Laser energy automatic compensation method based on absorption spectrum

Abstract

The invention relates to a laser energy automatic compensation method based on an absorption spectrum, belongs to the field of laser, and solves the problem that the size and weight of a device are increased due to tedious elements required by an existing method. The method comprises the following steps: measuring the driving current I0 of the LD, the pumping energy # imgabs0 # of the laser and the output energy E0 of the laser at normal temperature; calculating an adjustment coefficient SE (T) between pumping energy Ep (T) required by the output energy E0 of the laser and # imgabs 1 # at different temperatures of the LD; the adjustment coefficient SE (T) is obtained based on the light absorption spectrum of the laser crystal and the emission spectrum of the LD at different temperatures; based on the adjustment coefficient SE (T) of the pumping energy, the adjustment coefficient SI (T) and the adjustment formula of the driving current required by the LD at different temperatures are calculated, and the adjustment coefficient SI (T) and the adjustment formula are burnt into a control module of the laser; and the control module monitors the temperature of the LD in real time, and adjusts the driving current according to the adjustment coefficient SI (T) of the driving current, so that the output energy of the laser is E0. The method for compensating laser energy is simple and effective, and the size of an original device is maintained.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular, to an automatic laser energy compensation method based on absorption spectroscopy. Background Art

[0002] During the operation of a laser, crystal thermal effects, pump energy fluctuations, pump wavelength drift, etc. will all affect the output energy of the laser. Among them, crystal thermal effects can be suppressed by using optical fibers or slab crystals with a larger heat dissipation volume ratio; pump energy fluctuations can be overcome by optimizing the drive circuit to make the supply current more stable; while pump wavelength drift is an inherent property of a laser diode (LD). Simply put, when an LD operates, not all electrical energy can be converted into light energy, resulting in 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 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, but in application scenarios with high requirements for volume and weight, only conduction cooling or air cooling can be used for heat dissipation. Therefore, it is still difficult to avoid the influence of LD temperature fluctuations on the laser energy; in addition, Patent CN115986548B discloses an automatic real-time calibration method for the output power of a temperature-compensated laser. 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 LD drive current 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, the existing methods for compensating the output energy of LD lasers have the defect that external devices need to be added, resulting in an increase in the volume and weight of the device. Summary of the Invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide an automatic laser energy compensation method based on absorption spectroscopy to solve the problem that existing methods need to add external devices, resulting in an increase in the volume and weight of the laser.

[0006] The embodiments of the present invention provide an automatic laser energy compensation method based on absorption spectroscopy, including:

[0007] Step S1, measure the drive current I of the LD 0 at room temperature T 0, the pump energy of the laser and the output energy E of the laser 0 ;

[0008] Step S2, calculate the pump energy E 0 required when the output energy of the laser is E p (T) and the adjustment coefficient S E (T);

[0009] 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 drive current required by the LD at different temperatures and the adjustment formula, and burn them into the control module of the laser;

[0010] Step S4, the control module monitors the temperature of the LD in real time, and adjusts the drive current according to the adjustment coefficient S I (T) to make the output energy of the laser E 0 , and the temperature of the LD is collected by the temperature measuring resistor in the LD module.

[0011] Specifically, the calculation of the pump energy E 0 required when the output energy of the laser is E p (T) and the adjustment coefficient S E (T) includes:

[0012] Step S201, measure the optical absorption spectrum η(λ) of the laser crystal;

[0013] Step S202, measure the emission spectra of the LD at different temperatures T;

[0014] Step S203, based on the emission spectra of the LD at different temperatures T, read the central wavelength λ 0 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, 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;

[0015] 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 ; where, for any emission wavelength λ j the required pump energy and E p (λ j ) and Adjustment coefficient between:

[0016]

[0017] 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 ;

[0018] Step S205. Based on the adjustment coefficient S E (λ) of the pump energy required for different emission wavelengths, and the drift coefficient, obtain the adjustment coefficient S p between the pump energy E and E at different temperatures T.

[0019] 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:

[0020]

[0021] Specifically, the adjustment coefficient S p between the pump energy E and E at different temperatures T is:

[0022] S E (T) = S E [λ(T)]

[0023] where

[0024] λ(T) = λ 0 + p(T - T 0 ).

[0025] Specifically, based on the adjustment coefficient S E (T) of the pump energy required by the laser, calculate the adjustment coefficient S I (T) of the driving current required by the LD at different temperatures, and calculate according to the following formula:

[0026] S I (T) = S E (T).

[0027] Specifically, the adjustment formula for the driving current is:

[0028] I(T) = I 0 × S I (T).

[0029] Specifically, the adjustment formula for the drive current is as follows:

[0030] I(T) = I 0 ×S I (T) + ΔI(T)

[0031] where ΔI(T) is the additional compensation amount of the drive current at different temperatures.

[0032] The additional compensation amount ΔI(T) of the drive current at different temperatures is obtained in the following manner:

[0033] Place the laser in a high and low temperature chamber and run it. Adjust the temperature to T i , after the control module obtains the temperature information, according to the adjustment formula I(T) = I 0 ×S I (T) automatically compensates the drive current, monitors the output energy of the laser, and observes whether it is E 0 , if not, then 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 is the additional compensation amount ΔI i (T i ) of the drive current at this temperature;

[0034] Adjust the temperature in sequence and repeat the above operations to obtain the additional compensation amount ΔI(T) of the drive current at different temperatures.

[0035] The measurement of the optical absorption spectrum η(λ) of the laser crystal is completed using a spectrophotometer or an absorption spectrometer.

[0036] Compared with the prior art, the present invention can at least achieve the following beneficial effects:

[0037] 1), Compared with the method of using water cooling to keep the operating temperature of the LD stable so as to keep the laser output energy stable, the present invention compensates the drive current of the LD according to the programmed adjustment coefficient by real-time monitoring of the temperature of the LD. On the one hand, no additional refrigeration equipment is required, and on the other hand, the compensation effect is more accurate and reliable;

[0038] 2), The method of the present invention does not require additional photosensitive elements to measure the output light intensity of the laser at different temperatures during the measurement process, nor does it require temperature detection elements to compensate the measurement results of the photosensitive elements, that is, no additional equipment is required. On the one hand, it is simple and effective, and has high feasibility. On the other hand, it avoids the defects of the laser in terms of volume and weight.

[0039] 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 from the content specifically pointed out in the specification and the drawings. Description of the Drawings

[0040] The drawings are only for the purpose of showing specific embodiments, and are not considered as a limitation to the present invention. Throughout the drawings, the same reference signs denote the same components.

[0041] Figure 1 It is a flowchart of the automatic laser energy compensation method based on the absorption spectrum according to the present invention.

[0042] Figure 2 It is for calculating the pump energy E p (T) and the flowchart of the adjustment coefficient therebetween.

[0043] Figure 3 It is a schematic structural diagram of the laser according to the present invention.

[0044] Figure 4 It is the optical absorption spectrum of the Nd:YAG laser crystal with a doping concentration of 1%.

[0045] Figure 5 It is the adjustment coefficient of the LD drive current at different temperatures. Detailed Embodiments

[0046] The preferred embodiments of the present invention will be specifically described below in conjunction with the drawings. The drawings form a part of this application and are used together with the embodiments of the present invention to explain the principles of the present invention, rather than to limit the scope of the present invention.

[0047] Since the temperature of the laser diode LD gradually rises during operation, the emission wavelength of the LD drifts, gradually deviating from the main absorption peak of the laser crystal, resulting in a decrease in the laser pump energy, and thus a decrease in the output energy and a decrease in the laser stability. The present invention proposes to compensate the drive current of the LD to increase the optical power of the LD, make up for the problem of the decrease in the pump energy caused by the deviation of the emission wavelength of the LD from the main absorption peak of the laser crystal, and finally maintain the stability of the laser output.

[0048] A specific embodiment of the present invention discloses an automatic laser energy compensation method based on the absorption spectrum, as Figure 1 shown, including:

[0049] Step S1, measuring the drive current I of the LD at room temperature T 0 and 0, the pump energy of the laser and the output energy E of the laser 0 ;

[0050] Step S2, calculate the pump energy E 0 required when the output energy of the laser is E p (T) and the adjustment coefficient S E (T) between; where

[0051]

[0052] the adjustment coefficient S of the pump energy E (T) 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 2 shown, specifically including the following steps:

[0053] Step S201, measure the optical absorption spectrum η(λ) of the laser crystal;

[0054] 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;

[0055] Step S202, measure the emission spectrum of the LD at different temperatures T;

[0056] Step S203, based on the emission spectrum of the LD at different temperatures T, read the central wavelength λ 0 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. Based on this relationship, calculate the drift coefficient of the central wavelength λ of the emission spectrum with respect to λ 0 with temperature;

[0057] Among them, the definition of the drift coefficient p of the central wavelength λ of the emission spectrum with respect to λ 0 at different temperatures is:

[0058]

[0059] where p is the drift coefficient and λ is the central wavelength of the LD emission spectrum at temperature T;

[0060] 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 any emission wavelength λj The required pump energy and E p (λ j ) and Adjustment coefficient between:

[0061]

[0062] 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 ;

[0063] 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 center wavelength λ of the emission spectrum with temperature, obtain the adjustment coefficient S p of the pump energy E and E at different temperatures T:

[0064] Specifically, according to the definition of the above drift coefficient, the emission center wavelength λ at any temperature T can be expressed as:

[0065] λ(T) = λ 0 + p(T - T 0 )

[0066] Naturally, substituting the above formula into the adjustment coefficient S E (λ) of the pump energy required for different emission wavelengths, the adjustment coefficient between the pump energy E p (T) and at different temperatures T can be obtained:

[0067] S E (T) = S E [λ(T)];

[0068] Step S3. Based on the adjustment coefficient S E (T) of the pump energy required for the laser calculated in Step S2, calculate the adjustment coefficient S I (T) of the driving current required for the LD at different temperatures and the adjustment formula, and burn them into the control module of the laser; where

[0069] the adjustment coefficient S I (T) of the driving current required for the LD is calculated according to the following formula:

[0070] S I (T) = S E (T)

[0071] The adjustment formula for the driving current required by the LD is as follows:

[0072] I(T) = I 0 × S I (T),

[0073] wherein, I 0 is the driving current of the LD at room temperature T 0 .

[0074] Preferably, considering the inconsistency in the assembly of each laser and the change in the pumping power of each LD at different temperatures, the above adjustment formula for the driving current can be modified as:

[0075] I(T) = I 0 × S I (T) + ΔI(T)

[0076] wherein, ΔI(T) is the additional compensation amount of the driving current at different temperatures. 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 operate, adjust the temperature to T i , after the control module obtains the temperature information, adjust the driving current automatically according to the I(T) = I 0 × S I (T) adjustment formula, monitor the output energy of the laser, and observe whether it is E 0 . If not, manually adjust the driving current until the output energy of the laser reaches E 0 , and the current adjustment amount that makes the output energy E 0 is the additional compensation amount ΔI i (T i ); Adjust the temperature in turn, and the additional compensation amount of the driving current at different temperatures can be obtained according to the above operations; Record the additional compensation amount ΔI(T) of the driving current at each temperature, and burn the above optimized driving current adjustment formula into the control module to make the compensation result more accurate;

[0077] Step S4: The control module monitors the temperature of the LD in real time, and adjusts the driving current according to the adjustment coefficient S I (T) of the driving current to make the output energy of the laser E 0 .

[0078] During implementation, the LD temperature measurement resistor inside the LD module collects the temperature of the LD and transmits it to the control module. After the control module reads the temperature of the LD, it adjusts the drive circuit of the LD according to the pre-burned adjustment coefficient of the LD drive current, so as to output the adjusted drive current to the LD, thereby adjusting the pumping energy of the LD on the laser crystal, and finally keeping the output energy of the laser stable.

[0079] The adjustment coefficient S I (T) for calculating the required drive current of the LD at different temperatures is as follows:

[0080] 1. First, calculate the adjustment coefficient S E (T) for the pumping energy required by the laser at different temperatures, which is as follows:

[0081] The output energy E(λ) of the laser and the pumping energy E p (λ) satisfy:

[0082] E(λ) = E p (λ) × η(λ) × C

[0083] where η(λ) is the optical absorption rate spectrum of the laser crystal, and C represents the optical-optical conversion rate of the laser.

[0084] Specifically, at room temperature T 0 , the output energy E 0 of the laser and the pumping energy satisfy:

[0085]

[0086] where the central wavelength of the LD emission spectrum is λ 0 , the pumping energy is , the optical absorption rate of the laser crystal is η(λ 0 ), and the output energy is E 0 .

[0087] Similarly, for any emission wavelength λ j , the pumping energy E p (λ j ) and the output energy E(λ j ) satisfy:

[0088] E(λ j ) = E p (λ j ) × η(λ j ) × C.

[0089] To keep the output energy E(λ j ) corresponding to any emission wavelength λ of the LD j as E0 , namely:

[0090] E(λ j ) = E p (λ j ) × η(λ j ) × C = E 0 ,

[0091] It is easy to obtain that the required pump energy E j at this wavelength λ p (λ j ) and should satisfy:

[0092]

[0093] Among them, is called the adjustment coefficient between the pump energy E p (λ j ) and .

[0094] According to the above principle, the adjustment coefficient S between the required pump energy at all wavelengths and E (λ) can be calculated;

[0095] 2), further, by measuring the drift coefficient of the central wavelength λ of the LD emission spectrum with temperature, that is, obtaining the central wavelength - temperature relationship λ(T), and substituting it into S E (λ), the S E [λ(T)] can be obtained, which is the adjustment coefficient S between the pump energy at different temperatures and E (T);

[0096] 2. Then, using the fact that there is a basically linear relationship between the drive current I(T) of the LD and the pump energy E p (T) of the laser, it can be obtained that the relationship between the LD drive current adjustment coefficient S I (T) and the pump energy adjustment coefficient S E (T) is: S I (T) = S E (T).

[0097] On the other hand, the embodiment of the present invention provides a laser using the above laser energy automatic compensation method, as Figure 3 shown, including: a control module, an LD drive circuit, an LD module, a resonant cavity, and a laser crystal; the control module is programmed with the adjustment coefficient S I(T) and adjustment formula I(T), whose signal input terminal is connected to the LD module, and the signal output terminal is connected to the LD driving circuit, is used to receive the temperature signal of the LD module, calculate the driving current required by the LD module at this temperature according to the adjustment formula of the LD driving current, and transmit the signal corresponding to the calculation result to the LD driving circuit; the output terminal of the LD driving circuit is connected to the LD module, and is used to input a specific driving current to the LD module according to the calculation result output by the control module; the LD module is used to provide pumping energy for the laser crystal.

[0098] Specifically, as Figure 3 shown, the control module has software functions and can output control signals externally according to a certain program, including two signal output terminals, which are respectively used to output the first signal and the 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 and off of the LD driving circuit to generate a pulse driving 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 driving current to adjust the voltage amplitude of the above LD pulse driving signal.

[0099] 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 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 LD feedback voltage signal. The second signal is obtained by the control module according to the LD driving 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 driving current according to this comparison result to generate the driving current required by the LD.

[0100] Specifically, as Figure 3 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 to be transmitted 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, 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.

[0101] Specifically, the resonant cavity is a plano-concave cavity, and the laser emitted by the LD is coupled into the laser crystal through the waveguide by means of side pumping; the laser crystal is a Nd:YAG crystal with a doping concentration of 1%.

[0102] During implementation, after the control module collects the temperature of the LD, according to the pre-burned 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 first signal received by the LD drive circuit has a high-level pulse signal, the comparator compares the second signal with the LD feedback voltage and the second signal, and the current adjustment circuit 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.

[0103] Exemplarily, for a 1% doped concentration Nd:YAG laser crystal; the measurement results are as Figure 4 shown, the wavelength corresponding to the main absorption peak of Nd:YAG is 808 nm.

[0104] Exemplarily, in the present invention, the drive current of the LD measured at room temperature T 0 is I 0 = 40 A, and the output energy of the laser is E 0 = 40 mJ.

[0105] Exemplarily, taking an array semiconductor laser with an electro-optical efficiency of 50% and a peak light output 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 is 0.284 nm / °C.

[0106] Exemplarily, based on Figure 4 the laser crystal light absorption rate spectrum shown, and the above drift coefficient of the LD emission central wavelength with temperature, the present invention obtains the adjustment coefficients of the LD drive current at different temperatures, as Figure 5 shown.

[0107] All in all, compared with the prior art, the present invention can at least achieve the following beneficial effects:

[0108] 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 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 on the other hand, the compensation effect is more accurate and reliable;

[0109] 2) For the existing "automatic real-time calibration method for the output power of a temperature-compensated laser", 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 method described in 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 by the built-in temperature-measuring resistor inside the LD. Therefore, no additional equipment is required during the measurement process. On the one hand, it is simple, effective, and highly feasible. On the other hand, it avoids the defects of the laser in terms of volume and weight.

[0110] 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.

[0111] As mentioned above, the above are only the preferred specific embodiments 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. An automatic laser energy compensation method based on absorption spectrum, characterized in that, comprising: Step S1: Measure the ambient temperature T 0 and 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 required when the output energy of the laser is E 0 at different temperatures T of the LD, and the adjustment coefficient S E (T) between them; 0 when the output energy of the laser 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 and the adjustment formula, and burn them into the control module of the laser; Step S4: The control module monitors the temperature of the LD in real time and adjusts the drive current according to the adjustment coefficient S I (T) and the adjustment formula to make the output energy of the laser be E 0 , and the temperature of the LD is collected by the temperature measuring resistor in the LD module.

2. The automatic laser energy compensation method based on absorption spectrum according to claim 1, 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, measuring the optical absorption spectrum η(λ) of the laser crystal; Step S202, measuring 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 with 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, for any emission wavelength λ j the required pump energy and E p (λ j ) and the adjustment coefficient therebetween is S E (λ j ); Step S205: Obtain the adjustment coefficient S E (λ) of the pump energy required for different emission wavelengths, and based on the drift coefficient, obtain the adjustment coefficient S p (T) between the pump energy E and E (T) at different temperatures T.

3. The automatic laser energy compensation method based on absorption spectrum according to claim 2, 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:

4. The automatic laser energy compensation method based on absorption spectrum according to claim 3, characterized in that, Any of the emission wavelengths λ j The required pump energy and E p (λ j ) and The adjustment coefficient S between E (λ j ) is: 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 .

5. The automatic laser energy compensation method based on absorption spectrum according to claim 4, characterized in that, At the different temperatures T, the pump energy E p (T) and The adjustment coefficient S E (T) is: S E (T) = S E [λ(T)] wherein, λ(T) = λ 0 + p(T - T 0 )。 6. The automatic laser energy compensation method based on absorption spectrum 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 automatic laser energy compensation method based on absorption spectrum according to claim 6, characterized in that, The adjustment formula of the drive current is: I(T) = I 0 × S I (T).

8. The automatic laser energy compensation method based on absorption spectrum according to claim 6, characterized in that, The adjustment formula of the drive current is: I(T) = I 0 × S I (T) + ΔI(T) wherein, ΔI(T) is the additional compensation amount of the drive current at different temperatures.

9. The automatic laser energy compensation method based on absorption spectrum according to claim 8, characterized in that, The additional compensation amount ΔI(T) of the drive current at different temperatures is obtained by the following method: Place the laser in a high and low temperature chamber and adjust the temperature to T i , after the control module obtains the temperature information, it automatically compensates the drive current according to the adjustment formula I(T)=I 0 ×S I (T), 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 is the additional compensation amount ΔI of the drive current at this temperature i (T i ); Adjust the temperature in sequence and repeat the above operations to obtain the additional compensation amount ΔI(T) of the drive current at different temperatures.

10. The automatic laser energy compensation method based on absorption spectrum according to any one of claims 2-9, characterized in that, The measurement of the optical absorption spectrum η(λ) of the laser crystal is completed using a spectrophotometer or an absorption spectrometer.

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