A method for measuring the up-conversion rate of energy transfer in gain crystals

Abstract

The present invention claims a method for measuring the energy transfer upconversion rate of a gain crystal, which first obtains the laser output power P under consideration of the energy transfer upconversion effect. out Formula: Laser output power P out is about the injected pump power P in , the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2; then, under the steady-state condition of the laser, take the two sets of data (P in1 , P out1 ) and (P in2 , P out2 ), the calculated injection pump power P in1 and P in2 The corresponding average laser cross-sectional area A1 and A2 at the gain crystal; finally, the two sets of data are substituted into the laser output power formula to obtain a set of two-variable linear equations about the gain crystal energy transmission upconversion rate γ and the radiation-free decay lifetime τ2, and the values ​​of the gain crystal energy transmission upconversion rate γ and the radiation-free decay lifetime τ2 are obtained by solving the set of equations. The present invention provides a method for measuring the gain crystal energy transmission upconversion rate γ and the radiation-free decay lifetime τ2 in a laser that is being debugged, has been debugged, or has been packaged.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular to a method for measuring the up-conversion rate of energy transmission of a gain crystal. The method can simultaneously obtain the radiation-free decay lifetime of the gain crystal, and is particularly suitable for measuring the energy transmission up-conversion rate of a new gain crystal with an unknown radiation-free decay lifetime. Background Art

[0002] In the preparation of high-quality all-solid-state lasers, the energy transfer upconversion rate of the gain crystal affects the output power of the laser by affecting the number of effective inversion particles. At the same time, the heat generated by the energy transfer upconversion process of the gain crystal will narrow the working stable region of the laser, degrade the beam quality of the laser, and even affect the service life of the laser. Measuring the energy transfer upconversion rate of the gain crystal in the laser is of great significance for optimizing the doping concentration of the gain crystal, optimizing the design of the laser cavity structure, and accurately predicting the output power of the laser.

[0003] A current method for measuring the upconversion rate of gain crystal energy transfer is based on the reciprocal of the focal length of the laser thermal lens, that is, the function expression of the diopter D. The expression of diopter is: in, dn / dT is the thermo-optic coefficient. For a given laser system, C is a constant, K is the thermal conductivity, and η q is the size of the quantum defect, p a is the absorbed pump power, Δn is the population inversion density. When the temperature T is a constant, D increases with p a The increase of increases linearly, the intercept It is related to the energy transfer upconversion rate γ. First, this method needs to introduce an additional probe laser to measure the size of the experimental measurement of the refractive power, and the value of γ is obtained from the intercept of the corresponding straight line, and the measurement device is complicated. Secondly, this method requires that the non-radiative decay lifetime τ2 of the gain crystal is known. The energy transfer upconversion rate γ of the gain crystal with unknown non-radiative decay lifetime τ2 cannot be measured. Furthermore, this method is powerless to measure the energy transfer upconversion rate of the gain crystal in the packaged laser. Summary of the invention

[0004] The present invention aims to solve the above problems of the prior art. A method for measuring the up-conversion rate of gain crystal energy transmission is proposed. The technical solution of the present invention is as follows:

[0005] A method for measuring the up-conversion rate of gain crystal energy transmission comprises the following steps:

[0006] First, considering the effect of energy transfer upconversion, the laser output power P is obtained.out Formula: Laser output power P out is about the injected pump power P in , the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2;

[0007] Then, under the steady-state condition of the laser, take two sets of data (P in1 , P out1 ) and (P in2 , P out2 ), the calculated injection pump power P in1 and P in2 The corresponding values ​​of the average laser cross-sectional areas A1 and A2 at the gain crystal;

[0008] Finally, the two sets of data are substituted into the laser output power formula to obtain a set of two-variable linear equations about the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2. By solving the set of equations, the values ​​of the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2 are obtained.

[0009] Furthermore, the laser output power P out The specific formula is:

[0010]

[0011] P in is the injected pump power, τ1 is the fluorescence lifetime of the gain crystal energy, τ2 is the radiationless decay lifetime, γ is the energy transfer upconversion rate, η a is the absorption efficiency of the gain medium for pump light, h is Planck's constant, v p is the pump laser frequency, σ is the stimulated emission cross section of the gain crystal, l is the length of the gain crystal, t is the transmittance of the output coupling mirror, L is the intracavity loss, v l is the output laser frequency, V m is the volume of the pump region in the gain crystal.

[0012] Furthermore, the calculation obtains the injected pump power P in1 and P in2 The corresponding values ​​of the average laser cross-sectional areas A1 and A2 at the gain crystal include:

[0013] Among them, λ p is the wavelength of the pump laser, ω p is the size of the pump waist spot at the gain crystal, A is the average cross-sectional area of ​​the laser at the gain crystal, z represents the object to be integrated, and its range is 0 to l / 2. l is the wavelength of the output laser, ω l is the size of the laser waist at the gain crystal, is the actual laser slope efficiency, P th Indicates the laser threshold.

[0014]

[0015] Furthermore, the two sets of data are brought into the laser output power formula to obtain a set of two-variable linear equations about the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2, and the values ​​of the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2 are obtained by solving the set of equations, specifically including:

[0016] Read the laser threshold P according to the laser input-output power curve th , and according to the injected pump power, they are P in1 and P in2 When, and the corresponding output power is P out1 and P out2 When the corresponding actual laser slope efficiency η is calculated s1 and η s2 , and then obtain A1 and A2 at two different injection powers, and bring the data into the output power P out From the formula, we get a set of linear equations of two variables. By solving the set of equations, we can get the energy transfer upconversion rate γ of the gain crystal, and at the same time, we can get the value of the radiation-free decay lifetime τ2 of the gain crystal.

[0017] Furthermore, the laser under test is a fully solid-state continuous 1047nm continuous wave laser with a four-mirror ring cavity structure. The laser resonant cavity is composed of a first cavity mirror (3), a second cavity mirror (4), a third cavity mirror (5), and a fourth cavity mirror (6). The first cavity mirror (3) is a plano-convex mirror with a curvature radius of R=-1500mm, the second cavity mirror (4) is a plane mirror, the third cavity mirror (5) and the fourth cavity mirror (6) are two plano-concave lenses with a curvature radius of R=100mm, the front end surface of the first cavity mirror (3) is coated with a 880nm high-transmittance film, and the rear end surface is coated with a 880nm high-transmittance film and a 1047nm high-reflection film; the front end surfaces of the second cavity mirror (4) and the third cavity mirror (5) are coated with a 1047nm high-reflection film, and the front end surface of the output fourth cavity mirror (6) is coated with a 1047nm transmittance T 1047nm=21%, and the rear end face is coated with a 1047nm high-transmittance film; the pump source (1) is an 880nm fiber-coupled laser diode, and the core diameter and numerical aperture of the coupled fiber are 400μm and 0.22 respectively; the pump laser (1) is focused at the center of the gain crystal (7) through the coupling system (2) with a waist spot of 0.500mm; in order to adjust the working range of the laser, a plano-convex lens (8) with a focal length of 100mm is inserted into the laser resonant cavity; in order to eliminate the spatial hole burning effect and to achieve unidirectional propagation of the laser, An optical isolator (9) composed of an 8 mm long terbium gallium garnet (TGG) crystal and a half-wave plate is used in the resonant cavity; the optical path from the first cavity mirror (3) to the center of the gain crystal (7) is 25 mm, the optical path from the center of the gain crystal (7) to the second cavity mirror (4) is 115 mm, the optical path from the second cavity mirror (4) to the third cavity mirror (5) is 126 mm, the optical path between the third cavity mirror (5) and the fourth cavity mirror (6) is 90 mm, and the optical path from the fourth cavity mirror (6) to the first cavity mirror (3) is 126 mm.

[0018] Furthermore, the gain crystal (7) is a piece of Nd with a length of 30 mm. 3+ Nd:LiYF4(S1, S2:AR doped with 1at.% 880nm；1047nm ). The back end of the gain crystal is cut at a small angle of 1.5° to ensure stable polarization of the laser.

[0019] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for measuring the up-conversion rate of gain crystal energy transmission as described in any one of the items is implemented.

[0020] A non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method for measuring the up-conversion rate of gain crystal energy transfer as described in any one of the above.

[0021] The advantages and beneficial effects of the present invention are as follows:

[0022] 1. The present invention does not need to know the radiation-free decay lifetime of the gain crystal when measuring the energy transmission upconversion rate of the gain crystal, and has a wider application range. In addition, the energy transmission upconversion rate and radiation-free decay lifetime of the gain crystal can be obtained simultaneously through the present invention.

[0023] 2. When measuring the upconversion rate of the energy transmission of the gain crystal, the present invention does not require an additional probe laser to measure the thermal focal length of the gain crystal, and the measurement method is fast and simple.

[0024] 3. The present invention can be used to quickly measure the energy transmission up-conversion rate of the same gain crystal under different doping concentrations, and then the energy transmission up-conversion coefficient of the gain crystal can be obtained.

[0025] 4. The method provided by the present invention is a quick and easy method for measuring the energy transmission up-conversion coefficient of the gain crystal, which is beneficial to the optimal design of the laser cavity structure and the accurate prediction of the laser output total power. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of an implementation device for measuring the up-conversion rate of laser gain crystal energy transmission according to a preferred embodiment of the present invention.

[0027] Figure 2 A diagram showing the structure of the device of the Nd:YLF laser under test;

[0028] Figure 3 It is a block diagram of the method for measuring the up-conversion rate of gain crystal energy transmission of the present invention. DETAILED DESCRIPTION

[0029] The following will describe the technical solutions in the embodiments of the present invention in detail in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention.

[0030] The technical solution of the present invention to solve the above technical problems is:

[0031] The following is combined with Figure 1 The present invention is further described with reference to the structure diagram of the laser device, but the application scope of the present invention is not limited to the gain crystal in this embodiment and the laser cavity structure in this embodiment.

[0032] The laser under test is a solid-state 1047nm continuous wave laser with a four-mirror ring cavity structure, such as Figure 1 As shown. The laser resonant cavity is composed of four cavity mirrors (3, 4, 5, 6). Cavity mirror (3) is a plano-convex mirror with a curvature radius of R = -1500mm, cavity mirror (4) is a plane mirror, and cavity mirrors (5) and (6) are two plano-concave lenses with a curvature radius of R = 100mm. The front end of cavity mirror (3) is coated with a 880nm high-transmittance film (T 880nm >99.5%), the rear end is coated with 880nm high transmittance film and 1047nm high reflection film (R 1047nm >99.7%). The front end surfaces of cavity mirrors (4) and (5) are coated with a 1047nm high reflection film (R 1047nm >99.7%). The front end of the output coupling mirror (6) is coated with a 1047nm transmittance of T 1047nm=21%, and the rear end face is coated with a 1047nm high-transmittance film. The pump source (1) is an 880nm fiber-coupled laser diode, and the core diameter and numerical aperture of the coupling fiber are 400μm and 0.22 respectively. The pump laser (1) is focused at the center of the gain crystal (7) through the coupling system (2) with a waist spot of 0.500mm. The gain crystal (7) is a piece of Nd with a length of 30mm. 3+ Nd:LiYF4(S1,S2:AR doping concentration of 1at.%) 880nm；1047nm ). A small angle of 1.5° is cut at the rear end of the gain crystal to ensure stable polarization of the laser. In order to adjust the working range of the laser, a plano-convex lens (8) with a focal length of 100 mm is inserted into the laser resonant cavity. In order to eliminate the spatial hole burning effect and to achieve unidirectional propagation of the laser, an optical isolator (9) composed of an 8 mm long terbium gallium garnet (TGG) crystal and a half-wave plate is used in the resonant cavity. The optical path from the cavity mirror (3) to the center of the gain crystal (7) is 25 mm, the optical path from the center of the gain crystal (7) to the high-reflection mirror (4) is 115 mm, the optical path from the cavity mirror (4) to the cavity mirror (5) is 126 mm, the optical path between the cavity (5) and the cavity mirror (6) is 90 mm, and the optical path between the cavity mirror (6) and the cavity mirror (3) is 126 mm.

[0033] The absorption efficiency η of the gain crystal for pump light obtained by actual measurement a is 0.7, and can be calculated based on the pump laser and output laser bands: By changing the power of the 880nm pump laser, the output power of the 1047nm laser is measured with a power meter (10) to draw a laser input-output power curve, such as Figure 2 As shown. Figure 2 Read the laser threshold power P th = 10W, select two groups of injected pump powers P above the laser threshold in1 =39.21W, P in2 =43.12W and the corresponding laser output power value P out1 =9.21W, P out2 =10.52W, according to the formula Calculate the actual slope efficiency of the laser and The actual absorption efficiency of the laser is η a =0.7, laser writing efficiency and t=21%,L=0.041,ω p =500*10 -6 m brought in in, Calculate ω l1 =408.88*10-6 m,ω l2 =412.73*10 -6 m. l =1047*10 -9 m and ω l1 =408.88*10 -6 m,ω l2 =412.73*10 -6 m, l = 30*10 -3 m brought in We get A1 = 0.558121*10 -6 m 2 Sum A2 = 0.67789*10 -6 m 2 . p =880*10 -9 m,ω p =500*10 -6 m brought in Get V m =2.355*10 -8 m 3 . in1 =39.21W and P in2 =43.12W, P out1 =9.21W and P out2 =10.52W,τ1=485*10 -6 s,η a =0.7, h=6.63*10 -34 , σ=1.8*10 -23 / m 2 , l = 30 * 10 -3 m, t = 21%, L = 0.048, V m =2.355*10 -8 , A1=0.558121*10 -6 m 2 Sum A2 = 0.67789*10 -6 m 2 , bring in The energy transfer upconversion rate Y of Nd:LiYF4 crystal is calculated to be 3.58938*10 -23 m 3 / s, non-radiative decay lifetime τ2=5.00895*10 -3 .

[0034] The principle of the present invention is: according to the laser output power P out is the injected pump power Pin , the gain crystal energy transfer upconversion rate γ and the radiation-free decay lifetime τ2. By adjusting the laser injection pump power P in , measure the output laser power P of the laser out , get the input-output power curve of the laser, and read the laser threshold P of the laser th Under steady-state laser working conditions, take a value far from the laser threshold P th The two sets of data (P in1 , P out1 ) and (P in2 , P out2 ). Calculate the values ​​of A1 and A2 at two different injection pump powers and substitute the data into the output power P out In the expression of , a set of two-variable linear equations is obtained. By solving the set of equations, the energy transfer upconversion rate Y of the gain crystal can be obtained, and at the same time, the value of the radiation-free decay lifetime τ2 of the gain crystal can be obtained.

[0035] When the laser is above the laser threshold P th When the laser is in steady state, its output power P out It is expressed as:

[0036]

[0037] Among them, P in is the injected pump power, τ1 is the fluorescence lifetime of the gain crystal, τ2 is the radiation-free decay lifetime, γ is the energy transfer upconversion rate, η a is the absorption efficiency of the gain crystal for pump light, h is Planck's constant, v p is the pump laser frequency, σ is the stimulated emission cross section, l is the gain crystal length, t is the transmittance of the output coupling mirror, L is the cavity loss, v l is the output laser frequency, V m is the volume of the pump region in the gain crystal, A is the average cross-sectional area of ​​the laser at the gain crystal, where V m It is expressed as:

[0038]

[0039] Among them, λ p is the pump laser wavelength, ω p is the pump waist size at the gain crystal.

[0040] In formula (1), A is expressed as:

[0041]

[0042] Among them, λ l is the output laser wavelength, ωl is the laser waist size at the gain crystal, ω l and ω p The relationship can be expressed as:

[0043]

[0044] in, η s is the measured laser slope efficiency, expressed as:

[0045]

[0046] Read the laser threshold P according to the laser input-output power curve th , and according to the injected pump power, they are P in1 and P in2 When, and the corresponding output power is P out1 and P out2 When the corresponding actual laser slope efficiency η is calculated s1 and η s2 , and then obtain A1 and A2 at two different injection powers, and bring the data into the output power P out From the formula, we get a set of linear equations of two variables. By solving the set of equations, we can get the energy transfer upconversion rate γ of the gain crystal, and at the same time, we can get the value of the radiation-free decay lifetime τ2 of the gain crystal.

[0047] The present invention provides a method for measuring the up-conversion rate of gain crystal energy transmission, comprising the following steps:

[0048] 1. Considering the influence of energy transfer upconversion, the laser output power P is obtained out The formula is:

[0049]

[0050] 2. Adjust the laser injection pump power, measure the laser output power, draw the laser input-output power curve, and read the laser threshold. In the laser stable working area, select two sets of data far away from the laser threshold.

[0051] 3. Based on the selected data, calculate the actual laser slope efficiency η s1 and η s2 , and further obtain the values ​​of the average laser cross sections A1 and A2 at the gain crystal at two different injection powers. Substituting the above data into the laser output power P outFrom the formula, we can get a set of linear equations about the energy transfer upconversion rate γ of the gain crystal and the non-radiative decay lifetime τ2. By solving the set of equations, we can get the energy transfer upconversion rate γ of the gain crystal, and at the same time, we can get the value of the non-radiative decay lifetime τ2 of the gain crystal.

[0052] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0053] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0054] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0055] The above embodiments should be understood to be only used to illustrate the present invention and not to limit the protection scope of the present invention. After reading the contents of the present invention, technicians can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. A method for measuring the up-conversion rate of gain crystal energy transfer, characterized in that: The following steps are involved: First, considering the effect of energy transfer upconversion, the laser output power P is obtained. out Formula: Laser output power P out is about the injected pump power P in , the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2; Then, under the steady-state condition of the laser, take two sets of data (P in1 ,P out1 ) and (P in2 ,P out2 ), the injected pump power P in1 and P in2 The corresponding values ​​of the average laser cross-sectional areas A1 and A2 at the gain crystal; Finally, the two sets of data are substituted into the laser output power formula to obtain a set of two-variable linear equations about the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2. By solving the set of equations, the values ​​of the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2 are obtained.

2. A method for measuring the up-conversion rate of gain crystal energy transmission according to claim 1, characterized in that: The laser output power P out The specific formula is: P in is the injected pump power, τ1 is the fluorescence lifetime of the gain crystal energy, τ2 is the radiationless decay lifetime, γ is the energy transfer upconversion rate, η a is the absorption efficiency of the gain medium for pump light, h is Planck's constant, v p is the pump laser frequency, σ is the stimulated emission cross section of the gain crystal, l is the length of the gain crystal, t is the transmittance of the output coupling mirror, L is the intracavity loss, v l is the output laser frequency, V m is the volume of the pump region in the gain crystal.

3. A method for measuring the up-conversion rate of gain crystal energy transmission according to claim 2, characterized in that: The calculation results show that the injected pump power P in1 and P in2 The corresponding values ​​of the average laser cross-sectional areas A1 and A2 at the gain crystal include: Among them, λ p is the wavelength of the pump laser, ω p is the size of the pump waist spot at the gain crystal, A is the average cross-sectional area of ​​the laser at the gain crystal, z represents the object to be integrated, and its range is 0~1 / 2; where λ l is the wavelength of the output laser, ω l is the size of the laser waist at the gain crystal, is the actual laser slope efficiency, P th represents the laser threshold; 4. The method for measuring the up-conversion rate of gain crystal energy transmission according to claim 2, characterized in that: The two sets of data are brought into the laser output power formula to obtain a set of two-variable linear equations about the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2. The values ​​of the gain crystal energy transfer upconversion rate γ and the non-radiative decay lifetime τ2 are obtained by solving the set of equations, specifically including: Read the laser threshold P according to the laser input-output power curve th , and according to the injected pump power, they are P in1 and P in2 When, and the corresponding output power is P out1 and P out2 When the corresponding actual laser slope efficiency η is calculated s1 and η s2 , and then obtain A1 and A2 at two different injection powers, and bring the data into the output power P out From the formula, we get a set of linear equations of two variables. By solving the set of equations, we can get the energy transfer upconversion rate γ of the gain crystal, and at the same time, we can get the value of the radiation-free decay lifetime τ2 of the gain crystal.

5. The method for measuring the up-conversion rate of gain crystal energy transmission according to claim 1, characterized in that: The laser under test is a full solid-state continuous 1047nm continuous wave laser with a four-mirror ring cavity structure. The laser resonant cavity is composed of four cavity mirrors, namely, a first cavity mirror (3) which is a concave-convex input mirror, a second cavity mirror (4) which is a plane reflector, a third cavity mirror (5) which is a plano-concave reflector, and a fourth cavity mirror (6) which is a plano-concave output mirror. The first cavity mirror (3) is a plano-convex mirror with a curvature radius of R=1500mm, the second cavity mirror (4) is a plane mirror, the third cavity mirror (5) and the fourth cavity mirror (6) are two plano-concave lenses with a curvature radius of R=-100mm, the front end surface of the first cavity mirror (3) is coated with a 880nm high-transmittance film, and the rear end surface is coated with an 880nm high-transmittance film and a 1047nm high-reflection film; the front end surfaces of the second cavity mirror (4) and the third cavity mirror (5) are coated with a 1047nm high-reflection film, and the front end surface of the fourth cavity mirror (6) is coated with a 1047nm transmittance T 1047nm =21%, and the rear end face is coated with a 1047nm high-transmittance film; the pump source (1) is an 880nm fiber-coupled laser diode, and the core diameter and numerical aperture of the coupled fiber are 400μm and 0.22 respectively; the pump laser (1) is focused on the waist spot of the gain crystal (7) at the center through the coupling system (2) with a size of 0.500mm; in order to adjust the working range of the laser, a plano-convex lens (8) with a focal length of 100mm is inserted into the laser resonant cavity; in order to eliminate the spatial hole burning effect and to achieve unidirectional propagation of the laser An optical isolator (9) composed of an 8 mm long terbium gallium garnet TGG crystal and a half-wave plate is used in the resonant cavity; the optical path from the first cavity mirror (3) to the center of the gain crystal (7) is 25 mm, the optical path from the center of the gain crystal (7) to the second cavity mirror (4) is 115 mm, the optical path from the second cavity mirror (4) to the third cavity mirror (5) is 126 mm, the optical path between the third cavity mirror (5) and the fourth cavity mirror (6) is 90 mm, and the optical path from the fourth cavity mirror (6) to the first cavity mirror (3) is 126 mm.

6. A method for measuring the up-conversion rate of gain crystal energy transmission according to claim 5, characterized in that: The gain crystal (7) is a 30 mm long Nd 3+ Nd:LiYF4(S1,S2:AR doping concentration of 1at.%) 880nm；1047nm ), the back end of the gain crystal is cut with a small angle of 1.5° to ensure stable polarization of the laser.

7. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for measuring the up-conversion rate of gain crystal energy transmission as claimed in any one of claims 1 to 6 is implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for measuring the gain crystal energy transfer up-conversion rate according to any one of claims 1 to 6 is implemented.

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