CN114518218A - Method and device for measuring loss in solid laser cavity - Google Patents

Abstract

The invention discloses a method and device for measuring the loss in the cavity of a solid laser. The method first draws the input-output power curve of the laser according to the injection pump power of the laser and the corresponding laser output power, and then uses the measured laser threshold value of the laser. , combined with the obtained input-output power curve, read a set of laser output power corresponding to the injection pump power above the laser threshold, calculate the slope efficiency of the laser, and then at the injection pump power, use the ABCD matrix to calculate The size of the resonator mode waist spot at the laser crystal, and finally the laser slope efficiency and the square value of the ratio of the resonator mode waist spot at the laser crystal to the pump laser waist spot are calculated to achieve fast and accurate calculation of the laser cavity. This method can take into account the measurement of the loss in the cavity of the fundamental frequency optical solid-state laser with single transverse mode, single longitudinal mode and multi-mode output.

Description

A method and device for measuring the loss in a solid-state laser cavity

technical field

The invention relates to the field of laser technology, in particular to a method and a device for measuring the loss in a solid-state laser cavity.

Background technique

In the production, development and maintenance of solid-state lasers, the intra-cavity loss of the laser will limit the output power of the laser by affecting the laser gain. The intra-cavity loss is an important index parameter to measure the quality of the laser. How to accurately measure the intra-cavity loss of the laser will help It is used to guide the optimal design of the laser resonator and optimize the output performance and service life of the laser.

At present, the Findlay-Clay analysis method, rate equation, method based on laser power and relaxation oscillation frequency, and the method of using nonlinear loss to measure the linear loss in the cavity of an all-solid-state intra-cavity frequency-doubling laser are generally used to measure the loss in the laser wall. The Findlay-Clay analysis method needs to replace several groups of output coupling transmittances during operation. This operation will inevitably change the structure of the laser resonator, which will bring errors to the measurement results. At the same time, this method cannot do anything for the packaged laser; the rate equation is analyzed in the analysis A variety of approximations are used in the process, which requires a comprehensive analysis of the energy level transition process of the low-gain laser medium. This method is difficult to apply to the measurement of the intra-cavity loss of high-gain lasers; measurement based on laser power and relaxation oscillation frequency The intra-cavity loss method must be applied in the scenario of single longitudinal mode stable operation. Otherwise, when the laser has mode hopping, although the laser power does not change much, the relaxation oscillation frequency will change in a large range. As a result, large errors are brought about, and it is impossible to measure the intra-cavity loss of single-transverse-mode lasers with multiple oscillation frequencies and multi-mode operating lasers; the method of measuring the linear loss in the cavity of an all-solid-state intra-cavity frequency-doubling laser by using nonlinear loss, By measuring the fundamental wave and the second harmonic output power corresponding to the two operating temperature points of the frequency-doubling crystal in the single frequency region, and then substituting into the expression of the laser cavity linear loss to calculate the laser cavity linear loss value, this method Intra-cavity loss cannot be performed on multi-mode operating lasers and lasers without intra-cavity frequency doubling.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is that the current method for measuring the loss in the laser cavity cannot take into account the lasers in multiple modes. Therefore, the present invention provides a method and device for measuring the loss in the cavity of a solid laser, which can take into account the single transverse mode, single Intracavity loss measurement of fundamental frequency optical solid-state lasers with longitudinal mode and multimode output.

The present invention is achieved through the following technical solutions:

A method for measuring loss in a solid-state laser cavity, comprising:

Obtain the injection pump power and the corresponding laser output power of the laser under test, and draw an input-output power curve based on the injection pump power and the laser output power;

Read the laser threshold value of the tested laser, and select a group of injection pump power and laser output power at the input-output power curve higher than the laser threshold value, and calculate the laser slope efficiency;

Obtain the pump laser waist spot, and calculate the resonator film spot at the laser crystal through the resonator matrix at the injected pump power; wherein, the pump laser waist spot refers to the pump laser waist spot size at the laser crystal;

The laser cavity loss calculation formula is called to calculate the laser oblique efficiency, the pump laser waist spot and the resonant cavity mode waist spot at the laser crystal, and the laser cavity loss value is obtained.

Further, obtaining the injection pump power and the corresponding laser output power of the laser under test includes:

By injecting pump laser power into the laser under test, the power meter in the laser under test calculates the corresponding laser output power based on the injected pump laser power.

Further, the laser threshold value of the laser under test is read, and a group of injection pump power and laser output power are selected on the input-output power curve higher than the laser threshold value, and the laser slope efficiency is calculated, including:

Call the calculation formula of laser slope efficiency to calculate the selected injection pump power, output power and laser threshold to obtain the laser slope efficiency;

Wherein, the calculation formula of the laser oblique efficiency is specifically:

In the formula, η _s represents the laser slope efficiency, P _out represents the selected output power, P _in represents the selected input power, and P _th represents the laser threshold.

Further, the invoking laser cavity loss calculation formula is used to calculate the laser oblique efficiency, the pump laser waist spot and the resonant cavity mode waist spot at the laser crystal to obtain the laser cavity loss value, including:

Based on the pump laser waist spot and the cavity mode waist spot at the laser crystal, calculate the square value of the ratio of the resonator cavity mode waist spot at the laser crystal to the pump laser waist spot;

Call the laser cavity loss calculation formula to calculate the laser oblique efficiency and the square value of the ratio of the resonant cavity mode waist spot at the laser crystal to the pump laser waist spot to obtain the laser cavity loss value.

Further, the calculation formula of the laser cavity loss is specifically:

其中，ω_l表示激光晶体处谐振腔模腰斑的大小，ω_p表示泵浦激光腰斑的大小。In the formula, δ represents the laser cavity loss; η _a represents the absorption efficiency of the pump laser by the gain medium, η _a =1-exp(-αl), where α represents the absorption of the pump laser by the gain medium in the measured laser coefficient, l represents the radial length of the gain medium; η _s represents the laser slope efficiency; ν _l represents the output laser frequency, ν _p represents the pump laser frequency, T represents the transmittance of the output coupling mirror in the laser under test; β represents the laser The square value of the ratio of the resonator cavity mode waist spot to the pump laser waist spot at the crystal,

Among them, ω _l represents the size of the cavity mode waist spot at the laser crystal, and ω _p represents the size of the pump laser waist spot.

Further, the laser under test includes a pump laser source, a coupling system, a power meter, a laser resonant cavity formed by an input coupling mirror, a first high-reflection mirror, a second high-reflection mirror and an output coupling mirror. The cavity is sequentially provided with a laser crystal and an optical unidirectional device;

The pump laser source emits laser light, which is coupled by the coupling system and then transmitted to the input coupling mirror. The laser reflected by the second high-reflection mirror, the second high-reflection mirror transmits the received laser light to the output coupling mirror, and the output coupling mirror sends the received laser light to the input coupling mirror; the power meter 9 is used to measure the output coupling mirror 6 The output power when outputting the laser.

Further, the pump laser source adopts a fiber-coupled laser diode, the input coupling mirror adopts a concave lens, the first high-reflection mirror adopts a convex lens, the second high-reflection mirror and the output coupling mirror plano-concave lens.

A device for measuring the loss in a solid-state laser cavity, comprising:

an input-output power curve drawing module, used to obtain the injection pump power and the corresponding laser output power of the laser under test, and draw an input-output power curve based on the injection pump power and the laser output power;

a laser slope efficiency calculation module, used to read the laser threshold value of the laser under test, and select a group of injected pump power and laser output power at the input-output power curve higher than the laser threshold value to calculate the laser slope efficiency;

The parameter acquisition module for calculating the loss value in the cavity is used to obtain the pump laser waist spot, and at the injected pump power, the resonator film spot at the laser crystal is calculated through the resonator matrix; wherein, the pump laser waist spot refers to the pump The size of the waist spot of the Pu laser at the laser crystal;

The intra-cavity loss value calculation module calls the laser intra-cavity loss calculation formula to calculate the laser slant efficiency, the pump laser waist spot and the resonant cavity mode waist spot at the laser crystal, and obtains the laser's intra-cavity loss value.

Further, the in-cavity loss value calculation module includes:

The first calculation unit of the intra-cavity loss value is used to calculate the square value of the ratio of the resonant cavity mode waist spot at the laser crystal to the pump laser waist spot based on the pump laser waist spot and the resonant cavity mode waist spot at the laser crystal;

The second calculation unit for the intra-cavity loss value is used to call the laser intra-cavity loss calculation formula to calculate the laser slope efficiency, the square value of the ratio of the resonant cavity mode waist spot at the laser crystal to the pump laser waist spot, and obtain the laser The cavity loss value.

Further, the calculation formula of the laser cavity loss is specifically:

其中，ω_l表示激光晶体处谐振腔模腰斑的大小，ω_p表示泵浦激光腰斑的大小。In the formula, δ represents the laser cavity loss; η _a represents the absorption efficiency of the pump laser by the gain medium, η _a =1-exp(-αl), where α represents the absorption of the pump laser by the gain medium in the measured laser coefficient, l represents the radial length of the gain medium; η _s represents the laser slope efficiency; v _l represents the output laser frequency, v _p represents the pump laser frequency, T represents the transmittance of the output coupling mirror in the laser under test; β represents the laser The square value of the ratio of the resonator cavity mode waist spot to the pump laser waist spot at the crystal,

Among them, ω _l represents the size of the cavity mode waist spot at the laser crystal, and ω _p represents the size of the pump laser waist spot.

The invention provides a method and a device for measuring the loss in a solid-state laser cavity. First, the input-output power curve of the laser is drawn according to the injection pump power of the laser and the corresponding laser output power, and then the measured laser threshold value of the laser is combined with The obtained input-output power curve, read a set of laser output power corresponding to the injection pump power above the laser threshold, calculate the slope efficiency of the laser, and then use the ABCD matrix to calculate the laser crystal at the injection pump power. The size of the mode waist spot of the resonator at the laser crystal is calculated, and finally the laser slant efficiency and the square value of the ratio of the resonator mode waist spot to the pump laser waist spot at the laser crystal are calculated to realize the fast and accurate calculation of the intra-cavity loss value of the laser. , the method can take into account the measurement of the loss in the cavity of the fundamental frequency optical solid-state laser with single transverse mode, single longitudinal mode and multi-mode output.

Description of drawings

The accompanying drawings described herein are used to provide further understanding of the embodiments of the present invention, and constitute a part of the present application, and do not constitute limitations to the embodiments of the present invention. In the attached image:

FIG. 1 is a flowchart of a method for measuring the loss in a solid-state laser cavity according to the present invention.

FIG. 2 is a specific flowchart of step S40 in FIG. 1 of the present invention.

FIG. 3 is a schematic diagram of the principle of the laser under test in a specific embodiment of the present invention.

FIG. 4 is an input-output power curve diagram in a specific embodiment of the present invention.

FIG. 5 is a schematic diagram of a device for measuring the loss in a solid-state laser cavity according to the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. as a limitation of the present invention.

Example 1

As shown in FIG. 1 , the present invention provides a method for measuring the loss in a solid-state laser cavity, including:

S10: Obtain the injection pump power P _in and the corresponding laser output power P _out of the laser under test, and draw an input-output power curve based on the injection pump power P _in and the laser output power P _out .

Specifically, by injecting the pump laser power P _in into the laser under test, the power meter in the laser under test calculates the corresponding laser output power P _out based on the injected pump laser power.

As shown in FIG. 3, the laser under test in this embodiment includes a pump laser source 1, a coupling system 2, a power meter 9, an input coupling mirror 3, a first high-reflection mirror 4, a second high-reflection mirror 5 and an output The laser resonator formed by the coupling mirror 6 is provided with a laser crystal 7 and an optical unidirectional device 8 in sequence.

Specifically, the pump laser source 1 emits laser light, which is coupled by the coupling system 2 and then transmitted to the input coupling mirror 3, and the input coupling mirror 3 sends the received light to the first high-reflection mirror through the laser crystal 7 and the optical unidirectional device 8 4. The first high-reflection mirror 4 reflects the received light to the second high-reflection mirror 5, the second high-reflection mirror 5 transmits the received light to the output coupling mirror 6, and the output coupling mirror 6 sends the received light to the input coupling mirror 3. The power meter 9 is used to measure the laser output power when the output coupling mirror 6 outputs laser light, so as to facilitate the subsequent drawing of the laser input-output power curve.

Further, the pump laser source 1 adopts a fiber-coupled laser diode, the input coupling mirror 3 adopts a concave lens, the first high reflection mirror 4 adopts a convex lens, and the second high reflection mirror 5 and the output coupling mirror 6 adopt a plano-concave lens.

S20: Read the laser threshold P _th of the laser under test, and select a group of injection pump power P _in and laser output power at the input-output power curve higher than the laser threshold P _th , and calculate the laser slope efficiency.

Specifically, read the laser threshold of the laser under test, select a set of injection pump power and laser output power at the input-output power curve higher than the laser threshold, and call the laser slope efficiency calculation formula for the selected injection pump power. , output power and laser threshold are calculated to obtain the laser slope efficiency.

Among them, the calculation formula of laser oblique efficiency is as follows:

In the formula, η _s represents the laser slope efficiency, P _out represents the selected output power, P _in represents the selected input power, and P _th represents the laser threshold.

S30: Obtain the pump laser waist spot, and calculate the resonator film spot at the laser crystal through the resonator matrix at the injected pump power; the pump laser waist spot refers to the pump laser waist spot size at the laser crystal.

Specifically, the pump laser waist spot is obtained, and at the injected pump power, the resonator film spot at the laser crystal is calculated through the resonator ABCD matrix.

S40: Call the laser cavity loss calculation formula to calculate the laser oblique efficiency, the pump laser waist spot and the resonator cavity mode waist spot at the laser crystal, and obtain the laser cavity loss value.

Further, as shown in FIG. 2, in step S40, the calculation formula of the laser cavity loss is called to calculate the laser slant efficiency, the pump laser waist spot and the resonant cavity mode waist spot at the laser crystal, and the laser cavity loss value is obtained. It includes the following steps:

S41: Based on the pump laser waist spot and the resonator cavity mode waist spot at the laser crystal, calculate the square value of the ratio of the resonator cavity mode waist spot at the laser crystal to the pump laser waist spot.

S42: Call the laser cavity loss calculation formula to calculate the laser oblique efficiency and the square value of the ratio of the resonator cavity mode waist spot at the laser crystal to the pump laser waist spot to obtain the laser cavity loss value.

Specifically, the calculation formula of the laser cavity loss is as follows:

其中，ω_l表示激光晶体处谐振腔模腰斑的大小，ω_p表示泵浦激光腰斑的大小。In the formula, δ represents the laser cavity loss. η _a represents the absorption efficiency of the gain medium to the pump laser, η _a =1-exp(-αl), where α represents the absorption coefficient of the gain medium to the pump laser in the measured laser, and l represents the radial length of the gain medium . η _s represents the laser slope efficiency. ν _l is the output laser frequency, ν _p is the pump laser frequency, and T is the transmittance of the output coupling mirror in the laser under test. β represents the square value of the ratio of the mode waist spot of the resonator cavity to the pump laser waist spot at the laser crystal,

Among them, ω _l represents the size of the cavity mode waist spot at the laser crystal, and ω _p represents the size of the pump laser waist spot.

For ease of understanding, the following examples are used to illustrate:

The tested laser is an all-solid-state continuous 1064nm continuous wave laser with a four-mirror ring cavity structure. The input coupling mirror 3 adopts a concave lens with a curvature radius of 1500mm. The 1064nm high-reflection film is greater than 99.7%; the first high-reflection mirror 4 adopts a convex lens with a curvature radius of 1500mm, and the convex lens is coated with a 1064nm high-reflection film with a reflectivity greater than 99.7%; the second high-reflection mirror 5 adopts a curvature radius of - 100mm plano-concave lens, which is coated with a 1064nm high-reflection film with a reflectivity greater than 99.7%; the output coupling mirror 6 adopts a plano-concave lens with a curvature radius of -100mm, and the plano-concave lens is coated with 1064nm with a transmittance of 20%. Translucent film.

The pump source 1 adopts an 888nm fiber-coupled laser diode. The core diameter of the coupled fiber is 400μm and the numerical aperture is 0.22; ; The laser crystal 7 is composed of a 3mm undoped end cap and a 20mm composite YVO ₄ /Nd:YVO ₄ (S1, S2: AR _{888nm; 1064nm} ) doped with Nd at 0.8at.%. The back end of the laser crystal is cut A small angle of 1.5° is set to ensure the stable polarization of the laser.

In order to eliminate the spatial hole burning effect and achieve the unidirectional propagation of the laser light, an optical unidirectional device 8 composed of an 8 mm long terbium gallium garnet TGG crystal and a half-wave plate is used in the laser resonator. The optical path from the input coupling mirror 3 to the center of the laser crystal 7 is 10mm, the optical path from the center of the laser crystal 7 to the high-reflection mirror 4 is 120mm, the optical path from the high-reflection mirror 4 to the high-reflection mirror 5 is 128mm, the high-reflection mirror 5 and The optical path between the output coupling mirrors 6 is 96 mm, and the optical path between the output coupling mirror 6 and the input coupling mirror 3 is 125 mm.

通过升降888nm泵浦激光源的注入泵浦功率，用功率计9测量1064nm输出激光的激光输出功率，作出该激光器的输入-输出功率曲线，如图4所示。从图4读取激光阈值P_th＝32.33W，在高于激光阈值处选取一组注入泵浦功率P_in＝58W和对应的激光输出功率P_out＝13.35W，根据公式

计算得到激光器实际的激光斜效率

When the 808nm laser pump power is 58W, the focal length of the equivalent thermal lens of the laser crystal is 137mm, and the resonator mode ω _l =0.347mm at the laser crystal is calculated by using the ABCD matrix in the resonator. According to the calculation formula of the absorption efficiency of the gain medium to the laser: η _a = 1-exp(-αl), α = 1.07/cm, l = 20mm, the absorption efficiency of the laser crystal is calculated, and according to the laser light emitted by the pump laser source and the output laser band can be calculated as:

By raising and lowering the injection pump power of the 888nm pump laser source, measuring the laser output power of the 1064nm output laser with a power meter 9, the input-output power curve of the laser is drawn, as shown in Figure 4. Read the laser threshold value P _th =32.33W from FIG. 4 , select a set of injection pump power P _in =58W and corresponding laser output power P _out =13.35W above the laser threshold, according to the formula

Calculate the actual laser slope efficiency of the laser

激光器的输出耦合镜透射率T＝20％，代入激光器腔内损耗计算公式

中进行计算，得到激光器的腔内损耗δ＝5.28％。The actual parameter of the laser η _a =1-exp(-107*0.02),

The transmittance of the output coupling mirror of the laser is T=20%, which is substituted into the calculation formula of the loss in the laser cavity

Calculation is carried out in , and the intracavity loss δ=5.28% of the laser is obtained.

It should be noted that the numerical values in the above embodiments are only for illustration, and are not intended to limit the protection scope of the present embodiments.

The invention provides a method for measuring the loss in the cavity of a solid-state laser. First, draw the input-output power curve of the laser according to the injection pump power of the laser and the corresponding laser output power, and then combine the obtained laser threshold with the measured laser threshold. Input-output power curve, read a set of laser output power corresponding to the injection pump power above the laser threshold, calculate the slope efficiency of the laser, and then use the ABCD matrix to calculate the resonance at the laser crystal at the injection pump power The size of the cavity mode waist spot is finally calculated to obtain the laser oblique efficiency and the square value of the ratio of the resonant cavity mode waist spot at the laser crystal to the pump laser waist spot, so as to quickly and accurately calculate the cavity loss value of the laser. The method can take into account the measurement of the intra-cavity loss of the fundamental frequency optical solid-state laser with single transverse mode, single longitudinal mode and multi-mode output.

Example 2

As shown in FIG. 5 , this embodiment provides a device for measuring the loss in the cavity of a solid-state laser, which corresponds one-to-one with the method for measuring the loss in the cavity of a solid-state laser in Embodiment 1, including an input-output power curve drawing module 10. The laser oblique efficiency calculation module 20 , the intracavity loss value calculation parameter acquisition module 30 and the intracavity loss value calculation module 40 . The detailed description of each functional module is as follows:

The input-output power curve drawing module 10 is used for the input-output power curve drawing module, which is used to obtain the injection pump power and the corresponding laser output power of the laser under test, and draw the input- output power curve.

The laser slope efficiency calculation module 20 is used to read the laser threshold value of the laser under test, and select a group of injected pump power and laser output power at the input-output power curve higher than the laser threshold value to calculate the laser slope efficiency.

The parameter obtaining module 30 for calculating the loss value in the cavity is used to obtain the pump laser waist spot, and at the injected pump power, calculate the resonator film spot at the laser crystal through the resonator matrix. The pump laser waist spot refers to the waist spot size of the pump laser at the laser crystal.

The intra-cavity loss value calculation module 40 invokes the laser intra-cavity loss calculation formula to calculate the laser slant efficiency, the pump laser waist spot and the resonator cavity mode waist spot at the laser crystal to obtain the laser's intra-cavity loss value.

Further, the intra-cavity loss value calculation module includes a first intra-cavity loss value calculation unit and a second intra-cavity loss value calculation unit.

The first calculation unit for the intra-cavity loss value is used to calculate the square value of the ratio of the cavity mode waist spot at the laser crystal to the pump laser waist spot based on the pump laser waist spot and the resonator cavity mode waist spot at the laser crystal.

The second calculation unit of the intra-cavity loss value is used to call the laser intra-cavity loss calculation formula to calculate the laser slant efficiency, the square value of the ratio of the resonant cavity mode waist spot at the laser crystal to the pump laser waist spot, and obtain the intra-cavity loss of the laser. value.

Further, the formula for calculating the loss in the laser cavity is as follows:

其中，ω_l表示激光晶体处谐振腔模腰斑的大小，ω_p表示泵浦激光腰斑的大小。In the formula, δ represents the laser cavity loss. η _a represents the absorption efficiency of the gain medium to the pump laser, η _a =1-exp(-αl), where α represents the absorption coefficient of the gain medium to the pump laser in the measured laser, and l represents the radial length of the gain medium . η _s represents the laser slope efficiency. v _l is the output laser frequency, v _p is the pump laser frequency, and T is the transmittance of the output coupling mirror in the laser under test. β represents the square value of the ratio of the mode waist spot of the resonator cavity to the pump laser waist spot at the laser crystal,

Among them, ω _l represents the size of the cavity mode waist spot at the laser crystal, and ω _p represents the size of the pump laser waist spot.

For the specific definition of a device for measuring the loss in the cavity of a solid-state laser, please refer to the definition of a method for measuring the loss in the cavity of a solid-state laser, which will not be repeated here.

Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned functions can be allocated to different functional units, Module completion, that is, dividing the internal structure of the device into different functional units or modules to complete all or part of the functions described above.

The above specific embodiments further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Within the spirit and principle of the present invention, any modifications, equivalent replacements, improvements, etc. made should be included within the protection scope of the present invention.

Claims (10)

1. a method for measuring the loss in a solid-state laser cavity, is characterized in that, comprising: Obtain the injection pump power and the corresponding laser output power of the laser under test, and draw an input-output power curve based on the injection pump power and the laser output power; Read the laser threshold value of the tested laser, and select a group of injection pump power and laser output power at the input-output power curve higher than the laser threshold value, and calculate the laser slope efficiency; Obtain the pump laser waist spot, and calculate the resonator film spot at the laser crystal through the resonator matrix at the injected pump power; wherein, the pump laser waist spot refers to the pump laser waist spot size at the laser crystal; The laser cavity loss calculation formula is called to calculate the laser oblique efficiency, the pump laser waist spot and the resonant cavity mode waist spot at the laser crystal, and the laser cavity loss value is obtained. 2. a kind of method for measuring the loss in the cavity of solid-state laser according to claim 1, is characterized in that, described obtaining the injection pump power and corresponding laser output power of the laser under test, comprising: By injecting pump laser power into the laser under test, the power meter in the laser under test calculates the corresponding laser output power based on the injected pump laser power. 3. The method for measuring the loss in the cavity of a solid-state laser according to claim 1, wherein the laser threshold value of the laser to be read is read, and the input-output power curve is higher than the laser threshold value. Select a set of injection pump power and laser output power to calculate the laser slope efficiency, including: Call the calculation formula of laser slope efficiency to calculate the selected injection pump power, output power and laser threshold to obtain the laser slope efficiency; Wherein, the calculation formula of the laser oblique efficiency is specifically:

In the formula, η _s represents the laser slope efficiency, P _out represents the selected output power, P _in represents the selected input power, and P _th represents the laser threshold. 4. a kind of method for measuring the loss in the cavity of solid-state laser according to claim 1, is characterized in that, described calling the calculation formula of the loss in the cavity of the laser to resonate at the laser oblique efficiency, pump laser waist spot and laser crystal place The cavity mode waist spot is calculated to obtain the cavity loss value of the laser, including: Based on the pump laser waist spot and the cavity mode waist spot at the laser crystal, calculate the square value of the ratio of the resonator cavity mode waist spot at the laser crystal to the pump laser waist spot; Call the laser cavity loss calculation formula to calculate the laser oblique efficiency and the square value of the ratio of the resonant cavity mode waist spot at the laser crystal to the pump laser waist spot to obtain the laser cavity loss value. 5. The method for measuring the loss in a solid-state laser cavity according to claim 4, wherein the calculation formula for the loss in the laser cavity is specifically:

In the formula, δ represents the laser cavity loss; η _a represents the absorption efficiency of the pump laser by the gain medium, η _a =1-exp(-αl), where α represents the absorption of the pump laser by the gain medium in the measured laser coefficient, l represents the radial length of the gain medium; η _s represents the laser slope efficiency; v _l represents the output laser frequency, v _p represents the pump laser frequency, T represents the transmittance of the output coupling mirror in the laser under test; β represents the laser The square value of the ratio of the resonator cavity mode waist spot to the pump laser waist spot at the crystal,

Among them, ω _l represents the size of the cavity mode waist spot at the laser crystal, and ω _p represents the size of the pump laser waist spot. 6. A method for measuring the intracavity loss of a solid-state laser according to claim 1, wherein the laser under test comprises a pump laser source (1), a coupling system (2), a power meter (9), a (3) a laser resonant cavity formed by a first high-reflection mirror (4), a second high-reflection mirror (5) and an output coupling mirror (6), the laser resonator is sequentially provided with a laser crystal (7) and an optical unit direction device (8); The pump laser source (1) emits laser light, which is coupled by a coupling system (2) and then transmitted to an input coupling mirror (3), and the input coupling mirror (3) sends the received laser light through a laser crystal (7) and an optical unidirectional device ( 8) Send to the first high-reflection mirror (4), the first high-reflection mirror (4) reflects the received laser light to the second high-reflection mirror (5), and the second high-reflection mirror (5) reflects the received laser light It is transmitted to the output coupling mirror (6), and the output coupling mirror (6) sends the received laser light to the input coupling mirror (3); the power meter 9 is used to measure the output power when the output coupling mirror 6 outputs the laser light. 7. The method for measuring the loss in a solid-state laser cavity according to claim 6, characterized in that, The pump laser source (1) adopts a fiber-coupled laser diode, the input coupling mirror (3) adopts a concave lens, the first high-reflection mirror (4) adopts a convex lens, and the second high-reflection mirror (5) and The output coupling mirror (6) is a plano-concave lens. 8. A device for measuring the loss in a solid-state laser cavity, comprising: an input-output power curve drawing module, used to obtain the injection pump power and the corresponding laser output power of the laser under test, and draw an input-output power curve based on the injection pump power and the laser output power; a laser slope efficiency calculation module, used to read the laser threshold value of the laser under test, and select a group of injected pump power and laser output power at the input-output power curve higher than the laser threshold value to calculate the laser slope efficiency; The parameter acquisition module for calculating the loss value in the cavity is used to obtain the pump laser waist spot, and at the injected pump power, the resonator film spot at the laser crystal is calculated through the resonator matrix; wherein, the pump laser waist spot refers to the pump The size of the waist spot of the Pu laser at the laser crystal; The intra-cavity loss value calculation module calls the laser intra-cavity loss calculation formula to calculate the laser slant efficiency, the pump laser waist spot and the resonant cavity mode waist spot at the laser crystal, and obtains the laser's intra-cavity loss value. 9. The device for measuring the intra-cavity loss of a solid-state laser according to claim 8, wherein the intra-cavity loss value calculation module comprises: The first calculation unit of the intra-cavity loss value is used to calculate the square value of the ratio of the resonant cavity mode waist spot at the laser crystal to the pump laser waist spot based on the pump laser waist spot and the resonant cavity mode waist spot at the laser crystal; The second calculation unit for the intra-cavity loss value is used to call the laser intra-cavity loss calculation formula to calculate the laser slope efficiency, the square value of the ratio of the resonant cavity mode waist spot at the laser crystal to the pump laser waist spot, and obtain the laser The cavity loss value. 10. The device for measuring the loss in a solid-state laser cavity according to claim 9, wherein the calculation formula of the loss in the laser cavity is specifically:

In the formula, δ represents the laser cavity loss; η _a represents the absorption efficiency of the pump laser by the gain medium, η _a =1-exp(-αl), where α represents the absorption of the pump laser by the gain medium in the measured laser coefficient, l represents the radial length of the gain medium; η _s represents the laser slope efficiency; ν _l represents the output laser frequency, ν _p represents the pump laser frequency, T represents the transmittance of the output coupling mirror in the laser under test; β represents the laser The square value of the ratio of the resonator cavity mode waist spot to the pump laser waist spot at the crystal,

Among them, ω _l represents the size of the cavity mode waist spot at the laser crystal, and ω _p represents the size of the pump laser waist spot.

Images