiment;

[0015] Figure 6A and Figure 6B These are graphs showing the stability of transmitted power and the linearity of the phase ramp in the model calculations for a single frequency shifter; and

[0016] Figure 7 It is a graphical representation of the spectrum of a square ultrawide bandwidth pulse, in which a set of seven Rydberg sensors are designed to sense the pulse; and

[0017] Figure 8 It is a flowchart based on a specific implementation of a sensing method. Detailed Implementation

[0018] In the following detailed description, embodiments are fully described to enable those skilled in the art to practice the invention. It should be understood that other embodiments may be utilized without departing from the scope of the invention. Therefore, the following detailed description should not be considered limiting.

[0019] This paper describes a broadband radio frequency (RF) spectrum real-time monitoring sensor system. The sensor system of this invention is based on atoms excited to a variety of so-called "Rydberg" states when prepared by lasers of appropriate wavelengths. Within these Rydberg states, each state can be selected and detected, where the atoms are sensitive to specific frequencies emitted by the RF.

[0020] In one specific implementation, the sensor system is a Rydberg spectrum analyzer employing an array of Rydberg detectors that provide monitoring to continuously map RF spectrum stripes up to 20 GHz, with each Rydberg detector tuned to a slightly different RF frequency. By applying a small electric field (e.g., less than 1 V / cm), a single detector can span approximately 100 MHz along the RF spectrum. Furthermore, the numerous detectors in the array can resolve different Rydberg levels. For example, approximately 200 detectors can be used to extend the total sensing range of the RF frequency to approximately 20 GHz. Electrodes can be fabricated as part of a package to deliver a highly controlled electric field.

[0021] In some implementations, fabricating large-scale parallel array probes for sensor systems involves the use of integrated photonics. For example, a photonic integrated pump / probe delivery array is described below. In other implementations, integrated photonics can be replaced by fiber-optic based systems, as further described below.

[0022] The sensor system of the present invention can achieve simultaneous readout within a 100 MHz range around each Rydberg level by applying an electric field gradient and spatially distinguishing the probe beam along the electric field gradient.

[0023] A Rydberg electrometer can be viewed as a "staircase" electromagnetically induced transparent (EIT) system, where the EIT is "disrupted" by coupling a fourth energy level to the third coherence of the staircase system. Traditionally, the transition to a lower energy level is called probing, and the transition to a higher energy level is called pumping. The higher energy levels of the staircase system are Rydberg states, whose large electric dipole moments allow for the establishment of third coherence even in extremely weak RF fields. The RF can be tuned to a resonance close to another nearby Rydberg level. This forms a second EIT-sampled system nested within the first system, which modulates the absorption of the probe, which can be used to determine the intensity of the microwave field.

[0024] In its simplest form, the Rydberg electrometer is an amplitude-modulated (AM) RF field sensor. The amplitude of the RF modulates the absorption frequency of the probe beam, which is typically measured by measuring the intensity of the beam after it passes through the vapor in a vapor chamber. If the RF field is a carrier frequency with amplitude modulation, the signal is detected by the Rydberg sensor and carried to baseband, thus replacing the antenna and heterodyne front end of the radio receiver.

[0025] Without applying additional techniques, the sensed RF field must be close to the resonant of the permissible Rydberg-to-Rydberg transition. The term "RF" encompasses frequencies from MHz to THz, but Rydberg sensors can also operate continuously at frequencies as low as a few kHz or even DC, where sensitivity is lost when the sensed field is not close to resonance. Due to the abundance of n and L states in the Rydberg manifold, Rydberg sensors exhibit high sensitivity over a wide bandwidth at hundreds of discrete frequencies without requiring multiple front-ends (antennas and heterodyne elements) to achieve the full range.

[0026] The following section describes various implementation schemes in more detail with reference to the accompanying drawings.

[0027] Figure 1A This is a schematic diagram of a sensor system 10 according to one embodiment. The sensor system 10 includes a laser source 12 configured to emit a pump beam at a first wavelength and a probe beam at a second wavelength. A photonic integrated circuit 20 (such as a photonic chip) is configured to receive the pump beam and probe beam from the laser source 10. The photonic integrated circuit 20 includes an array of cascaded frequency shifters 22 operable to generate a plurality of substantially parallel beams, each beam having a different frequency than the pump beam and the probe beam. The frequency shifters 22 are described in further detail below.

[0028] Optical device 30 is configured to receive a light beam from photonic integrated circuit 20 and guide the beam to unit 40. In various embodiments, optical device 30 may be a lens configuration, grating, optical metamaterial, etc.

[0029] In one exemplary embodiment, cell 40 is a vapor chamber containing alkali atoms such as rubidium (Rb) or cesium (Cs). Cell 40 is configured to allow a light beam to pass through it, such that the atoms in cell 40 are excited to multiple Rydberg levels (e.g., principal quantum number n, where n is 30-100). Dichroic filter 50 is configured to receive the light beam passing through cell 40 and is operable to separate the pump beam light and the probe beam light prior to detection.

[0030] Detector array 60 is configured to receive a light beam passing through dichroic filter 50. Detector array 60 includes a two-dimensional array of light sensors 62 configured to map the transmission of a corresponding beam of light corresponding to the probe beam passing through unit 40. Beam data can be sent as an output signal from detector array 60 to a processor for data analysis and subsequent display.

[0031] Figure 1B This is a schematic diagram of a sensor system 70 according to an alternative embodiment, which is connected to sensor system 10 ( Figure 1A A similar approach can be used, except that the photonic chip can be replaced by a fiber-based arrangement. Therefore, the sensor system 70 includes a laser source 72 configured to emit a pump beam at a first wavelength and a probe beam at a second wavelength. A fiber-based arrangement 80, which can be bundled in various configurations, is operable to receive the pump beam and probe beam from the laser source 72. The fiber-based arrangement 80 includes a cascaded fiber array 82 and a fiber splitter 86, which are connected to a corresponding fiber-coupled phase modulator 84 configured to provide frequency shift.

[0032] Similar to the photonic chip described above, the fiber-based arrangement 80 is operable to generate multiple light beams, each with a frequency different from the pump beam and the probe beam. The beam at each frequency is guided to a corresponding measurement vapor chamber 90 connected to a corresponding fiber 82. A dichroic filter can be used to receive the beam passing through each vapor chamber 90. The dichroic filter is operable to separate the pump beam and the probe beam before detection. For example, for sensor system 10 ( Figure 1A The detector array described above can be used to receive light beams passing through a dichroic filter. The beam data can be sent as an output signal from the detector array to a processor for data analysis and subsequent display.

[0033] Use such as Figure 1BThe advantages of the fiber-optic-based sensor system illustrated are the availability of the fiber-coupled phase modulator and other optical devices used in the system. Another advantage of the fiber-optic-based sensor system is the ability to have different measurement vapor chambers, which will not have some of the potential complexities of a fully integrated system, such as cross-coupling, due to the close proximity of sensing elements at different frequencies. However, compared to integrated systems, fiber-optic-based systems can reduce the possible number of modulator elements and / or increase the overall device size.

[0034] Rydberg Spectrum Analyzer

[0035] Figure 2 This is a schematic diagram of a sensor system 100 implemented as a Rydberg spectrum analyzer according to one embodiment. The sensor system 100 includes a laser source 110 configured to emit a pump beam and a probe beam, and a photonic chip 120 configured to receive the pump / probe beams from the laser source 110. The photonic chip 120 includes an array of integrated frequency shifters 122 (δf) operable to generate a plurality of parallel pump / probe beams, each having a different frequency. The integrated frequency shifters 122 on the photonic chip 120 are described in further detail below.

[0036] A parallel pump / probe beam generated by photonic chip 120 is elongated / broadened by optical devices and guided through a vapor chamber having one or more electric field plates 130 configured to generate an electric field gradient 132. A detector array 140 (such as a charge-coupled device (CCD)) comprises a two-dimensional array of optical sensors 142 configured to map the elongated / broadened pump / probe beam (e.g., f0-nδf, f0, f0+nδf). A processor 150 is operable to acquire beam data for data analysis and subsequent display (e.g., f...). RF v. time) output signal.

[0037] Figure 3 An exemplary embodiment of a sensor system 200 for fast spectral scanning according to a specific implementation is shown. The sensor system 200 includes a first laser device 210 and a second laser device 214. The first laser device is configured to emit a pump beam 212 at a first wavelength (e.g., 480 nm, blue light), and the second laser device is configured to emit a backpropagating probe beam 216 at a second wavelength (e.g., 780 nm, red light). An in-plane pump photonic chip 220 is configured to receive the pump beam 212 from the first laser device 210. An in-plane probe photonic chip 222 is configured to receive the probe beam 216 from the second laser device 214.

[0038] Pump photonic chip 220 includes an integrated frequency shifter array operable to generate multiple substantially parallel beams, each having a different frequency than the pump beam 212. Photonic chip 220 may include a beam splitter / phase shifter array to propagate light across different layers of photonic chip 220. Modulation can be applied to the frequency shifter to modulate the laser beam with RF for heterodyne measurements, and a sawtooth ramp 218 (e.g., about 4 MHz) can be applied to photonic chip 220 to shift the pump frequency. Probe photonic chip 222 includes a beam splitter array to generate multiple substantially parallel beams from a backpropagating probe beam 216, but this probe photonic chip does not have a frequency shifter.

[0039] The first cylindrical lens system 224 is configured to receive parallel beams from the pump photonic chip 220 and broaden each beam into a corresponding out-of-plane sheet 226. The second cylindrical lens system 228 is configured to receive parallel beams from the probe photonic chip 222 and broaden each of these beams into a corresponding out-of-plane sheet 229.

[0040] Vapor chamber 230 is configured to receive light plates 226 and 229 from cylindrical lens systems 224 and 228, respectively, and to allow light plates 226 and 229 to pass through it. One or more electric field plates 232 are coupled to vapor chamber 230 and configured to generate out-of-plane electric field (DC) gradients. Tilted dichroic mirror array 234 guides the probe light (light plate 229) toward detector array 240.

[0041] Detector array 240 includes a two-dimensional array of light sensors 242 configured to map the transmission of light from vapor chamber 230 along two axes through light sheets 226 and 229. Detector array 240 can be a CCD chip or a custom array of photodiodes with appropriate spacing. Detector array 240 can be implemented with discrete 100MHz steps (Stark tuning) along one dimension, and along another dimension, this 100MHz can be broken down into smaller frequency steps (optical tuning). The electrical output signal from detector array 240 is then sent to a processor for data analysis and display.

[0042] Figure 4 This is an exemplary embodiment of a sensor system 300 for rapid spectral scanning, according to another specific implementation. The sensor system 300 includes a laser source 310 configured to emit a pump beam 312 at a first wavelength (e.g., 480 nm, blue light) and a co-propagating probe beam 314 at a second wavelength (e.g., 780 nm, red light). An in-plane photonic chip 320 is configured to receive the pump beam 312 and the probe beam 314 from the laser source 310.

[0043] Photonic chip 320 includes an integrated frequency shifter array operable to generate multiple parallel beams, each having a different frequency from the pump beam 312 and the probe beam 314. Photonic chip 320 may include beam splitters and phase shifter arrays to co-propagate two colors of light onto different layers of photonic chip 320, or to propagate the light in the same direction within the same broadband waveguide. A sawtooth ramp 318 (e.g., about 4 MHz) may be applied to photonic chip 320.

[0044] A cylindrical lens system 324 is configured to receive parallel light beams from a photonic chip 320 and broaden each beam into a corresponding out-of-plane light sheet 326. A vapor chamber 330 is configured to receive the light sheet 326 from the cylindrical lens system 324 and allow the light sheet 326 to pass through it. One or more electric field plates 332 are coupled to the vapor chamber 330 and configured to generate an out-of-plane electric field (DC) gradient. A dichroic filter or coating separates the pump light and the probe light, such that only the probe light from the light sheet 326 is transmitted to the detector array 340. In one embodiment, the dichroic filter or coating may be formed on the light-receiving surface of the detector array 340.

[0045] The detector array 340 includes a two-dimensional array of light sensors 342 configured to map the transmission of light from the vapor chamber 330 along two axes via a light sheet 326. The detector array 340 can be a CCD chip or a custom array of photodiodes with appropriate spacing. The detector array 340 can be implemented with discrete 100MHz steps along one dimension, and along the other dimension, the 100MHz can be broken down into smaller frequency steps. The electrical output signal from the detector array 340 is then sent to a processor for data analysis and display.

[0046] In one example of a sensor array implemented according to this method, the vapor chamber is configured with 200 pump / probe beams resolving different Rydberg states, each pump / probe beam spaced 100 MHz apart. This sensor array can span a 20 GHz spectrum with 100 MHz granularity. The field gradient provides a 100 MHz difference in Stark offset across the dimensions of the sensor array. Using a 200×200 array of optical sensors, each 100 MHz of spectrum is sensed within a 500 kHz frequency band.

[0047] Increased frequency resolution can be achieved by slightly jittering the applied DC electric field to scan a 500kHz span, at the cost of reduced time resolution. For example, a 1kHz jitter can be applied, allowing the device to sense for 1ms every 500Hz at a level of 100μV / cm, thereby obtaining 20GHz bandwidth information at 500Hz resolution within 1 second.

[0048] Rydberg applications using photonic integration

[0049] Photonic integration has been used to miniaturize laser-based sensors such as ring laser gyroscopes, LiDAR (LiDAR) sensors, and cold atom clocks. Enabling technologies such as couplers, gratings, in-layer (vertical) couplers, phased arrays, and phase shifters can be used to generate a large number of parallel Rydberg sensors.

[0050] The basic idea behind massively parallel sensors is to use a vapor chamber through which numerous laser beams (e.g., hundreds of beams) pass, each tuned to a specific Rydberg level in a pump / probe configuration. A two-dimensional array of photodiodes measures the absorbance of each probe (initially low due to EIT). Each of these probes is sensitive to a set of RF frequencies.

[0051] Typically, Rydberg sensors are arranged in a Doppler-free configuration (backpropagation pumping and detection) to achieve higher sensitivity, such as... Figure 3 As in the exemplary implementation. Figure 4 Among the alternative approaches, it has been determined that, for the drawback of only twice the sensitivity, the co-propagation configuration can be used to simplify the sensor, especially to simplify its alignment.

[0052] In one specific implementation, a laser beam array is generated from an input laser using phase shifters in a photonic integrated circuit. Performance modeling of an array of 200 lithium niobate (LiNbO3) phase shifters shows that they can be cascaded to produce a frequency shift of up to approximately 144 MHz in each stage. Therefore, this method can achieve addressable laser wavelengths of up to approximately 28 GHz in a space of approximately 0.5 mm × 0.5 mm on a photonic chip.

[0053] Figure 5 This is a schematic diagram of a small portion of a photonic chip 400 having multiple frequency shifters 410 according to one embodiment. The frequency shifters 410 are arranged in a cascaded manner via multiple integrated waveguides 412 and waveguide couplers 414. The frequency shifters 410 operate by rapidly frequency-modulating the phase of the pump light wavefront 420 from a laser source. This is accomplished by employing an electro-optic effect in one or more low-Q optical resonators. The resonators are used to enhance the phase shift obtained from a given electro-optic coefficient.

[0054] A voltage corresponding to the sawtooth waveform is applied to the constituent waveguides in the photonic chip 400, and the constant-time derivative of the optical phase is equal to the frequency change. Measurements are performed during the phase ramp (at a constant frequency) and paused during the reset time of the sawtooth ramp. For example, using 4MHz, 20V... p-p The ramp-driven phase shifter can achieve a phase ramp of 9e8 radians / second, corresponding to a frequency offset of 144MHz.

[0055] Optical system 424 is configured to receive a parallel beam 426 from photonic chip 400. Optical system 424 includes collimators and beam-shaping optics to broaden or otherwise shape each beam in beam 426. Vapor chamber 430 is configured to receive beam 426 from optical system 424 and allow beam 426 to pass through it, as previously described.

[0056] Figure 6A and Figure 6B These are graphs showing the stability of transmitted power and the linearity of the phase ramp in the model calculations of a single frequency shifter. Figure 6A The transmitted power (au) is shown relative to time (ns), and Figure 6B The output phase (in radians) is shown relative to time (ns). During the first nanosecond of operation ( Figure 6A The instability of transmitted power is a result of the time required for light to travel from the device's input to its output, and this instability does not adversely affect performance. For even larger frequency shifts, a coupled cavity method can be used.

[0057] The “staircase” EIT configuration requires the pump (blue) beam (480 nm, in the case of Rb) to be tuned to the Rydberg level, while the probe beam remains essentially close to resonance with the intermediate state. Therefore, photonic phase shifters operate on the blue light. Since ultra-low loss waveguides are not as advanced in blue light as they are in red light, a relatively high loss factor of 30 dB / m is assumed. Therefore, approximately 60% of the light transmission is predicted through an array of 200 phase shifters. Taking into account the propagation loss of each output, the coupling ratio of the splitters is arranged to make the outputs equal at each frequency.

[0058] For a co-propagating Doppler configuration, a single photonic chip can be used, featuring a photonic integrated phase shifter, beam splitter, and outputs of a pump (e.g., 480 nm or 508 nm) beam and a probe (e.g., 780 nm or 852 nm) beam, with the detector sensor array located on opposite sides of the vapor chamber (see example...). Figure 4 For a backpropagation Doppler-free configuration, a separate chip can be used with a splitter for the D2 probe beam (see, for example...). Figure 3 ), and the pump output chip has a receiver for transmitting the probe beam; or a single chip can be used, which has a hole or other gap in the middle to allow insertion into the vapor chamber.

[0059] Fast spectrum search

[0060] Fast spectrum search is used in electronic warfare to detect narrow-band or frequency-varying signals of unknown origin within a wide bandwidth of the RF spectrum. State-of-the-art techniques in fast spectrum search are exemplified by systems where the RF signal of interest is written onto an optical carrier by an electro-optic modulator and subsequently detected via optical hole burning in atomic-like dopants within a cryogenically cooled crystal. These systems demonstrate the ability to acquire fast (less than 1 ms) snapshots of wide (greater than 10 GHz) stripes of the RF spectrum with a resolution bandwidth of approximately 1 MHz, but are unsuitable for low-size, low-weight, and low-power (SWaP) applications due to cryogenic requirements. Current non-cryo-climate alternatives utilize 10 Gbit analog-to-digital (A / D) converters with massively parallel computing to achieve a 10 GHz spectrum for rapid signal analysis.

[0061] This approach provides competitive-grade RF context awareness in a low size, weight, and power (SWaP) format and utilizes a large number of parallel Rydberg sensors operating simultaneously without cryogenic requirements.

[0062] This sensor system can be used to continuously map an RF spectrum strip of approximately 20 GHz using a Rydberg detector array, with each Rydberg detector tuned to a discrete span (e.g., approximately 100 MHz) along the RF spectrum and continuously tunable within that (100 MHz) span. Each transition can be continuously tuned over 100 MHz with an applied electric field of less than 1 V / cm.

[0063] Ultra-wideband communication

[0064] The characteristics of Rydberg sensors also meet the requirements of ultra-wideband (UWB) communication. In its simplest form, a UWB signal is a "delta function" pulse (typically around 1 μs in implementation), where the pulse's insufficiency causes RF energy to spread across a wide spectrum. Therefore, very little energy exists at any given frequency. Communication can be established by applying an encoding scheme on top of the UWB signal.

[0065] It has been demonstrated that Rydberg atoms arranged to measure a single frequency can be used to detect RF pulses with a duration of 1 μs, where the pulse shape is determined with a resolution of 10 ns. This suggests that even shorter pulses can be detected if needed. The beneficial characteristics of UWB sensors include high sensitivity to low RF power and the ability to sense simultaneously across the entire Fourier bandwidth of short pulses without additional equipment.

[0066] As described in this paper, a highly parallel photonic integrated sensor is well-suited for use as a UWB sensor. The RF carrier and Rydberg stages are chosen such that resonance can be used for the RF carrier and its multiple odd harmonics. The sensor uses a parallel beam to simultaneously probe each of these stages. UWB pulses are sensed simultaneously on all components of the parallel array. Due to the sensitivity of the Rydberg atoms, a smaller signal can be used for the detector array, and the signal-to-noise ratio (S / N) is further enhanced by finding the correlation between the signals of each array output in the array output. For this application, an array with a single dimension can be used.

[0067] Figure 7 It is a graphical representation of the spectrum of a square UWB pulse, in which a set of seven Rydberg sensors (R1 to R7) are designed to sense the UWB pulse. Figure 7 This shows the RF signal strength (ff) detected by the Rydberg sensor relative to the carrier frequency. 载波 ).

[0068] Figure 8 This is a flowchart of a sensing method 500 according to a specific implementation. Initially, method 500 emits at least one light beam from at least one laser source (box 510) and broadens the at least one light beam into at least one optical sheet (box 520). Then, method 500 applies an electric field gradient to the at least one optical sheet (box 530) and detects the frequency range of the at least one optical sheet after applying the electric field gradient (box 540).

[0069] Method 500 can be implemented using the various embodiments described above. For example, a photonic chip can be used to generate multiple substantially parallel beams from the at least one beam, each substantially parallel beam having a different frequency. Furthermore, the at least one light sheet can be guided through a vapor chamber having an electric field gradient.

[0070] Exemplary Implementation

[0071] Example 1 includes a sensor system comprising: a laser source configured to emit a pump beam at a first wavelength and a probe beam at a second wavelength; an optical device configured to receive the pump beam and the probe beam from the laser source, the optical device being operable to generate a plurality of beams, each beam having a different frequency from the pump beam and the probe beam; one or more units configured to receive one or more of the beams from the optical device and allow the one or more beams to pass through therein, the one or more units containing a plurality of base atoms; a dichroic filter configured to receive the one or more beams from the one or more units, the dichroic filter being operable to separate the pump beam light and the probe beam light from the one or more beams; and a detector array configured to receive the probe beam light from the dichroic filter, the detector array comprising a two-dimensional array of optical sensors operable to map the transmission of a corresponding beam corresponding to the probe beam light passing through the one or more units.

[0072] Example 2 includes the sensor system according to Example 1, wherein: the pump beam and the probe beam propagate in the same direction; and a first wavelength of the pump beam generates blue light and a second wavelength of the probe beam generates red light.

[0073] Example 3 includes a sensor system according to any one of Examples 1 to 2, wherein the optical device includes a photonic integrated circuit configured to receive a pump beam and a probe beam, the photonic integrated circuit including a cascaded frequency shifter array operated to generate a plurality of beams, each beam having a different frequency from the pump beam and the probe beam.

[0074] Example 4 includes the sensor system according to Example 3, wherein the frequency shifter is cascaded on a photonic integrated circuit via multiple integrated waveguides and waveguide couplers.

[0075] Example 5 includes the sensor system according to Example 4, wherein the photonic integrated circuit includes a splitter and a phase shifter array configured to propagate pump beams and probe beams in the same direction to different layers of the photonic integrated circuit, or to propagate pump beams and probe beams in the same direction in the same broadband waveguide.

[0076] Example 6 includes a sensor system according to any one of Examples 3 to 5, the sensor system further comprising: an optical device configured to receive a light beam from a photonic integrated circuit, wherein the optical device is configured to deliver a corresponding light beam to the one or more units.

[0077] Example 7 includes the sensor system according to Example 6, wherein the optical device includes a cylindrical lens system configured to broaden a light beam into a corresponding light sheet.

[0078] Example 8 includes a sensor system according to any one of Examples 1 to 2, wherein the optical device includes an optical fiber-based arrangement configured to receive a pump beam and a probe beam, the optical fiber-based arrangement including a cascaded optical fiber array connected to a corresponding optical fiber-coupled phase modulator operable to generate the plurality of beams, each beam having a different frequency than the pump beam and the probe beam.

[0079] Example 9 includes a sensor system according to any one of Examples 1 to 8, wherein the alkali atoms in the one or more units are excited to multiple Rydberg levels by a light beam.

[0080] Example 10 includes a sensor system according to any one of Examples 1 to 9, wherein the one or more units include one or more vapor chambers, and the alkali atom includes rubidium or cesium.

[0081] Example 11 includes a sensor system according to any one of Examples 1 to 10, the sensor system further comprising: one or more electric field plates coupled to the one or more units and configured to generate an electric field gradient.

[0082] Example 12 includes a sensor system according to any one of Examples 1 to 11, the sensor system further comprising: a processor operable to acquire an output signal from a detector array for data analysis and subsequent display.

[0083] Example 13 includes a sensor system according to any one of Examples 1 to 12, wherein the system is implemented as a Rydberg spectrum analyzer including a Rydberg detector array.

[0084] Example 14 includes the sensor system according to Example 13, wherein the system is operable to continuously map a span of approximately 20 GHz of radio frequency (RF) spectrum, wherein each Rydberg detector is tuned to a slightly different RF frequency.

[0085] Example 15 includes the sensor system according to Example 14, wherein each Rydberg detector is operable to span approximately 100 MHz along the RF spectrum and can be further tuned within the 100 MHz span.

[0086] Example 16 includes a sensor system according to any one of Examples 1 to 15, wherein the system is operable for ultra-wideband (UWB) communication or fast spectrum scanning.

[0087] Example 17 includes a sensor system comprising: a first laser device configured to emit a pump beam at a first wavelength; a second laser device configured to emit a backpropagating probe beam at a second wavelength; a first photonic chip configured to receive the pump beam from the first laser device, the first photonic chip including a cascaded frequency shifter array operable to generate a plurality of substantially parallel pump beams, each substantially parallel pump beam having a different frequency from the pump beam; a second photonic chip configured to receive the probe beam from the second laser device, the second photonic chip including a splitter array operable to generate a plurality of substantially parallel probe beams from the probe beam; and a first optical device configured to receive the pump beam from the first photonic chip, wherein the first optical device is configured to direct the pump beam... Each pump beam in the first optical chip is broadened into a corresponding pump sheet; a second optical device configured to receive the probe beam from the second photonic chip, wherein the second optical device is configured to broaden each probe beam in the probe beam into a corresponding probe sheet; a vapor chamber configured to receive the pump sheet from the first optical device and the probe sheet from the second optical device, the vapor chamber containing a plurality of base atoms; one or more electric field plates coupled to the vapor chamber and configured to generate an electric field gradient; a dichroic mirror array configured to reflect the probe sheet through the vapor chamber; and a detector array configured to receive the probe sheet from the dichroic mirror array, the detector array including a two-dimensional array of optical sensors operable to map the transmission of the probe sheet from the vapor chamber along two axes.

[0088] Example 18 includes the sensor system according to Example 17, wherein: a sawtooth ramp is applied to a first photonic chip; and a detector array is configured to provide Stark tuning along one dimension and optical tuning along another dimension.

[0089] Example 19 includes a method comprising: emitting at least one light beam from the at least one laser source; broadening the at least one light beam into at least one optical sheet; applying an electric field gradient to the at least one optical sheet; and detecting the frequency range of the at least one optical sheet after applying the electric field gradient.

[0090] Example 20 includes the method according to Example 19, the method further comprising: generating a plurality of substantially parallel light beams, each substantially parallel light beam having a different frequency from the at least one light beam in the photonic chip; and guiding the at least one light sheet through a vapor chamber having an electric field gradient.

[0091] Based on the foregoing, it should be understood that although specific embodiments have been described herein for illustrative purposes, various modifications may be made without departing from the scope of this disclosure. Therefore, the embodiments described are to be considered in all respects as illustrative rather than restrictive. Furthermore, all variations within the meaning and scope of the equivalence of the claims are to be covered within their scope.

Claims

1. A sensor system, comprising: A laser source configured to emit a pump beam at a first wavelength and a probe beam at a second wavelength; An optical device for receiving the pump beam and the probe beam from the laser source, the optical device being operable to generate multiple beams, each beam having a different frequency from the pump beam and the probe beam, wherein the optical device comprises: At least one photonic integrated circuit configured to receive the pump beam and the probe beam, the at least one photonic integrated circuit including a cascaded frequency shifter array operable to generate beams substantially parallel to the pump beam, each beam having a different frequency, and beams substantially parallel to the probe beam. One or two optical devices configured to receive the substantially parallel light beam from the at least one photonic integrated circuit and configured to broaden the light beam into a corresponding optical sheet; A vapor chamber configured to receive the light sheet from one or both optical devices and configured to allow the light sheet to pass through it, the vapor chamber containing a plurality of base atoms that can be excited to a plurality of Rydberg energy levels by the light beam; One or more electric field plates coupled to the vapor chamber are configured to generate an electric field gradient; A dichroic filter, configured to receive the light from the vapor chamber, operable to separate the pump beam and the probe beam, such that only the probe beam is delivered to the detector array; and The detector array is configured to receive the probe beam light from the dichroic filter, and the detector array includes a two-dimensional array of optical sensors operable to map the transmission of the probe beam from the vapor chamber along two axes.

2. The sensor system according to claim 1, The laser source includes a first laser device configured to emit the pump beam at the first wavelength; A second laser device, configured to emit a backpropagating probe beam at the second wavelength; The optical device includes a first photonic chip configured to receive the pump beam from the first laser device, the first photonic chip including a cascaded frequency shifter array operable to generate a plurality of substantially parallel pump beams, each substantially parallel pump beam having a different frequency from the pump beam; and A second photonic chip, configured to receive the probe beam from the second laser device, includes a splitter array operable to generate the plurality of substantially parallel probe beams from the probe beam.

3. A sensing method, comprising: At least one laser beam is emitted from at least one laser source, the beam being configured to excite base atoms to the Rydberg level; Broaden the at least one light beam into at least one light sheet; An electric field gradient is applied to the at least one optical sheet; as well as At a detector array comprising a two-dimensional array of optical sensors, after the electric field gradient is applied, the frequency range of the at least one optical sheet is detected, the two-dimensional array of optical sensors being operable to map the transmission of the at least one optical sheet along two axes.

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