Microwave imaging system and method based on a rydberg atom array gas cell

Abstract

The embodiment of the application provides a microwave imaging system and method based on a Rydberg atom array gas chamber, and belongs to the technical field of electromagnetic field detection. The system comprises a detection light module, a coupling light module, a detection module and an imaging module. The detection module comprises a Rydberg atom array gas chamber, which is arranged in a space where a microwave signal to be detected exists. The detection light module is used to generate detection light. The coupling light module is used to generate coupling light. The Rydberg atom array gas chamber is used to receive the detection light and the coupling light from different directions to perform Rydberg atom transition. The transmission light with different light intensities is transmitted through a plurality of optical cavity units. The imaging module is used to receive the transmission light with different light intensities to obtain a two-dimensional optical image. The electric field inversion is performed on a plurality of two-dimensional optical images to obtain a two-dimensional electric field distribution corresponding to the microwave signal to be detected. The embodiment of the application can improve the imaging speed.

Description

Technical Field

[0001] This application relates to the field of electromagnetic field detection technology, and in particular to a microwave imaging system and method based on a Rydberg atomic array gas cell. Background Technology

[0002] With the rapid development of terahertz and microwave technologies in wireless communication, precision detection, and systems-on-a-chip, the demand for high-resolution microwave inversion imaging of complex targets and micro / nano-scale devices is becoming increasingly urgent. When processing objects such as high-frequency integrated circuits and antenna arrays, their electromagnetic characteristics often exhibit significant subwavelength structures, making far-field measurements limited by the diffraction limit and unable to provide sufficient spatial spectral information. Therefore, modern microwave imaging technology has shifted its focus to near-field detection and refined inversion: by measuring the electromagnetic distribution within the near-field range with high precision, and using inversion algorithms such as inverse scattering or beamforming, the observed field quantities are mapped back to the dielectric constant, permeability, or geometric morphology of the object under test.

[0003] Currently, commonly used microwave near-field measurement methods in engineering and scientific research mainly include microwave probe scanning, scanning near-field optical microscopy, electro-optic sampling, and antenna-based field strength detection. However, these methods generally face problems such as insufficient detection accuracy, complex system calibration, and poor repeatability in strong electromagnetic environments or complex structures.

[0004] In recent years, electromagnetic field measurement techniques based on Rydberg atoms have gradually emerged. Rydberg atoms possess extremely high principal quantum numbers, and their outer electrons are far from the nucleus, giving them extremely strong polarizability and transition dipole moments in microwave electric fields, thus enabling highly sensitive detection of weak electric fields. Related Rydberg atom measurement methods mostly employ single-point detection or finite-channel scanning imaging, typically relying on mechanical scanning or single-pixel readout, resulting in slow imaging speeds and difficulty meeting the real-time measurement requirements of dynamic field distributions. Furthermore, the large size of traditional gas-cell structures limits spatial resolution.

[0005] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the Invention

[0006] The main objective of this application is to propose a microwave imaging system and method based on a Rydberg atomic array gas cell, which can improve imaging speed.

[0007] To achieve the above objectives, one aspect of this application proposes a microwave imaging system based on a Rydberg atomic array gas cell, characterized in that the system includes a probe optical module, a coupling optical module, a probe module, and an imaging module, wherein the probe module includes a Rydberg atomic array gas cell, and the Rydberg atomic array gas cell is disposed in a space containing the microwave signal to be measured; The detection light module is used to generate detection light; The coupling light module is used to generate coupling light; The Rydberg atom array gas cell is used to receive the probe light and the coupling light from different directions to perform Rydberg atom transitions; transmitted light of different intensity is transmitted through multiple optical cavity units; The imaging module is used to receive transmitted light of different intensities to obtain a two-dimensional optical image; electric field inversion is performed on multiple frames of the two-dimensional optical image to obtain the two-dimensional electric field distribution corresponding to the microwave signal under test. In some embodiments, In some embodiments, the detection optical module includes a first laser, a first λ / 2 waveplate, and a first polarizing beam splitter. The first laser is used to generate a beam of a first wavelength; The first λ / 2 waveplate is used to adjust the polarization state of the first wavelength beam; The first polarizing beam splitter is used to split the first wavelength beam after the polarization state has been adjusted to obtain the probe light and the frequency-stabilized light.

[0008] In some embodiments, the system further includes a saturated absorption frequency stabilization module; The saturated absorption frequency stabilization module is used to pass the frequency-stabilized light generated by the probe light module and the coupling light through the atomic gas cell to obtain a saturated absorption spectrum signal, which is used to stabilize the probe light.

[0009] In some embodiments, the saturated absorption frequency stabilization module includes a reflector, a λ / 4 waveplate, an atomic gas cell, a second polarization beam splitter, and a photodetector; The second polarizing beam splitter is used to refract the frequency-stabilized light and the coupled light, so that the coupled light enters the atomic gas cell and the frequency-stabilized light passes through the λ / 4 waveplate; The reflector is used to reflect the frequency-stabilized light, so that the frequency-stabilized light passes sequentially through the λ / 4 waveplate, the atomic gas cell, the second polarizing beam splitter, and the photodetector; The photodetector is used to receive the frequency-stabilized light passing through the atomic gas cell and generate the saturated absorption spectrum signal.

[0010] In some embodiments, the coupled optical module includes a second laser, a second λ / 2 waveplate, a third polarizing beam splitter, and a beam expander. The second laser is used to generate a beam of a second wavelength; The second λ / 2 waveplate is used to adjust the polarization state of the second wavelength beam; The third polarizing beam splitter is used to split the second wavelength beam after adjusting its polarization state to obtain the coupled light. The beam expander is used to expand and collimate the coupled light before directing it into the detection module.

[0011] In some embodiments, the detection module includes a detection dichroic mirror, a beam splitter, a collimation grating, a Rydberg atomic array cell, and a coupling dichroic mirror, wherein the detection dichroic mirror, the beam splitter, the collimation grating, the Rydberg atomic array cell, and the coupling dichroic mirror are arranged coaxially along the optical path in sequence. The detection dichroic mirror is used to refract the detection light onto the beam splitter; The beam splitter is used to split the probe light into multiple sub-beams; The collimating grating is used to collimate the sub-beam into the Rydberg atom array gas cell; The coupling dichroic mirror is used to refract the probe light into the Rydberg atom array gas cell; The coupled dichroic mirror is also used to direct the transmitted light into the imaging module.

[0012] In some embodiments, the Rydberg atom array gas chamber includes an optical cavity array and a storage cavity, wherein the optical cavity array includes a plurality of optical cavity units, and each optical cavity unit is connected to the storage cavity via a microchannel.

[0013] In some embodiments, the imaging module includes an area scan camera and a host computer; The area array camera is used to receive transmitted light of different intensities to form the two-dimensional optical image; The host computer is used to perform electric field inversion based on the two-dimensional optical image to obtain the two-dimensional electric field distribution corresponding to the microwave signal under test.

[0014] To achieve the above objectives, another aspect of this application proposes a microwave imaging method based on a Rydberg atomic array gas cell, the method comprising: Acquire multiple frames of two-dimensional optical images; Spectral lines are constructed based on the light intensity changes of each pixel in the two-dimensional optical image to obtain a local EIT spectrum or an AT split spectrum. Feature parameters are extracted from the local EIT spectrum or the AT split spectrum to obtain spectral parameters; The spectral line parameters are mapped to the microwave electric field intensity at the corresponding position to obtain a two-dimensional electric field distribution.

[0015] To achieve the above objectives, another aspect of this application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method described above.

[0016] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the methods described above.

[0017] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer program product, including a computer program that, when executed by a processor, implements the aforementioned method.

[0018] The embodiments of this application include at least the following beneficial effects: This application provides a microwave imaging system, method, electronic device, storage medium, and program product based on a Rydberg atomic array gas cell. This solution receives the probe light and the coupling light from different directions through the Rydberg atomic array gas cell. Multiple optical cavity units of the Rydberg atomic array gas cell transmit transmitted light with different illumination intensities. The imaging module receives the transmitted light with different intensities to obtain a two-dimensional optical image. Electric field inversion is performed on multiple frames of the two-dimensional optical image to obtain the two-dimensional electric field distribution corresponding to the microwave signal under test, realizing subwavelength resolution microwave near-field imaging. The design of multiple optical cavity units of the Rydberg atomic array gas cell realizes arrayed spatial sampling, improving spatial resolution, thereby realizing direct two-dimensional acquisition of microwave near-field distribution. Compared with traditional single-point scanning or mechanical scanning methods, it effectively improves imaging speed and measurement efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a microwave imaging system based on a Rydberg atomic array gas cell provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the Rydberg atom array gas cell provided in the embodiments of this application; Figure 3 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application.

[0020] Figure descriptions: 100—Detector optical module, 200—Coupled optical module, 300—Detector module, 400—Imaging module, 500—Saturated absorption frequency stabilization module, 1—First laser, 2—First λ / 2 waveplate, 3—First polarizing beam splitter, 4—Mirror, 5—λ / 4 waveplate, 6—Atomic gas cell, 7—Second polarizing beam splitter, 8—Photodetector, 9—Detector dichroic mirror, 10—Beam splitter grating, 11—Collimating grating, 12—Horn antenna, 13—Rydberg atomic array gas cell, 14—Coupled dichroic mirror, 15—Second laser, 16—Second λ / 2 waveplate, 17—Third polarizing beam splitter, 18—Beam expander, 19—Area array camera, 20—Host computer, 131—Optical cavity array, 132—Storage cavity. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0023] With the rapid development of terahertz and microwave technologies in wireless communication, precision detection, and systems-on-a-chip, the demand for high-resolution microwave inversion imaging of complex targets and micro / nano-scale devices is becoming increasingly urgent. When dealing with objects such as high-frequency integrated circuits and antenna arrays, their electromagnetic characteristics often exhibit significant subwavelength structures, making traditional far-field measurements limited by the diffraction limit and unable to provide sufficient spatial spectral information. Therefore, modern microwave imaging technology has shifted its focus to near-field detection and refined inversion: by measuring the electromagnetic distribution within the near-field range with high precision, and using inversion algorithms such as inverse scattering or beamforming, the observed field quantities are mapped back to the dielectric constant, permeability, or geometric morphology of the object under test. Achieving this subwavelength-resolution inversion from "near-field distribution" to "object morphology" has crucial academic value and engineering significance for microwave device characterization, non-destructive testing, remote sensing, and security inspection.

[0024] Currently, commonly used microwave near-field measurement methods in engineering and scientific research mainly include microwave probe scanning, scanning near-field optical microscopy, electro-optic sampling, and antenna-based field strength detection. While microwave probe scanning offers some spatial resolution, its metal probe can disturb the measured field, and its scanning efficiency is relatively low. Optical microscopy and other techniques perform well in the optical frequency band, but extending them to the microwave band presents challenges such as implementation complexity and limited sensitivity. Electro-optic sampling relies on nonlinear crystals, resulting in complex systems and high environmental stability requirements. Antenna-based measurement methods are limited by probe size, making it difficult to overcome the diffraction limit and achieve true subwavelength resolution. Furthermore, these methods generally face problems such as insufficient detection accuracy, complex system calibration, and poor repeatability in strong electromagnetic environments or complex structures.

[0025] In recent years, electromagnetic field measurement techniques based on Rydberg atoms have gradually emerged. Rydberg atoms possess extremely high principal quantum numbers, and their outer electrons are far from the nucleus, giving them extremely strong polarizability and transition dipole moments in response to microwave electric fields, thus enabling highly sensitive detection of weak electric fields. Combining electromagnetically induced transparency (EIT) and the Autler-Townes (AT) splitting effect, microwave electric field intensity can be mapped to optical signals, achieving self-calibrated, broadband electric field measurements. However, existing Rydberg atom measurement methods mostly employ single-point detection or limited-channel scanning imaging, typically relying on mechanical scanning or single-pixel readout, resulting in slow imaging speeds that are difficult to meet the real-time measurement requirements of dynamic field distributions. Furthermore, the large size of traditional gas cell structures limits further improvements in spatial resolution and hinders the realization of arraying and integration.

[0026] In view of this, this application provides a microwave imaging system and method based on a Rydberg atomic array gas cell. The Rydberg atomic array gas cell is designed with multiple optical cavity units to achieve arrayed spatial sampling, thereby realizing direct two-dimensional acquisition of microwave near-field distribution and effectively improving imaging speed and measurement efficiency.

[0027] The microwave imaging method based on a Rydberg atomic array gas cell provided in this application relates to the field of electromagnetic field detection technology. This microwave imaging method based on a Rydberg atomic array gas cell can be applied to a terminal, a server, or software running on a terminal or server. In some embodiments, the terminal can be a smartphone, tablet, laptop, desktop computer, smart speaker, smartwatch, or vehicle terminal, but is not limited thereto; the server can be configured as an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network; the software can be an application implementing the microwave imaging method based on a Rydberg atomic array gas cell, but is not limited to the above forms.

[0028] Figure 1 This is an optional structural schematic diagram of a microwave imaging system based on a Rydberg atomic array gas cell provided in an embodiment of this application. The system includes a probe optical module 100, a coupling optical module 200, a probe module 300, and an imaging module 400. The probe module 300 includes a Rydberg atomic array gas cell, which is disposed in the space where the microwave signal to be measured exists. The detection light module 100 is used to generate detection light; The coupling light module 200 is used to generate coupling light; The Rydberg atom array gas cell is used to receive probe light and coupling light from different directions to perform Rydberg atom transitions; transmitted light of different intensity is transmitted through multiple optical cavity units; The imaging module 400 is used to receive transmitted light of different intensities to obtain two-dimensional optical images; electric field inversion is performed on multiple frames of two-dimensional optical images to obtain the two-dimensional electric field distribution corresponding to the microwave signal under test.

[0029] Specifically, the probe light and coupling light correspond to two laser beams representing the transitions of alkali metal atoms from the ground state to the excited state (probe light) and from the excited state to the Rydberg state (coupling light), respectively. The probe light and coupling light spatially overlap within the Rydberg atom array gas chamber 13, providing parallel illumination to each optical cavity unit within the chamber to construct the basis for two-dimensional imaging detection. At the Rydberg atom array gas chamber 13, the horn antenna 12 radiates the microwave signal to be measured into space. The microwave electric field couples the transitions between Rydberg states, causing AT splitting. Since the Rydberg atom array gas chamber 13 is composed of multiple microscale optical cavity units, each optical cavity unit corresponds to a local microwave electric field at a different spatial location, thus achieving spatial sampling. The transmitted light from the atom array region is mapped onto the imaging module 400. Each pixel corresponds to an independent optical cavity unit within the Rydberg atom array gas chamber 13. The imaging module 400 acquires spectral information of the two-dimensional light intensity distribution through multi-frame acquisition, realizing the reading of the electric field intensity of the entire measurement area. Multiple optical cavity units are designed to achieve arrayed spatial sampling, thereby enabling direct two-dimensional acquisition of microwave near-field distribution, effectively improving imaging speed and measurement efficiency.

[0030] In some embodiments, the detection optical module 100 includes a first laser, a first λ / 2 waveplate, and a first polarizing beam splitter. The first laser is used to generate a beam of the first wavelength. The first λ / 2 waveplate is used to adjust the polarization state of the first wavelength beam; The first polarizing beam splitter is used to split the first wavelength beam after the polarization state has been adjusted, so as to obtain the probe light and the frequency-stabilized light.

[0031] Specifically, please refer to Figure 1 The first laser 1 is an 852nm laser, and the wavelength of the first wavelength beam is 852nm. After the polarization state of the first wavelength beam is adjusted by the first λ / 2 waveplate 2, it enters the first polarization beam splitter prism 3, which splits the probe beam and the frequency stabilized beam, forming a beam splitting structure of the frequency stabilized optical path and the measurement optical path. The probe beam enters the probe module 300, and the frequency stabilized beam enters the saturated absorption frequency stabilized module 500.

[0032] In some embodiments, the system further includes a saturated absorption frequency stabilization module; The saturated absorption frequency stabilization module is used to pass the frequency-stabilized light and coupling light generated by the probe light module 100 through the atomic gas cell to obtain the saturated absorption spectrum signal, which is used to stabilize the probe light.

[0033] Specifically, by allowing the frequency-stabilized light and the coupling light to propagate in opposite collinear directions in atomic gas cell 6, a saturated absorption spectrum signal is generated. This signal contains a precise frequency reference for atomic transitions, enabling real-time locking and correction of the laser frequency.

[0034] In some embodiments, the saturated absorption frequency stabilization module includes a reflector, a λ / 4 waveplate, an atomic gas cell, a second polarization beam splitter, and a photodetector; The second polarizing beam splitter is used to refract the frequency-stabilized light and the coupling light, allowing the coupling light to enter the atomic gas cell and the frequency-stabilized light to pass through the λ / 4 waveplate. The mirror is used to reflect the frequency-stabilized light, which then passes sequentially through the λ / 4 waveplate, the atomic gas cell, the second polarizing beam splitter, and the photodetector. Photodetectors are used to receive frequency-stabilized light passing through an atomic gas cell and generate a saturated absorption spectrum signal.

[0035] Specifically, please refer to Figure 1 The atomic gas chamber 6 is a cesium atomic gas chamber. The second polarizing beam splitter 7 receives the frequency-stabilized light and the coupling light. The coupling light is reflected into the atomic gas chamber 6. With the cooperation of the λ / 4 waveplate 5 and the reflector 4, the probe light propagates in the opposite direction through the gas chamber. The probe light and the coupling light propagate in opposite directions collinearly inside the atomic gas chamber 6. The photodetector receives the probe light transmitted through the atomic gas chamber 6 and generates a saturated absorption spectrum signal. After processing, the saturated absorption spectrum generates a frequency-discriminating signal that acts on the first laser 1, thereby achieving frequency stabilization of the probe light.

[0036] In some embodiments, the beam polarization state can be optimized by adjusting the combination of the first λ / 2 waveplate 2 and the λ / 4 waveplate 5, thereby improving the contrast of the saturated absorption spectrum. At the same time, the power broadening effect can be reduced by controlling the incident light intensity, thereby improving the frequency calibration accuracy.

[0037] In some embodiments, the coupling optical module 200 includes a second laser, a second λ / 2 waveplate, a third polarizing beam splitter, and a beam expander. The second laser is used to generate a beam of the second wavelength. The second λ / 2 waveplate is used to adjust the polarization state of the second wavelength beam; The third polarizing beam splitter is used to split the second wavelength beam after the polarization state has been adjusted to obtain coupled light; The beam expander is used to expand and collimate the coupled light before directing it into the detector module 300.

[0038] Specifically, please refer to Figure 1The second laser 15 is a 510nm laser, and the wavelength of the second wavelength beam is 510nm. After the polarization state of the second wavelength beam is adjusted by the first λ / 2 waveplate 16, it enters the first polarization beam splitter 17 to obtain coupled light. The beam expander 18 expands and collimates the 510nm coupled light, so that the coupled light has good spatial uniformity in the Rydberg atom array gas cell 13 region, so that each atomic unit in the array is uniformly illuminated and excited, reducing the pixel response difference caused by uneven light intensity distribution. The coupled light after beam expansion and collimation can spatially coincide with the split 852nm probe light in the Rydberg atom array gas cell region, thereby constructing the EIT three-level structure in parallel in each unit of the array, providing a basis for subsequent microwave electric field measurement.

[0039] In some embodiments, the detection module 300 includes a detection dichroic mirror, a beam splitter grating, a collimating grating, a Rydberg atomic array cell, and a coupling dichroic mirror, which are arranged coaxially along the optical path in sequence. A detector dichroic mirror is used to refract the detector light onto a beam splitter grating; A beam splitter is used to split the probe light into multiple beams; Collimation gratings are used to collimate subbeams into the gas cells of the Rydberg atomic array; A coupling dichroic mirror is used to refract the probe light into the Rydberg atom array cell; The coupled dichroic mirror is also used to direct transmitted light into the imaging module 400.

[0040] Specifically, a probe dichroic mirror 9 refracts an 852nm probe light, causing it to coincide with the subsequent 510nm coupling light in the Rydberg atom array gas cell 13 region, thus constructing an EIT three-level system. A beam splitter grating 10 splits the incident 852nm probe light into multiple sub-beams, which are then directed into each optical cavity unit within the Rydberg atom array gas cell 13, achieving parallel illumination within the array. A collimating grating 11 collimates the split sub-beams, ensuring each sub-beam is perpendicularly incident on its corresponding gas cell unit in a parallel beam, improving the uniformity of the optical field. A horn antenna 12 radiates the microwave signal to be measured and loads it into the Rydberg atom array gas cell 13 region, coupling with the Rydberg states to generate the EIT / AT effect. The Rydberg atom array gas cell 13 contains cesium (or rubidium) atomic vapor. Each optical cavity unit independently responds to the local microwave electric field, achieving subwavelength spatially resolved electric field detection. The coupling dichroic mirror 14 is located after the Rydberg atomic array gas cell 13. It refracts 510nm coupled light into the Rydberg atomic array gas cell 13 and is also used to separate the transmitted light and guide it to the imaging module 400 for two-dimensional imaging detection.

[0041] In some embodiments, the Rydberg atomic array gas chamber includes an optical cavity array and a storage cavity. The optical cavity array includes multiple optical cavity units, each of which is connected to the storage cavity via a microchannel.

[0042] Specifically, please refer to Figure 2 The Rydberg atomic array gas chamber 13 employs a glass-silicon-glass sandwich structure, comprising a central storage cavity 132 and an optical cavity array 131. The optical cavity array 131 includes multiple optical cavity units, each connected to the storage cavity 132. The microchannels between each optical cavity and the storage cavity 132 utilize a symmetrical, equal-diameter design, ensuring diffusion balance and concentration consistency of atomic vapor within each array unit, thereby reducing imaging artifacts caused by uneven response of the sensing units. The structure is fabricated on a silicon wafer using MEMS micromachining technology and then bonded and encapsulated to obtain a sealed atomic gas chamber.

[0043] The Rydberg atomic array gas cell 13 uses a double-sided polished silicon wafer as the substrate. First, a photolithographic mask layer (Al) is deposited on the surface of the silicon wafer to define the central storage cavity and the radially distributed optical cavity array pattern through photolithography. Subsequently, anisotropic etching is performed on the silicon wafer using ICP plasma etching: a larger volume storage cavity is etched in the central region to store alkali metal release agents (such as cesium or rubidium); multiple optical cavity units of uniform size are etched in the periphery to realize electric field measurement; the storage cavity and each optical cavity are connected by microchannels to ensure uniform distribution of atomic vapor in the array.

[0044] After the silicon-based structure is microfabricated, it is integrated and packaged with two glass substrates. Specifically, an anodic bonding process is used at 300-400℃ and 1000V to achieve a high-strength, hermetic connection between the silicon and the glass substrates, ensuring excellent vacuum retention and long-term stability of the atomic vapor chamber. Before bonding and packaging, an alkali metal release agent is placed in the central storage cavity. After packaging, a high-power infrared laser is used to activate the release agent in situ, causing the generated atomic vapor to diffuse from the storage cavity through microchannels to each optical cavity array unit. In this integrated structure, the storage cavity provides a stable atomic source and buffers vapor pressure changes caused by temperature fluctuations, while the arrayed optical cavities serve as the actual light-atom interaction sensitive areas. Their miniaturized size and high-density arrangement determine the subwavelength spatial resolution of the system in microwave near-field detection.

[0045] The fabricated Rydberg atom array gas cell 13 serves as the core sensing unit, integrated with an external optical system. The probe light and coupling light are expanded to uniformly illuminate the entire array region. A microwave field is applied to the array region, coupling with the Rydberg states. The transmitted light signals corresponding to each optical cavity unit are projected onto a CCD camera through an imaging lens, achieving two-dimensional parallel readout. Since the array unit size is much smaller than the microwave wavelength, and each unit independently responds to a local electric field, subwavelength-resolution imaging of the microwave near-field is achieved, which can be used for device electromagnetic characteristic analysis, fault diagnosis, or field distribution optimization.

[0046] The alkali metal atom can be cesium, rubidium, or potassium, preferably cesium or rubidium. Optical transitions preferentially select the two-photon excitation path corresponding to the D1 or D2 line. The principal quantum number of the Rydberg state is selected according to the measurement sensitivity and frequency range to match the target microwave frequency band.

[0047] In some embodiments, the imaging module 400 includes an area array camera and a host computer; Area array cameras are used to receive transmitted light of different intensities to form two-dimensional optical images; The host computer is used to perform electric field inversion based on the two-dimensional optical image to obtain the two-dimensional electric field distribution corresponding to the microwave signal under test.

[0048] Specifically, please refer to Figure 1 The area array camera 19 acquires two-dimensional light intensity distribution data. Each CCD (area array camera) pixel corresponds one-to-one with an optical cavity unit in the Rydberg atomic array gas cell 13, enabling parallel reading of the microwave near-field distribution. The two-dimensional optical image acquired by the area array camera 19 is transmitted to the host computer 20 in real time. The host computer 20 processes the light intensity changes of each pixel, performs electric field inversion through multi-frame acquisition, obtains the two-dimensional electric field distribution, and completes the imaging.

[0049] In some embodiments, the following measures may be adopted to improve system stability and imaging accuracy: Real-time locking and correction of laser frequency is achieved using a frequency-stabilized optical path; The uniformity of the coupled light in the array region is improved by using beam expander 18; A temperature-controlled structure was used to stabilize the atomic density in cell 13 of the Rydberg atomic array. Background subtraction and multi-frame averaging are performed on images acquired by CCD to suppress noise; Optimize the polarization matching of the probe light and the coupling light to improve the contrast of the EIT signal.

[0050] In some embodiments, optical power and polarization optimization includes: adjusting the optical power of the probe light and the coupling light (in combination with the beam expander 18 and optical path attenuation control) to make the atoms work in the linear response range, reducing the EIT spectral distortion caused by power broadening and optical saturation effects; and optimizing the polarization matching relationship of the two beams using the first λ / 2 waveplate 2, the second λ / 2 waveplate 16, the first polarization beam splitter 3, and the third polarization beam splitter 17 to improve the contrast of the EIT signal and the stability of spectral line fitting, thereby improving the accuracy of electric field inversion.

[0051] Array uniformity and imaging consistency optimization includes: optimizing the beam expander 18 and beam shaping system to ensure good spatial uniformity of the coupled light in the Rydberg atom array gas cell 13 region; controlling the quality of the probe light spot to reduce pixel response differences caused by uneven light intensity; and improving two-dimensional imaging consistency and spatial resolution accuracy by combining pixel response correction and flat field calibration of the area array camera 19.

[0052] Noise reduction and signal enhancement include: background subtraction, dark field correction and multi-frame averaging processing of images acquired by the array camera 19 to effectively suppress ambient light interference and detection noise; at the same time, time modulation and phase-locked loop processing methods can be combined to improve the detection sensitivity to weak EIT or AT signal changes and enhance the stability of the system under low signal-to-noise ratio conditions.

[0053] Synchronous acquisition and frequency correction include: the host computer 20 synchronously controls the reference optical path and the imaging optical path, realizes real-time correction of the laser frequency axis through the reference spectrum, and reduces the impact of scanning nonlinearity and frequency drift on the measurement results; and maintains time synchronization during multi-frame acquisition to improve the consistency of spectral data of each pixel.

[0054] The optimization of array structure and spatial resolution includes: designing a high-density Rydberg atom array gas cell 13 using MEMS technology to reduce the size and spacing of array units, making them much smaller than microwave wavelengths, thereby achieving subwavelength spatial sampling; at the same time, by optimizing the array layout and channel structure, crosstalk between units is reduced, and the independence and accuracy of local electric field measurements are improved.

[0055] Microwave loading and system setup include: loading the field to be measured through a horn antenna 12 or other microwave radiation structure, and rationally designing its relative position and distance from the Rydberg atom array gas cell 13 to reduce the influence of reflection and standing wave effects on the measurement results; the system as a whole adopts a separate layout of optical and electronic modules to improve the flexibility and anti-interference capability in experimental and engineering applications.

[0056] Electric field inversion and algorithm optimization include: using spectral line fitting and parameter extraction algorithms (such as multi-peak fitting or split spacing extraction) in the host computer, and combining them with calibration curves to realize electric field intensity inversion; for complex field distributions, interpolation reconstruction or regularization algorithms can be used to improve imaging accuracy, and multi-pixel statistical fusion can be used to enhance the robustness and repeatability of the results.

[0057] Temperature control and long-term stability assurance: By implementing constant temperature control on the Rydberg atomic array gas chamber 13, the atomic vapor density is stabilized, reducing the impact of temperature drift on the EIT spectral lines; at the same time, frequency locking or stabilization control is performed on the first laser 1 and the second laser 15 to improve the reliability and measurement consistency of the system in long-term operation.

[0058] This application also proposes a microwave imaging method based on a Rydberg atomic array gas cell, which includes, but is not limited to, steps S101 to S104: Step S101: Acquire multiple frames of two-dimensional optical images; Step S102: Construct spectral lines based on the illumination intensity changes of each pixel in the two-dimensional optical image to obtain a local EIT spectrum or an AT split spectrum. Step S103: Extract feature parameters from the local EIT spectrum or AT split spectrum to obtain spectral parameters; Step S104: Map the spectral line parameters to the microwave electric field intensity at the corresponding position to obtain the two-dimensional electric field distribution.

[0059] In steps S101 to S104 of some embodiments, the host computer 20 receives multiple frames of two-dimensional optical images, processes the light intensity changes of each pixel, constructs a local EIT spectrum or AT split spectrum through multi-frame acquisition, and extracts key parameters (such as transmission peak positions or splitting intervals). Based on the Rydberg atomic level structure and transition dipole moment model, the host computer 20 maps the extracted spectral line parameters to the microwave electric field intensity at the corresponding position, realizing the inversion of the two-dimensional electric field distribution E(x,y). In some embodiments, when obvious AT splitting is observed, the splitting interval Δf can be used to... AT The relationship between the electric field amplitude and the electromagnetic field intensity can be quantitatively calculated. For EIT transmission variations under weak field conditions, the inversion can also be performed through the calibration relationship between light intensity variation and electric field intensity. By interpolating, filtering, and reconstructing the two-dimensional electric field distribution data, a subwavelength-resolution image of the microwave near field can be obtained to characterize the electromagnetic field distribution characteristics.

[0060] In some embodiments, the measurement method of a microwave imaging system based on a Rydberg atomic array gas cell includes: Laser generation and array illumination: A narrow linewidth laser source is provided, outputting two laser beams corresponding to the ground state → excited state transition of alkali metal atoms (probe light) and the excited state → Rydberg state transition (coupled light), respectively. Through the beam splitting module of the probe light and the beam expanding module of the coupled light, the probe light and the coupled light are made to coincide in space in the Rydberg atom array gas cell, so as to illuminate each atomic unit in the array in parallel, thereby constructing the basis for two-dimensional imaging detection.

[0061] EIT establishment and microwave coupling: Adjusting the frequency and polarization of the probe light and the coupling light to form an EIT three-level structure in the atomic system; applying a microwave electric field to the region to be measured to cause transitions between coupled Rydberg states, resulting in AT splitting or changes in the EIT transmission spectrum; the local intensity of the microwave electric field is mapped one-to-one with the optical response of the corresponding array unit.

[0062] Parallel optical readout of the array: The transmitted light field of the atomic array region is mapped to the area array camera using an imaging lens group, with each pixel corresponding to an independent spatial unit in the array; the spectral information of the two-dimensional light intensity distribution is obtained through multi-frame acquisition, so as to realize the reading of the electric field intensity of the entire measurement area.

[0063] Frequency scanning and multi-frame acquisition: Control the probe light or coupling light to perform frequency scanning, or modulate the frequency / amplitude of the microwave field to obtain a multi-frame transmission image sequence under different frequency conditions; thereby construct the local EIT spectrum or AT split spectrum corresponding to each pixel point for subsequent parameter extraction and inversion calculation.

[0064] Spectral line parameter extraction: The transmission spectrum of each array unit is fitted to extract the EIT resonance peak position, transmission peak depth, and AT splitting distance Δf. AT Key parameters include: the splitting quantity Δf. AT The amplitude of the local microwave electric field satisfies the relationship Δf AT ∝E, through the precise extraction of spectral line characteristic parameters, enables quantitative characterization of microwave electric field information.

[0065] Electric field distribution inversion: Based on the known transition dipole moments and energy level structure model of Rydberg atoms, the extracted spectral line parameters are mapped to the microwave electric field intensity at the corresponding positions to obtain the two-dimensional electric field amplitude distribution E(x,y); for complex field distributions, the system calibration parameters and numerical model can be combined for correction to improve the inversion accuracy and consistency.

[0066] Subwavelength imaging reconstruction and output: Utilizing the spatial sampling capability of a high-density atomic array, the acquired two-dimensional electric field data is interpolated, filtered, or reconstructed to achieve subwavelength-resolution imaging of the microwave near field; the final output is a spatial distribution map of the microwave electric field and related characteristic parameters, which can be used for device electromagnetic characteristic analysis, fault diagnosis, or field distribution optimization.

[0067] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method. This electronic device can be any smart terminal, including tablet computers, in-vehicle computers, etc.

[0068] It is understood that the content of the above method embodiments is applicable to this device embodiment. The specific functions implemented by this device embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0069] Please see Figure 3 , Figure 3 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes: The processor 901 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application. The memory 902 can be implemented as a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 902 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 902 and is called and executed by the processor 901 using the methods described in the embodiments of this application. The 903 input / output interface is used to implement information input and output. The communication interface 904 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.). Bus 905 transmits information between various components of the device (e.g., processor 901, memory 902, input / output interface 903, and communication interface 904); The processor 901, memory 902, input / output interface 903, and communication interface 904 are connected to each other within the device via bus 905.

[0070] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0071] It is understood that the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0072] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0073] It is understood that the content of the above method embodiments is applicable to the embodiments of this program product. The specific functions implemented by the embodiments of this program product are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0074] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0075] The microwave imaging system, method, apparatus, electronic device, storage medium, and program product based on a Rydberg atomic array gas cell provided in this application construct an electromagnetically induced transparent (EIT) structure within the Rydberg atomic array gas cell by beam splitting of the probe light and beam expansion of the coupling light. The microwave electric field to be measured couples to Rydberg state transitions, causing Autler–Townes (AT) splitting and resulting in changes in transmission spectral lines. Two-dimensional synchronous optical readout of the array units is performed using a planar array camera to obtain spectral line information corresponding to the spatial distribution of the microwave electric field. Local spectral characteristic parameters of each array unit are extracted through frequency scanning and spectral line fitting, and quantitative inversion of the microwave electric field amplitude is achieved by combining an atomic energy level model, ultimately realizing subwavelength-resolution microwave near-field imaging.

[0076] This application eliminates the need for metal probes to contact the measured field, reducing disturbance to the existing electromagnetic distribution. It features non-invasive measurement, strong self-calibration capabilities, and high traceability. Furthermore, the use of parallel atomic array detection and optical imaging readout significantly improves imaging speed and spatial resolution. The system structure is relatively simple, making it easy to integrate and miniaturize.

[0077] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0078] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0079] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0080] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0081] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0082] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0083] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0084] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0085] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0086] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0087] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A microwave imaging system based on a Rydberg atomic array gas cell, characterized in that, The system includes a detection optical module, a coupling optical module, a detection module, and an imaging module. The detection module includes a Rydberg atomic array gas cell, which is disposed in the space where the microwave signal to be measured exists. The detection light module is used to generate detection light; The coupling light module is used to generate coupling light; The Rydberg atom array gas cell is used to receive the probe light and the coupling light from different directions to perform Rydberg atom transitions; transmitted light of different intensity is transmitted through multiple optical cavity units; The imaging module is used to receive transmitted light of different intensities to obtain a two-dimensional optical image; electric field inversion is performed on multiple frames of the two-dimensional optical image to obtain the two-dimensional electric field distribution corresponding to the microwave signal under test.

2. The system according to claim 1, characterized in that, The detection optical module includes a first laser, a first λ / 2 waveplate, and a first polarizing beam splitter. The first laser is used to generate a beam of a first wavelength; The first λ / 2 waveplate is used to adjust the polarization state of the first wavelength beam; The first polarizing beam splitter is used to split the first wavelength beam after the polarization state has been adjusted to obtain the probe light and the frequency-stabilized light.

3. The system according to claim 1, characterized in that, The system also includes a saturated absorption frequency stabilization module; The saturated absorption frequency stabilization module is used to pass the frequency-stabilized light generated by the probe light module and the coupling light through the atomic gas cell to obtain a saturated absorption spectrum signal, which is used to stabilize the probe light.

4. The system according to claim 3, characterized in that, The saturated absorption frequency stabilization module includes a reflector, a λ / 4 waveplate, an atomic gas cell, a second polarization beam splitter, and a photodetector. The second polarizing beam splitter is used to refract the frequency-stabilized light and the coupled light, so that the coupled light enters the atomic gas cell and the frequency-stabilized light passes through the λ / 4 waveplate; The reflector is used to reflect the frequency-stabilized light, so that the frequency-stabilized light passes sequentially through the λ / 4 waveplate, the atomic gas cell, the second polarizing beam splitter, and the photodetector; The photodetector is used to receive the frequency-stabilized light passing through the atomic gas cell and generate the saturated absorption spectrum signal.

5. The system according to claim 1, characterized in that, The coupled optical module includes a second laser, a second λ / 2 waveplate, a third polarizing beam splitter, and a beam expander. The second laser is used to generate a beam of a second wavelength; The second λ / 2 waveplate is used to adjust the polarization state of the second wavelength beam; The third polarizing beam splitter is used to split the second wavelength beam after adjusting its polarization state to obtain the coupled light. The beam expander is used to expand and collimate the coupled light before directing it into the detection module.

6. The system according to claim 1, characterized in that, The detection module includes a detection dichroic mirror, a beam splitter, a collimation grating, a Rydberg atomic array cell, and a coupling dichroic mirror. The detection dichroic mirror, the beam splitter, the collimation grating, the Rydberg atomic array cell, and the coupling dichroic mirror are arranged coaxially along the optical path in sequence. The detection dichroic mirror is used to refract the detection light onto the beam splitter; The beam splitter is used to split the probe light into multiple sub-beams; The collimating grating is used to collimate the sub-beam into the Rydberg atom array gas cell; The coupling dichroic mirror is used to refract the probe light into the Rydberg atom array gas cell; The coupled dichroic mirror is also used to direct the transmitted light into the imaging module.

7. The system according to claim 1, characterized in that, The Rydberg atomic array gas chamber includes an optical cavity array and a storage cavity. The optical cavity array includes multiple optical cavity units, and each optical cavity unit is connected to the storage cavity through a microchannel.

8. The system according to claim 1, characterized in that, The imaging module includes an area array camera and a host computer; The area array camera is used to receive transmitted light of different intensities to form the two-dimensional optical image; The host computer is used to perform electric field inversion based on the two-dimensional optical image to obtain the two-dimensional electric field distribution corresponding to the microwave signal under test.

9. A microwave imaging method based on a Rydberg atomic array gas cell, characterized in that, The method is applied to the microwave imaging system based on a Rydberg atomic array gas cell as described in any one of claims 1 to 8, and the method includes: Acquire multiple frames of two-dimensional optical images; Spectral lines are constructed based on the light intensity changes of each pixel in the two-dimensional optical image to obtain a local EIT spectrum or an AT split spectrum. Feature parameters are extracted from the local EIT spectrum or the AT split spectrum to obtain spectral parameters; The spectral line parameters are mapped to the microwave electric field intensity at the corresponding position to obtain a two-dimensional electric field distribution.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in claim 9.

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