Microwave electric field detection method based on three-light excitation Rydberg atom eight-wave mixing

Abstract

The invention discloses a microwave electric field detection method based on three-light-excited Rydberg atom eight-wave mixing, and the method comprises the steps: building a microwave electric field detection device based on three-light-excited Rydberg atom eight-wave mixing, enabling a transmission path of decoration light Kd and a transmission path of coupling light Kc to reversely coincide with a transmission path of detection light KP in an atomic gas chamber, and enabling the transmission path of the coupling light Kc to be a transmission path of the detection light KP; a local oscillation microwave electric field KL is emitted to the atomic gas chamber from one side of the atomic gas chamber through the horn antenna; the horn antenna passively receives a signal microwave electric field KS in a free space and loads the signal microwave electric field KS to the atomic gas chamber; by observing the beat frequency electric signal output by the photoelectric detector, it is confirmed that the horn antenna receives the signal microwave electric field KS. Through a three-light excitation Rydberg atom scheme and an eight-wave mixing technology, the frequency resolution and sensitivity of electric field detection are remarkably improved, and a brand new technical path is provided for high-precision microwave electric field detection.

Description

Technical Field

[0001] This invention belongs to the field of atomic and molecular photophysics research, specifically involving a microwave electric field detection method based on three-light excitation of Rydberg atoms eight-wave mixing. Background Technology

[0002] With the development of microwave electric field detection technology, high-sensitivity microwave electric field detection methods based on Rydberg atoms have attracted widespread attention. Six-wave mixing technology enhances the signal through multiphoton nonlinear processes, improving detection sensitivity and achieving some success in the field of microwave detection. However, the six-wave mixing scheme has significant limitations. On the one hand, its spectral linewidth is relatively large, which to some extent limits the microwave frequency resolution; on the other hand, the system is susceptible to interference from low-frequency noise and laser common-mode noise, leading to a decrease in the signal-to-noise ratio and restricting further improvement in detection sensitivity. Therefore, to achieve high-sensitivity detection with high frequency resolution and low noise background, further development of microwave electric field detection technology is needed. Summary of the Invention

[0003] To address two major bottlenecks in existing six-wave mixing electric field detection schemes—insufficient microwave frequency resolution due to spectral limitation and the limitation of detection sensitivity by low-frequency noise interference—this invention proposes a microwave electric field detection method based on three-photon excitation of Rydberg atoms using eight-wave mixing. By optimizing excited state selection, spectral linewidth compression, and high-frequency modulation techniques, this method overcomes existing technical bottlenecks and significantly improves the sensitivity and frequency resolution of the detected electric field.

[0004] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0005] The microwave electric field detection method based on three-light excited Rydberg atom eight-wave mixing includes the following steps:

[0006] Step 1: Construct a microwave electric field detection device based on three-light excited Rydberg atom eight-wave mixing, so that in the atomic gas cell, the K-type light... d The transmission path and coupling light K c The transmission paths are all related to the probe light K. P The transmission paths coincide in opposite directions, and the local oscillator microwave electric field K L The probe light K is emitted from one side of the atomic gas chamber via a horn antenna and then into the atomic gas chamber; the photodetector receives the probe light K. P Among them, the detection light wave vector Adorned with light wave arrows Coupled optical wave vector satisfy Detector light K P The atoms in the atomic gas chamber are excited from the ground state |1> to the first excited state |2>, and then decorated with light K. d The atom is excited from the first excited state |2> to the intermediate state |3>, and coupled with light K.c Further excite the atom to the first Rydberg state |4>, the local microwave electric field K L Excite the atom from the first Rydberg state |4> to the second Rydberg state |5>;

[0007] Step 2, the horn antenna passively receives the signal microwave electric field K in the free space S And load the received signal microwave electric field K S Into the atomic cell;

[0008] Step 3, observe the electrical signal output by the photodetector; when the photodetector outputs a beat frequency electrical signal, it is confirmed that the horn antenna receives the signal microwave electric field K S .

[0009] The microwave electric field detection device based on the eight-wave mixing of the three-photon excited Rydberg atom as described above, comprising an electro-optical modulator, a probe light K P After high-frequency modulation by the electro-optical modulator, it is incident to the atomic cell, and the decorating light K d In turn, it is reflected by the beam splitter and transmitted by the polarization beam splitter prism and then incident to the atomic cell; the coupling light K c After reflection by the mirror, it is transmitted by the beam splitter and the polarization beam splitter prism in turn and then enters the atomic cell; the local microwave electric field K L And the signal microwave electric field K to be detected in the free space S Is emitted from one side of the atomic cell to the atomic cell by the horn antenna;

[0010] In the rubidium atomic cell, the decorating light K d , the coupling light K c , the probe light K P , the local microwave electric field K L And the signal microwave electric field K S Perform eight-wave mixing to generate an optical sideband carrying information of the signal microwave electric field K S , the probe light K P And the optical sideband are emitted from the atomic cell along the incident direction of the probe light K P And reflected by the polarization beam splitter prism to the photodetector, and the photodetector outputs a beat frequency electrical signal.

[0011] As described above, the horn antennas are multiple and connected side by side, the receiving end of each horn antenna faces different directions in the free space, and the output ends of all the horn antennas face the atomic cell, the local microwave electric field K L Is emitted from one side of the atomic cell to the atomic cell by one horn antenna.

[0012] As described above, the frequency difference between the frequency of the signal microwave electric field K S And the frequency of the local microwave electric field K L Is recorded as the microwave beat frequency δ s, 10KHz≤δ s <100KHz.

[0013] The photoelectric detector is an avalanche detector.

[0014] The frequency of the electro-optical modulator is greater than 1MHz.

[0015] The electro-optical modulator is integrated with a phase-locked amplifier, and the phase-locked amplifier extracts the first-order differential signal of the probe light K p The first-order differential signal of the modulated signal is output to the atomic cell at the modulation frequency of the electro-optical modulator.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] The present application uses three lasers to cooperatively excite rubidium atoms to high Rydberg states, and a local local-oscillator microwave electric field and a signal microwave electric field jointly act on the rubidium atoms, and through an eight-wave mixing process, an optical sideband carrying the signal microwave electric field is generated in the Rydberg atomic medium. Since the three-light eight-wave mixing scheme can better satisfy the photon momentum conservation than the two-light six-wave mixing scheme, the generated signal light has smaller spatial locality, and the signal contrast is higher. A photoelectric detector records the transmitted probe light and the generated optical sideband, and the probe light and the optical sideband are mixed on the photoelectric detector to generate a beat signal, thereby realizing direct measurement of the signal microwave electric field strength.

[0018] 1. Improve the frequency resolution accuracy. The high-order characteristics of eight-wave mixing are used, the optical signal has a smaller line width and higher sensitivity; the power spread is effectively suppressed, thereby compressing the spectral line width and significantly improving the microwave frequency resolution accuracy. Compared with six-wave mixing, the spatial locality is stronger and the spatial resolution is higher; and it will not be saturated due to the increase of the probe light intensity.

[0019] 2. Enhance the spatial locality of the signal light. Three-light cooperative excitation is used to realize eight-wave mixing, which can better satisfy the photon momentum conservation condition, so that the formed signal light has more concentrated spatial distribution and stronger locality, thereby improving the signal brightness and being beneficial to the extraction and detection of the signal.

[0020] 3. Improve the detection sensitivity. The probe light is phase-modulated by an electro-optical modulator, and high-frequency modulation is applied, so that the signal is shifted to the high-frequency region. Combined with a phase-locked amplifier to extract the first-order differential signal, the common-mode noise of laser intensity and phase is suppressed, and low-frequency noise is effectively avoided, thereby significantly improving the signal-to-noise ratio and the electric field detection sensitivity.

[0021] In summary, the application significantly improves the frequency resolution and sensitivity of electric field detection by innovative three-photon excited Rydberg atom scheme and eight-wave mixing technology, compared with the existing six-wave mixing scheme, and provides a new technical path for realizing high-precision microwave electric field detection. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Figure 1 is a schematic diagram of a microwave electric field detection device based on three-photon excited Rydberg atom eight-wave mixing.

[0023] Among them, 1 is an electro-optic modulator, 2 is an atomic cell, 3 is a horn antenna, 4 is a polarization beam splitter prism, 5 is a photodetector, 6 is a beam splitter, and 7 is a mirror.

[0024] Figure 2a Figure 4 is a schematic diagram of the generation of positive sidebands in the eight-wave mixing process.

[0025] Figure 2b Figure 5 is a schematic diagram of the generation of negative sidebands in the eight-wave mixing process.

[0026] Among them, ω p is the frequency of the probe light, ω d is the frequency of the dressing light, ω c is the frequency of the coupling light, ω L is the frequency of the local microwave electric field, ω S is the frequency of the signal microwave electric field, and the microwave difference frequency δ s , ω p - is the frequency of the negative sideband, ω p + is the frequency of the positive sideband; |1> represents the ground state, |2> represents the first excited state, |3> represents the intermediate state, |4> represents the first Rydberg state, and |5> represents the second Rydberg state.

[0027] Figure 3 Figure 7 is a beat signal diagram generated by mixing the probe light and the sideband light. DETAILED DESCRIPTION

[0028] In order to facilitate those skilled in the art to understand and implement the present application, the present application will be further described in detail below in conjunction with the embodiments, and it should be understood that the embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0029] Example 1

[0030] The microwave electric field detection device based on three-photon excited Rydberg atom eight-wave mixing, as shown in Figure 1, comprises an electro-optic modulator 1, an atomic cell 2, a horn antenna 3, a polarization beam splitter prism 4, a photodetector 5, a beam splitter 6, and a mirror 7. Figure 1As shown, including: electro-optic modulator 1 (EOM, 10 MHz), atomic gas cell 2, horn antenna 3, polarization beam splitter prism 4, photodetector 5 (APD, bandwidth 10 MHz), beam splitter 6, mirror 7, set as follows:

[0031] Probe light K P After high-frequency modulation by the electro-optic modulator 1, it is incident to the atomic gas cell 2, in this embodiment, the atoms filled in the atomic gas cell 2 are rubidium atoms; the dressing light K d After being reflected by the beam splitter 6 and transmitted by the polarization beam splitter prism 4 in turn, it is incident to the atomic gas cell 2; the coupling light K c After being reflected by the mirror 7, it is transmitted by the beam splitter 6 and the polarization beam splitter prism 4 in turn and enters the atomic gas cell 2; in the atomic gas cell 2, the transmission path of the probe light K P is opposite to that of the dressing light K d , and at the same time, the transmission path of the probe light K P is opposite to that of the coupling light K c , by adjusting the power of the probe light K p , the dressing light K d and the coupling light K c and performing three-light excitation, the rubidium atoms in the atomic gas cell 2 are excited to the Rydberg state (i.e. the probe light K P excites the atoms in the atomic gas cell 2 from the ground state |1> to the first excited state |2>, the dressing light K d excites the atoms from the first excited state |2> to the intermediate state |3>, and the coupling light K c further excites the atoms to the first Rydberg state |4>); the local microwave electric field K L is emitted from one side of the atomic gas cell 2 to the atomic gas cell 2 through the horn antenna 3, when the signal microwave electric field K S to be detected exists in the free space, and the signal microwave electric field K S to be detected is also emitted from one side of the atomic gas cell 2 to the atomic gas cell 2 through the horn antenna 3, then in the rubidium atomic gas cell 2, the dressing light K d , the coupling light K c , the probe light K P , the local microwave electric field K L and the signal microwave electric field K S perform eight-wave mixing, thereby generating optical sidebands (including positive sidebands and negative sidebands) carrying the information of the signal microwave electric field K S to be detected in the Rydberg atomic medium in the atomic gas cell 2, the probe light K P and the generated optical sidebands along the probe light K PThe incident direction of the detection light K L excited from the first Rydberg state |4> to the second Rydberg state |5>.

[0032] The amplitude of the beat frequency electric signal is proportional to the amplitude of the optical sideband, and the amplitude of the optical sideband is closely related to the intensity of the signal microwave electric field K S to be detected. By detecting the amplitude of the beat frequency electric signal, the signal microwave electric field K S to be detected is confirmed. By using the high-order characteristics of eight-wave mixing, power broadening can be better suppressed, thereby compressing the spectral linewidth and improving the frequency resolution. At the same time, the phase modulation detection light of the electro-optic modulator 1 is introduced to apply high-frequency modulation, effectively suppressing the common-mode noise of laser intensity and phase, and significantly improving the signal-to-noise ratio.

[0033] Further, in order to make the microwave electric field detection device based on three-light excited Rydberg atom eight-wave mixing in the application have more comprehensive signal receiving capability (especially for the signal microwave electric field K S from different directions), higher sensitivity and signal strength, improve the signal-to-noise ratio and system redundancy capability, the horn antenna 3 is multiple and connected side by side, the receiving end of each horn antenna 3 is directed to different directions of the free space, and the output ends of all horn antennas 3 are directed to the atomic cell 2. The local microwave electric field K L is emitted from one side of the atomic cell 2 to the atomic cell 2 through a horn antenna 3, and the signal microwave electric field K S to be detected in the free space is emitted from one side of the atomic cell 2 to the atomic cell 2 through any horn antenna 3. In the rubidium atomic cell 2, the dressing light K d , the coupling light K c , the detection light K P , the local microwave electric field K L and the signal microwave electric field K S perform eight-wave mixing to generate an optical sideband carrying information of the signal microwave electric field K S to be detected in the atomic cell 2. The detection light K P and the generated optical sideband are emitted from the atomic cell 2 along the incident direction of the detection light K P , reflected by the polarization beam splitter prism 4 to the photodetector 5, and mixed on the photodetector 5 to generate a beat frequency electric signal.

[0034] Further, the electro-optic modulator 1 is used to modulate the detection light K pPhase modulation is performed, high frequency modulation greater than 1MHz is applied, and the signal is shifted to the high frequency region. In this embodiment, the frequency of the electro-optical modulator 1 is 10MHz, and the probe light K is extracted by a phase-locked amplifier integrated in the electro-optical modulator 1 p The first-order differential signal in the modulated signal is output to the atomic cell 2 at the modulation frequency of the electro-optical modulator 1, thereby suppressing the laser intensity and phase common mode noise (main noise source), avoiding low frequency noise, and further improving the signal-to-noise ratio, and finally improving the detection sensitivity of the electric field.

[0035] In this embodiment, the photodetector 5 is an avalanche photodetector, which is used to record the probe light K P transmitted from the atomic cell 2 and the generated optical sideband, the wavelength of the probe light K p is 780nm, the wavelength of the decorating light K d is 776nm, and the wavelength of the coupling light K c is 1260nm. The frequency of the local microwave electric field K L is denoted as the local microwave electric field frequency ω L , the local microwave electric field frequency ω L is the resonance frequency of the first Rydberg state |4> to the second Rydberg state |5>, which is generally in the order of GHz; the frequency of the signal microwave electric field K S to be detected is denoted as the signal microwave electric field frequency ω S , and the frequency difference between the frequency of the signal microwave electric field K S and the frequency of the local microwave electric field K L , i.e. the frequency difference between the signal microwave electric field frequency ω S and the local microwave electric field frequency ω L is denoted as the microwave difference frequency δ s , 10KHz≤δ s <100KHz, in this embodiment, the microwave difference frequency δ s takes a value of 10KHz.

[0036] Embodiment 2

[0037] The microwave electric field detection method based on the eight-wave mixing of three-photon excited Rydberg atoms, and the microwave electric field detection device based on the eight-wave mixing of three-photon excited Rydberg atoms, specifically comprising the following steps:

[0038] Step 1, build the microwave electric field detection device based on the eight-wave mixing of three-photon excited Rydberg atoms as described in embodiment 1, so that the transmission path of the decorating light K d and the transmission path of the coupling light K c in the atomic cell 2 are both opposite to the transmission path of the probe light K P , and the transmission path of the local microwave electric field K LThe horn antenna 3 emits the probe light K from one side of the atomic cell 2 to the atomic cell 2; the photodetector 5 receives the probe light K P ; wherein the probe light wave vector The decorative light wave vector The coupling light wave vector satisfies The probe light K P excites the atom in the atomic cell (2) from the ground state |1> to the first excited state |2>, the decorative light K d excites the atom from the first excited state |2> to the intermediate state |3>, the coupling light K c further excites the atom to the first Rydberg state |4>, the local microwave electric field K L excites the atom from the first Rydberg state |4> to the second Rydberg state |5>;

[0039] Step 2, the horn antenna 3 passively receives the signal microwave electric field K S in free space, and transmits the received signal microwave electric field K S after processing (such as collimation, shaping) to the atomic cell 2, so that the signal microwave electric field K S is loaded to the atomic cell 2;

[0040] Step 3, observe the electrical signal output by the photodetector 5; when the photodetector 5 outputs a beat frequency electrical signal, as shown in Figure 3 , it indicates that the photodetector 5 not only receives the probe light K P , but also receives the optical sidebands obtained by eight-wave mixing of the decorative light K d , the coupling light K c , the probe light K P , the local microwave electric field K L and the signal microwave electric field K S , thereby confirming that the horn antenna 3 receives the signal microwave electric field K S .

[0041] In the case where there is no signal microwave electric field K S at the initial moment, no optical sideband will be generated in the system; however, in the experiment, the spectral signal of the probe light K P may be observed first, because when there is no signal microwave electric field K S , the spectrum near the probe light K P will be affected by other light fields (such as the local microwave electric field K L ); when both the signal microwave electric field K S and the local microwave electric field K L act on the atomic system in the atomic cell 2, the Rydberg atom undergoes transition, thereby generating positive and negative sidebands, and the positive and negative sidebands are associated with the probe light K PFrequency mixing generates a beat frequency signal; therefore, the appearance of the beat frequency signal is due to the microwave electric field K of the signal. S The received direct flag.

[0042] In this embodiment, the probe light K P (The frequency of the probe light is denoted as ω) p After being high-frequency modulated by electro-optic modulator 1, the light passes through an atomic gas cell 2 filled with rubidium. This process excites the rubidium atoms in the atomic gas cell 2 from the ground state |1> to the first excited state |2>; the adorned light K d (The frequency of the decorative light is denoted as ω) d The light is reflected by beam splitter 6 and then enters atomic gas cell 2 through polarizing beam splitter prism 4, where it interacts with probe light K. p Reverse alignment, thereby exciting rubidium atoms from the first excited state |2> to the intermediate state |3>; coupled light K c (The frequency of the coupled light is ω) c After being reflected by mirror 7, it passes sequentially through beam splitter 6 and polarizing beam splitter 4 into atomic gas cell 2, where it also interacts with probe light K. p Reverse overlap further excites rubidium atoms to the first Rydberg state |4>; the microwave electric field K of the signal to be detected S The frequency of the microwave electric field of the signal ω S With local oscillator microwave electric field K L The local oscillator microwave electric field frequency ω L The frequency difference between them is denoted as microwave difference frequency δ. S =ω L -ω S Two microwave electric fields are emitted via horn antenna 3 to the rubidium-filled atomic gas chamber 2. The local oscillator microwave electric field frequency ω L Precisely match the energy level transition frequency of rubidium atoms in the Rydberg state to achieve resonant coupling with the transition from the first Rydberg state |4> to the second Rydberg state |5>.

[0043] Detector light K P Adorned with light K d Coupled light K c And the local oscillator microwave electric field K L And the microwave electric field K of the signal to be detected S As the input field, a microwave electric field K carrying the signal is generated through a complex eight-wave mixing process. S The optical sidebands of microwave information (optical sidebands include positive and negative sidebands, the frequency of the positive sideband is ω) p + =ω p +δ s The frequency ω of the negative sideband p - =ω p -δ s ), transmitted probe light Kp The positive and negative sidebands mix in the photodetector 5, generating a beat frequency equal to the microwave difference frequency δ. S Beat frequency electrical signal; amplitude S(δ) of beat frequency electrical signal s The amplitude of the optical sideband is proportional to the mode length of the signal microwave electric field K. S The intensity of the microwave electric field is closely related to the amplitude of the beat frequency electrical signal. Therefore, by measuring the change in amplitude of the beat frequency electrical signal, the change in intensity of the microwave electric field can be obtained. Based on this principle, a microwave electric field detection device can be used to detect whether the microwave electric field K of the signal to be detected exists in space. S .

[0044] The energy matching of atomic level transitions follows the energy level path (in order to achieve the following energy level transitions). 87 Taking the Rb atom as an example, see Figures 2a-2b ):

[0045] (1) The forward process generates positive sidebands, such as Figure 2a As shown:

[0046] The corresponding input field is: Ornamental Light K d Coupled light K c Detector light K P Local oscillator microwave electric field K L .

[0047] path:

[0048] Condition: ω p + =ω p +δ s (δ s =ω L -ω S ).

[0049] ω p To detect the frequency of light, ω d To adorn the frequency of light, ω c For the frequency of the coupled light, ω L The frequency of the local oscillator microwave electric field, ω S The frequency of the signal microwave electric field is denoted as .

[0050] (2) The reverse process generates negative sidebands, such as Figure 2b As shown:

[0051] The corresponding input field is: Ornamental Light K d Coupled light K c Detector light K P , signal microwave electric field K S .

[0052] Path:

[0053] Condition: ω p - = ω p - δ s .

[0054] Microwave frequency difference δ s Matching Rydberg state energy level spacing ( h = 2π reduced Planck's constant), thus ensuring energy conservation.

[0055] The eight-wave mixing process needs to follow the principles of energy conservation and momentum conservation:

[0056] (1) Energy conservation process:

[0057] The eight-wave mixing process involves the exchange of energy between input and output fields.

[0058] Input fields: probe light K P , dressing light K d , coupling light K c , local microwave electric field K L , signal microwave electric field K S .

[0059] Output fields: optical sidebands (including positive and negative sidebands).

[0060] Positive sideband generation (ω p + = ω p + δ S ):

[0061] ω P + ωd+ ω c + ω L = ω p + + ω d + ω c + ω S ,

[0062] After simplification:

[0063] ω p + = ω p + (ω L - ω S ) = ω p + δ s .

[0064] Where, the atom absorbs dressing light K d , coupling light K cDetector light K P Transitioning to the first Rydberg state |4>, absorbing the local oscillator microwave electric field K L The energy transition to the second Rydberg state |5> absorbs the microwave electric field K. S It generates energy and releases a frequency equal to the frequency ω of the signal microwave electric field. S The energy is also released at a frequency equal to the microwave difference frequency δ. s The energy is transmitted to the light field, generating a frequency equal to the frequency ω of the positive sideband. p + Photon.

[0065] Negative sideband generation (ω) p - =ω p -δ S ):

[0066] ω P +ωd+ω c +ω S =ω p - +ω d +ω c +ω L ,

[0067] After simplification:

[0068] ω p - =ω p -(ω L -ω S )=ω p -δ s .

[0069] In this process, atomic absorption detector light K P Adorned with light K d Coupled light K c It then transitions to the first Rydberg state |4>, absorbing the local oscillator microwave electric field K. L The energy transition to the second Rydberg state |5> absorbs the microwave electric field K. L After absorbing the energy, it releases a microwave electric field with a frequency equal to the signal microwave electric field frequency ω. S The photon will also have a frequency equal to the microwave difference frequency δ s The energy difference is released into the light field, generating a frequency equal to the frequency of the negative sideband, which is ω. p - Photon. The corresponding stimulated emission process, signal microwave electric field K. S Enhance conversion efficiency.

[0070] (2) Momentum conservation process

[0071] The eight-wave mixing process also follows the principle of momentum conservation, the wave vectors of the input and output must keep the total wave vector conservation.

[0072] Positive sideband:

[0073]

[0074] where, is the wave vector of the probe light, is the wave vector of the decorating light, is the wave vector of the coupling light, is the wave vector of the local microwave field, is the wave vector of the positive sideband light.

[0075] Negative sideband:

[0076]

[0077] where, is the wave vector of the negative sideband light, the microwave wave vector can be ignored because the microwave wavelength (centimeter level) is much larger than the light wave (micron level), The final matching condition is simplified as: (i.e. the optical sideband and the probe light are in the same direction K P ).

[0078] The decorating light K d and the coupling light K c are all in the opposite direction of the probe light K p , so that thus effectively canceling the transverse momentum component, satisfying the momentum matching condition in the multi-wave mixing process.

[0079] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or use similar ways to replace, but will not deviate from the spirit of the present application or exceed the scope defined by the appended claims.

Claims

1. A method for microwave electric field detection based on three-photon excitation Rydberg atom eight-wave mixing, characterized in that, comprising the steps of: Step 1, build a microwave electric field detection device based on three light excitation Rydberg atom eight wave mixing, so that in the atomic cell (2), the transmission path of the dressing light K d and the transmission path of the coupling light K c are both opposite to the transmission path of the detection light K P , the local microwave electric field K L is emitted from one side of the atomic cell (2) to the atomic cell (2) through the horn antenna (3); the photodetector (5) receives the detection light K P ; wherein the detection light wave vector K , the dressing light wave vector K and the coupling light wave vector K satisfy The detection light K P excites the atoms in the atomic cell (2) from the ground state |1> to the first excited state |2>, the dressing light K d excites the atoms from the first excited state |2> to the intermediate state |3>, the coupling light K c further excites the atoms to the first Rydberg state |4>, the local microwave electric field K L excites the atoms from the first Rydberg state |4> to the second Rydberg state |5>; Step 2, the horn antenna (3) passively receives the signal microwave electric field K in free space S and loads the received signal microwave electric field K S into the atomic gas cell (2); Step 3, observe the electrical signal output by the photodetector (5); when the photodetector (5) outputs a beat frequency electrical signal, it is confirmed that the horn antenna (3) receives the signal microwave electric field K S .

2. The method of claim 1, wherein the method is based on a three-photon excitation of Rydberg atoms and an eight-wave mixing of microwaves. The microwave electric field detection device based on the three-photon excitation Rydberg atom eight-wave mixing comprises an electro-optic modulator (1), detection light K P After high-frequency modulation by the electro-optic modulator (1), the detection light K d After being reflected by a mirror (7), the detection light K c After being reflected by a mirror (7), the detection light K L After being reflected by a mirror (7), the detection light K S After being reflected by a mirror (7), the detection light K In the rubidium atom gas chamber (2), adorned with light K d Coupled light K c Detector light K P Local oscillator microwave electric field K L And signal microwave electric field K S Eight-wave mixing is performed to generate a microwave electric field K carrying the signal. S The optical sidebands of the information, the detector light K P and the optical sideband along the probe light K P The incident direction is emitted from the atomic gas chamber (2) and reflected by the polarizing beam splitter (4) to the photodetector (5), and the photodetector (5) outputs a beat frequency electrical signal.

3. The method of claim 2, wherein the method is based on a three-photon excitation of Rydberg atoms and an eight-wave mixing of microwaves. The horn antennas (3) are multiple and connected in parallel, the receiving end of each horn antenna (3) faces different directions of the free space, the output end of all horn antennas (3) faces the atomic gas chamber (2), the local microwave electric field K L The microwave is emitted from one side of the atomic gas chamber (2) to the atomic gas chamber (2) through a horn antenna (3).

4. The method of claim 1, wherein the method is based on a three-photon excitation of Rydberg atoms and an eight-wave mixing of microwaves. The signal microwave electric field K S The frequency and the local oscillator microwave electric field K L The frequency difference between the frequencies is denoted as microwave frequency difference δ. s 10kHz≤δ s <100KHz.

5. The method of claim 1, wherein the method is based on a three-photon excitation of Rydberg atoms and an eight-wave mixing of microwaves. The photodetector (5) is an avalanche detector.

6. The method of claim 2, wherein the eight-wave mixing is based on three-photon excitation of a Rydberg atom. The frequency of the electro-optical modulator (1) is greater than 1 MHz.

7. The method of claim 6, wherein the method is based on a three-photon excitation of Rydberg atoms and an eight-wave mixing of microwaves. The phase-locked amplifier is integrated in the electro-optical modulator (1), and the phase-locked amplifier extracts probe light K p The first-order differential signal in the modulated signal is output to the atomic cell (2) with the amplitude of the first-order differential signal at the modulation frequency of the electro-optical modulator (1).

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