Laser capable of automatically compensating laser energy

Abstract

The invention relates to a laser capable of automatically compensating laser energy, belongs to the field of laser, and solves the problems that devices need to be additionally arranged, the compensation scheme is complex and the feasibility is low during laser energy compensation in the prior art. The laser comprises a control module, an LD driving circuit, an LD module, a resonant cavity and a laser crystal. An adjusting formula I (T) of the LD driving current at different temperatures is burnt in the control module; the LD module is used for receiving a temperature signal of the LD module, calculating a driving current required by the LD module at the temperature according to an adjustment formula I (T) of the LD driving current, and transmitting an electric signal corresponding to a calculation result to the LD driving circuit; the output end of the LD driving circuit is connected with the LD module, and the LD driving circuit is used for inputting specific driving current to the LD module according to the calculation result output by the control module; and the LD module is used for providing pumping energy for the laser crystal. The laser can automatically compensate energy according to the temperature and maintain the original size and weight.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular, to a laser with automatic laser energy compensation. Background Art

[0002] The pump wavelength drift is an inherent property of a laser diode (LD). That is to say, when the LD operates, it cannot convert all electrical energy into light energy, resulting in a part of the electrical energy being converted into heat energy, causing it to heat up. The emission wavelength of the LD drifts due to the influence of temperature, and the pump energy of the laser crystal is thus affected, resulting in unstable output energy of the laser. In short, during the operation of a semiconductor laser, the deviation of the emission wavelength from the absorption band of the laser crystal will lead to a decrease in laser energy.

[0003] Currently, the operating temperature of the LD can be controlled by water cooling or other cooling systems. However, the cooling system often increases the volume and weight of the device. Therefore, this method is not applicable to application scenarios with high requirements for volume and weight. In addition, Patent CN115986548B discloses a method for automatically and real-time calibrating the output power of a laser with temperature compensation. This method uses a photosensitive sensor to monitor the output laser of the laser in real time and uses a closed-loop control strategy to control the driving current of the LD in real time to achieve stable laser output. During the process, a temperature sensor is also used to monitor the temperature of the photosensitive sensor to make the compensation calculation more accurate. Although this solution can correct the influence of LD temperature fluctuations on the output laser, its defect is that additional photosensitive sensors and temperature sensors are added to the device, increasing the complexity of the optical path, reducing the reliability, and increasing the volume and weight of the device.

[0004] Generally speaking, since the existing methods for compensating the output energy of LD lasers have the defect that additional external devices need to be added, resulting in an increase in the volume and weight of the device, the lasers based on the existing energy compensation methods also correspondingly have the defects of complex laser structure, increased volume and weight. Summary of the Invention

[0005] In view of the above analysis, an embodiment of the present invention aims to provide a laser with automatic laser energy compensation to solve the problem that existing lasers capable of completing energy compensation need to add external devices during the test stage, resulting in an increase in the volume and weight of the lasers.

[0006] An embodiment of the present invention provides a laser with automatic laser energy compensation, which includes a control module, an LD driving circuit, an LD module, a resonant cavity, and a laser crystal. The control module is programmed with an adjustment formula I(T) for the LD driving current at different temperatures, and is configured to receive the temperature signal of the LD module, calculate the driving current required for the LD module at this temperature according to the adjustment formula I(T) for the LD driving current, and transmit the corresponding electrical signal of the calculation result to the LD driving circuit. The output end of the LD driving circuit is connected to the LD module, and is configured to input a specific driving current to the LD module according to the calculation result output by the control module. The LD module is configured to provide pumping energy for the laser crystal.

[0007] Specifically, the control module includes two signal output ends. The LD driving circuit includes: a switch circuit, a comparator circuit, and a current adjustment circuit that are electrically connected in sequence. Among them, the input end of the switch circuit is connected to the first signal output end of the control module. The first signal is a pulse signal with a specific voltage amplitude, which is used to control the on / off of the LD driving circuit and generate a pulse driving signal for the LD. The two signal input ends of the comparator circuit respectively receive the second signal output by the control module and the feedback voltage signal of the LD. The second signal is obtained by the control module according to the adjustment formula for the LD driving current to adjust the voltage amplitude of the above LD pulse driving signal.

[0008] Specifically, based on the adjustment coefficient S I (T) of the LD driving current at different temperatures, the adjustment formula I(T) is obtained. Obtaining the adjustment coefficient S I (T) of the LD driving current at different temperatures includes:

[0009] Step S1: Measure the driving current I 0 of the LD, the pumping energy of the laser, 0 and the output energy E of the laser at room temperature T 0 ;

[0010] Step S2: Calculate the adjustment coefficient S 0 between the required pumping energy E p (T) and when the output energy of the laser is E E at different temperatures T of the LD;

[0011] Step S3: Based on the adjustment coefficient S E (T) of the required pumping energy of the laser calculated in Step S2, calculate the adjustment coefficient S I (T) of the driving current required for the LD at different temperatures.

[0012] Specifically, calculating the adjustment coefficient S 0The required pump energy E p (T) and The adjustment coefficient S between E (T), including:

[0013] Step S201, measure the optical absorption spectrum η(λ) of the laser crystal;

[0014] Step S202, measure the emission spectra of the LD at different temperatures T;

[0015] Step S203, based on the emission spectra of the LD at different temperatures T, read the central wavelength λ of the LD emission spectrum at room temperature T 0 and establish the relationship λ(T) between the central wavelength λ of the emission spectrum and the temperature T, and calculate the drift coefficient of the central wavelength λ of the emission spectrum with respect to λ 0 with temperature based on the relationship; 0 The drift coefficient of the central wavelength λ of the emission spectrum with temperature;

[0016] Step S204, based on the optical absorption spectrum η(λ) of the laser crystal, obtain the adjustment coefficient S between the pump energy required for different emission wavelengths and The adjustment coefficient S between E (λ); where any emission wavelength λ j The required pump energy and E p (λ j ) and The adjustment coefficient S between E (λ j ) is:

[0017]

[0018] where η(λ 0 ) and η(λ j ) respectively represent the optical absorption rates of the laser crystal for wavelengths λ 0 and wavelength λ j ;

[0019] Step S205, based on the adjustment coefficient S of the pump energy required for different emission wavelengths E (λ), and the drift coefficient, obtain the adjustment coefficient S between the pump energy E p (T) and The adjustment coefficient S between E (T) at different temperatures T.

[0020] Specifically, the definition of the drift coefficient p of the central wavelength λ of the emission spectrum with temperature at different temperatures with respect to λ 0 is:

[0021]

[0022] Specifically, the adjustment coefficient S E (T) for the pump energy required by the laser is used to calculate the adjustment coefficient S I (T) of the driving current required by the LD at different temperatures, which is calculated according to the following formula:

[0023] S I (T) = S E (T).

[0024] Specifically, the adjustment formula for the driving current is as follows:

[0025] I(T) = I 0 ×S I (T).

[0026] Specifically, the LD module includes: an LD, an LD temperature measuring resistor, and an LD radiator; among them, the LD temperature measuring resistor is installed inside the LD package for collecting the temperature signal of the LD in real time and converting it into an electrical signal for transmission to the control module; the radiator is installed on the heat dissipation surface of the LD for dissipating heat and cooling the LD.

[0027] Furthermore, the radiator is of a fin structure and dissipates heat from the LD through heat conduction and convective heat transfer.

[0028] Specifically, the resonant cavity is a plano-concave cavity, and the laser emitted by the LD is coupled into the laser crystal by means of side pumping; the laser crystal is a Nd:YAG crystal.

[0029] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0030] 1), Compared with a laser that uses a cooling system to keep the operating temperature of the LD stable, the laser of the present invention compensates the driving current of the LD by real-time monitoring of the temperature of the LD and according to the adjustment coefficient pre-recorded in the control module. On the one hand, no additional refrigeration equipment is required, and the volume and weight of the original equipment can be maintained unchanged. On the other hand, the compensation effect is more accurate and reliable;

[0031] 2), For the laser with automatic laser energy compensation of the present invention, there is no need to change the optical path structure of the laser and no additional equipment is required to obtain the current compensation coefficient during the preliminary test stage, which is simple, effective, and highly feasible.

[0032] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combined solutions. Other features and advantages of the present invention will be described in the subsequent specification, and some advantages can be made obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the content specifically pointed out in the specification and the drawings. Description of the Drawings

[0033] The accompanying drawings are only for the purpose of showing specific embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference numerals represent the same components;

[0034] Figure 1 Schematic diagram of the laser for automatic compensation of laser energy according to the present invention;

[0035] Figure 2 To calculate the adjustment coefficient S I (T) of the drive current at different temperatures;

[0036] Figure 3 To calculate the pump energy E p (T) and Flow chart of the adjustment coefficient therebetween;

[0037] Figure 4 Optical absorption spectrum of Nd:YAG laser crystal with 1% doping concentration;

[0038] Figure 5 Adjustment coefficient of LD drive current at different temperatures. Specific embodiments

[0039] The following will specifically describe the preferred embodiments of the present invention with reference to the accompanying drawings. Among them, the accompanying drawings form a part of this application and are used together with the embodiments of the present invention to explain the principle of the present invention, rather than to limit the scope of the present invention.

[0040] The embodiment of the present invention provides a laser for automatic compensation of laser energy, as Figure 1 shown, including: a control module, an LD drive circuit, an LD module, a resonator cavity, and a laser crystal; the control module is programmed with the adjustment formula I(T) of the LD drive current at different temperatures; it is used to receive the temperature signal of the LD module and calculate the drive current required by the LD module at this temperature according to the adjustment formula I(T) of the LD drive current, and transmit the corresponding electrical signal of the calculation result to the LD drive circuit; the output end of the LD drive circuit is connected to the LD module, and is used to input a specific drive current to the LD module according to the calculation result output by the control module; the LD module is used to provide pump energy for the laser crystal.

[0041] Specifically, as Figure 1As shown, the control module has software functions and can output control signals externally according to a certain program. It includes two signal output terminals, which are respectively used to output a first signal and a second signal. The first signal is a pulse signal, and its frequency is set according to the absorption characteristics of the crystal material, and is used to control the on-off of the LD drive circuit to generate a pulse drive signal for the LD. The second signal is a voltage control signal, which is obtained by the control module according to the adjustment formula of the LD drive current to adjust the voltage amplitude of the above LD pulse drive signal.

[0042] The LD drive circuit includes: a switch circuit, a comparator circuit, and a current adjustment circuit that are electrically connected in sequence. Among them, the input terminal of the switch circuit is connected to the first signal output terminal of the control module. The two signal input terminals of the comparator circuit respectively receive the second signal output by the control module and the feedback voltage signal of the LD. The second signal is obtained by the control module according to the LD drive current adjustment formula. The comparator obtains the comparison result of the second signal and the LD feedback voltage signal, and the current adjustment circuit continuously adjusts the LD drive current according to this comparison result to generate the drive current required by the LD.

[0043] Specifically, as Figure 1 shown, the LD module includes: an LD, a temperature-measuring resistor of the LD, and a heat dissipation module of the LD. Among them, the temperature-measuring resistor of the LD is integrated inside the LD, that is, encapsulated inside the housing of the LD, and is used to collect the core temperature of the LD heating device in real time and convert it into an electrical signal and transmit it to the signal input terminal of the control module. The radiator is installed on the heat dissipation surface of the LD. Exemplarily, the radiator adopts a fin structure and the material is pure copper, and dissipates heat and cools the LD through heat conduction and convective heat transfer. Further, an indium foil is added to the LD thermal interface to reduce the thermal resistance. The radiator has a certain heat capacity and its weight is more than 3 times that of the LD.

[0044] Specifically, the resonant cavity is a plano-concave cavity, and the laser emitted by the LD is coupled into the laser crystal through side pumping through a waveguide. The laser crystal is a Nd:YAG crystal with a doping concentration of 1%.

[0045] During implementation, after the control module collects the temperature of the LD, according to the pre-programmed adjustment coefficient and adjustment formula of the drive current, it obtains the second signal, outputs the first signal to the switching circuit in the LD drive circuit, and outputs the second signal to the comparator; when the pulse signal in the first signal received by the LD drive circuit is at a high level, the comparator compares the second signal with the LD feedback voltage and the second signal, and the current adjustment circuit continuously adjusts the current across the LD according to the comparison result, finally adjusting the current flowing through the LD according to the second signal of the control module; when the pulse signal is at a low level, the drive circuit is disconnected; under the combined action of the first signal and the second signal, the LD drive circuit provides the required pulse current for the LD module; compensating the luminous power of the LD, that is, adjusting the pumping energy of the laser crystal; finally compensating the output energy of the laser.

[0046] Specifically, the adjustment coefficient S I (T) of the LD drive current at different temperatures is obtained by using the automatic laser energy compensation method based on the absorption spectrum, as Figure 2 shown, including:[[]]

[0047] Step S1: Measure the drive current I 0 of the LD, the pumping energy 0 of the laser, and the output energy E of the laser at room temperature T 0 ;

[0048] Step S2: Calculate the adjustment coefficient S 0 (T) between the required pumping energy E p (T) and when the output energy of the laser is E at different temperatures T of the LD; among them, E

[0049]

[0050] The adjustment coefficient S E (T) of the pumping energy is obtained based on the optical absorption spectrum of the laser crystal and the emission spectrum of the LD at different temperatures T, as Figure 3 shown, specifically including the following steps:

[0051] Step S201: Measure the optical absorption spectrum η(λ) of the laser crystal;

[0052] Specifically, when measuring the optical absorption spectrum η(λ) of the laser crystal, according to the doping concentration and absorption length of the laser crystal, use a spectrophotometer or an absorption spectrometer to measure the optical absorption rate spectrum of the crystal near the main absorption band. Preferably, during the measurement, make the spectral resolution as high as possible;

[0053] ​Step S202: Measure the emission spectra of the LD at different temperatures T.

[0054] Step S203: Based on the emission spectra of the LD at different temperatures T, read the central wavelength λ of the emission spectrum of the LD at room temperature T 0 and establish the relationship λ(T) between the central wavelength λ of the emission spectrum and the temperature T. Calculate the drift coefficient of the central wavelength λ of the emission spectrum with respect to the temperature based on the said relationship 0 ; 0 wherein, the definition of the drift coefficient p of the central wavelength λ of the emission spectrum with respect to different temperatures is as follows:

[0055] wherein, p is the drift coefficient, and λ is the central wavelength of the emission spectrum of the LD at temperature T; 0

[0056]

[0057]

[0058] Step S204: Based on the optical absorption spectrum η(λ) of the laser crystal, obtain the adjustment coefficient S (λ) between the pump energy required for different emission wavelengths and E ; wherein, for any emission wavelength λ j the adjustment coefficient between the required pump energy and E p (λ j ) and is as follows:

[0059]

[0060] wherein, η(λ 0 ) and η(λ j ) respectively represent the optical absorption rates of the laser crystal for wavelength λ 0 and wavelength λ j ;

[0061] Step S205: Based on the adjustment coefficient S E (λ) of the pump energy required for different emission wavelengths and the drift coefficient p of the central wavelength λ of the emission spectrum with respect to the temperature, obtain the adjustment coefficient S p (T) between the pump energy E and E at different temperatures T;

[0062] Specifically, according to the definition of the above drift coefficient, the emission center wavelength λ at any temperature T can be expressed as:

[0063] λ(T) = λ 0 + p(T - T 0 ) ​​

[0064] Naturally, substituting the above formula into the adjustment coefficient S of the pump energy required for different emission wavelengths E (λ), the pump energy E p (T) at different temperatures T can be obtained and the adjustment coefficient between

[0065] S E (T) = S E [λ(T)];

[0066] Step S3: Based on the adjustment coefficient S E (T) of the pump energy required by the laser calculated in step S2, calculate the adjustment coefficient S I (T) of the driving current required by the LD at different temperatures and the adjustment formula, and burn them into the control module of the laser; where

[0067] the adjustment coefficient S I (T) of the driving current required by the LD is calculated according to the following formula:

[0068] S I (T) = S E (T)

[0069] The adjustment formula for the driving current required by the LD is:

[0070] I(T) = I 0 ×S I (T),

[0071] where I 0 is the driving current of the LD at room temperature T 0 ;

[0072] Preferably, considering the inconsistency of each laser assembly and the change of the pump power of each LD at different temperatures, the above adjustment formula for the driving current can be modified as:

[0073] I(T) = I 0 ×S I (T) + ΔI(T)

[0074] where ΔI(T) is the additional compensation amount of the driving current at different temperatures, and the additional compensation amount ΔI i of the driving current at any temperature T i (T i ) is obtained through the following method: after the laser is assembled, place the laser in a high and low temperature chamber to run, adjust the temperature to T i , after the control module obtains the temperature information, press I(T) = I 0 ×S I(T) Adjust the formula to automatically compensate the drive current, monitor the output energy of the laser, and observe whether it is E 0 , if not, manually adjust the drive current until the output energy of the laser reaches E 0 , so that the output energy is E 0 The current adjustment amount for making the output energy E is the additional compensation amount ΔI of the drive current at this temperature i (T i ); Adjust the temperature in sequence, and the additional compensation amount of the drive current at different temperatures can be obtained according to the above operations; Record the additional compensation amount ΔI(T) of the drive current at each temperature, and burn the optimized drive current adjustment formula into the control module, so that the compensation result can be more accurate.

[0075] Exemplarily, for a Nd:YAG laser crystal with a doping concentration of 1%; the measurement results are as Figure 4 shown, the wavelength corresponding to the main absorption peak of Nd:YAG is 808 nm.

[0076] Exemplarily, the drive current of the LD measured by the present invention at room temperature T 0 is I 0 = 40 A, and the output energy of the laser is E 0 = 40 mJ.

[0077] Exemplarily, taking an array semiconductor laser with an electro-optical efficiency of 50% and a light output peak power of 7200 W when supplying a current of 300 A as an example, measuring the spectra of the LD at different temperatures, the central wavelengths of the emission spectra of the LD at 5 °C, 25 °C, and 60 °C can be obtained as 802.9 nm, 808.3 nm, and 818.5 nm respectively. From this, the drift coefficient p of the emission central wavelength of the LD with temperature can be obtained as 0.284 nm / °C.

[0078] Exemplarily, based on Figure 4 the light absorption rate spectrum of the laser crystal shown, and the drift coefficient of the emission central wavelength of the above LD with temperature, the present invention obtains the adjustment coefficients of the LD drive current at different temperatures, as Figure 5 shown.

[0079] All in all, compared with the prior art, the present invention can at least achieve the following beneficial effects:

[0080] 1), compared with the method of using water cooling to stabilize the operating temperature of the LD to make the laser output energy stable, the laser of the present invention compensates the drive current of the LD according to the burned adjustment coefficient by real-time monitoring of the temperature of the LD. On the one hand, no additional refrigeration equipment is required, and the original volume and weight can be maintained. On the other hand, the compensation effect is more accurate and reliable;

[0081] 2) For existing lasers based on the "Automatic Real-time Calibration Method for Laser Output Power with Temperature Compensation", during the preliminary test stage, an external photosensitive element is required to measure the output light intensity of the laser, and at the same time, a temperature detector is required to detect the temperature of the photosensitive element in real time; while the core of the compensation method adopted by the laser of the present invention is to measure the optical absorption spectrum of the laser crystal inside the laser and the drift of the LD emission wavelength with temperature, and the latter can be completed only with the built-in temperature measurement resistor inside the LD. Therefore, no additional equipment is required during the measurement process, nor is it necessary to change the optical path structure. On the one hand, it is simple, effective and highly feasible, and on the other hand, it avoids the defects of the laser in terms of volume and weight.

[0082] Those skilled in the art can understand that all or part of the processes for implementing the methods of the above embodiments can be completed by instructing relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. Among them, the computer-readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory, etc.

[0083] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A laser with automatic laser energy compensation, characterized in that, it includes a control module, an LD drive circuit, an LD module, a resonant cavity and a laser crystal; The control module is programmed with an adjustment formula I(T) for the LD drive current at different temperatures; it is used to receive the temperature signal of the LD module, calculate the drive current required by the LD module at this temperature according to the adjustment formula I(T) of the LD drive current, and transmit the corresponding electrical signal of the calculation result to the LD drive circuit; The output end of the LD drive circuit is connected to the LD module, and is used to input a specific drive current to the LD module according to the calculation result output by the control module; the LD module is used to provide pump energy for the laser crystal.

2. The laser with automatic laser energy compensation according to claim 1, characterized in that, The control module includes two signal output ends; the LD drive circuit includes: a switch circuit, a comparator circuit and a current adjustment circuit connected in sequence; wherein, the input end of the switch circuit is connected to the first signal output end of the control module, and the first signal is a pulse signal, which is used to control the on and off of the LD drive circuit and generate a pulse drive signal for the LD; two signal input ends of the comparator circuit respectively receive the second signal output by the control module and the feedback voltage signal of the LD, and the second signal is obtained by the control module according to the adjustment formula of the LD drive current to adjust the voltage amplitude of the above LD pulse drive signal.

3. The laser with automatic laser energy compensation according to claim 1, characterized in that, Adjustment coefficient S of LD drive current at different temperatures I (T) to obtain the adjustment formula I(T); Obtain the adjustment coefficient S of the LD drive current at different temperatures I (T), including: Step S1: Measure the ambient temperature T 0 The drive current I of the LD 0 , the pump energy of the laser and the output energy E of the laser 0 ; Step S2: Calculate the pump energy E p (T) required when the output energy of the laser is E 0 at different temperatures T of the LD, and the adjustment coefficient S (T) between them; 0 when the laser output energy is E p (T) and the adjustment coefficient S E (T); Step S3: Based on the adjustment coefficient S of the pump energy required by the laser calculated in Step S2 E (T), calculate the adjustment coefficient S I (T) of the drive current required by the LD at different temperatures.

4. The laser with automatic laser energy compensation according to claim 3, characterized in that, When the calculated LD is at different temperatures T, the pump energy E required for the laser output energy to be E 0 is p (T) and the adjustment coefficient S between them, including: E (T), including: Step S201, measure the optical absorption spectrum η(λ) of the laser crystal; Step S202, measure the emission spectrum of the LD at different temperatures T; Step S203: Based on the emission spectra of the LD at different temperatures T, read the central wavelength λ of the LD emission spectrum at room temperature T 0 and establish the relationship λ(T) between the central wavelength λ of the emission spectrum and the temperature T. Calculate the drift coefficient of the central wavelength λ of the emission spectrum with respect to λ 0 as a function of temperature based on the said relationship; 0 ​ Step S204: Based on the optical absorption spectrum η(λ) of the laser crystal, obtain the adjustment coefficient S between the pump energy required for different emission wavelengths and E (λ); where the pump energy required for any emission wavelength λ j and E p (λ j ) and the adjustment coefficient S E (λ j ) is as follows: where η(λ 0 ) and η(λ j ) respectively represent the light absorption rates of the laser crystal for wavelengths λ 0 and wavelength λ j ; Step S205. Obtain the adjustment coefficient S E (λ) between the pump energy E p (T) required for different emission wavelengths and the drift coefficient at different temperatures T, and the adjustment coefficient S between them E (T).

5. The laser with automatic laser energy compensation according to claim 4, characterized in that, Said relative to λ 0 , the definition of the drift coefficient p of the central wavelength λ of the emission spectrum with temperature at different temperatures is:

6. The laser with automatic laser energy compensation according to claim 5, characterized in that, The adjustment coefficient S based on the pump energy required by the laser E (T), calculate the adjustment coefficient S of the drive current required by the LD at different temperatures I (T), calculated according to the following formula: S I (T) = S E (T).

7. The laser with automatic laser energy compensation according to claim 6, characterized in that, The adjustment formula of the drive current is: I(T) = I 0 × S I (T).

8. The laser with automatic laser energy compensation according to claim 2, characterized in that, The LD module includes: an LD, an LD temperature measurement resistor and an LD radiator; wherein, the LD temperature measurement resistor is installed inside the LD package and is used to collect the temperature signal of the LD in real time and convert it into an electrical signal to be transmitted to the control module; the radiator is installed on the heat dissipation surface of the LD and is used to dissipate heat and cool the LD.

9. The method for automatic compensation of laser energy based on absorption spectrum according to claim 8, characterized in that, The radiator is a fin structure and dissipates heat from the LD by means of heat conduction and convective heat transfer.

10. The method for automatic compensation of laser energy based on absorption spectrum according to claim 9, characterized in that, The resonant cavity is a plano-concave cavity, and the laser emitted by the LD is coupled into the laser crystal by means of end pumping; the laser crystal is a Nd:YAG crystal.

Images