Infrared laser device in 1-micron wave band direct pump light parameter and regulation and control method thereof

Abstract

The invention relates to the technical field of all-solid-state laser, and provides a 1-micron wave band direct pump optical parameter intermediate infrared laser device and a regulation and control method thereof, the device comprises a fundamental frequency light source, a shaping lens module, a pulse modulation module and a synchronous pump resonant cavity, and a gain medium with matched phases is arranged in the cavity. The pumping laser is injected into the gain medium to generate intermediate infrared laser which is output through the output mirror. The intermediate infrared pulse laser device is provided with a resonant cavity with a simple structure and can stably output intermediate infrared laser with high conversion efficiency and high output power under the condition of high repetition frequency, and the problem that when an existing intermediate infrared pulse laser device generates high-power intermediate infrared laser in the high repetition frequency pumping process, a crystal is prone to generating a serious heat effect, and thermally-induced stress damage is caused is solved.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular to a 1-micron-band directly pumped optical parametric mid-infrared laser device and a control method thereof. Background Art

[0002] Mid-infrared laser technology is at the forefront of current laser research, boasting broad application prospects, particularly in the medical, industrial processing, remote sensing, and military fields. In the medical field, particularly during the ablation and resection of biological tissue, mid-infrared laser technology offers the advantages of high efficiency and minimal collateral damage to surrounding tissues, making it one of the most effective laser knife technologies currently available.

[0003] Currently, mid- and far-infrared lasers generated from 1 μm pump sources for use in laser medical and industrial applications require high repetition rates to improve efficiency. However, increasing the repetition rate can lead to severe thermal effects on the crystal, causing thermal stress damage and limiting its application scenarios.

[0004] Therefore, how to reduce the thermal effect of crystals under high repetition rate conditions has become one of the problems that need to be solved urgently. Summary of the Invention

[0005] The present invention aims to provide a 1-micron-band directly pumped optical parametric mid-infrared laser device. This device utilizes pulse control technology to achieve pulse mode adjustment, employs a stress application submodule to apply or release stress to the gain medium, and utilizes a stress detection module and pulse width detection. Compared to existing technologies, this device offers more comprehensive adjustment capabilities, enabling precise control of the entire optical system, reducing crystal damage, and enabling efficient laser operation at high repetition rates and high powers.

[0006] The present invention provides a 1 micron band directly pumped optical parametric mid-infrared laser device, comprising: A pump light source for providing pump laser in the 1 micron band; The pulse control module is provided on one side of the pump light source and is used to receive the pump laser and adjust the repetition frequency of the pump laser. f and pulse width τ p Modulation is performed, and the modulated pump laser has a high repetition frequency and an appropriate pulse width; A resonant cavity, arranged on the optical path of the pump laser, comprising an input lens and an output lens; The gain medium is arranged in the resonant cavity and is used to receive the modulated pump laser and perform nonlinear frequency conversion to generate mid-infrared laser. The maximum stress that the gain medium can withstand is the stress threshold F th ; A stress regulating heat sink is arranged to enclose the gain medium, and the stress applying submodule is used to apply or release stress to the gain medium; A stress detection module, provided on one side of the stress regulating heat sink, for detecting the stress value F of the gain medium; The pulse width monitoring module is set on one side of the pulse control module and is used to monitor the pulse width τ of the modulated pump laser. p ; The power monitoring module is set on the output optical path to monitor the output mid-infrared laser power P and the repetition frequency of the modulated pump light. f ; A processor for determining a pulse width τ based on the stress value F of the gain medium and the pulse width τ p Increase the power of the pump light source, when the stress value F is less than the stress threshold F th When the power of the pump light source is increased to 80%, the stress value F detected by the stress detection module will increase accordingly until the stress value reaches the stress threshold F. th After the pulse width reaches 80%, the processor sends an adjustment signal to the pulse control module so that the pulse width τ p The processor sends an adjustment instruction to the stress adjustment heat sink so that the stress value F detected by the stress detection module is less than the stress threshold F th After a×80%, the processor repeatedly increases the power of the pump light source, adjusts the pulse control module and adjusts the stress adjustment heat sink until the output mid-infrared laser reaches the target power value, wherein the range of a is: 0.85 <a<0.95。

[0007] According to the 1 micron band direct pump optical parametric mid-infrared laser device provided by the present invention, the repetition frequency f of the modulated pump light and the pulse width τ of the modulated pump laser are p The relationship between the stress value F detected by the stress detection module satisfies: , where f is the laser repetition frequency; is the pulse width; τ th is the thermal relaxation time; E is the elastic modulus; μ is the Poisson's ratio; α T is the thermal expansion coefficient; α is the absorption coefficient; η is the pump light heat generation rate; k is the thermal conductivity; 𝜔 eff is the effective radius of the pump spot.

[0008] According to the 1 micron band directly pumped optical parametric mid-infrared laser device provided by the present invention, the stress adjustment heat sink includes: At least two stress applying submodules are movably disposed at the periphery of the gain medium, and the stress applying submodules are used to apply or release stress to the gain medium.

[0009] According to the 1-micron-band directly pumped optical parametric mid-infrared laser device provided by the present invention, the stress-regulating heat sink further includes a stress monitoring submodule, which is attached to the gain medium or attached to the stress applying submodule to monitor the surface thermal stress value borne by the surface of the gain medium and send the surface thermal stress value to the processor. The processor adjusts the stress applying submodule according to the surface thermal stress value and the stress threshold so that the surface thermal stress value is less than the stress threshold.

[0010] According to the 1 micron band direct pump optical parametric mid-infrared laser device provided by the present invention, the initial stress value of the gain medium detected by the stress detection module is less than the stress threshold F th 80% of.

[0011] According to the 1 micron band directly pumped optical parametric mid-infrared laser device provided by the present invention, the pulse control module includes at least one of an acousto-optic modulator, an electro-optic modulator, and a saturable absorber.

[0012] According to the 1 micron band direct pumped optical parametric mid-infrared laser device provided by the present invention, the material of the gain medium is one of BGSe, BGGSe, BGS, CSP, LISe, and LIS.

[0013] Optionally, a shaping module is further included, located between the pulse control module and the resonant cavity, to shape the pump light entering the resonant cavity.

[0014] The present invention also provides a control method for a 1-micron-band directly pumped optical parametric mid-infrared laser device, which is used for any of the above-mentioned 1-micron-band directly pumped optical parametric mid-infrared laser devices, and the control method comprises: Start the mid-infrared laser device and set the repetition frequency of the pump laser f 0 , pulse width τ p0 , the stress regulating heat sink applies an initial stress to the gain medium and a target power value of the output mid-infrared laser, wherein the initial stress value borne by the gain medium is less than the stress threshold F th 80%; The stress detection module detects the stress value F of the gain medium, and the pulse width monitoring module monitors the pulse width τ of the pump laser. p The power detection module detects the repetition frequency of the pump laser f ; As the power of the pump light source increases, the stress value F detected by the stress detection module will increase until the stress value reaches the stress threshold F. thAfter 80% of the pulse width, reduce the pulse width τ p At the same time, the stress adjustment submodule releases the stress so that the stress value F is less than the stress threshold F th a×80%, where a range is: 0.85 <a<0.95; Repeat the parameter adjustment process until the power detection module detects that the output mid-infrared laser reaches the target power value.

[0015] Optionally, the stress regulating heat sink further includes a stress monitoring module to monitor the surface thermal stress value borne by the surface of the gain medium; The control method further comprises: Adjust the stress application submodule so that the surface thermal stress value is less than the stress threshold F th 80% of.

[0016] The 1 micron band direct pump optical parametric mid-infrared laser device provided by the present invention has a processor based on the stress value F of the gain medium and the pulse width τ p， By setting the pulse control module, when the stress on the gain medium reaches 80% of the stress threshold, the pump laser pulse width τ is changed. p , keeping the internal stress of the gain medium below this value. By providing a stress-regulating heat sink, when the stress on the gain medium reaches 80% of the stress threshold, the stress applied to the gain medium by one or more stress-applying submodules is regulated, thereby reducing the internal stress of the gain medium. A stress detection module and a power monitoring module are provided to monitor the stress on the gain medium and the output mid-infrared laser power in real time, ensuring that the target power value is achieved within the stress threshold range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a schematic diagram of the optical path of a 1-micron-band directly pumped optical parametric mid-infrared laser device provided by an embodiment of the present invention; Figure 2 Schematic diagram of the structure of a stress regulating heat sink provided by an embodiment of the present invention.

[0019] Figure 3 This is a flow chart of a control method for a 1-micron-band directly pumped optical parametric mid-infrared laser device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0021] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0022] The following is combined with Figures 1 to 3 The present invention will be described in detail.

[0023] See also Figure 1 As shown, the present invention provides a 1-micron band directly pumped optical parametric mid-infrared laser device including: a pump light source 1, a pulse control module 2, a resonant cavity 3, a gain medium 4, a stress adjustment heat sink 5, a stress detection module 6, a pulse width monitoring module 7, a power monitoring module 8 and a processor 9.

[0024] The pump light source 1 provides a 1-micron-wavelength pump laser. Due to its mature technology and stable output, 1-micron-wavelength pump lasers are often used in nonlinear frequency-conversion laser technology research and are ideal for generating high-power parametric lasers. A pulse control module 2, located adjacent to the pump light source 1, receives the pump laser and modulates its repetition frequency and pulse width. This module sets the pump laser's repetition frequency and adjusts its pulse width. The modulated repetition frequency is tailored to industry-accepted high repetition frequencies, such as 20 kHz to 2000 kHz.

[0025] The resonant cavity 3 is arranged in the optical path of the pump laser and includes an input lens 31 and an output lens 32. The gain medium 4 is arranged in the resonant cavity 3. The modulated pump laser acts on the gain medium 4, oscillates and amplifies in the resonant cavity 3, and performs nonlinear frequency conversion to generate mid-infrared laser. The maximum stress that the gain medium 4 can withstand is the stress threshold Fth It is understood that different gain media 4 have their own maximum thermal stress values ​​that they can withstand, which is the stress threshold F in this application. th .

[0026] Please refer to Figure 2 As shown, the stress-adjusting heat sink 5 includes at least two stress-applying submodules 51, which are arranged to enclose the gain medium 4. The stress-applying submodules 51 are used to apply or release stress to the gain medium 4. In the present invention, stress can be applied or released to the gain medium 4 by adjusting the position, i.e., the tightness, of the stress-applying submodules 51.

[0027] The stress detection module 6 is provided on one side of the stress regulating heat sink 5 and is used to detect the stress value of the gain medium 4. The initial stress value of the gain medium 4 detected by the stress detection module 6 is less than the stress threshold F th 80% of the gain medium 4. It is understandable that the stress-regulating heat sink 5 applies stress to the gain medium 4 in the initial state, and the stress detection module 6 can detect the stress value borne by the gain medium 4 in the initial state. In a specific embodiment, the stress detection module 6 can emit a detection light to the gain medium 4, which enters the stress detection module 6 after being reflected by the gain medium 4. This method can reflect the thermal stress value inside the gain medium 4. It should be noted that when the gain medium 4 is subjected to stress, it will produce a birefringence phenomenon on the detection light emitted by the stress detection module 6, that is, the medium affects the polarization state of the light, resulting in a phase difference between the detection light and the detection light. These phase differences will form interference fringes after passing through the analyzer. The distribution of thermal stress inside the medium can be analyzed and calculated based on the density and direction of the interference fringes. The density of the interference fringes reflects the magnitude of the stress, and the direction of the fringes reflects the direction of the stress.

[0028] The pulse width monitoring module 7 is set on one side of the pulse control module 2 and is used to monitor the pulse width τ of the modulated pump laser. p .

[0029] The power monitoring module 8 is set on the output optical path to monitor the output power P of the mid-infrared laser and the repetition frequency of the modulated pump light. f It is understood that the repetition frequency of the pump laser is the same as the repetition frequency of the output mid-infrared laser. Therefore, the repetition frequency of the pump laser can be determined by monitoring the repetition frequency of the output mid-infrared laser. The repetition frequency of the pump laser can be determined by technicians based on actual needs.

[0030] The processor 9 receives the stress value F detected by the stress detection module 6 and the pulse width τ monitored by the pulse width monitoring module 7. p , when the stress value F is less than the stress threshold F thWhen the power of the pump light source is increased, the stress value F detected by the stress detection module 6 will increase accordingly until the stress value reaches the stress threshold F th After the pulse width reaches 80%, the processor 9 sends an adjustment signal to the pulse control module 2 so that the pulse width τ p The processor 9 sends an adjustment instruction to the stress adjustment heat sink 5, so that the stress adjustment submodule 51 releases the stress, so that the stress value F detected by the stress detection module 6 is less than the stress threshold F th After a×80%, the processor 9 repeats the process of increasing the power of the pump light source 1, adjusting the pulse control module 2 and adjusting the stress regulating heat sink 5 until the output mid-infrared laser reaches the target power value, where a range: 0.85 <a<0.95。

[0031] In this embodiment of the 1-micron-band directly pumped optical parametric mid-infrared laser device, a removable stress-applying submodule 51 within the stress-regulating heat sink 5 can apply or release stress to the gain medium 4. The thermal stress on the gain medium 4 is adjusted by adjusting the power of the pump light source 1, while the pulse width is simultaneously adjusted by the pulse control module 2. Ultimately, by increasing the power of the pump light source 1, adjusting the pulse control module 2, and adjusting the stress-regulating heat sink 5, the output mid-infrared laser reaches the target power value. This embodiment of the present invention achieves high-power output at a high repetition rate while maintaining controllable thermal stress, and can be applied in medical and industrial fields.

[0032] In some embodiments, the repetition frequency f of the modulated pump light and the pulse width τ of the modulated pump laser are p The relationship between the stress value F detected by the stress detection module 6 satisfies the following equation: , where f is the laser repetition frequency; is the pulse width; τ th is the thermal relaxation time; E is the elastic modulus; μ is the Poisson's ratio; α T is the thermal expansion coefficient; α is the absorption coefficient; η is the pump light heat generation rate; k is the thermal conductivity; 𝜔 eff is the effective radius of the pump spot. Through this relationship, the repetition frequency f of the modulated pump light and the pulse width τ of the modulated pump laser can be more accurately determined. p The relationship between the stress value F detected by the stress detection module is convenient for adjustment.

[0033] In some embodiments, please refer to Figure 2As shown, the stress-regulating heat sink 5 also includes a stress monitoring submodule 52. The stress monitoring submodule 52 is attached to the gain medium 4 or attached to the stress applying submodule 51 to monitor the surface thermal stress of the gain medium 4 and transmit the surface thermal stress value to the processor 9. The processor 9 adjusts the stress applying submodule 51 based on the surface thermal stress value and the stress threshold value to reduce the surface thermal stress value to less than the stress threshold value. It will be understood that in this embodiment, the stress monitoring submodule 52 monitors the thermal stress on the outer surface of the gain medium 4. There can be one or more stress monitoring submodules 52. When there are multiple stress monitoring submodules 52, they can be positioned at different locations on the gain medium 4 to monitor the local thermal stress of the gain medium 4, and the position of the stress applying submodule 51 at that location can be adjusted to apply or release stress.

[0034] In any of the above embodiments, the material of the gain medium 4 is one of BGSe, BGGSe, BGS, CSP, LISe, and LIS. The pulse control module 2 includes at least one of an acousto-optic modulator, an electro-optic modulator, and a saturable absorber.

[0035] An acousto-optic modulator (AOM) utilizes the acousto-optic effect to diffract or modulate the intensity of light through the periodic refractive index changes caused by acoustic waves propagating through a medium. Adjusting the frequency of the periodic radio frequency (RF) signal driving the AOM directly changes the modulation period, thereby adjusting the pulse repetition frequency. An electro-optic modulator (EOM) is based on the electro-optic effect (such as the Pockels effect). By applying an external electric field to alter the refractive index of a crystal, the phase or intensity of light can be periodically modulated. Adjusting the frequency of the RF signal driving the EOM directly changes the pulse repetition frequency. Both AOMs and EOMs can be combined with dispersion compensation devices (such as prism pairs or grating pairs) to compress chirped pulses, thereby achieving pulse width modulation.

[0036] Saturable absorbers exploit the nonlinear absorption properties of materials, resulting in strong absorption at low light intensities and saturation at high light intensities. They are often used in hybrid modulation, for example, with an electro-optical modulator. The modulator's driving frequency controls the repetition rate, while the saturable absorber assists in stabilizing the pulses, thereby adjusting the pulse repetition rate. By utilizing optically or electrically controlled saturable absorbers (such as graphene and topological insulators), the absorption properties can be adjusted in real time through external stimulation, achieving pulse width control.

[0037] Any of the above embodiments further includes a shaping module (not shown), located between the pulse control module 2 and the resonant cavity 3, to shape the pump laser light entering the resonant cavity 3. The shaping module can utilize an optical lens combination, specifically designed based on the laser wavelength and desired beam shape. When the laser light passes through the optical lens assembly, the beam changes, achieving beam shaping. For example, a previously diverging / focused beam can be shaped into a parallel beam, or a previously diverging / focused beam can be shaped into a focused / diverging beam. During device installation, the position and angle of the optical lens are precisely adjusted to ensure that the laser beam accurately passes through the shaping module and enters the gain medium 4 in the desired shape.

[0038] The shaping module optimizes the propagation characteristics of the pump laser in the gain medium. A parallel beam excites the gain medium 4 more evenly, improving the efficiency and uniformity of mid-infrared laser generation. A flat-top beam produces a more uniform energy distribution across the gain medium 4, avoiding crystal damage caused by concentrated energy. Improving the pump laser contributes to a more stable and high-quality Raman laser, further enhancing the performance of the spectrum manipulation device. The specific structure of the shaping module is not restricted.

[0039] The present invention also provides a control method for a 1 micron band directly pumped optical parametric mid-infrared laser device, which is used for the 1 micron band directly pumped optical parametric mid-infrared laser device of any of the above embodiments. Figure 3 , the control method comprises: S100: Start the mid-infrared laser device and set the repetition frequency of the pump laser f 0 , pulse width τ p0 , the stress regulating heat sink applies initial stress to the gain medium and the target power value of the output mid-infrared laser, wherein the initial stress value borne by the gain medium is less than the stress threshold F th 80% of.

[0040] S200: The stress detection module detects the stress value F of the gain medium, and the pulse width monitoring module monitors the pulse width τ of the pump laser. p , the power detection module detects the repetition frequency of the pump laser f .

[0041] S300: Adjust parameters: When the stress value F is less than the stress threshold F th When the stress value F detected by the stress detection module increases to 80%, the power of the pump light source is increased, and the stress value F detected by the stress detection module will increase accordingly until the stress value reaches the stress threshold F th After 80% of the pulse width, reduce the pulse width τ p At the same time, the stress adjustment submodule releases the stress so that the stress value F is less than the stress threshold F th80% of a, where the range of a is: 0.85 < a < 0.95.

[0042] Among them, a stress threshold F is set th Taking 80% of it as the critical value for stress adjustment can ensure good contact between the gain medium and the stress adjustment heat sink, thus achieving better heat dissipation. At the same time, it ensures that the performance of the crystal does not change significantly, ensures that the crystal is in a normal working state, and finally realizes the efficient conversion of pump laser into parametric light. Secondly, the stress adjustment range in each stress adjustment process is set as the stress threshold F th with 0.85 < a < 0.95, so that the gain medium always maintains a small fluctuation during the stress adjustment process, ensuring that the gain medium will not be damaged due to a large stress difference, and at the same time ensuring high-precision stress adjustment, thereby generating high-power mid-infrared laser.

[0043] S400: Output mid-infrared laser: Repeat the process of adjusting parameters until the power detection module detects that the output mid-infrared laser reaches the target power value.

[0044] The regulation method of the 1-μm band direct-pumped light parametric mid-infrared laser device in this embodiment adjusts the power of the pump light source, adjusts the thermal stress borne by the gain medium, and at the same time adjusts the pulse width through the pulse control module. Then, through the process of increasing the power of the pump light source, adjusting the pulse control module, and adjusting the stress adjustment heat sink, until the output mid-infrared laser reaches the target power value. It realizes high-power output with thermal stress within a controllable range under high repetition rate, and can be applied to the fields of medical treatment and industry.

[0045] In some embodiments, the stress adjustment heat sink further includes a stress monitoring sub-module to monitor the surface thermal stress value borne by the surface of the gain medium; The regulation method further includes: Adjust the stress application sub-module to make the surface thermal stress value less than 80% of the stress threshold F th

[0046] In summary, the regulation method of a 1-μm band direct-pumped light parametric mid-infrared laser device provided by the present invention has a more comprehensive adjustment function, can achieve precise regulation of the entire pipeline system, and can reduce the problem of crystal damage, realizing the high-efficiency operation of the laser at high repetition rate and high power.

[0047] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or modes and features of different embodiments or modes described in this specification without contradiction.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A 1 micron band directly pumped optical parametric mid-infrared laser device, characterized in that: include: A pump light source for providing pump laser in the 1 micron band; The pulse control module is provided on one side of the pump light source and is used to receive the pump laser and adjust the repetition frequency of the pump laser. f and pulse width τ p Perform modulation; A resonant cavity, arranged on the optical path of the pump laser, comprising an input lens and an output lens; The gain medium is arranged in the resonant cavity and is used to receive the modulated pump laser and perform nonlinear frequency conversion to generate mid-infrared laser. The maximum stress that the gain medium can withstand is the stress threshold F th ; A stress-adjusting heat sink is disposed around the gain medium, and is used for dissipating heat and applying or releasing stress to the gain medium; A stress detection module, provided on one side of the stress regulating heat sink, for detecting the stress value F of the gain medium; The pulse width monitoring module is set on one side of the pulse control module and is used to monitor the pulse width τ of the modulated pump laser. p ; The power monitoring module is set on the output optical path to monitor the output mid-infrared laser power P and the repetition frequency of the modulated pump light. f ; A processor for determining a pulse width τ based on the stress value F of the gain medium and the pulse width τ p Increase the power of the pump light source, when the stress value F is less than the stress threshold F th When the power of the pump light source is increased to 80%, the stress value F detected by the stress detection module will increase accordingly until the stress value reaches the stress threshold F. th After the pulse width reaches 80%, the processor sends an adjustment signal to the pulse control module so that the pulse width τ p The processor sends an adjustment instruction to the stress adjustment heat sink so that the stress value F detected by the stress detection module is less than the stress threshold F th After a×80%, the processor repeatedly increases the power of the pump light source, adjusts the pulse control module and adjusts the stress adjustment heat sink until the output mid-infrared laser reaches the target power value, wherein the range of a is: 0.85 <a<0.95。。 2. The 1 micron band directly pumped optical parametric mid-infrared laser device according to claim 1, characterized in that: The repetition frequency f of the modulated pump light and the pulse width τ of the modulated pump laser p The relationship between the stress value F detected by the stress detection module satisfies: , where f is the laser repetition frequency; is the pulse width; τ th is the thermal relaxation time; E is the elastic modulus; μ is the Poisson's ratio; α T is the thermal expansion coefficient; α is the absorption coefficient; η is the pump light heat generation rate; k is the thermal conductivity; 𝜔 eff is the effective radius of the pump spot.

3. The 1 micron band directly pumped optical parametric mid-infrared laser device according to claim 1, characterized in that: The stress regulating heat sink comprises: At least two stress applying submodules are movably disposed at the periphery of the gain medium, and the stress applying submodules are used to apply or release stress to the gain medium.

4. The 1 micron band directly pumped optical parametric mid-infrared laser device according to claim 3, wherein the stress adjustment heat sink further comprises: A stress monitoring module is provided in close contact with the gain medium or in close contact with the stress applying submodule to monitor a surface thermal stress value borne by the surface of the gain medium and transmit the surface thermal stress value to the processor. The processor adjusts the stress applying submodule according to the surface thermal stress value and the stress threshold value so that the surface thermal stress value is less than the stress threshold value.

5. The 1 micron band directly pumped optical parametric mid-infrared laser device according to claim 1, characterized in that: The initial stress value of the gain medium detected by the stress detection module is less than 80% of the stress threshold.

6. The 1 micron band directly pumped optical parametric mid-infrared laser device according to claim 1, characterized in that: The pulse control module includes at least one of an acousto-optic modulator, an electro-optic modulator, and a saturable absorber.

7. The 1 micron band directly pumped optical parametric mid-infrared laser device according to claim 1, characterized in that: The material of the gain medium is one of BGSe, BGGSe, BGS, CSP, LISe, and LIS.

8. The 1 micron band directly pumped optical parametric mid-infrared laser device according to claim 1, characterized in that: It also includes a shaping module located between the pulse control module and the resonant cavity to shape the pump light entering the resonant cavity.

9. A control method for a 1-micron-band directly pumped optical parametric mid-infrared laser device, used for the 1-micron-band directly pumped optical parametric mid-infrared laser device according to any one of claims 1 to 6, characterized in that: The control method comprises: Start the mid-infrared laser device and set the repetition frequency of the pump laser f 0 , pulse width τ p0 , the stress regulating heat sink applies an initial stress to the gain medium and the target power value of the output mid-infrared laser, wherein the initial stress value borne by the gain medium is less than the stress threshold F th 80%; The stress detection module detects the stress value F of the gain medium, and the pulse width monitoring module monitors the pulse width τ of the pump laser. p The power detection module detects the repetition frequency of the pump laser f ; As the power of the pump light source increases, the stress value F detected by the stress detection module will increase until the stress value reaches the stress threshold F. th After 80% of the pulse width, reduce the pulse width τ p At the same time, the stress adjustment submodule releases the stress so that the stress value F is less than the stress threshold F th a×80%, where a range is: 0.85 <a<0.95; Repeat the parameter adjustment process until the power detection module detects that the output mid-infrared laser reaches the target power value.

10. The control method of a 1 micron band direct pump optical parametric mid-infrared laser device according to claim 9, characterized in that: The stress regulating heat sink further includes a stress monitoring submodule to monitor the surface thermal stress value borne by the surface of the gain medium; The control method further comprises: Adjust the stress application submodule so that the surface thermal stress value is less than the stress threshold F th 80% of.

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