CN104466651A - Annular integrated laser frequency doubling device - Google Patents

Abstract

The present invention provides an integrated ring laser frequency doubling device, which includes a PPKTP (Periodically Polarized KTP) frequency doubling crystal and a ring frequency doubling cavity; wherein the ring cavity includes a plane mirror M1 , M2 and concave mirrors M3, M4; both ends of the PPKTP crystal are coated with anti-reflection coatings for fundamental frequency light and second harmonic. The invention utilizes a 1064nm frequency-stabilized laser and a PPKTP frequency-doubling crystal, combined with quasi-phase matching and annular external cavity frequency-doubling technology, to realize 1064nm and 532nm stable laser output with strict multiples of wavelength, and has good wavelength and power stability and narrow line width It can calibrate the wavelength linearity of the grating spectrometer; realize the miniaturization of the 1064nm frequency-stabilized laser wavelength standard device, with stable performance, compact structure and strong anti-interference ability.

Description

Integrated ring laser frequency doubling device

technical field

The invention relates to the technical field of laser frequency doubling, in particular to an integrated ring laser frequency doubling device.

Background technique

Commonly used laser output wavelengths are usually near-infrared single-frequency lasers. With the development of science and technology, the demand for lasers in various industries has greatly increased, and higher requirements have been placed on the output wavelength of lasers. It is necessary to extend the output wavelength of lasers to infrared and ultraviolet bands. expand. Laser output wavelengths that cannot be achieved by ordinary lasers can be obtained through nonlinear frequency conversion technology, such as ultraviolet, mid-infrared and far-infrared lasers, among which blue lasers are used in high-density optical data storage, laser medicine, spectroscopy, absorption imaging and laser cooling. Infrared coherent lasers are widely used in spectral research, laser guidance, laser directional infrared interference, atmospheric monitoring and other fields.

Nonlinear frequency conversion technology is an effective technology to expand the application range of lasers. It uses the nonlinear optical effect of optical media in strong radiation fields to generate new frequencies and expand the frequency of existing laser sources. It is used in scientific research and production. has a wide range of applications. The frequency doubling generation of light waves, also known as Second Harmonic Generation (SHG), is a typical nonlinear optical process, which originates from the second-order nonlinear response or polarization of the medium to the optical field. In recent years, the development direction of frequency doubling technology is to produce laser with shorter wavelength, and obtain more stable output with higher frequency doubling efficiency.

Commonly used laser frequency doubling techniques include birefringent phase-matching frequency doubling technology and quasi-phase-matching frequency doubling technology. The traditional birefringence phase-matching frequency doubling technology uses the birefringence effect and dispersion characteristics of uniaxial or biaxial crystals to achieve phase matching by selecting the wave vector direction and polarization direction of light waves, thereby obtaining high frequency doubling conversion efficiency. Technology is limited by the material itself, not all crystals can achieve birefringent phase matching, only certain crystals with special structures can achieve birefringent phase matching, and birefringent crystals need to be cut in a special direction, or a specific operating temperature , In addition, the technology cannot apply the maximum nonlinear coefficient of the crystal, which greatly limits the use of the technology.

The quasi-phase-matched frequency doubling technology uses a periodically polarized crystal to achieve phase matching, and compensates the phase loss between the pump light and the parametric light caused by the refractive index dispersion in the optical parametric process through the periodic modulation of the nonlinear polarizability of the crystal. Matching, so as to obtain the enhancement of the nonlinear optical effect. The quasi-phase matching frequency doubling technology expands the application range of existing nonlinear optical materials, and can utilize the maximum nonlinear coefficient of the crystal without walk-off effect. Quasi-phase matching frequency doubling technology has unique advantages and is widely used in nonlinear optical frequency conversion, optical pulse shaping, all-optical switching, all-optical wavelength conversion, electro-optic modulation, and acousto-optic modulation.

Contents of the invention

The purpose of the present invention is to provide an integrated ring laser frequency doubling device to realize the frequency doubling of 1064nm fundamental frequency light, obtain a 532nm frequency doubling resonant laser with high efficiency, stability and high power output, and at the same time realize the small size of the laser frequency doubling device change.

To achieve the above purpose, the present invention provides an integrated ring laser frequency doubling device, including:

PPKTP (periodically polarized KTP) frequency doubling crystal and ring frequency doubling cavity;

Wherein, the annular cavity includes plane mirrors M1, M2 and concave mirrors M3, M4; both ends of the PPKTP crystal are coated with anti-reflection coatings for fundamental frequency light and second harmonic.

Wherein, the plane reflector M1 is a coupling mirror, which is used to receive the fundamental frequency light, so as to realize the coupling of the fundamental frequency light from outside the cavity to the cavity; according to the transmittance of the plane reflector M1, "impedance matching" can be realized .

Wherein, the plane reflector M2, the concave reflector M3 and the concave reflector M4 have high reflectivity to the fundamental frequency light;

Wherein the concave mirror M4 has a high transmittance to the doubled frequency light.

Further, the device also includes a detector 1 and a detector 2, the detector 1 is located on the extension line of the M4, M1; the detector 2 is located on the extension line of the M1, M2; the The detector 1 and the detector 2 are used to monitor the misalignment between the laser wavelength of the ring frequency doubling cavity and the resonant wavelength of the resonant cavity.

Further, the device also includes a servo control circuit system, its input end is connected to the detector 2, and its output end is connected to the piezoelectric ceramic driver of the ring frequency doubling cavity;

The servo control circuit system is used to process the error signal generated when the detector 1 and the detector 2 monitor the misalignment between the laser wavelength of the ring frequency doubling cavity and the resonant wavelength of the resonator; and the processing result is fed back to the A piezoceramic driver for a ring frequency doubling cavity.

Further, the piezoelectric ceramic driver of the ring-shaped frequency doubling cavity is used to control the expansion and contraction of the piezoelectric ceramics of the ring-shaped frequency doubling cavity, so as to adjust the cavity length of the ring-shaped frequency doubling cavity, thereby realizing the ring-shaped frequency doubling cavity Tracking and locking between the frequency cavity and the 1064nm frequency-stabilized laser.

Preferably, the device also includes a 1064nm frequency-stabilized laser, a λ/4 wave plate, a λ/2 wave plate, a mode matching lens Len and a mirror;

Wherein, the 1064nm frequency-stabilized laser is used to generate the fundamental frequency light, and transmit the fundamental frequency light to the λ/4 wave plate;

The λ/4 wave plate and the λ/2 wave plate are used to successively receive and process the fundamental frequency light, so that the fundamental frequency light is converted from elliptically polarized light into linearly polarized light to achieve spatial polarization state matching;

The mode matching lens Len is used to receive the processed fundamental frequency light, and couple it into the cavity of the ring frequency doubling cavity through the reflector.

Further, the size of the optical path part of the device can be set to 20×12×9 cm ³ .

The above technical scheme has the following beneficial effects:

The invention utilizes a 1064nm frequency-stabilized laser and a PPKTP frequency-doubling crystal, combined with quasi-phase matching and annular external cavity frequency doubling technology, to realize stable laser output with strict multiples of wavelengths at 1064nm and 532nm, with good wavelength and power stability and narrow line width It can calibrate the wavelength linearity of the grating spectrometer; realize the miniaturization of the 1064nm frequency-stabilized laser wavelength standard device, with stable performance, compact structure and strong anti-interference ability.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the structural representation of the annular frequency doubling cavity of the embodiment of the present invention;

2 is a schematic structural view of an integrated ring laser frequency doubling device according to an embodiment of the present invention;

Fig. 3 is a graph showing power stability measurement at 532nm.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention utilizes a 1064nm frequency-stabilized laser and combines quasi-phase matching and ring external cavity frequency doubling technology to design an integrated ring laser frequency doubling device.

The basic principle of laser frequency doubling: light propagates in the medium and interacts with the medium. If the response of the medium to light is nonlinear, a new frequency will be generated when the light propagates in the medium. This process is called nonlinear frequency. Transformation, the incident light is the pump light, and the light of the new frequency generated is called the parametric light. When using a medium for frequency conversion, due to the different refractive indices of different medium materials, the same material has different refractive indices for different wavelengths of light, so that the propagation speed of light waves in the medium is a function of frequency (wavelength). The frequency of the pump light and the parametric light are different, the phase velocity is different, and the phase is also different. Only when a certain phase relationship is satisfied can efficient nonlinear frequency conversion be obtained. Their phase relationship is an important physical quantity that affects the gain and conversion efficiency of the parametric light. .

Commonly used laser frequency doubling techniques include birefringent phase-matching frequency doubling technology and quasi-phase-matching frequency doubling technology. The traditional birefringence phase-matching frequency doubling technology uses the birefringence effect and dispersion characteristics of uniaxial or biaxial crystals to achieve phase matching by selecting the wave vector direction and polarization direction of light waves, thereby obtaining high frequency doubling conversion efficiency. There are two ways to achieve birefringence phase matching: angle phase matching and temperature phase matching. Angle phase matching is to achieve the purpose of phase matching by changing the angle of the incident light to the crystal; temperature phase matching is to use the crystal whose refractive index is sensitive to temperature, and change the refractive index by changing the crystal temperature, so as to achieve the purpose of phase matching . Crystals commonly used for birefringent phase matching include KTP, BBO, LBO, CLBO, etc. The effective nonlinear coefficient of KTP crystal is larger than that of other crystals, and it is widely used in low and medium power. LBO crystal has a high damage threshold, can realize non-critical phase matching, and is mostly used in high power situations. However, the birefringence phase-matching frequency doubling technology mainly has the following disadvantages: ①Limitation of the material itself. There are many types of crystals, and not all crystals can achieve birefringent phase matching, and only certain crystals with special structures can achieve birefringent phase matching. Moreover, birefringent crystals need to be cut in a special direction, or have a specific working temperature, which greatly limits their use. ② Due to the inconsistency of the interaction direction of the mixed frequency light waves, the interaction length is limited and the conversion efficiency is reduced. ③ The maximum nonlinear coefficient of the crystal cannot be applied.

The quasi-phase-matching frequency doubling technology is to change the phase of the wave vector of light propagating in the crystal by π after a coherence length, that is, phase inversion. The method of inverting the phase of the wave vector of light wave is to periodically change the nonlinearity of the crystal The sign of the coefficient. Quasi-phase-matched frequency doubling technology broadens the application range of nonlinear crystals and greatly improves the frequency conversion efficiency of interacting light waves. It has become a research hotspot in the fields of nonlinear optical materials and solid-state lasers.

Quasi-Phase Matching (QPM) is another phase-matching frequency multiplication technology for efficient nonlinear frequency conversion. Periodic modulation to compensate the phase mismatch between the pump light and the parametric light caused by the refractive index dispersion in the optical parametric process, so as to obtain the enhancement of the nonlinear optical effect.

The quasi-phase-matching technology satisfies the phase-matching condition by designing the crystal into a periodic structure. Ferroelectric materials are currently the most ideal materials for quasi-phase matching. All ferroelectric crystals exhibit spontaneous polarization characteristics below the Curie temperature, and can effectively realize ferroelectric domain inversion and change the spontaneous polarization direction of the crystal under the action of an external electric field. The directions of the spontaneous polarization vectors of two adjacent ferroelectric domains are opposite, so the physical properties of the ferroelectric domains associated with odd-order tensors, such as nonlinear optical coefficients, electro-optic coefficients, and piezoelectric coefficients, are all of the same value but opposite. No., so the physical properties of such crystals are no longer constants but periodic functions of space coordinates. So far, quite a lot of crystals have been used to make quasi-phase-matched frequency doubling components, such as PPLN, PPKTP, PPLT and PPRTA crystals. For example, using the nonlinear coefficient d31 of ferroelectric crystal LiNbO3 can achieve birefringence angle phase matching, but its largest nonlinear coefficient d33 cannot achieve phase matching, but d33 of LiNbO3 can be used through quasi-phase matching, and the LiNbO3 system A ferroelectric domain structure that is periodically reversed, that is, the sign of the nonlinear coefficient is periodically changed, so that the parametric light intensity continues to strengthen along the direction of the light in the area that should attenuate, thereby obtaining high-efficiency nonlinear frequency conversion.

From the point of view of energy, in the nonlinear frequency conversion of the parameter generation process, the energy of the pump light wave is continuously coupled into the parameter light wave through the nonlinear polarization of the medium, and the phase signs of the interacting light waves are the same within a coherence length, The frequency shift is continuously enhanced, but the phase sign of the interacting light waves is opposite in another coherence length, and the energy is returned from the parametric light wave to the pump light wave through nonlinear polarization. The quasi-phase matching technology is equivalent to making a modulation on the parametric light waves generated by each part, which can make the parametric light waves continue to strengthen in some areas that should be weakened, so it only needs to periodically change the sign of the nonlinear coefficient to realize the phase cycle. Inversion of the nature, so that the phases of the parametric light waves generated at different positions of the crystal are consistent, and the energy of the pump light wave is continuously coupled into the parametric light wave, realizing high-efficiency nonlinear frequency conversion.

The ring frequency doubling cavity is designed as an integrated cavity structure, which enhances the stability of the ring frequency doubling cavity. Because the cavity is relatively closed, it has a good improvement effect on the temperature control of the cavity, crystal control and avoiding the deformation of the cavity mirror frame that may be caused by the change of the external environment temperature.

PPKTP frequency doubling crystal (periodically-poled KTP, periodically poled KTP crystal) for laser frequency doubling from 1064nm to 532nm, its working temperature is close to room temperature, and can achieve non-critical phase matching at room temperature, effective nonlinear coefficient comparison Large, zero walk-off angle, high damage threshold, and its comprehensive optical, physical and chemical properties make it a frequency-doubling crystal that people are very interested in using.

Laser frequency doubling is divided into extracavity frequency doubling and intracavity frequency doubling. Intracavity frequency doubling can obtain higher energy conversion efficiency, but extracavity frequency doubling is easy to implement. Extra-cavity frequency doubling is divided into single-pass frequency doubling crystal frequency doubling and external cavity enhanced frequency doubling. The energy conversion efficiency of single-pass frequency doubling is low, and external cavity enhanced frequency doubling can obtain relatively high energy conversion efficiency. However, It requires careful adjustment of the external cavity and an electronic cavity lock system, and it is not as convenient to use as the single-pass frequency multiplication method in terms of frequency tuning requirements at any time, especially for fast frequency tuning responses. Commonly used frequency doubling cavities in external cavity enhanced frequency doubling include two mirror cavities (standing wave cavities) and ring cavities (traveling wave cavities). The two mirror cavities are easy to adjust, and because there are only two cavity mirrors, the loss is small, so the two mirror cavities can obtain relatively high conversion efficiency, but the two mirror cavities have inherent optical feedback caused by specular reflection, and optical isolation must be added device to reduce its impact. The ring cavity can be further divided into a single block ring cavity and a discrete component ring cavity. It is difficult to manufacture a monolithic ring frequency doubling cavity, and it is not easy to continuously tune a wide range of frequencies. In contrast, although the efficiency of the split-element ring cavity is lower than that of the two-mirror cavity and the single-piece ring cavity, it fundamentally avoids direct optical feedback, avoids processing difficulties, can be tuned in a wide range, and is easy to realize laser at the same time frequency lock. Although the integrated ring frequency doubling cavity is difficult to process, it has more stable characteristics than the separation element ring cavity. At the same time, compared with the straight cavity, it fundamentally avoids direct optical feedback. Therefore, the present invention uses the integrated ring cavity as the frequency doubling cavity.

In order to improve the beam quality and increase the output power of 532nm wavelength, the present invention adopts quasi-phase-matched PPKTP as frequency doubling crystal, uses 1064nm frequency-stabilized laser, combines quasi-phase matching and ring external cavity frequency doubling technology, and designs an integrated ring frequency doubling Cavity, developed a miniaturized 1064nm frequency doubling device, the size of the optical path part is 20×12×9cm ³ , obtained a 532nm green resonant laser output with stable wavelength and power, the output power is 450mW, and its power stability is excellent At 0.7% (4 hours), it lays the foundation for the frequency doubling of the 532nm laser wavelength to 266nm ultraviolet laser output, and then realizes the calibration of the wavelength index of the short wavelength band of the spectrometer.

The present invention is specifically described below by specific examples. Embodiment one

Fig. 1 is a schematic structural diagram of an annular frequency doubling cavity according to an embodiment of the present invention. As shown in Figure 1,

The integrated ring laser frequency doubling device includes:

PPKTP (periodically polarized KTP) frequency doubling crystal and ring frequency doubling cavity;

Wherein, the annular cavity includes plane mirrors M1, M2 and concave mirrors M3, M4; both ends of the PPKTP crystal are coated with anti-reflection coatings for fundamental frequency light and second harmonic.

Wherein, the plane reflector M1 is a coupling mirror, which is used to receive the fundamental frequency light, so as to realize the coupling of the fundamental frequency light from outside the cavity to the cavity; according to the transmittance of the plane reflector M1, "impedance matching" can be realized .

Wherein, the plane reflector M2, the concave reflector M3 and the concave reflector M4 have high reflectivity to the fundamental frequency light;

As shown in FIG. 1 , the concave reflector M4 has a high transmittance for frequency-doubled light, and is used for passing the 532nm light.

Figure 2 is a schematic structural diagram of the integrated ring laser frequency doubling device of this embodiment, as shown in Figure 2:

The device also includes a detector 1 and a detector 2, the detector 1 is located on the extension line of the M4, M1; the detector 2 is located on the extension line of the M1, M2; the detector 1 The sum detector 2 is used to monitor the misalignment between the laser wavelength of the ring frequency doubling cavity and the resonant wavelength of the resonant cavity.

Further, the device also includes a servo control circuit system, its input end is connected to the detector 2, and its output end is connected to the piezoelectric ceramic driver of the ring frequency doubling cavity;

The servo control circuit system is used to process the error signal generated when the detector 1 and the detector 2 monitor the misalignment between the laser wavelength of the ring frequency doubling cavity and the resonant wavelength of the resonator; and the processing result is fed back to the A piezoceramic driver for a ring frequency doubling cavity.

Further, the piezoelectric ceramic driver of the ring-shaped frequency doubling cavity is used to control the expansion and contraction of the piezoelectric ceramics of the ring-shaped frequency doubling cavity, so as to adjust the cavity length of the ring-shaped frequency doubling cavity, thereby realizing the ring-shaped frequency doubling cavity Tracking and locking between the frequency cavity and the 1064nm frequency-stabilized laser.

Preferably, the device also includes a 1064nm frequency-stabilized laser, a λ/4 wave plate, a λ/2 wave plate, a mode matching lens Len and a mirror;

Wherein, the 1064nm frequency-stabilized laser is used to generate the fundamental frequency light, and transmit the fundamental frequency light to the λ/4 wave plate;

The λ/4 wave plate and the λ/2 wave plate are used to successively receive and process the fundamental frequency light, so that the fundamental frequency light is converted from elliptically polarized light into linearly polarized light to achieve spatial polarization state matching;

The mode matching lens Len is used to receive the processed fundamental frequency light, and couple it into the cavity of the ring frequency doubling cavity through the reflector.

Further, the size of the optical path part of the device can be set to 20×12×9 cm ³ .

Embodiment two

This embodiment provides a method for generating frequency-doubled light using the above-mentioned device. As shown in FIG. 2, the 1064nm fundamental frequency elliptically polarized light is converted into linearly polarized light by a λ/4 wave plate and a λ/2 wave plate to realize a spatial polarization state match. The matching lens couples the 1064nm fundamental frequency light into the ring frequency doubling cavity to achieve spatial mode matching. The annular cavity is composed of plane mirrors M1, M2 and concave mirrors M3, M4, among which M1 is a coupling mirror, which is used to realize the coupling of the fundamental frequency beam from the outside of the cavity to the inside of the cavity, and its transmittance is specially selected to achieve " impedance matching". The mirrors M2, M3, and M4 have high reflectivity for the fundamental frequency light, and M4 has a high transmittance for the frequency doubled light at the same time, so as to realize the effective extraction of the 532nm frequency doubled light. Both ends of the PPKTP crystal are coated with anti-reflection coatings for fundamental frequency light and second harmonic. Detector 1 and detector 2 in the figure are used to monitor the misalignment between the laser wavelength of the frequency-doubled cavity and the resonant wavelength of the resonant cavity. The error signal generated during misalignment is processed by the servo control circuit system and fed back to the driver of the piezoelectric ceramic of the frequency doubler cavity. The cavity length is adjusted through the expansion and contraction of the piezoelectric ceramic to realize the tracking and locking between the frequency doubler cavity and the laser. When the laser frequency is consistent with a certain frequency in the resonant frequency comb of the frequency doubling cavity, the optical power in the cavity is enhanced due to the resonance effect, and the 532nm frequency doubling optical power is much greater than that of a single pass through the frequency doubling crystal.

After the servo loop of the 532nm ring frequency doubling cavity is locked, the output power stability of the frequency doubling laser is measured with the Thorlabs Optical Power Detector S310C. The output of the optical power meter is connected to the digital multimeter 2700 of Keithley Company, and its power drift value is recorded by the computer. The measurement time is 14578s, and the average, maximum and minimum values are 0.21026V, 0.21087V, and 0.20937V respectively. During this period, the maximum relative drift of optical power is , and the minimum value corresponds to . The 532nm optical power stability measurement curve is shown in Figure 3.

The size of the optical path of the miniaturized 1064nm laser frequency doubling device is 20×12×9 cm ³ .

Above embodiment can reach following beneficial effect:

The device uses a 1064nm frequency-stabilized laser and a PPKTP frequency-doubling crystal, combined with quasi-phase matching and annular external cavity frequency doubling technology, to achieve stable laser output at 1064nm and 532nm with strict multiples of wavelength, and has good wavelength and power stability and narrow line width. It can calibrate the wavelength linearity of the grating spectrometer; realize the miniaturization of the 1064nm frequency-stabilized laser wavelength standard device, with stable performance, compact structure and strong anti-interference ability.

Those skilled in the art can also understand that various illustrative logical blocks (illustrativelogical blocks), units, and steps listed in the embodiments of the present invention can be implemented by electronic hardware, computer software, or a combination of both. To clearly demonstrate the interchangeability of hardware and software, the various illustrative components, units and steps above have generally described their functions. Whether such functions are implemented by hardware or software depends on the specific application and overall system design requirements. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementation should not be understood as exceeding the protection scope of the embodiments of the present invention.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (8)

1. An integrated ring laser frequency doubling device, characterized in that, comprising: PPKTP (periodically polarized KTP) frequency doubling crystal and ring frequency doubling cavity; Wherein, the annular cavity includes plane mirrors M1, M2 and concave mirrors M3, M4; both ends of the PPKTP crystal are coated with anti-reflection coatings for fundamental frequency light and second harmonic. 2. The device according to claim 1, wherein the plane reflector M1 is a coupling mirror for receiving the fundamental frequency light, so as to realize the coupling of the fundamental frequency light from outside the cavity to the cavity; according to the plane The transmittance of the mirror M1 can realize "impedance matching". 3. The device according to claim 1, wherein the plane reflector M2, the concave reflector M3 and the concave reflector M4 have a high reflectivity to the fundamental frequency light; Wherein the concave mirror M4 has a high transmittance to the doubled frequency light. 4. The device according to claim 1, further comprising a detector 1 and a detector 2, the detector 1 is located on the extension line of the M4 and M1; the detector 2 is located on the M1 , M2 on the extension line of the connection; the detector 1 and the detector 2 are used to monitor the misalignment between the laser wavelength of the ring frequency doubling cavity and the resonant wavelength of the resonant cavity. 5. The device according to claim 4, further comprising a servo control circuit system, its input end is connected to the detector 2, and its output end is connected to the piezoelectric ceramic driver of the ring frequency doubling cavity ; The servo control circuit system is used to process the error signal generated when the detector 1 and the detector 2 monitor the misalignment between the laser wavelength of the ring frequency doubling cavity and the resonant wavelength of the resonator; and the processing result is fed back to the A piezoceramic drive for a ring frequency doubling cavity. 6. The device according to claim 5, characterized in that, the piezoelectric ceramic driver of the annular frequency doubling cavity is used to control the expansion and contraction of the piezoelectric ceramics of the annular frequency doubling cavity, so as to adjust the The cavity length of the frequency cavity realizes the tracking and locking between the ring-shaped frequency doubling cavity and the 1064nm frequency-stabilized laser. 7. The device according to any one of claims 1-5, further comprising: a 1064nm frequency-stabilized laser, a λ/4 wave plate, a λ/2 wave plate, a mode-matching lens Len, and a mirror; Wherein, the 1064nm frequency-stabilized laser is used to generate the fundamental frequency light, and transmit the fundamental frequency light to the λ/4 wave plate; The λ/4 wave plate and the λ/2 wave plate are used to successively receive and process the fundamental frequency light, so that the fundamental frequency light is converted from elliptically polarized light into linearly polarized light to achieve spatial polarization state matching; The mode matching lens Len is used to receive the processed fundamental frequency light, and couple it into the cavity of the ring frequency doubling cavity through the reflector. 8. The device according to claim 7, wherein the size of the optical path part of the device is 20×12×9 cm ³ .