A mid-infrared sequence pulse laser

Abstract

The present invention provides a mid-infrared sequence pulse laser, the laser comprising a pump laser module, a laser Q-switching module and a mid-infrared laser module; wherein the pump laser module is used to generate continuous pump light for exciting the mid-infrared laser module; the laser Q-switching module is used to adjust the intracavity loss of the pump laser module to form a sequence pulse laser; the mid-infrared laser module is used to absorb the sequence pulse laser and generate mid-infrared laser. The laser in the present invention uses a sequence pulse laser as a pump source to pump the mid-infrared laser module, and the obtained mid-infrared pulse laser has the characteristic that a single pulse train contains a plurality of sub-pulses, and its repetition frequency is determined by the time interval of the sub-pulses in the pulse train, so the laser repetition rate can be greatly improved.

Description

Technical Field

[0001] The invention relates to the field of laser technology, in particular to a mid-infrared sequence pulse laser. Background Art

[0002] As the atmospheric window with the least attenuation, the mid-infrared band has extremely important application value and prospects in many fields such as imaging, remote sensing, communications, medical treatment, and spectroscopy.

[0003] In the prior art, Xie Yuzhou et al. from the Southwest Institute of Technical Physics published a paper titled "Research on Mid-Infrared PPMgLN Optical Parametric Oscillator Technology" in the third issue of Laser Technology in May 2014, which disclosed a new technology for producing 3.8um continuous mid-infrared laser using an optical parametric oscillator based on magnesium oxide-doped lithium niobate crystals. The specific principle and structure are as follows: Figure 1 As shown in the schematic diagram, the resonant cavity of the fundamental frequency light is a flat cavity, and the optical parametric oscillator (OPO) is a straight cavity.

[0004] The optical parametric oscillator includes an input mirror 101 for pump light, an acousto-optic Q-switched crystal 102, a Nd:YAG crystal 103, an optical rotator 104, a Nd:YAG crystal 105, an acousto-optic Q-switched crystal 106, a polarizer 107, an output mirror 108 for fundamental frequency light, a focusing mirror 109, an input mirror 110 for optical parametric oscillator (OPO), a MgO:PPLN crystal 111 and an output mirror 112 for OPO. The pump light pumps the Nd:YAG crystals 103 and 105 from the side, forming a linearly polarized 1064nm fundamental frequency laser oscillation in the resonant cavity 101→102→103→104→105→106→107→108, and is incident on the mid-infrared module through the focusing mirror 109. The OPO resonant cavity composed of the device 110→111→112 performs optical parametric oscillation under the action of the 1064nm fundamental frequency light, and outputs signal light and idler light. The signal light is in the near-infrared band, and the idler light is in the mid-infrared band.

[0005] The above-mentioned prior art has the following deficiencies: First, the output laser is a pulsed laser, and the repetition rate of the pulsed laser is limited by the characteristics of the acousto-optic Q-switched crystal and the pump energy, and is mostly in the order of tens of kHz. Second, the single pulse energy of the output pulsed laser gradually decreases with the increase of the repetition rate, which is determined by the characteristics of the single pulse laser itself. Third, the pump energy power density is low when the extracavity optical parametric oscillation method is adopted, and the nonlinear conversion efficiency depends on the pump energy density, so it is impossible to obtain a higher optical-to-optical conversion efficiency (the efficiency mentioned in the article is 11.14%).

[0006] Therefore, the need for a new type of sequential pulse laser is an urgent problem to be solved. Summary of the invention

[0007] In view of this, an embodiment of the present invention provides a mid-infrared sequence pulse laser to eliminate or improve one or more defects existing in the prior art.

[0008] The technical solution of the present invention is as follows:

[0009] The laser comprises a pump laser module, a laser Q-switching module and a mid-infrared laser module; wherein the pump laser module is used to generate continuous pump light for exciting the mid-infrared laser module; the laser Q-switching module is used to adjust the intracavity loss of the pump laser module to form a sequence pulse laser; and the mid-infrared laser module is used to absorb the sequence pulse laser and generate mid-infrared laser.

[0010] In some embodiments, the pump laser module includes a side pump laser, a first laser crystal, a polarizer, a half-wave plate, an input mirror and a first reflector arranged in sequence along the optical path; wherein the side pump laser is used to output laser to provide pump energy to the first laser crystal; the first laser crystal is used to absorb the energy of the side pump laser and output near-infrared laser; the polarizer is used to control the polarization characteristics in the cavity to ensure that the output laser is a polarized laser; the half-wave plate is used to control the polarization direction to generate the maximum loss in the cavity; the input mirror is used to serve as a reflector of the resonant cavity of the pump laser module to ensure the gain effect of the laser; the first reflector is used to serve as an output mirror of the resonant cavity of the pump laser module to ensure the resonant gain of the laser.

[0011] In some embodiments, the first laser crystal is a neodymium-doped yttrium aluminum garnet crystal doped with a specific concentration of neodymium; the side pump laser is used to output 808nm laser, and the neodymium-doped yttrium aluminum garnet crystal is used to output 1064nm near-infrared laser.

[0012] In some embodiments, the laser Q-switching module includes a signal generator, a Q-switching driver and a Q-switching crystal; the signal generator is connected to the Q-switching driver, and the Q-switching driver is connected to the Q-switching crystal; wherein the signal generator is used to generate a sequence pulse signal; the Q-switching driver is used to convert the sequence pulse signal generated by the signal generator into a high-voltage electrical signal to achieve driving and control of the Q-switching crystal; the Q-switching crystal is located between the first laser crystal and the input mirror in the optical path, and the Q-switching crystal is used to simultaneously generate controllable specific losses in the cavity to ensure complete shutdown of the resonant cavity, so that the pump laser module generates a sequence pulse laser.

[0013] In some embodiments, the mid-infrared laser module includes a second reflector, a second laser crystal, a temperature-controlled furnace, a first reflector and an output mirror of the pump laser module, which are arranged in sequence along the optical path, and the second reflector is arranged in the optical path behind the half-wave plate; wherein the second reflector is used to transmit the fundamental frequency laser through the half-wave plate and reflect the mid-infrared laser of the mid-infrared laser module; the second laser crystal is used to absorb the sequence pulse laser as pump light energy and output the mid-infrared laser through the action of optical parametric oscillation; the temperature-controlled furnace is used to control the temperature of the second laser crystal to ensure the stability of its output wavelength; the first reflector is also used as an input mirror of the mid-infrared laser to reflect the mid-infrared laser to ensure the gain effect of the mid-infrared laser; the output mirror is used as an output mirror of the mid-infrared laser to specifically transmit the mid-infrared laser to ensure the resonant gain of the mid-infrared laser.

[0014] In some embodiments, the mid-infrared laser module of the laser is arranged in the cavity of the pump laser module, and optical parametric oscillation is performed in the form of intracavity pumping to obtain mid-infrared laser.

[0015] In some embodiments, the second laser crystal is a PPLN crystal; the output laser of the pump laser module after being acted upon by the laser Q-switching module is a sequential pulse laser, and the PPLN crystal is pumped with sequential pulse pump light, and the obtained mid-infrared laser is a sequential pulse laser.

[0016] In some embodiments, the input mirror is a plane mirror with high reflection for coated pump light and fundamental frequency light; the Q-switched crystal is an electro-optical Q-switched crystal; the side pump laser is an 808nm pump module; the polarizer is a polarization selection device; the half-wave plate is a plane mirror that delays the fundamental frequency light by 1 / 2λ; the second reflector is a plane mirror with high transmittance for coated fundamental frequency light and high reflection for signal light and idle frequency light at 45°; the PPLN crystal is a PPLN crystal etched with a polarization period; the temperature control furnace is a device for temperature control of the PPLN crystal; the first reflector is a concave mirror with high reflection for fundamental frequency light, signal light and idle frequency light; the Q-switched driver is a driver for generating high voltage electricity; the signal generator is a signal generator for generating a sequence pulse signal; the output mirror is a concave mirror with a specific transmittance for coated signal light or idle frequency light.

[0017] In some embodiments, the signal generator is also used to control and adjust the repetition rate and timing of the group pulses and sub-pulses of the mid-infrared sequence pulse laser output by the laser.

[0018] In some embodiments, the wavelength of the mid-infrared sequence pulse laser output by the laser is 3.8 um.

[0019] Compared with the commonly used optical parametric oscillation method, the laser in the present invention uses a serial pulse laser as a pump source to pump the mid-infrared laser module. The obtained mid-infrared pulse laser has the characteristic that a single pulse train contains several sub-pulses, and its repetition frequency is determined by the time interval of the sub-pulses in the pulse train. Therefore, the laser repetition rate can be greatly improved.

[0020] Additional advantages, purposes, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention may be achieved and obtained by the structures specifically pointed out in the written description, claims, and drawings.

[0021] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention. The components in the drawings are not drawn to scale, but are only for illustrating the principles of the present invention. In order to facilitate the illustration and description of some parts of the present invention, the corresponding parts in the drawings may be enlarged, that is, they may become larger relative to other components in the exemplary device actually manufactured according to the present invention. In the drawings:

[0023] Figure 1 The figure is a schematic diagram of the structural principle of an optical parametric oscillator in the prior art.

[0024] Figure 2 Schematic diagram of the structure of a mid-infrared sequence pulse laser in one embodiment of the present invention.

[0025] Figure 3 A signal generator for a laser in one embodiment of the present invention generates a sequence of pulse waveforms.

[0026] Figure 4 FIG. 4 is a diagram showing the intracavity loss and pump timing distribution of a laser in an embodiment of the present invention.

[0027] Figure 5 FIG. 4 is a timing diagram of sequential pulse laser output of a laser in one embodiment of the present invention.

[0028] Reference numerals:

[0029] 1. Input mirror; 2. Q-switched crystal; 3. Side pump laser; 4. First laser crystal; 5. Polarizer; 6. Half-wave plate; 7. Second reflector; 8. Second laser crystal; 9. Temperature control furnace; 10. First reflector; 11. Q-switched drive; 12. Signal generator; 13. Output mirror DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0031] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0032] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0033] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0035] The invention provides a mid-infrared sequence pulse laser to solve or alleviate the problem of low laser repetition rate in the prior art.

[0036] In some embodiments, the mid-infrared sequence pulse laser (hereinafter referred to as laser) includes a pump laser module, a laser Q-switching module and a mid-infrared laser module. The pump laser module is used to generate continuous pump light for exciting the mid-infrared laser module; the laser Q-switching module is used to adjust the cavity loss of the pump laser module to form a sequence pulse laser; the mid-infrared laser module is used to absorb the sequence pulse laser and generate mid-infrared laser, and the generated mid-infrared laser is a sequence pulse laser.

[0037] In the above embodiment, compared with the commonly used optical parametric oscillation method, the laser in the present invention uses a serial pulse laser as a pump source to pump the mid-infrared laser module. The obtained mid-infrared pulse laser has the characteristic that a single pulse train contains several sub-pulses, and its repetition frequency is determined by the time interval of the sub-pulses in the pulse train. Therefore, the laser repetition rate can be increased to more than 100kHz.

[0038] like Figure 2 As shown, in some embodiments, the pump laser module includes a side pump laser 3, a first laser crystal 4, a polarizer 5, a half-wave plate 6, an input mirror 1 and a first reflector 10 which are sequentially arranged along the optical path.

[0039] Among them, the side pump laser 3 is used to output laser to provide pump energy to the first laser crystal 4; the first laser crystal 4 is used to absorb the energy of the side pump laser 3 and output near-infrared laser; the polarizer 5 is used to control the polarization characteristics in the cavity to ensure that the output laser is polarized laser; the half-wave plate 6 is used to control the polarization direction to generate the maximum loss in the cavity; the input mirror 1 is used to serve as a reflector of the resonant cavity of the pump laser module to ensure the gain effect of the laser; the first reflector 10 is used to serve as an output mirror of the resonant cavity of the pump laser module to ensure the resonant gain of the laser.

[0040] In some embodiments, the first laser crystal 4 is a neodymium-doped yttrium aluminum garnet crystal doped with a specific concentration of neodymium; the neodymium doping concentration can be set according to actual conditions. The side pump laser 3 is used to output 808nm laser, and the neodymium-doped yttrium aluminum garnet crystal is used to output 1064nm near-infrared laser.

[0041] In some embodiments, the first laser crystal 4 may also be a single-end pumped or double-end pumped laser crystal, and the direction of the energy provided by the side pumping laser 3 needs to be changed accordingly. For example, when the first laser crystal 4 is a single-end pumped laser crystal, a semiconductor laser or other pumping source is used to provide pumping energy from the single-end pumped first laser crystal 4. Here, the side pumping laser 3 may also be other forms of pumping sources, such as a flash lamp, a light emitting diode, etc.

[0042] like Figure 2 As shown, in some embodiments, the laser Q-switching module includes a signal generator 12, a Q-switching driver 11 and a Q-switching crystal 2. The signal generator 12 is connected to the Q-switching driver 11, and the Q-switching driver 11 is connected to the Q-switching crystal 2.

[0043] Among them, the signal generator 12 is used to generate a sequence pulse signal; the Q-switched driver 11 is used to convert the sequence pulse signal generated by the signal generator 12 into a high-voltage electrical signal to achieve the drive and control of the Q-switched crystal 2; the Q-switched crystal 2 is located between the first laser crystal 4 and the input mirror 1 in the optical path, and the Q-switched crystal 2 is used to simultaneously generate controllable specific losses in the cavity to ensure the complete shutdown of the resonant cavity, so that the pump laser module generates a sequence pulse laser.

[0044] Figure 3 The signal generator 12 for the laser in one embodiment of the present invention generates a sequence of pulse waveforms. Figure 4 FIG. 4 is a diagram showing the intracavity loss and pump timing distribution of a laser in an embodiment of the present invention. Figure 5 The figure is a timing diagram of the sequential pulse laser output of the laser in one embodiment of the present invention. In the above embodiment, the signal generator 12 is also used to control and adjust the repetition rate and timing of the group pulses and sub-pulses of the mid-infrared sequential pulse laser output by the laser. The laser can adjust the timing and number of sub-pulses in the pulse train through the signal generator 12 to ensure that the sub-pulses at different repetition rates have higher energy.

[0045] like Figure 2 As shown, in some embodiments, the mid-infrared laser module includes a second reflector 7, a second laser crystal 8, a temperature control furnace 9, a first reflector 10 of the pump laser module and an output mirror 13, which are arranged in sequence along the optical path, and the second reflector 7 is arranged in the optical path behind the half-wave plate 6. The second reflector 7 is used to transmit the fundamental frequency laser through the half-wave plate 6 and reflect the mid-infrared laser of the mid-infrared laser module; the second laser crystal 8 is used to absorb the sequence pulse laser as pump light energy and output the mid-infrared laser through the action of optical parametric oscillation; the temperature control furnace 9 is used to control the temperature of the second laser crystal 8 to ensure the stability of its output wavelength; the first reflector 10 is also used as the input mirror of the mid-infrared laser to reflect the mid-infrared laser to ensure the gain effect of the mid-infrared laser; the output mirror 13 is used as the output mirror of the mid-infrared laser to specifically transmit the mid-infrared laser to ensure the resonance gain of the mid-infrared laser.

[0046] In the above embodiment, the mid-infrared laser module of the laser is arranged in the cavity of the pump laser module, and optical parametric oscillation is performed in the form of intracavity pumping to obtain mid-infrared laser. Specifically, the mid-infrared laser module is located in the optical path between the half-wave plate 6 and the first reflector 10. It should be noted here that the first reflector 10 is both a device of the pump laser module and is used as an output mirror of the laser resonant cavity; the first reflector 10 is also a device of the mid-infrared laser module and is used as an input mirror of the mid-infrared laser to reflect the mid-infrared laser and ensure the gain effect of the mid-infrared laser.

[0047] In this embodiment, the laser of the present invention adopts the method of intracavity pumping OPO, which can improve the power density of pumping light and then improve the light-to-light conversion efficiency.

[0048] In some embodiments, the second laser crystal 8 is a PPLN crystal; the output laser of the pump laser module after being acted upon by the laser Q-switching module is a sequential pulse laser, and the PPLN crystal is pumped with sequential pulse pump light, and the obtained mid-infrared laser is a sequential pulse laser.

[0049] In some embodiments, the input mirror 1 is a plane mirror with high reflection of the pump light and the fundamental frequency light, for example, a 1064nm and 808nm high reflection coating; the Q-switched crystal 2 is an electro-optical Q-switched crystal 2, for example, an RTP (RbTiOPO4) crystal, and its two end surfaces are coated with 1064nm high transmittance; the side pump laser 3 is an 808nm pump module; the polarizer 5 is a polarization selection device; the half-wave plate 6 is a plane mirror with a 1 / 2λ delay for the 1064nm wavelength; the second reflector 7 is a 1064nm high transmittance coated, 1.4-1.6um & 3.6-4.2um 45° high-reflection plane mirror; the second laser crystal 8 is a PPLN crystal doped with 0.5% MgO and etched with a polarization period of 29um; the temperature control furnace 9 has a temperature control range of 25-200℃ and a temperature control accuracy of 1℃; the first reflector 10 is a concave mirror with a radius of curvature of 500mm, a wavelength of 1064nm, a high reflection of 1.4-1.6 & 3.6-4.2um; the Q-switched drive 11 is a driver for generating high voltage electricity, and the signal generator 12 is a signal generator 12 for generating a sequence pulse signal; the output mirror 13 is a concave mirror with a coating of 1.4-1.6um, a transmittance of 10%, a high transmittance of 3.6-4.2um, and a curvature radius of 500mm.

[0050] In some embodiments, after the entire mid-infrared sequence pulse laser reaches a stable state, a mid-infrared sequence pulse laser with a wavelength of 3.8 um is output.

[0051] The working principle of the mid-infrared sequence pulse laser of the embodiment of the present invention is as follows: the pump light is emitted by the side pump laser 3, and the first laser crystal 4 is pumped, so that the λ1 spectrum line transitions in the first laser crystal 4 and forms laser oscillation in the resonant cavity (1→4→10), and forms a continuous laser with adjustable polarization direction under the action of the polarizer 5 and the half-wave plate 6. At the same time, the signal generator 12 generates a sequence pulse signal, which is converted into a high-voltage signal through the Q-switched drive 11 (electro-optical drive), and forms a specific loss in the cavity through the electro-optical Q-switched crystal 2, and finally converts the continuous laser into a sequence pulse laser. The sequence pulse laser enters the PPLN crystal, and forms an optical parametric oscillation in the second reflector 7, the first reflector 10 and the output mirror 13, and outputs a mid-infrared laser of a specific wavelength under the temperature matching of the temperature-controlled furnace 9.

[0052] The long mid-infrared sequence pulse laser produced by the present invention can effectively enhance the application potential and application value of mid-infrared lasers in the above fields because of its characteristics of high repetition rate, high peak power and multi-wavelength sequential output.

[0053] The long mid-infrared sequence pulse laser in the present invention uses a sequence pulse laser to perform intracavity pumping on a PPLN crystal to generate a high-efficiency mid-infrared sequence pulse laser composed of a plurality of sub-pulse lasers. The sequence pulse can obtain a mid-infrared sequence pulse laser with a high repetition rate and high energy output by adjusting the timing and number of the sub-pulses, thereby having a broad application market and prospect.

[0054] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A mid-infrared sequence pulse laser, characterized in that: The laser includes a pump laser module, a laser Q-switching module and a mid-infrared laser module; The pump laser module is used to generate continuous pump light for exciting the mid-infrared laser module; the laser Q-switching module is used to adjust the intracavity loss of the pump laser module to form a sequence pulse laser; the mid-infrared laser module is used to absorb the sequence pulse laser and generate mid-infrared laser; The pump laser module comprises a side pump laser, a first laser crystal, a polarizer, a half-wave plate, an input mirror and a first reflector which are sequentially arranged along the optical path; Wherein, the side pump laser is used to output laser to provide pump energy to the first laser crystal, and the side pump laser is used to output 808nm laser; The first laser crystal is used to absorb the energy of the side pump laser and output near-infrared laser, the first laser crystal is a neodymium-doped yttrium aluminum garnet crystal doped with a specific concentration of neodymium, and the neodymium-doped yttrium aluminum garnet crystal is used to output 1064nm near-infrared laser; The polarizer is used to control the polarization characteristics in the cavity to ensure that the output laser is polarized laser; The half-wave plate is used to control the polarization direction to generate the maximum loss in the cavity; The input mirror is used as a reflector of the resonant cavity of the pump laser module to ensure the gain effect of the laser; The first reflector is used as an output mirror of the resonant cavity of the pump laser module to ensure the resonant gain of the laser; The laser Q-switching module comprises a signal generator, a Q-switching driver and a Q-switching crystal; the signal generator is connected to the Q-switching driver, and the Q-switching driver is connected to the Q-switching crystal; Wherein, the signal generator is used to generate a sequence pulse signal; The Q-switching driver is used to convert the sequence pulse signal generated by the signal generator into a high-voltage electrical signal to achieve driving and control of the Q-switching crystal; The Q-switched crystal is located between the first laser crystal and the input mirror in the optical path, and is used to simultaneously generate controllable specific losses in the cavity to ensure complete shutoff of the resonant cavity, thereby enabling the pump laser module to generate sequence pulse lasers.

2. The mid-infrared sequence pulse laser according to claim 1, characterized in that: The mid-infrared laser module comprises a second reflector, a second laser crystal, a temperature-controlled furnace, a first reflector and an output mirror of the pump laser module, which are sequentially arranged along the optical path, and the second reflector is arranged in the optical path behind the half-wave plate; Wherein, the second reflector is used to transmit the fundamental frequency laser through the half-wave plate and reflect the mid-infrared laser of the mid-infrared laser module; The second laser crystal is used to absorb the sequence of pulsed lasers as pump light energy and output the mid-infrared laser through the action of optical parametric oscillation; The temperature-controlled furnace is used to control the temperature of the second laser crystal to ensure the stability of its output wavelength; The first reflector is also used as an input mirror of the mid-infrared laser to reflect the mid-infrared laser to ensure a gain effect of the mid-infrared laser; The output mirror is used as an output mirror of the mid-infrared laser to specifically transmit the mid-infrared laser to ensure the resonance gain of the mid-infrared laser.

3. The mid-infrared sequence pulse laser according to claim 2, characterized in that: The mid-infrared laser module of the laser is arranged in the cavity of the pump laser module, and performs optical parametric oscillation in the form of intracavity pumping to obtain mid-infrared laser.

4. The mid-infrared sequence pulse laser according to claim 2, characterized in that: The second laser crystal is a PPLN crystal; The output laser of the pump laser module after being acted upon by the laser Q-switching module is a sequential pulse laser. The PPLN crystal is pumped by the sequential pulse pump light, and the obtained mid-infrared laser is a sequential pulse laser.

5. The mid-infrared sequence pulse laser according to claim 4, characterized in that: The input mirror is a plane mirror with high reflection of the coated pump light and fundamental frequency light; The Q-switched crystal is an electro-optical Q-switched crystal; The side pump laser is an 808nm pump module; The polarizer is a polarization selective device; The half-wave plate is a plane mirror that delays the fundamental frequency light by 1 / 2λ; The second reflector is a plane mirror with high transmittance of the coated fundamental frequency light and high reflectivity of the signal light and the idler frequency light at 45°; The PPLN crystal is a PPLN crystal etched with a polarization period; The temperature control furnace is a device for controlling the temperature of the PPLN crystal; The first reflector is a concave mirror with high reflection for fundamental frequency light, signal light and idler frequency light; The Q-switched driver is a driver for generating high voltage electricity; The signal generator is a signal generator that generates a sequence pulse signal; The output mirror is a concave mirror with a specific transmittance of the coated signal light or the idler light.

6. The mid-infrared sequence pulse laser according to claim 5, characterized in that: The signal generator is also used to control and adjust the repetition rate and timing of the group pulses and sub-pulses of the mid-infrared sequence pulse laser output by the laser.

7. The mid-infrared sequence pulse laser according to claim 6, characterized in that: The wavelength of the mid-infrared sequence pulse laser output by the laser is 3.8um.

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