A device and method for stabilizing the frequency of a laser at an arbitrary detuning

Abstract

The application provides a laser arbitrary detuning frequency stabilizing device and method, which comprises a pumping laser atomic resonance point frequency stabilizing structure, an optical resonant cavity length locking structure and a detection laser arbitrary detuning frequency stabilizing structure. The pumping laser is stabilized at the atomic resonance point by a saturated absorption frequency stabilizing method, and then the cavity length of the optical resonant cavity is locked by using the stabilized pumping light as a reference. Two different frequency modulation signals are superimposed by using a Bias Tee, and the detection laser is subjected to double phase modulation by an electro-optic phase modulator, so that a stable error signal is demodulated while the modulation sideband is generated. Then, the first order sideband is locked on the longitudinal mode of the optical resonant cavity near the optimal detuning point, and the frequency continuous tuning in the detection laser frequency stabilizing process is realized by adjusting the first order sideband frequency. The volume and cost are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser frequency stabilization control in quantum precision measurement technology, in particular to the field of non-atomic resonance point frequency stabilization of a laser, and specifically relates to a laser arbitrary frequency stabilization device and method. BACKGROUND

[0002] In the field of atomic spin inertial measurement, the frequency stability of the detection laser will affect the atomic polarization performance and the light spin angle detection performance, thereby directly affecting the precision and stability of the atomic spin inertial measurement system. In order to achieve stable atomic polarization performance, the operating frequency of the pumping laser needs to be stabilized at the atomic resonance point, and in order to suppress the pumping effect introduced by the detection laser on the atom, the operating frequency of the detection laser needs to deviate from the alkali metal atomic absorption line. Studies have shown that there is an optimal frequency point that can maximize the suppression of the influence of the detection laser on the atomic spin polarization performance, in addition, the optimal frequency detuning point of the detection laser will change with different conditions of the alkali metal cell in the atomic spin inertial measurement system, such as cell temperature, atomic density and initial pumping light power. Although the atomic resonance frequency is stable, it cannot support the frequency stabilization of the detection laser because its frequency is fixed. The longitudinal mode of the optical resonator can be used as a reference for laser frequency stabilization, and its longitudinal mode distribution is widespread, so the laser frequency is locked to a certain longitudinal mode of the optical resonator to achieve frequency stabilization, such as the PDH (Pound-Drever-Hall) frequency stabilization technology. However, the longitudinal mode distribution of the optical resonator is not continuous, and there is a large frequency interval between adjacent longitudinal modes, which is called the free spectral range, which will limit the frequency tuning of the laser locked to the optical resonator, which will not meet the needs of the detection laser to reach the optimal frequency detuning point in the atomic spin inertial measurement system. In addition, the cavity length of the optical resonator is sensitive to environmental disturbances such as temperature fluctuations and mechanical vibrations, which will cause the frequency stability of the laser locked to the cavity to deteriorate. The use of a super-stable cavity with high stability and placed in a vacuum chamber can to some extent suppress the cavity length drift of the resonator, but this solution is bulky and expensive, making it difficult to apply. SUMMARY

[0003] To solve the above technical problems, the application provides a laser arbitrary detuning frequency stabilizing device and method, which mainly comprises a pumping laser atomic resonance point frequency stabilizing light path, an optical resonant cavity locking light path and a detection laser arbitrary detuning frequency stabilizing light path.

[0004] To achieve the above object, the technical scheme adopted by the application is as follows:

[0005] A laser arbitrary detuning frequency stabilizing device, comprising a pumping laser atomic resonance point frequency stabilizing light path, an optical resonant cavity locking light path and a detection laser arbitrary detuning frequency stabilizing light path; the pumping laser atomic resonance point frequency stabilizing light path is used for locking the frequency of pumping light to an atomic resonance point; the optical resonant cavity locking light path takes the frequency of the stabilized pumping light as a frequency standard and locks the cavity length of the optical resonant cavity on the pumping light; and the detection laser arbitrary detuning frequency stabilizing light path locks the detection laser on the optical resonant cavity.

[0006] Further, the pumping laser atomic resonance point frequency stabilizing light path comprises a pumping laser, a first optical isolator, a first half-wave plate, a first polarization beam splitter prism, a 50:50 transmissive-reflection mirror, an atomic cell, a first mirror, a first photodetector, a first signal generator, a first frequency discriminator, a first low-pass filter, a first PI controller and a power divider; the pumping laser with a central wavelength of 770 nm passes through the first optical isolator, and then is divided into two parts by the first half-wave plate and the first polarization beam splitter prism: the reflected part enters the 50:50 transmissive-reflection mirror and is reflected into the potassium atomic cell as pump light, the pump light is reflected by the first mirror back into the potassium atomic cell as detection light, the pump light and the detection light intersect to generate saturated absorption spectrum, the detection light carrying spectral information is detected by the first photodetector after passing through the 50:50 transmissive-reflection mirror; the first signal generator generates a sweep signal and a modulation signal with a frequency of ​The demodulation signal is input to the first frequency discriminator, and the signal detected by the first photodetector is output to the first frequency discriminator to mix with the demodulation signal and demodulate the error signal. The error signal is transmitted to the first PI controller through the first low-pass filter and generates a feedback control signal. Finally, the control signal is transmitted to the frequency tuning port of the pump laser to realize laser frequency locking.

[0007] Further, the optical resonant cavity locking light path comprises a second mirror, a second half-wave plate, a second polarization beam splitter prism, a first quarter-wave plate, a dichroic mirror, a convex lens, an optical resonant cavity, a piezoelectric ceramic, a second photodetector, a phase shifter, a second frequency discriminator, a second low-pass filter, and a second PI controller. The part transmitted by the first polarization beam splitter prism is reflected by the second mirror, and then transmitted through the second half-wave plate, the second polarization beam splitter prism, the first quarter-wave plate, the dichroic mirror and the convex lens in turn, and then coupled into the optical resonant cavity. The reflected light containing the resonant cavity phase information returns along the original light path, and then transmits through the convex lens and the dichroic mirror in turn, and then is reflected by the second polarization beam splitter prism into the second photodetector. The signal at the other end of the power divider is considered as a demodulation signal after passing through the phase shifter, and then is sent to the second frequency discriminator. The signal detected by the second photodetector is output to the second frequency discriminator to mix with the demodulation signal and demodulate the error signal. The error signal is transmitted to the second PI controller through the second low-pass filter and generates a feedback control signal. Then the feedback control signal is transmitted to the port of the piezoelectric ceramic 32 of the optical resonant cavity to realize the cavity length locking of the optical resonant cavity.

[0008] Further, the detection laser arbitrary detuning frequency stabilization light path comprises a detection laser, a second optical isolator, a third half-wave plate, an electro-optic phase modulator, a third polarization beam splitter prism, a second quarter-wave plate, a third photodetector, a third frequency discriminator, a second signal generator, a radio frequency source, a radio frequency amplifier, a Bias Tee, an EOM driver, a third low-pass filter, a third PI controller, and an adder. The laser with a center wavelength of 795 nm from the detection laser passes through the second optical isolator, and then transmits through the third half-wave plate, the electro-optic phase modulator, the third polarization beam splitter prism, and the second quarter-wave plate in turn, and is reflected by the dichroic mirror. Then the laser is coupled into the optical resonant cavity through the convex lens. The reflected light containing the resonant cavity phase information returns along the original light path, and then transmits through the convex lens and is reflected by the dichroic mirror into the third polarization beam splitter prism, and then is reflected by the third polarization beam splitter prism into the third photodetector. The radio frequency source generates a high-frequency modulation signal with a frequency of The relatively low frequency modulation signal of the detection laser is amplified by a radio frequency amplifier, and then output to the DC port of the Bias Tee; the RF&DC port of the Bias Tee is connected with the EOM driver, and then the electro-optical phase modulator is driven to apply double-phase modulation to the detection laser; the frequency of the detection laser is tuned to the optimal detuning point, and a sweep signal is applied to the detection laser; the reflection spectrum of the optical resonant cavity is observed, and then the output frequency of the radio frequency source is adjusted so that the resonance peak generated by the first-order sideband is moved to the median point of the sweep signal; then the signal detected by the third photodetector is output to the third frequency discriminator phase detector to be mixed with the demodulation signal and demodulate the error signal; the error signal is transmitted to the third PI controller through the third low-pass filter and generates a feedback control signal; finally, the control signal is transmitted to the frequency tuning port of the detection laser to realize the frequency locking of the laser.

[0009] Further, the optical resonant cavity is attached with a piezoelectric ceramic on one of the cavity mirrors, and the cavity length of the optical resonant cavity is adjusted by adjusting the piezoelectric ceramic.

[0010] The application also provides a frequency stabilization method of the laser arbitrary detuning frequency device, comprising the following steps:

[0011] Step one, the pumping laser is stabilized at the atomic resonance point by the saturated absorption frequency stabilization method;

[0012] Step two, the modulation information carried by the saturated absorption frequency stabilization of the pumping light is multiplexed with the reference pumping light, and the error signal is demodulated, so as to lock the cavity length of the optical resonant cavity;

[0013] Step three, the Bias Tee is used to superimpose two modulation signals with different frequencies, the detection laser is applied with double-phase modulation by the electro-optical phase modulator, the stable error signal is demodulated while the modulation sideband is generated, then the first-order sideband is locked on the longitudinal mode of the optical resonant cavity close to the optimal detuning point, and the frequency continuous tuning in the detection laser frequency stabilization process is realized by adjusting the first-order sideband frequency, so that the detection laser frequency is accurately tuned to the optimal frequency detuning point while the frequency stability is ensured.

[0014] The application has the following beneficial effects compared with the prior art:

[0015] The application can stabilize the frequency of the laser at any detuning frequency point in its frequency tuning range, and obtain frequency stability comparable to that of atomic resonance frequency. The pump light in the atomic spin inertial measurement system is used as the reference to lock the optical resonant cavity, so that the resources can be reused. No additional modulation device is needed in the optical resonant cavity locking process, and a small volume commercial optical resonant cavity can be used without considering its stability, so that the volume and cost are reduced. The double-phase modulation frequency locking technology designed in the application uses a Bias Tee to superimpose two modulation signals, and only uses a single EOM (electro-optic phase modulator) to realize double-phase modulation of the light beam, so that the error signal can be demodulated while the modulation sideband is generated, thereby further reducing the volume and cost. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The structure diagram of the laser arbitrary detuning frequency stabilizing device of the application is shown in the figure.

[0017] In the figure, the reference signs have the following meanings: 1 is a pump laser, 2 is a first optical isolator, 3 is a first half-wave plate, 4 is a first polarization beam splitter, 5 is a first photodetector, 6 is a 50:50 transmissive-reflective mirror, 7 is an atomic cell, 8 is a first mirror, 9 is a power divider, 10 is a first signal generator, 11 is a first frequency discriminator, 12 is a first low-pass filter, 13 is a first PI controller, 14 is a second mirror, 15 is a second half-wave plate, 16 is a second polarization beam splitter, 17 is a first quarter-wave plate, 18 is a second photodetector, 19 is a phase shifter, 20 is a second frequency discriminator, 21 is a second low-pass filter, 22 is a second PI controller, 23 is a detection laser, 24 is a second optical isolator, 25 is a third half-wave plate, 26 is an electro-optic phase modulator, 27 is a third polarization beam splitter, 28 is a second quarter-wave plate, 29 is a dichroic mirror, 30 is a convex lens, 31 is an optical resonant cavity, 32 is a piezoelectric ceramic, 33 is a third photodetector, 34 is a third frequency discriminator, 35 is an EOM driver, 36 is a radio frequency source, 37 is a Bias Tee, 38 is a radio frequency amplifier, 39 is a second signal generator, 40 is a third low-pass filter, 41 is a third PI controller, and 42 is an adder. DETAILED DESCRIPTION

[0018] The embodiments of the application are described in detail below: The embodiments are implemented on the premise of the technical solutions of the application, and detailed implementation manners and specific operation processes are given. It should be noted that, for those skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are all within the protection scope of the application.

[0019] The application is further described below in combination with the drawings and specific implementation examples.

[0020] As Figure 1 shown, the laser arbitrary detuning frequency stabilizing device of the application comprises a pumping laser atomic resonance point frequency stabilizing light path, an optical resonant cavity locking light path and a detection laser arbitrary detuning frequency stabilizing light path. The pumping laser atomic resonance point frequency stabilizing light path is used for locking the frequency of pumping light to the atomic resonance point, the optical resonant cavity locking light path locks the cavity length of the optical resonant cavity on the pumping light with the frequency stabilized pumping light as the frequency standard, and finally, the detection laser arbitrary detuning frequency stabilizing light path locks the detection laser on the optical resonant cavity.

[0021] The pumping laser atomic resonance point frequency stabilizing light path comprises a pumping laser 1, a first optical isolator 2, a first half-wave plate 3, a first polarization beam splitter prism 4, a 50:50 transmissive-reflection mirror 6, an atomic cell 7, a first mirror 8, a first photodetector 5, a first signal generator 10, a first frequency discriminator 11, a first low-pass filter 12, a first PI controller 13 and a power divider 9.

[0022] The optical resonant cavity locking light path comprises a second mirror 14, a second half-wave plate 15, a second polarization beam splitter prism 16, a first quarter-wave plate 17, a dichroic mirror 29, a convex lens 30, an optical resonant cavity 31, a piezoelectric ceramic 32, a second photodetector 18, a phase shifter 19, a second frequency discriminator 20, a second low-pass filter 21 and a second PI controller 22.

[0023] The detection laser arbitrary detuning frequency stabilizing light path comprises a detection laser 23, a second optical isolator 24, a third half-wave plate 25, an electro-optic phase modulator (EOM) 26, a third polarization beam splitter prism 27, a second quarter-wave plate 28, a third photodetector 33, a third frequency discriminator 34, a second signal generator 39, a radio frequency source 36, a radio frequency amplifier 38, a Bias Tee 37, an EOM driver 35, a third low-pass filter 40, a third PI controller 41 and an adder 42.

[0024] The pump laser 1 with central wavelength of 770 nm passes through the first optical isolator 2, and then passes through the first half-wave plate 3 and the first polarization beam splitter prism 4 to be divided into two parts: the reflected part enters the 50:50 transmissive mirror 6 and is reflected into the potassium atom cell 7 as a pump light, the pump light is reflected by the first mirror 8 back into the potassium atom cell as a detection light, the pump light and the detection light intersect to generate a saturated absorption spectrum, the detection light carrying the spectral information is transmitted through the 50:50 transmissive mirror 6 and is detected by the first photodetector 5. The first signal generator 10 generates a sawtooth wave sweeping signal with a frequency of 10 Hz and an amplitude of 5 V and a modulation signal with a frequency of 30 kHz and an amplitude of 40 mV, and then inputs them into the power divider 9, one end of the power divider 9 is connected to the pump laser 1, and the other end is connected to the phase shifter 19. The first signal generator 10 simultaneously generates a demodulation signal with a frequency of 30 kHz and inputs it into the first frequency discriminator 11, and the signal detected by the first photodetector 5 is output to the first frequency discriminator 11 to be mixed with the demodulation signal and demodulate the error signal, which is transmitted to the first PI controller 13 through the first low-pass filter 12 and generates a feedback control signal, and the control signal is finally transmitted to the pump laser frequency tuning port to realize laser frequency locking.

[0025] The part transmitted by the first polarization beam splitter prism 4 is reflected by the second mirror 14, and then sequentially transmits through the second half-wave plate 15, the second polarization beam splitter prism 16, the first quarter-wave plate 17, the dichroic mirror 29 and the convex lens 30 to be coupled into the optical resonant cavity 31, the reflected light containing the resonant cavity phase information returns along the original light path, and then sequentially transmits through the convex lens 30 and the dichroic mirror 29 to be reflected by the second polarization beam splitter prism 16 into the second photodetector 18. The signal at the other end of the power divider 9 can be regarded as a demodulation signal after passing through the phase shifter 19, and then is sent to the second frequency discriminator 20, and the signal detected by the second photodetector 18 is output to the second frequency discriminator 20 to be mixed with the demodulation signal and demodulate the error signal, which is transmitted to the second PI controller 22 through the second low-pass filter 21 and generates a feedback control signal, and then is transmitted to the port of the piezoelectric ceramic 32 of the optical resonant cavity to realize the cavity length locking of the optical resonant cavity.

[0026] The laser with central wavelength of 795 nm from the detection laser 23 passes through the second optical isolator 24, and then sequentially transmits through the third half-wave plate 25, the electro-optic phase modulator (EOM) 26, the third polarization beam splitter prism 27, the second quarter-wave plate 28 to be reflected by the dichroic mirror 29, and then passes through the convex lens 30 to be coupled into the optical resonant cavity 31, the reflected light containing the resonant cavity phase information returns along the original light path, and then transmits through the convex lens 30 to be reflected by the dichroic mirror 29 into the third polarization beam splitter prism 27, and then is reflected by the third polarization beam splitter prism 27 into the third photodetector 33. The radio frequency source 36 generates a modulation signal with a frequency of 10 MHz and an amplitude of 40 mV, which is input into the power divider 9, and then is transmitted to the EOM 26 through the phase shifter 19. =500 MHz power 7dbm high frequency modulation signal and output to the RF port of Bias Tee 37, the second signal generator 39 generates frequency =30 MHz amplitude 100mV relative low frequency modulation signal, amplified by RF amplifier 38 power output to the DC port of Bias Tee 37, the RF&DC port of Bias Tee 37 connects EOM drive 35, then drives electro-optic phase modulator 26 to impose double phase modulation on the detection laser. Tuning the detection laser frequency to the best detuning point, the second signal generator 39 generates a sawtooth signal through the adder 42 applied to the detection laser. Observe the reflection spectrum of the optical resonator 31, adjust the output frequency of the RF source 36 again, so that the first-order sideband resonance peak generated is shifted to the median point of the sweep signal, and then the signal detected by the third photodetector 33 is output to the third frequency discriminator 34 and mixed with the demodulation signal to demodulate the error signal. After passing through the third low-pass filter 40, the feedback control signal is transmitted to the third PI controller 41 and generates a feedback control signal, and the control signal is finally transmitted to the detection laser frequency tuning port to realize laser frequency locking.

[0027] Therefore, the laser arbitrary detuning frequency stabilization method of the embodiment of the application comprises the following steps:

[0028] Step one, stabilize the pumping laser at the atomic resonance point by the saturated absorption frequency stabilization method;

[0029] Step two, multiplex the modulation information carried by the saturated absorption frequency stabilized pumping light, demodulate the error signal, and lock the cavity length of the optical resonator, with the stabilized pumping light as a reference;

[0030] Step three, superimpose two modulation signals of different frequencies by Bias Tee, impose double phase modulation on the detection laser by electro-optic phase modulator, demodulate the stable error signal while generating modulation sidebands, and then lock the first-order sideband on the longitudinal mode of the optical resonator near the best detuning point. By adjusting the first-order sideband frequency, the frequency continuous tuning in the detection laser frequency stabilization process is realized, so that the detection laser frequency is accurately tuned to the best frequency detuning point while ensuring the frequency stability.

[0031] Specifically, the step one comprises:

[0032] The center wavelength of the pumping laser 1 is 770 nm. After passing through the first optical isolator 2, the pumping laser 1 is split into two parts by the first half-wave plate 3 and the first polarization beam splitter 4. The reflected part enters the 50:50 partial reflector 6 and is reflected into the potassium atom cell 7 as a pump light. The pump light is reflected by the first mirror 8 back into the potassium atom cell as a detection light. The pump light and the detection light intersect to produce a saturated absorption spectrum. The detection light carrying the spectral information is transmitted through the 50:50 partial reflector 6 and is detected by the first photodetector 5. The first signal generator 10 generates a sawtooth wave sweeping signal with a frequency of 10 Hz and an amplitude of 5 V and a modulation signal with a frequency of 30 kHz and an amplitude of 40 mV, and then inputs the signals into the power divider 9. One end of the power divider 9 is connected to the pumping laser 1, and the other end is connected to the phase shifter 19. The first signal generator 10 simultaneously generates a demodulation signal with a frequency of 30 kHz and inputs the signal into the first frequency discriminator 11. The signal detected by the first photodetector 5 is output to the first frequency discriminator 11 and mixed with the demodulation signal to demodulate an error signal. The error signal is transmitted to the first PI controller 13 through the first low-pass filter 12 and generates a feedback control signal. The control signal is finally transmitted to the frequency tuning port of the pumping laser to realize laser frequency locking.

[0033] Specifically, the step two includes:

[0034] The part transmitted by the first polarization beam splitter 4 is reflected by the second mirror 14, and then sequentially transmitted through the second half-wave plate 15, the second polarization beam splitter 16, the first quarter-wave plate 17, the dichroic mirror 29, and the convex lens 30 and is coupled into the optical resonant cavity 31. The reflected light containing the phase information of the resonant cavity returns along the original light path, sequentially transmits through the convex lens 30 and the dichroic mirror 29, and is reflected by the second polarization beam splitter 16 into the second photodetector 18. The signal at the other end of the power divider 9 can be regarded as a demodulation signal after passing through the phase shifter 19, and then is sent to the second frequency discriminator 20. The signal detected by the second photodetector 18 is output to the second frequency discriminator 20 and mixed with the demodulation signal to demodulate an error signal. The error signal is transmitted to the second PI controller 22 through the second low-pass filter 21 and generates a feedback control signal, and then is transmitted to the port of the piezoelectric ceramic 32 of the optical resonant cavity to realize the cavity length locking of the optical resonant cavity.

[0035] Specifically, step three includes: the laser light from the detection laser 23 with a central wavelength of 795nm passes through the second optical isolator 24, and then passes through the third half-wave plate 25, the electro-optical phase modulator (EOM) 26, the third polarization beam splitter prism 27, the second quarter-wave plate 28, and is reflected by the dichroic mirror 29. Then, it passes through the convex lens 30 and is coupled into the optical resonant cavity 31. The reflected light containing the phase information of the resonant cavity will return along the original optical path, pass through the convex lens 30, and is reflected by the dichroic mirror 29 into the third polarization beam splitter prism 27, and is reflected by it into the third photodetector 33. The RF source 36 generates a frequency of =500 MHz high frequency modulation signal with power of 7dBm is output to the RF port of Bias Tee 37, and the second signal generator 39 generates a frequency of A relatively low-frequency modulation signal with a frequency of 30 MHz and an amplitude of 100 mV is amplified by an RF amplifier 38 and output to the DC port of the bias tee 37. The RF&DC port of the bias tee 37 is connected to the EOM driver 35, which then drives the electro-optical phase modulator 26 to apply dual-phase modulation to the detection laser. The detection laser frequency is tuned to the optimal detuning point, and a swept frequency signal is applied to the detection laser. The reflection spectrum of the optical resonator 31 is observed, and the output frequency of the RF source 36 is adjusted to shift the resonance peak generated by the first-order sideband to the midpoint of the swept frequency signal. The signal detected by the third photodetector 33 is then output to the third frequency and phase detector 34, where it is mixed with the demodulated signal and demodulated to produce an error signal. This signal is then transmitted through a third low-pass filter 40 and transmitted to the third PI controller 41 to generate a feedback control signal. This control signal is finally transmitted to the frequency tuning port of the detection laser to lock the laser frequency.

[0036] Preferably, in step 2, a piezoelectric ceramic 32 is attached to one of the cavity mirrors of the optical resonant cavity 31. The cavity length of the optical resonant cavity can be adjusted by adjusting the piezoelectric ceramic 32. A dichroic mirror 29 is used to distinguish between the pump laser and the detection laser. The pump light with a wavelength of 770nm can pass through the dichroic mirror 29, while the detection light with a wavelength of 795nm will be reflected by the dichroic mirror 29. The pump laser coupled into the optical resonant cavity 31 contains the same modulation information as in step 1. Therefore, during the cavity length locking process of the optical resonant cavity 31, this modulation information can be used to demodulate the error signal without applying additional modulation to the resonant cavity.

[0037] Preferably, the tuning bandwidth of the RF source 36 needs to cover at least half of the free spectral range in order to achieve frequency stabilization at any frequency point. The DC port of the Bias Tee 37 attenuates the power of the higher frequency signal, so the second signal generator 39 needs to be amplified by the RF amplifier 38 before connecting to the DC port of the Bias Tee 37. Unlike the frequency mixer, the Bias Tee 37 can superimpose the high frequency signal with frequency and the low frequency signal with frequency without generating sum frequency signal and difference frequency signal. By adjusting the frequency of the RF source output signal, the tuning of the detection laser locking frequency can be achieved.

[0038] The contents not described in detail in the present invention belong to the prior art known to those skilled in the art.

Claims

1. A laser arbitrary detuning frequency stabilization device, characterized in that: It includes a pumping laser atomic resonance point frequency stabilization optical path, an optical resonant cavity locking optical path, and a detection laser arbitrary detuned frequency stabilization optical path; the pumping light atomic resonance point frequency stabilization optical path is used to lock the pumping light frequency to the atomic resonance point, the optical resonant cavity locking optical path uses the stabilized pumping light as the frequency standard, and locks the cavity length of the optical resonant cavity to the pumping light; the detection laser arbitrary detuned frequency stabilization optical path locks the detection laser to the optical resonant cavity; The optical path for stabilizing the frequency of the detection laser's arbitrary detuned frequency includes a detection laser, a second optical isolator, a third half-wave plate, an electro-optical phase modulator, a third polarization beam splitter prism, a second quarter-wave plate, a third photodetector, a third frequency and phase detector, a second signal generator, a radio frequency source, a radio frequency amplifier, a Bias Tee, an EOM driver, a third low-pass filter, a third PI controller, and an adder. The laser light from the detection laser with a central wavelength of 795 nm passes through the second optical isolator, and then passes through the third half-wave plate, the electro-optical phase modulator, the third polarization beam splitter prism, and the second quarter-wave plate in sequence, and is reflected by the dichroic mirror. Then, the laser light passes through the convex lens and couples into the optical resonant cavity. The reflected light containing the phase information of the resonant cavity returns along the original optical path, passes through the convex lens, is reflected by the dichroic mirror, enters the third polarization beam splitter prism, and is reflected by the dichroic mirror into the third photodetector. The radio frequency source generates a high-frequency modulation signal with a frequency of ω1 and outputs it to the RF port of the Bias Tee. The second signal generator generates a relatively low-frequency modulation signal with a frequency of ω2, which is amplified in power by the radio frequency amplifier and output to the Bias The DC port of the Tee and the RF & DC port of the Bias Tee are connected to the EOM driver, which then drives the electro-optical phase modulator to apply dual-phase modulation to the detection laser; Tuning the detection laser frequency to an optimal detuning point and applying a frequency sweep signal to the detection laser; Observe the reflection spectrum of the optical resonant cavity, then adjust the output frequency of the RF source to move the resonance peak generated by the first-order sideband to the median point of the swept frequency signal. Then, the signal detected by the third photodetector is output to the third frequency and phase detector, mixed with the demodulated signal, and demodulated to obtain an error signal. After passing through the third low-pass filter, it is transmitted to the third PI controller to generate a feedback control signal. The control signal is finally transmitted to the frequency tuning port of the detection laser to achieve laser frequency locking.

2. The laser arbitrary detuning frequency stabilization device according to claim 1, characterized in that: The pumping laser atomic resonance point frequency stabilization optical path includes a pumping laser, a first optical isolator, a first half-wave plate, a first polarization beam splitter, a 50:50 transflective mirror, an atomic gas chamber, a first reflector, a first photodetector, a first signal generator, a first frequency and phase detector, a first low-pass filter, a first PI controller, and a power divider. After the pumping laser with a central wavelength of 770 nm passes through the first optical isolator, it is divided into two parts by the first half-wave plate and the first polarization beam splitter: the reflected part enters the 50:50 transflective mirror and is then reflected into the potassium atomic gas chamber to generate pump light, and the pump light is reflected back to the potassium atomic gas chamber by the first reflector as detection light. The pump light and the detection light intersect to generate a detection light. A saturated absorption spectrum is generated, and the detection light carrying the spectral information is detected by the first photodetector after passing through the 50:50 transflective mirror; the first signal generator generates a sweep frequency signal and a modulation signal with a frequency of ω0, which are then input into the power divider, one end of the power divider is connected to the pump laser, and the other end is connected to the phase shifter; the first signal generator simultaneously generates a demodulation signal with a frequency of ω0 and inputs it into the first frequency detector and phase detector, and the signal detected by the first photodetector is output to the first frequency detector and phase detector, mixed with the demodulation signal and demodulated to obtain an error signal, which is then transmitted to the first PI controller after passing through the first low-pass filter and generates a feedback control signal, and the control signal is finally transmitted to the frequency tuning port of the pump laser to achieve laser frequency locking.

3. The laser arbitrary detuning frequency stabilization device according to claim 1, characterized in that: The optical resonant cavity locking optical path includes a second reflector, a second half-wave plate, a second polarization beam splitter prism, a first quarter-wave plate, a dichroic mirror, a convex lens, an optical resonant cavity, a piezoelectric ceramic, a second photodetector, a phase shifter, a second frequency detector, a second low-pass filter, and a second PI controller; the portion transmitted by the first polarization beam splitter prism is reflected by the second reflector, and then sequentially passes through the second half-wave plate, the second polarization beam splitter prism, the first quarter-wave plate, the dichroic mirror, and the convex lens before being coupled into the optical resonant cavity, containing the phase information of the resonant cavity The reflected light will return along the original optical path, pass through the convex lens and the dichroic mirror in sequence, and then be reflected by the second polarization beam splitter prism into the second photodetector; the signal at the other end of the power divider is regarded as a demodulated signal after passing through the phase shifter, and then sent to the second frequency detector. The signal detected by the second photodetector is output to the second frequency detector, mixed with the demodulated signal and demodulated to obtain an error signal. After passing through the second low-pass filter, it is transmitted to the second PI controller to generate a feedback control signal, and then transmitted to the port of the piezoelectric ceramic of the optical resonator to achieve cavity length locking of the optical resonator.

4. The laser arbitrary detuning frequency stabilization device according to claim 1, characterized in that: The optical resonant cavity has piezoelectric ceramics attached to one of the cavity mirrors, and the cavity length of the optical resonant cavity can be adjusted by adjusting the piezoelectric ceramics.

5. A frequency stabilization method for a laser arbitrary detuning frequency device according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: Stabilize the pump laser frequency at the atomic resonance point by using the saturation absorption frequency stabilization method; Step 2: Using the pump light after frequency stabilization as a reference, multiplexing the modulation information carried by the pump light after saturation absorption stabilization to demodulate the error signal, thereby locking the cavity length of the optical resonator; Step 3: Use Bias Tee to superimpose two modulation signals of different frequencies, apply dual-phase modulation to the detection laser through the electro-optical phase modulator, and demodulate a stable error signal while generating modulation sidebands. Then, lock the first-order sideband to the longitudinal mode of the optical resonator close to the optimal detuning point. By adjusting the first-order sideband frequency, continuous frequency tuning is achieved during the frequency stabilization process of the detection laser, thereby accurately tuning the detection laser frequency to the optimal frequency detuning point while ensuring frequency stability.

6. The frequency stabilization method according to claim 5, characterized in that: The step one comprises: After passing through the first optical isolator, the pump laser with a central wavelength of 770nm is divided into two parts by the first half-wave plate and the first polarization beam splitter prism: the reflected part enters the 50:50 reflective mirror and is reflected into the potassium atomic gas chamber to generate pump light. The pump light is reflected back to the potassium atomic gas chamber by the first reflector and serves as detection light. The pump light and the detection light intersect to generate a saturated absorption spectrum. The detection light carrying spectral information is detected by the 50:50 reflective mirror and detected by the first photodetector. The first signal generator generates a sweep frequency signal and a modulation signal with a frequency of ω0, which are then input into a power divider. One end of the power divider is connected to the pump laser, and the other end is connected to a phase shifter. The first signal generator also generates a demodulation signal with a frequency of ω0, which is input into the first frequency and phase detector. The signal detected by the first photodetector is output to the first frequency and phase detector, mixed with the demodulation signal, and demodulated to obtain an error signal. After passing through the first low-pass filter, it is transmitted to the first PI controller to generate a feedback control signal. The control signal is finally transmitted to the frequency tuning port of the pump laser to achieve laser frequency locking.

7. The frequency stabilization method according to claim 6, characterized in that: The second step includes: The part transmitted by the first polarization beam splitter is reflected by the second reflector, and then passes through the second half-wave plate, the second polarization beam splitter, the first quarter-wave plate, the dichroic mirror and the convex lens in sequence before being coupled into the optical resonant cavity. The reflected light containing the phase information of the resonant cavity will return along the original optical path, pass through the convex lens and the dichroic mirror in sequence, and then be reflected by the second polarization beam splitter prism into the second photodetector; the signal at the other end of the power divider is regarded as a demodulated signal after passing through the phase shifter, and is then sent to the second frequency detector. The signal detected by the second photodetector is output to the second frequency detector, mixed with the demodulated signal and demodulated to obtain an error signal. After passing through the second low-pass filter, it is transmitted to the second PI controller to generate a feedback control signal, which is then transmitted to the port of the piezoelectric ceramic of the optical resonant cavity to achieve cavity length locking of the optical resonant cavity.

8. The frequency stabilization method according to claim 6, characterized in that: The step three includes: The laser light from the detection laser with a central wavelength of 795nm passes through the second optical isolator, and then passes through the third half-wave plate, the electro-optical phase modulator, the third polarization beam splitter prism, and the second quarter-wave plate in sequence, and is reflected by the dichroic mirror. It then passes through the convex lens and couples into the optical resonant cavity. The reflected light containing the phase information of the resonant cavity will return along the original optical path, pass through the convex lens, be reflected by the dichroic mirror, and enter the third polarization beam splitter prism, and be reflected by it into the third photodetector; the RF source generates a high-frequency modulation signal with a frequency of ω1 and outputs it to the RF port of the Bias Tee. The second signal generator generates a relatively low-frequency modulation signal with a frequency of ω2, which is amplified by the RF amplifier and output to the DC port of the Bias Tee. The RF&DC port of the BiasTee is connected to the EOM Drive, and then drive the electro-optical phase modulator to apply dual-phase modulation to the detection laser; tune the detection laser frequency to the optimal detuning point, and apply a sweep frequency signal to the detection laser; observe the reflection spectrum of the optical resonant cavity, and then adjust the output frequency of the radio frequency source to move the resonance peak generated by the first-order sideband to the median point of the sweep frequency signal, and then output the signal detected by the third photodetector to the third frequency and phase detector to mix with the demodulation signal and demodulate the error signal, and then transmit it to the third PI controller after passing through the third low-pass filter to generate a feedback control signal, and the control signal is finally transmitted to the frequency tuning port of the detection laser to achieve laser frequency locking.

9. The frequency stabilization method according to claim 8, characterized in that: In the step three, the tuning bandwidth of the RF source covers at least half of the free spectrum range; the third signal generator is connected to the DC port of the BiasTee after amplifying the power through the RF amplifier; unlike the mixer, the BiasTee superimposes a high-frequency signal with a frequency of ω1 and a low-frequency signal with a frequency of ω2 without generating a sum frequency signal and a difference frequency signal; by adjusting the frequency ω1 of the RF source output signal, the tuning of the detection laser locking frequency is achieved.

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