CN115343541A - Method, storage medium and system for expanding microwave measurement bandwidth and sensitivity - Google Patents

Abstract

The invention relates to a method for expanding microwave measurement bandwidth and sensitivity, which comprises the following steps: constructing a microwave electric field sensor of a rydberg atom; radiating signal microwaves and local microwaves into a rubidium atom steam pool to realize interference, and measuring beat frequency signals formed by the interference through a Reidberg atom microwave electric field sensor; the measurement bandwidth and the sensitivity of the microwave electric field to be measured are improved by the auxiliary microwave electric field. The invention also provides a storage medium and a system for expanding the microwave measurement bandwidth and sensitivity, and the method, the storage medium and the system for expanding the microwave measurement bandwidth and sensitivity solve the problem that the microwave electric field frequency is limited by the discrete energy level of the Reidberg, and can realize higher measurement sensitivity in the expanded linear response interval.

Description

A method, storage medium and system for expanding microwave measurement bandwidth and sensitivity

technical field

The invention belongs to the technical field of microwave measurement, and in particular relates to a method, a storage medium and a system for expanding microwave measurement bandwidth and sensitivity.

Background technique

Accurate measurement of microwave electric field strength has important applications in radar, communication, remote sensing, non-destructive detection, etc. In recent years, atom-based quantum sensors have developed rapidly, and people have used the quantum properties of atoms to achieve higher precision and sensitivity than traditional measurements. Among them, the microwave electric field sensor based on Rydberg atoms has full-band, traceable to fundamental physical constants, self-calibration, all-optical reading without electronic dark current noise interference in measuring microwaves, etc. Unique advantages have received extensive attention and research.

Although people can demonstrate electric field measurements in the hundreds of MHz to THz range by choosing Rydberg states with different principal quantum numbers n, due to the discrete characteristics of the Rydberg atomic energy levels, when the microwave frequency is far away from the Rydberg energy level When the resonant transition frequency is reached, the measurement sensitivity will decrease rapidly, so in fact, the bandwidth covered by each Rydberg energy level is only about 10MHz, and the Rydberg energy levels with different principal quantum numbers n are separated by hundreds of MHz, so even It can overcome difficulties to realize a high-power laser system with tunable wavelength in a wide range, but it cannot completely compensate for the frequency range corresponding to the Rydberg energy level interval of different principal quantum numbers n.

At present, researchers' efforts to expand the bandwidth of the Rydberg atomic microwave electric field sensor are mainly focused on making use of various energy level splitting effects generated by adding an external field to the target energy level to make the microwave frequency resonate with the split energy level for measurement. There are mainly static magnetic field control atomic energy level method, electrostatic field control atomic energy level method, but applying electrostatic field or static magnetic field to the system will change the energy levels of all atoms, which will undoubtedly cause great trouble to theory and experiment. In 2021, people proposed the method of using auxiliary microwave electric field to control the atomic energy level, and demonstrated the use of auxiliary microwave electric field and Rydberg electromagnetic induction transparency-Autler-Townes splitting spectrum to measure the microwave frequency of adjacent principal quantum numbers n intervals. In 2022, it was proposed to use the non-resonant heterodyne technology to introduce a local microwave field (LO field) with a frequency similar to that of the signal microwave field (SIG field), and the two form a frequency mixing, which can realize high-sensitivity measurement in the non-resonant near area. And it will not affect the atomic energy level. This method can cover a wide frequency range of 0-20GHz, but when the microwave frequency is detuned from the resonance transition frequency of the atomic level, the system changes from a linear response to a nonlinear response, due to the limitation of the non-resonant second-order Stark effect, resulting in The sensitivity at detuning is 20dB lower than that at resonance, and the sensitivity in the non-resonance region is far below that of the resonance region.

Contents of the invention

Aiming at the defects in the prior art, the object of the present invention is to provide a method for expanding microwave measurement bandwidth and sensitivity, a storage medium and a system that can achieve higher measurement sensitivity within the extended linear response range.

In order to achieve the above purpose, the technical solution adopted by the present invention is: a method for expanding microwave measurement bandwidth and sensitivity, comprising the steps of: constructing a Rydberg atomic microwave electric field sensor; radiating signal microwaves and local microwaves into a rubidium atomic vapor pool Interference is realized, and the beat frequency signal formed by the interference is measured by the Rydberg atomic microwave electric field sensor; the measurement bandwidth and sensitivity of the microwave electric field to be measured are improved through the auxiliary microwave electric field.

Further, the auxiliary microwave electric field can regulate the position of the target Rydberg energy level, and the system of the energy level is the Rydberg five-level model under the auxiliary microwave embellishment, where 3, 4, and 5 energy levels are the principal quantum The Rydberg level with a large number n.

Further, the electromagnetically induced transparency (EIT) quantum interference effect is realized by utilizing the transition from 1-level to 2-level resonant with the frequency of the probe light, and the transition from 2-level to 3-level resonant with the frequency of the coupling light.

Further, by introducing an auxiliary microwave field that resonates with the transition from the 5th energy level to the 4th energy level, the electric field strength and frequency of the auxiliary field are selected to regulate the change of the 4th energy level, so as to make the detuned microwave field to be measured reconnect with the target DePauw level transition re-resonance effect.

Further, in the Rydberg five-level model, the 1 energy level is 5S _1/2 , the 2 energy level is 5P _3/2 , the 3 energy level is 61D _5/2 , the 4 energy level is 62P _3/2 , the 5 The energy level is 62P _3/2 .

Further, after the auxiliary microwave electric field acts, the detuned microwave field resonates with the target Rydberg energy level transition, and the response of the microwave electric field to be measured returns from insensitive nonlinearity to sensitive linear relationship.

Further, the signal microwave and the local microwave are respectively radiated into the rubidium atomic vapor cell through two microwave antennas, wherein the polarization of the local microwave is linear and constant.

Further, the microwave antenna is a rectangular horn antenna.

The invention provides a storage medium, characterized in that:

A computer program is stored in the storage medium, wherein the computer program is configured to execute the method for expanding microwave measurement bandwidth and sensitivity when running.

The present invention also provides a system for expanding microwave measurement bandwidth and sensitivity, including: a Rydberg atomic microwave electric field sensor building block, used to construct a Rydberg atomic microwave electric field sensor to measure beat frequency signals; a beat frequency module, It is used to radiate signal microwaves and local microwaves into the rubidium atomic steam cell to achieve interference, and measure the beat frequency signal formed by the interference through the Rydberg atomic microwave electric field sensor; the auxiliary microwave module is used to improve the waiting time through the auxiliary microwave electric field Measurement bandwidth and sensitivity of microwave electric field.

The effect of the present invention is that by adjusting the Rydberg atomic energy level through an auxiliary microwave field, the energy level decorated by the auxiliary microwave electric field can resonate with the microwave field to be measured, that is, the response of the system to the microwave electric field to be measured is never sensitive. The second-order nonlinear interactions become sensitive first-order linear interactions, which will help improve the sensitivity of the sensor. Moreover, on the basis that the linear response interval of a Rydberg energy level transition can be increased by at least hundreds of MHz, this basically covers the adjacent Rydberg energy level intervals, thereby solving the problem that the frequency of the microwave electric field is affected by the Rydberg The challenge of discrete energy level limitations also enables higher measurement sensitivity over an extended linear response range.

Description of drawings

Fig. 1 is a flow chart of steps of a method for expanding microwave measurement bandwidth and sensitivity of the present invention;

Figure 2 is a schematic diagram of the experimental energy level;

Figure 3 is a schematic diagram of the experimental setup;

Figure 4 is a schematic diagram of the EIT-AT splitting spectrum generated by the local microwave field before and after the auxiliary microwave electric field embellishment;

Fig. 5 is a schematic diagram of the influence of the auxiliary microwave electric field on the beat frequency signal output by the mixer under the heterodyne method;

Fig. 6 is a schematic diagram of the relationship between the amplitude of the beat frequency signal at the resonance point and the detuning point of the heterodyne method before and after the intervention of the auxiliary microwave field and the intensity of the microwave electric field to be measured;

Fig. 7 is a schematic diagram of the relationship between the measured microwave power sensitivity and the amount of microwave detuning before and after the intervention of the auxiliary microwave field under the non-resonant heterodyne method.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1-3, a method for expanding microwave measurement bandwidth and sensitivity provided by the present invention includes steps:

S1, constructing the Rydberg atomic microwave electric field sensor;

Specifically, using ⁸⁷ Rb atoms, the involved Rydberg atoms consist of four energy levels, namely 5S _1/2 (F=2), 5P _3/2 (F=3), 61D _5/2 (F =4), 62P _3/2 (F=3), but not limited to these specific atomic levels. Among them, the 780nm laser (probe light) acts on the transition of 5S _1/2 (F=2)→5P _3/2 (F=3), and the 480nm laser (coupled light) acts on 5P _3/2 (F=3) → 61D _5/2 (F=4) transition, 9.2GHz microwave acts on 61D _5/2 (F=4) → 62P _3/2 (F=3) transition. The 780nm laser (probe light) and the 480nm laser (coupled light) overlap and propagate in the rubidium atom vapor pool to form the electromagnetically induced transparency (EIT) of Rydberg atoms. At this time, after applying a microwave electric field, EIT will occur Autler -Townes splitting, the change of microwave electric field intensity can be measured by detecting the change of light transmittance at the EIT resonance position.

In a specific embodiment, the parameters of the laser include: the detection light power is 60 microwatts, the diameter in the rubidium atom vapor is about 800 micrometers, the coupling light power is 50 milliwatts, and the diameter in the rubidium atom vapor is about 900 micrometers.

It should be noted that, in this embodiment, the intensity of coupled light is modulated with a 30 kHz sinusoidal period by using an acousto-optic modulator, and the 30 kHz modulation signal is simultaneously sent to the lock-in amplifier as a reference signal, and then the lock-in amplifier is used to Improve the signal-to-noise ratio of the probe light. During the experiment, the frequency of the probe light is locked at the transition of 5S _1/2 (F=2)→5P _3/2 (F=3), and the frequency of the coupling light is locked at 5P _3/2 (F=3)→61D _{5/ 2} (F=4) transitions. At this time, when microwaves are applied to the rubidium atomic vapor cell, the intensity of the probe light will change, and the intensity of the microwave electric field can be obtained by measuring the change of the transmittance (or light intensity) of the probe light.

S2, irradiate the signal microwave and the local microwave into the rubidium atomic steam cell to achieve interference, and measure the beat frequency signal formed by the interference through the Rydberg atomic microwave electric field sensor;

Specifically, signal microwaves and local microwaves are radiated into the rubidium atomic vapor pool through two microwave antennas, and interference is realized in the rubidium atomic vapor pool, and the beat frequency signal of the interference is measured by the Rydberg atomic microwave electric field sensor, that is The beat frequency signals of two microwave interferences are obtained by measuring the periodic sinusoidal variation of the detected light intensity with time. The amplitude of the beat frequency signal is proportional to the microwave electric field strength of the signal, so the microwave electric field strength can be obtained by measuring the amplitude of the beat frequency signal.

Taking a specific example as an illustration, a rectangular horn antenna is used to transmit the microwave electric field to the rubidium atomic vapor pool. The rectangular horn antenna can provide a very good linearly polarized microwave signal under far-field conditions. The interfering beat frequency signal is measured by the Rydberg atomic microwave electric field sensor, that is, the periodic sinusoidal change of the detected light intensity with time is obtained, and the frequency of the beat frequency is equal to the frequency difference Δ _MW of the two microwave electric fields. When the amplitude E _LO of the local microwave electric field is much larger than the amplitude E _SIG of the signal microwave electric field, the relationship between the detection light intensity T _p and the amplitude of the signal microwave electric field is as follows:

T _p ∝E _LO +E _SIG sin(Δ _MW t)

It can be understood that in this embodiment, only the change of the amplitude is focused, so the phase information of the local microwave electric field and the signal microwave electric field is ignored.

In a specific embodiment, the frequency difference between the two microwave electric fields, that is, the frequency difference between the signal microwave and the local microwave electric field is 1 kHz, the amplitude E _LO of the local microwave electric field=6.43mV/cm, and the amplitude E _SIG of the signal microwave electric field =1.73mV/cm, the gain of the two antennas is 10dB. The strong field power can be adjusted to adjust the oscillation peak-to-peak value of the transmitted light intensity of the detection light caused by the beat frequency signal under the condition of no magnetic field. It can be adjusted according to the actual measurement requirements. beat frequency signal. In actual operation, the frequency difference between the two microwave electric fields can reach 100kHz, which is mainly limited by the bandwidth of the lock-in amplifier used in the experiment at 100kHz.

S3, improving the measurement bandwidth and sensitivity of the microwave electric field to be measured through the auxiliary microwave electric field;

Specifically, the auxiliary microwave electric field can regulate the position of the target Rydberg energy level: as shown in Figure 2, the energy level system in this embodiment is the Rydberg five-level model under the auxiliary microwave embellishment, where 3, 4 , 5 energy level is the Rydberg energy level with larger principal quantum number n. Electromagnetically Induced Transparency (EIT) quantum interference effects are achieved by exploiting the 1-level to 2-level transition resonant with the probing light frequency _ωp , and the 2-level to 3-level transition resonant with the coupled light frequency _ωc , This part is a typical ladder-type three-level model to realize EIT. In addition, adding a signal field of frequency ω _t resonant with the transition from 4-level to 3-level, when the intensity E _MW of this microwave field is large enough, a symmetrical Autler- Townes splits, and the spectral split width Δf _MW generated at resonance is positively correlated with the Rabi frequency Ω _MW of the microwave field. The traditional method of using EIT-AT splitting to measure the microwave electric field strength to be measured requires that the frequency of the field to be measured resonates with the target Rydberg energy level transition frequency. When the frequency of the field to be measured is detuned from the atomic resonance transition frequency, the EIT-AT split becomes asymmetrical, and at this time, the relationship between Δf _MW and Ω _MW is no longer linear. will also be greatly reduced. In the case of detuning, by introducing an auxiliary microwave field with a frequency ω _t that resonates with the transition from the 5th energy level to the 4th energy level, the change of the 4th energy level is regulated by selecting the electric field strength and frequency of the auxiliary field, so as to achieve The effect of the detuned microwave field under test re-resonating with the target Rydberg level transition, thereby increasing the amplitude of the beat frequency signal.

In this example, 1 energy level is 5S _1/2 , 2 energy level is 5P _3/2 , 3 energy level is 61D _5/2 , 4 energy level is 62P _3/2 , and 5 energy level is 62P _3/2 .

Taking a specific example as an illustration, as shown in Figure 4, the EIT spectrum was first measured without any microwave electric field applied, showing a narrow electromagnetically induced transparent peak. The frequency of the microwave electric field to be measured is set to be the same as the transition frequency of Rydberg atomic energy levels 3 and 4, and the EIT-AT split of the microwave electric field at resonance is measured at that time, showing that the EIT-AT split caused by the microwave electric field at resonance Split doublets are symmetrical. Then the frequency of the microwave electric field to be measured is set to be 14.6MHz different from the transition frequency of Rydberg atomic energy levels 3 and 4, which is called detuning 14.6MHz, and then the EIT-AT split at this time is measured, showing that the microwave electric field is at The EIT-AT splitting doublets induced by detuning are asymmetrical, and show that as the amount of detuning increases, the asymmetry increases even though the separation of the doublets increases, that is, when the detuning The distance between EIT-AT splitting and the intensity of the microwave electric field to be measured is no longer a linear relationship. Specifically, the peak intensity close to the resonance with the atomic energy level transition frequency will become stronger and stronger, and the peak intensity far away from the resonance will become weaker and weaker until it disappears. , which means that the microwave electric field has no interaction with the Rydberg atoms when they are far out of tune.

When the microwave electric field to be tested is 14.6 MHz out of tune with the atomic resonance transition frequency, adding an auxiliary microwave electric field and adjusting the strength of the auxiliary microwave electric field can restore the asymmetrical EIT-AT splitting doublet to symmetry. At this time, the splitting interval It is different from resonance because the position of the Rydberg atomic energy level is not only changed after the auxiliary microwave electric field is adjusted, the energy level after the new adjustment is called the decoration level, but also the transition matrix element between the decoration levels is changed Therefore, the intervals of EIT-AT splits are different under the same microwave electric field strength to be tested. However, after the auxiliary microwave electric field is applied, the detuned microwave field resonates with the target Rydberg energy level transition, and the response of the system to the microwave electric field to be measured returns from the insensitive nonlinearity to the sensitive linear relationship.

It can be understood that in this part of the experimental demonstration, the frequency of the coupling light is not changed, and the frequency scanning range of the detection light is not changed at the same time, which means that it is successful to use the auxiliary microwave electric field to only regulate the position of the target Rydberg energy level.

As shown in Figure 5, when the microwave electric field to be measured resonates with the atomic transition, a local microwave electric field is introduced to obtain the beat frequency signal at this time. Then the frequency of the microwave electric field to be measured is changed from resonance to detuning -16MHz. Under the same experimental conditions, the amplitude of the beat frequency signal decreases sharply. Finally, after adding the auxiliary microwave electric field, the amplitude of the beat frequency signal becomes larger again. This shows that the auxiliary microwave electric field increases the amplitude of the beat frequency signal output by the mixer when the microwave electric field under test is detuned, which provides a basic guarantee for improving the bandwidth and sensitivity of the detector.

共振点处，普通外差法拍频信号振幅随待测微波电场强度的变化，最小电场强度可测值为18μV/cm。|Δ_LO＝-22MHz失谐点处，普通外差法拍频信号振幅随待测微波电场强度的变化，最小电场强度可测值为180μV/cm。

失谐点处，辅助场介入的外差法拍频信号振幅随待测微波电场强度的变化，最小电场强度可测值为18μV/cm。辅助场介入的外差法可基本达到共振时的测量极限值。As shown in Figure 6, by changing the intensity of the microwave electric field to be measured, the amplitude of the beat frequency signal output by the mixer is recorded. The comparison of microwave electric field measurement sensitivity is compared under the three situations of microwave electric field resonance (detuning amount = 0), detuning amount = -22MHz, and detuning amount = -22MHz under the action of auxiliary microwave electric field.

At the resonance point, the amplitude of the ordinary heterodyne beat frequency signal changes with the microwave electric field strength to be measured, and the minimum electric field strength can be measured to be 18μV/cm. |Δ _LO ＝-22MHz detuning point, the ordinary heterodyne beat frequency signal amplitude changes with the microwave electric field strength to be measured, and the minimum electric field strength can be measured to be 180μV/cm.

At the detuning point, the amplitude of the heterodyne beat frequency signal intervened by the auxiliary field varies with the microwave electric field strength to be measured, and the minimum electric field strength can be measured to be 18μV/cm. The heterodyne method with auxiliary field intervention can basically reach the measurement limit value at resonance.

的关系曲线。圆圈点线是在最佳匹配辅助场介入情况下，最小测量极限与失谐量

的关系曲线。在整个失谐区间内，辅助场的介入基本都可以实现更好的测量灵敏度，这体现在它拥有更小的测量极限。因此由实验结果可得出结论，当辅助场存在时，在0到-100MHz频率失谐区间内，测量最小微波功率有很大提升，最大可以提高20dB(100倍)，电场强度与功率的算术平方根成正比，也就是电场强度大约可提高10倍的测量灵敏度。印证了上述方法可以使得一个里德堡能级跃迁的线性响应区间增大至少百MHz量级的基础上，这基本上涵盖了相邻里德堡能级间隔，解决了微波电场频率受到里德堡分立能级限制的难题，在扩展的线性响应区间内还可以实现更高的测量灵敏度。As shown in Figure 7, under different detuning amounts of the microwave electric field to be measured, by optimizing the strength of the auxiliary microwave electric field, the improvement of the measurement sensitivity of the auxiliary microwave electric field in the range of detuning amount -100MHz to 0MHz was studied. As shown in Figure 7, the square dotted line is the minimum measurement limit and detuning amount without the intervention of the auxiliary field

relationship curve. The dotted line in the circle is the minimum measurement limit and detuning amount under the best matching auxiliary field intervention

relationship curve. In the entire detuning interval, the intervention of the auxiliary field can basically achieve better measurement sensitivity, which is reflected in its smaller measurement limit. Therefore, it can be concluded from the experimental results that when the auxiliary field exists, within the frequency detuning range of 0 to -100MHz, the measured minimum microwave power is greatly improved, and the maximum can be increased by 20dB (100 times). The arithmetic of electric field strength and power Proportional to the square root, that is, the electric field strength can increase the measurement sensitivity by approximately 10 times. It has been confirmed that the above method can increase the linear response interval of a Rydberg energy level transition by at least hundreds of MHz, which basically covers the interval between adjacent Rydberg energy levels, and solves the problem that the microwave electric field frequency is affected by the Reedberg energy level. Fort's discrete energy level limitation problem can also achieve higher measurement sensitivity in the extended linear response range.

The present invention also provides a storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of implementing a method for expanding microwave measurement bandwidth and sensitivity are realized.

It should be noted that the storage medium shown in this application may be a computer-readable signal medium or a storage medium or any combination of the above two. The storage medium may be, for example—but not limited to—electric, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems, or devices, or any combination thereof. More specific examples of storage media may include, but are not limited to, electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), fiber optics, portable compact disk read only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this application, a storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, system, or device. In this application, however, a storage medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code therein. Such propagated data signals may take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. The storage medium may also be any computer-readable medium other than a storage medium that can transmit, propagate, or transport the program for use by or in connection with the instruction execution system, system, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

The present invention also provides a system for expanding microwave measurement bandwidth and sensitivity, which includes:

The Rydberg atomic microwave electric field sensor building block is used to construct the Rydberg atomic microwave electric field sensor to measure the beat frequency signal;

The microwave adjustment module is used to generate local microwaves with constant phase and signal microwaves with adjustable polarization direction, and radiate the local microwaves and signal microwaves to the rubidium atomic vapor pool to achieve interference;

The conversion module is used for converting the measurement of microwave polarization into the measurement of beat frequency amplitude.

It can be seen from the above embodiments that the present invention can regulate the Rydberg atomic energy level through an auxiliary microwave field, and can make the energy level decorated by the auxiliary microwave electric field resonate with the microwave field to be measured, that is, the energy level of the system to be measured microwave electric field The response is changed from an insensitive second-order nonlinear interaction to a sensitive first-order linear interaction, which will help improve the sensitivity of the sensor. Moreover, on the basis that the linear response interval of a Rydberg energy level transition can be increased by at least hundreds of MHz, this basically covers the adjacent Rydberg energy level intervals, thereby solving the problem that the frequency of the microwave electric field is affected by the Rydberg The challenge of discrete energy level limitations also enables higher measurement sensitivity over an extended linear response range.

The method and system described in the present invention are not limited to the examples described in the specific implementation modes. Other implementation modes obtained by those skilled in the art according to the technical solution of the present invention also belong to the technical innovation scope of the present invention.

Claims (10)

1. A method for expanding microwave measurement bandwidth and sensitivity, characterized in that it comprises steps: Construction of Rydberg atomic microwave electric field sensor; The signal microwave and local microwave radiation are irradiated into the rubidium atomic steam cell to achieve interference, and the beat frequency signal formed by the interference is measured by the Rydberg atomic microwave electric field sensor; The measurement bandwidth and sensitivity of the microwave electric field to be measured are improved through the auxiliary microwave electric field. 2. a kind of method for expanding microwave measurement bandwidth and sensitivity as claimed in claim 1, is characterized in that: The auxiliary microwave electric field can regulate the position of the target Rydberg energy level, and the system of the energy level is the Rydberg five-level model under the auxiliary microwave embellishment, wherein the energy levels 3, 4, and 5 are the principal quantum numbers n Larger Rydberg levels. 3. a kind of method for expanding microwave measurement bandwidth and sensitivity as claimed in claim 2, is characterized in that: Electromagnetically Induced Transparency (EIT) quantum interference effects are realized by utilizing the transition from 1-level to 2-level resonant with the frequency of the probe light and the transition from 2-level to 3-level resonant with the frequency of the coupled light. 4. a kind of method for expanding microwave measurement bandwidth and sensitivity as claimed in claim 2, is characterized in that: By introducing an auxiliary microwave field that resonates with the transition from the 5th energy level to the 4th energy level, the electric field strength and frequency of the auxiliary field are selected to regulate the change of the 4th energy level, so that the detuned microwave field to be measured can reconnect with the target Rydberg The effect of energy level transition re-resonance. 5. A kind of method expanding microwave measurement bandwidth and sensitivity as claimed in claim 2, is characterized in that: In the Rydberg five-level model, the 1 energy level is 5S _1/2 , the 2 energy level is 5P _3/2 , the 3 energy level is 61D _5/2 , the 4 energy level is 62P _3/2 , and the 5 energy level for 62P _3/2 . 6. A kind of method expanding microwave measurement bandwidth and sensitivity as claimed in claim 4, is characterized in that: After the auxiliary microwave electric field acts, the detuned microwave field resonates with the target Rydberg energy level transition, and the response of the microwave electric field to be measured returns from an insensitive nonlinearity to a sensitive linear relationship. 7. A kind of method expanding microwave measurement bandwidth and sensitivity as claimed in claim 1, is characterized in that: The signal microwave and the local microwave are respectively radiated into the rubidium atom vapor cell through two microwave antennas, wherein the polarization of the local microwave is linear and constant. 8. a kind of method for expanding microwave measurement bandwidth and sensitivity as claimed in any one of claim 7, is characterized in that: The microwave antenna is a rectangular horn antenna. 9. A storage medium, characterized in that: A computer program is stored in the storage medium, wherein the computer program is configured to execute the method for expanding microwave measurement bandwidth and sensitivity described in any one of claims 1-8 during operation. 10. A system for expanding microwave measurement bandwidth and sensitivity, characterized in that it comprises: The Rydberg atomic microwave electric field sensor building block is used to construct the Rydberg atomic microwave electric field sensor to measure the beat frequency signal; The beat frequency module is used to radiate the signal microwave and local microwave into the rubidium atomic steam pool to achieve interference, and measure the beat frequency signal formed by the interference through the Rydberg atomic microwave electric field sensor; The auxiliary microwave module is used to improve the measurement bandwidth and sensitivity of the microwave electric field to be measured through the auxiliary microwave electric field.

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