A speed measuring device based on transient electromagnetic induction transparency effect

Abstract

This invention relates to a velocity measurement device based on the transient electromagnetic induction transparency effect. It utilizes two probe beams and two coupling beams to excite atoms in an atomic antenna to the Rydberg state. The probe beams are modulated into pulsed lasers to obtain the transient electromagnetic induction transparency signal of the Rydberg atoms. A first radio frequency signal source radiates electromagnetic waves to illuminate the target object; the reflected electromagnetic waves and the local oscillator electromagnetic waves radiated by a second radio frequency signal source simultaneously act on the Rydberg atoms at near-resonance. The velocity of the target object is measured by quantum precision measurement of the difference frequency signal generated by the interference of the two electromagnetic waves. Compared to traditional Rydberg atomic antennas, this invention's velocity measurement device based on the transient electromagnetic induction transparency effect can achieve velocity measurement of moving targets based on ultra-wideband, miniaturized quantum detection, thus expanding the functionality of Rydberg atomic antennas.

Description

Technical Field

[0001] This invention relates to the fields of velocity measurement technology and quantum detection, and in particular to a velocity measurement device based on the transient electromagnetic induction transparency effect. Background Technology

[0002] Quantum detection technology based on Rydberg atoms is a cutting-edge field that has attracted much attention in recent years. Its core lies in utilizing the extremely high sensitivity of Rydberg atoms to electromagnetic fields to transform the measurement of radio frequency or microwave signals into the detection of optical signals. This enables ultra-wideband, highly sensitive, and miniaturized quantum measurement of electromagnetic signals, showing great potential in electromagnetic environment monitoring and target detection and identification. Classical Rydberg atom antennas typically use continuous lasers to excite atoms to the Rydberg state, and detection is achieved by monitoring changes in the steady-state electromagnetic induction transparency (EIT) signal generated after the interaction between the atom and the electromagnetic field to be measured.

[0003] However, the classic Rydberg atomic antenna scheme has significant limitations. First, its main function is focused on detecting the presence, intensity, or frequency of signals, lacking the ability to directly measure the velocity of moving targets. This greatly limits its application in radar, navigation, motion analysis, and other fields requiring velocity measurement capabilities. Second, the establishment of a steady-state EIT signal involves the relaxation process of the atomic population, which has a relatively long response time (typically on the order of microseconds or slower). This results in a slow response to rapidly changing electromagnetic signals, making it difficult to meet the requirements for real-time, rapid velocity measurement of high-speed moving targets.

[0004] While existing technologies have attempted to utilize Rydberg atoms for velocity measurement, the fundamental problems mentioned above remain unresolved. For example, patent document CN110488265A discloses a radar velocity measurement system based on the electromagnetically induced transparency effect of Rydberg atoms, which utilizes the EIT-AT splitting effect of atomic energy levels under microwave fields to invert target velocity. However, this scheme essentially still relies on the steady-state EIT process excited by continuous lasers, and its slow response rate limits the dynamic performance and accuracy of the velocity measurement system, making it particularly unsuitable for capturing the instantaneous velocity of high-speed targets. On the other hand, some traditional velocity measurement devices, such as the laser plasma-generated target velocity measurement device disclosed in patent document CN105259361A, although achieving velocity measurement through methods such as spectral splitting and timing, are based on classical optical interference and photoelectric conversion principles, limiting their measurement range and accuracy. Furthermore, the systems are complex and lack the inherent quantum technology advantages of Rydberg atom antennas, such as ultra-wideband, high sensitivity, and resistance to electromagnetic interference.

[0005] Therefore, there is an urgent need in the existing technology for an innovative technical solution that can solve the problem of slow steady-state EIT response while retaining the advantages of Rydberg atomic antennas such as ultra-wideband, high sensitivity, and miniaturization, and endow them with the ability to quickly and accurately measure the velocity of moving targets. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the present invention aims to provide a velocity measurement device based on the transient electromagnetic induction transparency effect, which expands the velocity measurement function of moving targets on the basis of the ultra-wideband and miniaturized quantum detection capability of the classical Rydberg atomic antenna.

[0007] To achieve the above-mentioned objectives, the present invention provides a velocity measuring device based on transient electromagnetic induction transparency effect, comprising: a probe laser, a first beam splitter, a photodetector, a computer, a coupling laser, a third beam splitter, a first radio frequency signal source for radiating electromagnetic waves to irradiate a target object, and a second radio frequency signal source for radiating local oscillator electromagnetic waves.

[0008] The probe laser emits probe light, and the first beam splitter splits the probe light into a first probe light and a second probe light.

[0009] Along the optical path of the first detection light, a first reflecting mirror, a first dichroic mirror, an atomic gas cell, a second dichroic mirror, a second reflecting mirror, a second beam splitter, and a photodetector are arranged sequentially.

[0010] A third dichroic mirror, an atomic gas cell, a fourth dichroic mirror, a second beam splitter, and a photodetector are sequentially arranged along the optical path of the second probe beam.

[0011] The coupled laser emits coupled light, and the third beam splitter splits the coupled light into a first coupled light and a second coupled light.

[0012] A first dichroic mirror, an atomic gas cell, and a second dichroic mirror are sequentially arranged along the optical path of the first coupled light.

[0013] A third reflecting mirror, a fourth dichroic mirror, an atomic gas cell, and a third dichroic mirror are sequentially arranged along the optical path of the second coupled light.

[0014] The photodetector is connected to the computer;

[0015] The atomic gas chamber is encapsulated with alkali metal atomic vapor;

[0016] The probe light emitted by the probe laser is pulsed light, and the coupling light emitted by the coupling laser is continuous light.

[0017] According to one technical solution of the present invention, the first dichroic mirror, the second dichroic mirror, the third dichroic mirror, and the fourth dichroic mirror are used to reflect the probe light and transmit the coupling light, so that the first probe light and the first coupling light coincide in the atomic gas chamber, and the second probe light and the second coupling light coincide in the atomic gas chamber.

[0018] The photodetector is used to receive the first and second probe light pulses and to acquire the transient electromagnetic induction transparent signal of the Rydberg atom.

[0019] The first radio frequency signal source is used to radiate electromagnetic waves to irradiate the target object, and the reflected electromagnetic waves are received by the atomic gas cell;

[0020] The frequency of the second radio frequency signal source is the same as or close to the frequency of the signal electromagnetic wave. When the local oscillator electromagnetic wave and the signal electromagnetic wave act on the Rydberg atom at near resonance at the same time, a difference frequency signal is generated.

[0021] The computer is used to record and process the difference frequency signal in order to measure the speed of the moving target.

[0022] According to one technical solution of the present invention, the alkali metal atom encapsulated in the atomic gas chamber is a cesium atom.

[0023] According to one technical solution of the present invention, the pulse width of the pulsed light emitted by the probe laser is on the order of nanoseconds, and the first beam splitter splits the probe light into a first probe light and a second probe light with equal intensity, and the third beam splitter splits the coupling light into a first coupling light and a second coupling light with equal intensity.

[0024] According to one technical solution of the present invention, the photodetector is a high-speed photodiode or an avalanche photodiode.

[0025] According to one technical solution of the present invention, the computer is further used to calculate the relative angle θ of the target object based on the phase change of the difference frequency signal.

[0026] According to one aspect of the present invention, a speed measurement method based on transient electromagnetic induction transparency effect is proposed, employing a speed measurement device as described in any of the above technical solutions, comprising the following steps:

[0027] Step S1: Use a probe laser to emit pulsed probe light, and split it into a first probe light and a second probe light by a first beam splitter;

[0028] Step S2: Continuous coupled light is emitted using a coupled laser, and then split into first coupled light and second coupled light by a third beam splitter;

[0029] Step S3: The first probe light and the first coupling light are coincidentally incident into the atomic gas cell through a dichroic mirror, and the second probe light and the second coupling light are coincidentally incident into the atomic gas cell, thereby exciting the alkali metal atoms from the ground state to the Rydberg state.

[0030] Step S4: Collect the detection light pulses using a photodetector to obtain the transient electromagnetic induction transparent signal;

[0031] Step S5: Irradiate electromagnetic waves from the first radio frequency signal source to irradiate the target object, and the reflected electromagnetic waves are received by the atomic gas cell.

[0032] Step S6: Use the second radio frequency signal source to radiate local oscillator electromagnetic waves, so that they and the signal electromagnetic waves act on the Rydberg atoms in near resonance at the same time, generating a difference frequency signal.

[0033] Step S7: Process the difference frequency signal using a computer to calculate the velocity of the target object.

[0034] According to one technical solution of the present invention, in step S7, the specific method of calculating the speed includes: calculating the distance d between the target object and the atomic gas chamber by means of the time difference of the signal electromagnetic wave, calculating the angle θ between the target object and the atomic gas chamber by means of the relative phase of the difference frequency signal, and calculating the speed of the target object according to the rate of change of the angle θ.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] This invention proposes a velocity measurement device based on the transient electromagnetic induction transparency effect. It utilizes two probe beams and two coupling beams to excite atoms in an atomic antenna to the Rydberg state. The probe beams are modulated into pulsed lasers to obtain the transient electromagnetic induction transparency signal of the Rydberg atoms. A first radio frequency signal source radiates electromagnetic waves to illuminate the target object; the reflected electromagnetic waves and the local oscillator electromagnetic waves radiated by a second radio frequency signal source simultaneously act on the Rydberg atoms at near-resonance. The velocity of the target object is measured by quantum precision measurement of the difference frequency signal generated by the interference of the two electromagnetic waves. Compared to traditional Rydberg atomic antennas, this velocity measurement device based on the transient electromagnetic induction transparency effect can achieve velocity measurement of moving targets based on ultra-wideband, miniaturized quantum detection, thus expanding the functionality of Rydberg atomic antennas.

[0037] This invention utilizes pulsed lasers to acquire transient electromagnetic induction transparent signals of Rydberg atoms. Compared to the steady-state electromagnetic induction transparent signals obtained by continuous lasers using classical Rydberg atom antennas, this invention can improve the response rate of Rydberg atom antennas to radio frequency signals and enhance velocity measurement accuracy. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0039] Figure 1 This diagram illustrates the structure of a speed measuring device based on transient electromagnetic induction transparency effect in an embodiment of the present invention.

[0040] Figure 2 This diagram illustrates the Rydberg atomic energy levels in an embodiment of the present invention.

[0041] Figure 3 The diagram illustrates the speed measurement principle based on the transient electromagnetic induction transparency effect in an embodiment of the present invention.

[0042] Figure label:

[0043] 1. Probe laser; 2. First beam splitter; 3. First reflector; 4. First dichroic mirror; 5. Atomic gas cell; 6. Second dichroic mirror; 7. Second reflector; 8. Third dichroic mirror; 9. Fourth dichroic mirror; 10. Second beam splitter; 11. Photodetector; 12. Computer; 13. Coupled laser; 14. Third beam splitter; 15. Third reflector; 16. First radio frequency signal source; 17. Second radio frequency signal source. Detailed Implementation

[0044] The description of the embodiments in this specification should be taken in conjunction with the accompanying drawings, which should form part of the complete specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and may be indicated in a simplified or convenient manner. Furthermore, parts of the various structures in the drawings will be described separately; it is worth noting that elements not shown in the figures or not described in words are in a form known to those skilled in the art.

[0045] The descriptions of the embodiments herein, including any references to directions and orientations, are for ease of description only and should not be construed as limiting the scope of the invention. The following description of preferred embodiments involves combinations of features, which may exist independently or in combination; the invention is not particularly limited to the preferred embodiments. The scope of the invention is defined by the claims.

[0046] like Figure 1As shown, a velocity measuring device based on transient electromagnetic induction transparency effect of the present invention includes: a probe laser 1, a first beam splitter 2, a photodetector 11, a computer 12, a coupling laser 13, a third beam splitter 14, a first radio frequency signal source 16 for radiating electromagnetic waves to irradiate a target object, and a second radio frequency signal source 17 for radiating local oscillator electromagnetic waves.

[0047] The probe laser 1 emits a probe beam, and the first beam splitter 2 splits the probe beam into a first probe beam and a second probe beam.

[0048] Along the optical path of the first detection light, a first reflecting mirror 3, a first dichroic mirror 4, an atomic gas cell 5, a second dichroic mirror 6, a second reflecting mirror 7, a second beam splitter 10, and a photodetector 11 are arranged sequentially.

[0049] Along the optical path of the second probe light, a third dichroic mirror 8, an atomic gas cell 5, a fourth dichroic mirror 9, a second beam splitter 10, and a photodetector 11 are sequentially arranged.

[0050] The coupled laser 13 emits coupled light, and the third beam splitter 14 splits the coupled light into a first coupled light and a second coupled light.

[0051] A first dichroic mirror 4, an atomic gas cell 5, and a second dichroic mirror 6 are sequentially arranged along the optical path of the first coupled light.

[0052] A third reflecting mirror 15, a fourth dichroic mirror 9, an atomic gas cell 5, and a third dichroic mirror 8 are sequentially arranged along the optical path of the second coupled light.

[0053] Photodetector 11 is connected to computer 12;

[0054] Atomic gas chamber 5 is encapsulated with alkali metal atomic vapor;

[0055] The probe light emitted by probe laser 1 is pulsed light, and the coupling light emitted by coupling laser 13 is continuous light.

[0056] By constructing a core device framework comprising a probe laser 1, a first beam splitter 2, a photodetector 11, a computer 12, a coupling laser 13, a third beam splitter 14, and first and second radio frequency signal sources 17, and encapsulating alkali metal atomic vapor in an atomic gas chamber 5, setting the probe light as pulsed light and the coupling light as continuous light, a velocity measuring device based on transient electromagnetic induction transparency effect is obtained. This velocity measuring device can utilize the high sensitivity of Rydberg atoms to electromagnetic fields, laying a solid physical foundation and system architecture for subsequent realization of ultra-wideband, high-precision velocity measuring functions. It has significant advantages such as advanced principle, high system integration, and providing a core platform for subsequent functional expansion, opening up a new technical path for high-speed target detection of weak signals in complex electromagnetic environments.

[0057] In some embodiments of the present invention, the first dichroic mirror 4, the second dichroic mirror 6, the third dichroic mirror 8, and the fourth dichroic mirror 9 are used to reflect the probe light and transmit the coupling light, so that the first probe light and the first coupling light coincide in the atomic gas cell 5, and the second probe light and the second coupling light coincide in the atomic gas cell 5.

[0058] The photodetector 11 is used to receive the first and second probe light pulses and to acquire the transient electromagnetic induction transparent signal of the Rydberg atom;

[0059] The first radio frequency signal source 16 is used to radiate electromagnetic waves to irradiate the target object, and the reflected signal electromagnetic waves are received by the atomic gas chamber 5.

[0060] The frequency of the second radio frequency signal source 17 is the same as or close to the frequency of the signal electromagnetic wave. When the local oscillator electromagnetic wave and the signal electromagnetic wave act on the Rydberg atom at near resonance at the same time, a difference frequency signal is generated.

[0061] Computer 12 is used to record and process differential frequency signals in order to measure the speed of moving targets.

[0062] By defining the function of the dichroic mirror as reflecting the probe light and transmitting the coupling light to ensure that the two beams of light are precisely overlapped in the atomic gas cell 5, and specifying that the photodetector 11 is used to acquire the transient electromagnetic induction transparency (EIT) signal, and defining that the electromagnetic wave emitted by the first radio frequency signal source 16, after being reflected by the target, and the local oscillator electromagnetic wave emitted by the second radio frequency signal source 17, near-resonance occurs in the atomic gas cell 5 to generate a difference frequency signal, which is then processed by the computer 12, the abstract physical principle is transformed into a concrete and achievable signal generation and detection chain. This effectively integrates the transient EIT effect with radio frequency heterodyne interferometry velocimetry technology, significantly improving the system's response speed and measurement sensitivity to radio frequency signals. It overcomes the bottleneck of the traditional steady-state EIT effect having a long relaxation time, which is not conducive to high-speed measurement. It has outstanding effects such as high signal extraction efficiency, strong anti-environmental interference capability, and the ability to efficiently convert the speed information of high-speed moving targets into easily processed difference frequency electrical signals.

[0063] In some embodiments of the present invention, the alkali metal atoms encapsulated in the atomic gas chamber 5 are cesium atoms. By utilizing the mature energy level structure of cesium atoms and the known and easily excited Rydberg states, the precise matching and optimization of key system parameters (such as laser wavelength and radio frequency signal frequency) can be achieved. This avoids problems such as energy level uncertainty and difficulty in laser selection that may be caused by using other alkali metal atoms, and ensures the determinism and repeatability of the interaction between the atomic system and light and radio frequency fields. It has the technical effects of clear energy level structure, easy acquisition of optical transition wavelength, strong experimental controllability, and is conducive to the standardization and miniaturization of the device, providing a reliable material carrier for the stable operation and accurate measurement of the system.

[0064] Specifically, such as Figure 2As shown, the first and second probe beams excite the ground-state cesium atom to the intermediate state, and the first and second coupling beams excite the intermediate-state cesium atom to the Rydberg state.

[0065] In some embodiments of the present invention, the pulse width of the pulsed light emitted by the probe laser 1 is on the order of nanoseconds, and the first beam splitter 2 splits the probe light into a first probe light and a second probe light with equal intensity, and the third beam splitter 14 splits the coupling light into a first coupling light and a second coupling light with equal intensity.

[0066] Setting the light intensities of the first and second probe lights, as well as the first and second coupling lights, to be equal ensures that the process of exciting the Rydberg atom group has extremely fast time resolution (significantly shortening the setup time of the transient EIT signal). At the same time, it ensures the consistency of the interaction between the probe light and the coupling light propagating along the two paths within the atomic gas chamber 5, achieving a balance in excitation efficiency and a unified measurement benchmark.

[0067] In some embodiments of the present invention, the photodetector 11 is a high-speed photodiode or an avalanche photodiode.

[0068] In some embodiments of the present invention, the computer 12 is also used to calculate the relative angle θ of the target object based on the phase change of the difference frequency signal.

[0069] According to one aspect of the present invention, a speed measurement method based on transient electromagnetic induction transparency effect is proposed, employing a speed measurement device as described in any of the above technical solutions, comprising the following steps:

[0070] Step S1: Use the probe laser 1 to emit pulsed probe light, and use the first beam splitter 2 to split it into a first probe light and a second probe light;

[0071] Step S2: Continuous coupled light is emitted using the coupled laser 13, and then split into first coupled light and second coupled light by the third beam splitter 14;

[0072] Step S3: The first probe light and the first coupling light are coincidentally incident into the atomic gas cell 5 through the dichroic mirrors (including the first dichroic mirror 4, the second dichroic mirror 6, the third dichroic mirror 8, and the fourth dichroic mirror 9), and the second probe light and the second coupling light are coincidentally incident into the atomic gas cell 5, thereby exciting the alkali metal atoms from the ground state to the Rydberg state.

[0073] Step S4: Collect the detection light pulse through the photodetector 11 to obtain the transient electromagnetic induction transparent signal;

[0074] Step S5: Irradiate electromagnetic waves from the first radio frequency signal source 16 to irradiate the target object, and the reflected electromagnetic waves are received by the atomic gas chamber 5.

[0075] Step S6: Use the second radio frequency signal source 17 to radiate local oscillator electromagnetic waves, so that they and the signal electromagnetic waves act on the Rydberg atoms in near resonance at the same time, generating a difference frequency signal.

[0076] Step S7: The difference frequency signal is processed by computer 12 to calculate the speed of the target object.

[0077] First, the interaction between light and atoms is precisely controlled to prepare the Rydberg state and obtain the transient EIT signal (steps S1 to S3). Then, the heterodyne interference between the target reflection signal and the local oscillator signal is used to generate a difference frequency signal containing velocity information (steps S4 to S6). Finally, the information is extracted by calculation (step S7), thus realizing quantum velocimetry based on the transient EIT effect. The process is clear, the logic is rigorous, and it is easy to program and control. It can also effectively ensure the consistency of the measurement process and the reliability of the results.

[0078] In some embodiments of the present invention, the specific method for calculating the speed in step S7 includes: calculating the distance d between the target object and the atomic gas chamber 5 by means of the time difference of the signal electromagnetic wave, calculating the angle θ between the target object and the atomic gas chamber 5 by means of the relative phase of the difference frequency signal, and calculating the speed of the target object based on the rate of change of the angle θ.

[0079] Specific measurement methods are as follows: Figure 3 As shown, the distance between the first and second detector lights is r, and the horizontal and vertical distances are a and b, respectively. The first radio frequency signal source 16 radiates electromagnetic waves, and the distance between the target object and the atomic antenna is calculated as d by the time difference of the received reflected electromagnetic waves. The relative phase of the signal electromagnetic waves at the first and second detector lights is measured by the local oscillator electromagnetic waves radiated by the second radio frequency signal source 17, and then the angle of the target object relative to the atomic antenna is calculated as θ. The moving distance is calculated by the change of the angle of the target object relative to the atomic antenna, thereby realizing the speed measurement of the target object. This effectively improves the reliability and accuracy of the measurement, and has the technical effects of clear principle, robust algorithm, strong resistance to random errors, and the ability to further improve the reliability of the results through data fusion.

[0080] In summary, the present invention provides a velocity measurement device based on the transient electromagnetic induction transparency effect. This device uses two probe beams and two coupling beams to excite atoms in an atomic antenna to the Rydberg state. The probe beams are modulated into pulsed lasers to obtain the transient electromagnetic induction transparency signal of the Rydberg atoms. The target object is irradiated with electromagnetic waves from a first radio frequency signal source. The reflected electromagnetic waves and the local oscillator electromagnetic waves radiated by a second radio frequency signal source simultaneously act on the Rydberg atoms in near-resonance. The velocity of the target object is measured by quantum precision measurement of the difference frequency signal generated by the interference of the two electromagnetic waves. Compared to traditional Rydberg atomic antennas, the velocity measurement device based on the transient electromagnetic induction transparency effect proposed in this invention can measure the velocity of moving targets based on ultra-wideband, miniaturized quantum detection, thus expanding the functionality of Rydberg atomic antennas.

[0081] This invention utilizes pulsed lasers to acquire transient electromagnetic induction transparent signals of Rydberg atoms. Compared to the steady-state electromagnetic induction transparent signals obtained by continuous lasers using classical Rydberg atom antennas, this invention can improve the response rate of Rydberg atom antennas to radio frequency signals and enhance velocity measurement accuracy.

[0082] It should also be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0083] Finally, it should be noted that the above description represents a preferred embodiment of the present invention. It should be pointed out that although preferred embodiments have been described, those skilled in the art, once they understand the basic inventive concept of the present invention, can make various improvements and modifications without departing from the principles described herein. These improvements and modifications should also be considered within the scope of protection of the present invention. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Claims

1. A speed measuring device based on transient electromagnetic induction transparency effect, characterized in that, include: The detector laser (1), the first beam splitter (2), the photodetector (11), the computer (12), the coupling laser (13), the third beam splitter (14), the first radio frequency signal source (16) for radiating electromagnetic waves to irradiate the target, and the second radio frequency signal source (17) for radiating local oscillator electromagnetic waves. The probe laser (1) emits probe light, and the first beam splitter (2) splits the probe light into a first probe light and a second probe light; Along the optical path of the first detection light, a first reflector (3), a first dichroic mirror (4), an atomic gas cell (5), a second dichroic mirror (6), a second reflector (7), a second beam splitter (10), and a photodetector (11) are arranged in sequence. A third dichroic mirror (8), the atomic gas cell (5), a fourth dichroic mirror (9), a second beam splitter (10), and a photodetector (11) are sequentially arranged along the optical path of the second probe light. The coupled laser (13) emits coupled light, and the third beam splitter (14) splits the coupled light into a first coupled light and a second coupled light. The first dichroic mirror (4), the atomic gas cell (5), and the second dichroic mirror (6) are sequentially arranged along the optical path of the first coupled light. A third reflecting mirror (15), a fourth dichroic mirror (9), an atomic gas cell (5), and a third dichroic mirror (8) are sequentially arranged along the optical path of the second coupled light. The photodetector (11) is connected to the computer (12); The atomic gas chamber (5) is encapsulated with alkali metal atomic vapor; The probe light emitted by the probe laser (1) is pulsed light, and the coupling light emitted by the coupling laser (13) is continuous light.

2. The speed measuring device according to claim 1, characterized in that, The first dichroic mirror (4), the second dichroic mirror (6), the third dichroic mirror (8), and the fourth dichroic mirror (9) are used to reflect the probe light and transmit the coupling light, so that the first probe light and the first coupling light coincide in the atomic gas cell (5), and the second probe light and the second coupling light coincide in the atomic gas cell (5); The photodetector (11) is used to receive pulses of the first probe light and the second probe light, and to acquire the transient electromagnetic induction transparent signal of the Rydberg atom; The first radio frequency signal source (16) is used to radiate electromagnetic waves to irradiate the target object, and the reflected electromagnetic waves are received by the atomic gas cell (5). The frequency of the second radio frequency signal source (17) is the same as or close to the frequency of the signal electromagnetic wave. When the local oscillator electromagnetic wave and the signal electromagnetic wave act on the Rydberg atom at the same near resonance, a difference frequency signal is generated. The computer (12) is used to record and process the difference frequency signal in order to measure the speed of the moving target.

3. The speed measuring device according to claim 1, characterized in that, The alkali metal atoms encapsulated in the atomic gas chamber (5) are cesium atoms.

4. The speed measuring device according to claim 1, characterized in that, The pulse width of the pulsed light emitted by the probe laser (1) is on the order of nanoseconds, and the first beam splitter (2) splits the probe light into a first probe light and a second probe light with equal intensity, and the third beam splitter (14) splits the coupling light into a first coupling light and a second coupling light with equal intensity.

5. The speed measuring device according to claim 1, characterized in that, The photodetector (11) is a high-speed photodiode or an avalanche photodiode.

6. The speed measuring device according to claim 1, characterized in that, The computer (12) is also used to calculate the relative angle θ of the target object based on the phase change of the difference frequency signal.

7. A speed measurement method based on transient electromagnetic induction transparency effect, employing the speed measurement device as described in any one of claims 1-6, characterized in that, Includes the following steps: Step S1: Use the probe laser (1) to emit pulsed probe light, and split it into first probe light and second probe light by the first beam splitter (2); Step S2: Use the coupled laser (13) to emit continuous coupled light, and split it into first coupled light and second coupled light by the third beam splitter (14); Step S3: The first probe light and the first coupling light are coincidentally incident into the atomic gas cell (5) through a dichroic mirror, and the second probe light and the second coupling light are coincidentally incident into the atomic gas cell (5) to excite the alkali metal atoms from the ground state to the Rydberg state. Step S4: Collect the detection light pulse through the photodetector (11) to obtain the transient electromagnetic induction transparent signal; Step S5: Irradiate electromagnetic waves from the first radio frequency signal source (16) to irradiate the target object, and the reflected electromagnetic waves are received by the atomic gas chamber (5). Step S6: Use the second radio frequency signal source (17) to radiate local oscillator electromagnetic waves, so that they and the signal electromagnetic waves can resonate at the same time and act on the Rydberg atoms to generate a difference frequency signal. Step S7: Process the difference frequency signal using a computer (12) to calculate the velocity of the target object.

8. The speed measurement method according to claim 7, characterized in that, In step S7, the specific method for calculating the speed includes: calculating the distance d between the target object and the atomic gas chamber (5) by the time difference of the signal electromagnetic wave, calculating the angle θ of the target object relative to the atomic gas chamber (5) by the relative phase of the difference frequency signal, and calculating the speed of the target object based on the rate of change of the angle θ.

Images