A multi-wavelength mid-infrared sequence pulse laser

Abstract

The present invention provides a multi-wavelength mid-infrared sequence pulse laser, which includes a pump laser module, a laser Q-switching module, a beam control module and a mid-infrared laser module arranged along an optical path; wherein the pump laser module is used to generate continuous pump light; the laser Q-switching module is used to adjust the intracavity loss of the pump laser module so that the continuous pump light forms a sequence pulse laser, and the sequence pulse laser is also used as the pump light of the mid-infrared laser module; the beam control module is used to perform beam shaping on the formed sequence pulse laser; the mid-infrared laser module is used to absorb the sequence pulse laser and form a multi-wavelength mid-infrared laser with periodic output. As a new type of solid-state laser, the laser has multi-wavelength high-frequency sequential output compared to the existing mid-infrared laser, and each output wavelength has the characteristics of high repetition frequency and high peak power, which is of great significance in expanding the practicality and application scope of mid-infrared lasers.

Description

Technical Field

[0001] The invention relates to the field of laser technology, in particular to a multi-wavelength 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, Xing Shuang et al. from Changchun University of Science and Technology published a paper titled "Intracavity Wide-tuned Continuous Mid-infrared Optical Parametric Oscillator Based on Multi-period MgO:PPLN" in the 6th issue of "Journal of Photonics" in 2018, which disclosed a new technology for generating 3.2-4.1um continuous mid-infrared laser using an optical parametric oscillator based on magnesium oxide-doped lithium niobate crystal. 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 V-shaped cavity. The optical parametric oscillator includes an 808nm fiber laser 101, a 1:1.5 beam reduction mirror group 102, a plane mirror 103, a Nd:YVO4 crystal 104, a copper heat sink 105, a focusing lens 106 with a focal length of 150mm, a 15° deflection mirror 107, a MgO:PPLN crystal 108, a temperature control furnace 109, a plane mirror 110 and a plane mirror 111. Among them, the pump light is emitted from the 808nm fiber laser 101, passes through the beam reduction mirror group 102, and forms a 1064nm fundamental frequency light laser oscillation in the resonant cavity 103→104→106→111. At the same time, the intracavity devices 107→108→110→111 form a V-shaped cavity to perform optical parametric oscillation under the action of the 1064nm fundamental frequency light, and output signal light and idler light, wherein the signal light is in the near-infrared band and the idler light is in the mid-infrared band.

[0004] The above-mentioned prior art has the following deficiencies: First, it is impossible to achieve rapid switching of wavelengths. The known technology uses temperature control and translation of PPLN crystals to achieve wavelength switching, but temperature control is often measured in minutes, and translation of PPLN crystals is measured in seconds, and rapid switching cannot be achieved. Second, the output laser is a continuous laser without pulsed laser characteristics. The prior art uses continuous laser pumping and does not have pulsed laser characteristics, that is, it has no repetition frequency characteristics, and is characterized by extremely low peak power (equal to average power, watt level). Third, the light-to-light conversion efficiency is low. The principle of mid-infrared laser generation is optical parametric oscillator (OPO), and its conversion efficiency is positively correlated with peak power.

[0005] Therefore, the need for a new type of sequential pulse laser is an urgent problem to be solved. Summary of the invention

[0006] In view of this, an embodiment of the present invention provides a multi-wavelength mid-infrared sequence pulse laser to eliminate or improve one or more defects existing in the prior art.

[0007] The technical solution of the present invention is as follows:

[0008] The laser comprises a pump laser module, a laser Q-switching module, a beam control module and a mid-infrared laser module arranged along an optical path; 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 so that the continuous pump light forms a sequence pulse laser, and the sequence pulse laser is also used as the pump light of the mid-infrared laser module; the beam control module is used to perform beam shaping on the formed sequence pulse laser and control its action period with the mid-infrared laser module; the mid-infrared laser module is used to absorb the sequence pulse laser and form a multi-wavelength mid-infrared laser with periodic output.

[0009] 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 an output mirror arranged along an 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 of the resonant cavity formed in the pump laser module to ensure that the output laser is polarized laser; the half-wave plate is used to control the polarization direction to ensure that the fundamental frequency light matches the polarization of the laser Q-switching module, thereby generating maximum loss in the cavity; the input mirror is used as a reflector of the resonant cavity to ensure the gain effect of the laser; the output mirror is used as an output mirror of the resonant cavity to ensure the resonant gain of the laser.

[0010] In some embodiments, the first laser crystal is a neodymium-doped yttrium aluminum garnet crystal; the side pump laser is used to output 808nm laser; and the first laser crystal is used to output 1064nm near-infrared laser.

[0011] In some embodiments, the laser Q-switching module includes a first electro-optical Q-switching crystal, a first Q-switching driver, a second electro-optical Q-switching crystal, a second Q-switching driver and a signal generator; the first electro-optical Q-switching crystal is arranged in the optical path between the output mirror and the first laser crystal, and the first Q-switching driver is connected to the first electro-optical Q-switching crystal; the second electro-optical Q-switching crystal is arranged in the optical path between the half-wave plate and the input mirror, and the second Q-switching driver is connected to the second electro-optical Q-switching crystal; the signal generator is connected to the first Q-switching driver and the second Q-switching driver; wherein the signal generator is used to generate a sequence pulse signal; the first Q-switching driver is used to convert the sequence pulse signal generated by the signal generator into a high-voltage electrical signal to achieve drive control of the first electro-optical Q-switching crystal; the second Q-switching driver is used to convert the sequence pulse signal generated by the signal generator into a high-voltage electrical signal to achieve drive control of the second electro-optical Q-switching crystal; the first electro-optical Q-switching crystal and the second electro-optical Q-switching crystal are used to simultaneously generate controllable specific losses in the resonant cavity to ensure complete shutdown of the resonant cavity, thereby generating a sequence pulse laser.

[0012] In some embodiments, the beam control module includes a focusing mirror, a first fast deflection mirror and a second fast deflection mirror arranged along the optical path; wherein the focusing mirror is used to perform beam shaping on the sequence pulse laser generated after being processed by the laser Q-switching module to achieve effective pumping of the mid-infrared laser module; the first fast deflection mirror is used to periodically adjust the transmission direction of the sequence pulse laser to achieve periodic pumping of the mid-infrared laser module and thereby obtain a multi-wavelength mid-infrared sequence pulse laser; the second fast deflection mirror is used to achieve spatial output of the multi-wavelength mid-infrared laser excited by the mid-infrared laser module.

[0013] In some embodiments, the second fast deflection mirror is a controllable deflection mirror, and the beam control module also includes a deflection mirror controller connected to the second fast deflection mirror, the deflection mirror controller is used to generate a control signal and output it to the second fast deflection mirror, and the second fast deflection mirror responds to the control signal to perform angle control to achieve parallel emission.

[0014] In some embodiments, the mid-infrared laser module includes a second laser crystal, and the second laser crystal is used to absorb pump light energy and output mid-infrared laser through optical parametric oscillation.

[0015] In some embodiments, the second laser crystal is a fan-shaped PPLN crystal, and the fan-shaped PPLN crystal is used to combine with the second fast deflection mirror and a deflection mirror controller to obtain a multi-wavelength mid-infrared laser.

[0016] In some embodiments, the fan-shaped PPLN crystal is a multi-period PPLN crystal coated on both sides, with a period of 29um / 29.5um / 30um, and its input end is coated with 1064nm high transmittance and 1.4-1.6um, 3.6-4.5um high reflection, and the output end is coated with 1064nm high reflection and 1.4-1.6um high reflection and 3.6-4.5um, with a transmittance of 10%; the focusing mirror is a positive lens with a focal length of f=200mm; the output mirror is a plane mirror coated with 1064nm with a transmittance of 40%; the side pump laser is 880nm Semiconductor laser; the Nd:YAG crystal is a yttrium aluminum garnet crystal doped with 0.5% Nd:YAG; the polarizer is a polarization selection device; the half-wave plate is a plane mirror with a delay of 1 / 2λ at 1064nm; the input mirror is a plane mirror with high reflection at 1064nm; the first Q-switched drive and the second Q-switched drive are drivers for generating high voltage electricity; the first electro-optical Q-switched crystal and the second electro-optical Q-switched crystal are RTP crystals with a maximum loss of 90% at 1064nm in response to the first Q-switched drive and the second Q-switched drive; the signal generator is a signal generator for generating a sequence pulse signal.

[0017] In some embodiments, after the laser reaches a stable state, it outputs a multi-wavelength mid-infrared sequence pulse laser with wavelengths of 3.8um, 3.9um, and 4.0um.

[0018] The multi-wavelength mid-infrared sequence pulse laser according to the embodiment of the present invention can obtain the following beneficial effects:

[0019] As a new type of solid-state laser, this multi-wavelength mid-infrared sequence pulse laser has multi-wavelength high-frequency sequential output compared to existing mid-infrared lasers, and each output wavelength has the characteristics of high repetition frequency and high peak power. It is of great significance in expanding the practicality and application scope of mid-infrared lasers.

[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 It 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 multi-wavelength mid-infrared sequence pulse laser in one embodiment of the present invention.

[0025] Reference numerals:

[0026] 1. Deflection mirror controller; 2. Second fast deflection mirror; 3. Second laser crystal; 4. First fast deflection mirror; 5. Focusing mirror; 6. Output mirror; 7. Side pump laser; 8. First laser crystal; 9. Polarizer; 10. Half-wave plate; 11. Input mirror; 12. First Q-switching driver; 13. First electro-optical Q-switching crystal; 14. Signal generator; 15. Second Q-switching driver; 16. Second electro-optical Q-switching crystal; DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The present invention provides a multi-wavelength mid-infrared sequence pulse laser to solve or alleviate the problems in the prior art that the laser cannot achieve rapid wavelength switching and cannot output pulse laser.

[0033] In some embodiments, the laser includes a pump laser module, a laser Q-switching module, a beam control module, and a mid-infrared laser module arranged along an optical path.

[0034] 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, which is also used as the pump light of the mid-infrared laser module. The beam control module is used to perform beam shaping on the formed sequence pulse laser and control its action period with the mid-infrared laser module to form a multi-wavelength mid-infrared laser with periodic output. The mid-infrared laser module is used to absorb the sequence pulse laser and excite the multi-wavelength mid-infrared laser.

[0035] In the above embodiment, the multi-wavelength mid-infrared sequence pulse laser, as a new type of solid-state laser, has multi-wavelength high-frequency sequential output compared to the existing mid-infrared laser, and each output wavelength has the characteristics of high repetition frequency and high peak power, which is of great significance in expanding the practicality and application scope of mid-infrared lasers.

[0036] Figure 2 FIG. 1 is a schematic diagram of the structure of a multi-wavelength mid-infrared sequence pulse laser in one embodiment of the present invention. Figure 2 As shown, the pump laser module is used to generate continuous pump light, and includes a side pump laser 7, a first laser crystal 8, a polarizer 9, a half-wave plate 10, an input mirror 11 and an output mirror 6 arranged along the optical path.

[0037] Wherein, the side pump laser 7 is used to output laser to provide pump energy to the first laser crystal 8. The first laser crystal 8 is used to absorb the energy of the side pump laser 7 and output near-infrared laser. The polarizer 9 is used to control the polarization characteristics of the resonant cavity formed in the pump laser module to ensure that the output laser is a polarized laser. The half-wave plate 10 is used to control the polarization direction to ensure that the fundamental frequency light matches the polarization of the laser Q-switching module, thereby generating the maximum loss in the cavity. The input mirror 11 is used as a reflector of the resonant cavity to ensure the gain effect of the laser; the output mirror 6 is used as the output mirror 6 of the resonant cavity to ensure the resonant gain of the laser.

[0038] In this embodiment, the pump light of the laser is emitted by the side pump laser 7 to pump the first laser crystal 8, so that the λ1 spectral line transitions in the first laser crystal 8 and forms laser oscillation in the resonant cavity (13→8→11), and forms a continuous laser with adjustable polarization direction under the action of the polarizer 9 and the half-wave plate 10.

[0039] In the above-mentioned embodiment, the side pump laser 7 provides pumping energy to the first laser crystal 8 from the side thereof, that is, the side pump laser 7 emits laser light to the first laser crystal 8 from the side thereof.

[0040] Here, the side pumping laser 7 can adopt an 880nm semiconductor laser for outputting an 808nm laser; the first laser crystal 8 is used to output a 1064nm near-infrared laser, which can adopt a neodymium-doped yttrium aluminum garnet crystal, and further, the neodymium-doped yttrium aluminum garnet crystal is a yttrium aluminum garnet crystal doped with 0.5% neodymium. But it is not limited to this. In other embodiments, the first laser crystal 8 can also adopt a single-end pumped or double-end pumped laser crystal, and the direction of the energy provided by the side pumping laser 7 needs to be changed accordingly. For example, when the first laser crystal 8 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 8. Here, the side pumping laser 7 can also be other forms of pumping sources, such as a flash lamp, a light-emitting diode, etc.

[0041] In some embodiments, Figure 2 As shown, the laser Q-switching module is used to adjust the intracavity loss of the pump laser to form a sequence pulse laser, which includes a first electro-optical Q-switching crystal 13, a first Q-switching driver 12, a second electro-optical Q-switching crystal 16, a second Q-switching driver 15 and a signal generator 14.

[0042] The first electro-optical Q-switched crystal 13 is arranged in the optical path between the output mirror 6 and the first laser crystal 8, and the first Q-switched driver 12 is connected to the first electro-optical Q-switched crystal 13. The second electro-optical Q-switched crystal 16 is arranged in the optical path between the half-wave plate 10 and the input mirror 11, and the second Q-switched driver 15 is connected to the second electro-optical Q-switched crystal 16. The signal generator 14 is connected to the first Q-switched driver 12 and the second Q-switched driver 15.

[0043] The working principle of the laser Q-switching module is specifically as follows: the signal generator 14 is used to generate a sequence pulse signal; the first Q-switching driver 12 is used to convert the sequence pulse signal generated by the signal generator 14 into a high-voltage electrical signal to achieve drive control of the first electro-optical Q-switched crystal 13; the second Q-switching driver 15 is used to convert the sequence pulse signal generated by the signal generator 14 into a high-voltage electrical signal to achieve drive control of the second electro-optical Q-switched crystal 16; the first electro-optical Q-switched crystal 13 and the second electro-optical Q-switched crystal 16 are used to simultaneously generate controllable specific losses in the resonant cavity to ensure complete shutdown of the resonant cavity, thereby generating a sequence pulse laser.

[0044] In this embodiment, the signal generator 14 generates a sequence pulse signal, which is converted into a high-voltage signal through the first Q-switched driver 12 (electro-optical driver) and the second Q-switched driver 15 (electro-optical driver), and forms a specific loss in the cavity through the first electro-optical Q-switched crystal 13 and the second electro-optical Q-switched crystal 16, and finally converts the continuous laser into a sequence pulse laser.

[0045] In some embodiments, the beam control module is used to shape the beam of the sequential pulse laser and control its interaction period with the mid-infrared crystal, and includes a focusing mirror 5, a first fast deflection mirror 4 and a second fast deflection mirror 2 arranged along the optical path.

[0046] Among them, the focusing mirror 5 is used to perform beam shaping on the sequence pulse laser generated after being processed by the laser Q-switching module, so as to achieve effective pumping of the mid-infrared laser module; the first fast deflection mirror 4 is used to periodically adjust the transmission direction of the sequence pulse laser, so as to achieve periodic pumping of the mid-infrared laser module and thereby obtain a multi-wavelength mid-infrared sequence pulse laser; the second fast deflection mirror 2 is used to achieve spatial output of the multi-wavelength mid-infrared laser excited by the mid-infrared laser module.

[0047] In the above embodiment, the second fast deflection mirror 2 is a controllable deflection mirror, and the beam control module also includes a deflection mirror controller 1 connected to the second fast deflection mirror 2. The deflection mirror controller 1 is used to generate a control signal and output it to the second fast deflection mirror 2. The second fast deflection mirror 2 responds to the control signal to perform angle control to achieve parallel emission.

[0048] In some embodiments, the mid-infrared laser module includes a second laser crystal 3, which is a mid-infrared crystal. The second laser crystal 3 is used to absorb pump light energy and output mid-infrared laser through optical parametric oscillation.

[0049] Here, the second laser crystal 3 may be a fan-shaped PPLN crystal, and the fan-shaped PPLN crystal is used to combine the second fast deflection mirror 2 and the deflection mirror controller 1 to obtain a multi-wavelength mid-infrared laser.

[0050] In the above embodiment, the sequence pulse laser is coupled into the fan-shaped PPLN crystal (with D polarization periods engraved in the fan-shaped PPLN crystal) under the action of the focusing mirror 5 and the first fast deflection mirror 4, and the deflection mirror controller 1 is synchronously controlled in timing to generate a control signal with H×D repetition frequency according to the repetition frequency H generated by the signal generator 14, so as to ensure that each sequence pulse enters the fan-shaped PPLN crystal in a periodic deflection manner to generate a periodic multi-wavelength mid-infrared sequence pulse laser. Finally, the emitted multi-wavelength mid-infrared sequence pulse laser is controlled by the second fast deflection mirror 2 to achieve parallel emission.

[0051] The output laser of the pump laser module after the laser Q-switching module is a sequence pulse laser, which is used as pump light to directly pump the fan-shaped PPLN crystal, and the obtained mid-infrared laser is a pulse sequence laser; the fan-shaped PPLN crystal is used to absorb the pump light energy and output the mid-infrared laser through the action of optical parametric oscillation. The fan-shaped PPLN crystal generates mid-infrared laser, and multi-wavelength mid-infrared laser can be obtained by combining the second fast deflection mirror 4 and the deflection mirror controller 1.

[0052] In some embodiments, the fan-shaped PPLN crystal is a multi-period PPLN crystal coated on both sides, and the period is 29um / 29.5um / 30um. The input end is coated with 1064nm high transmittance and 1.4-1.6um, 3.6-4.5um high reflection, and the output end is coated with 1064nm high reflection and 1.4-1.6um high reflection and 3.6-4.5um, and the transmittance is 10%; the focusing mirror 5 is a positive lens with a focal length of f=200mm; the output mirror 6 is a plane mirror coated with 1064nm and the transmittance is 40%; the side pump laser 7 is an 880nm semiconductor laser; The Nd:Yttrium aluminum garnet crystal is a yttrium aluminum garnet crystal doped with 0.5% neodymium; the polarizer 9 is a polarization selection device; the half-wave plate 10 is a plane mirror with a delay of 1 / 2λ at 1064nm; the input mirror 11 is a plane mirror with high reflection at 1064nm; the first Q-switched drive 12 and the second Q-switched drive 15 are drivers for generating high voltage electricity; the first electro-optical Q-switched crystal 13 and the second electro-optical Q-switched crystal 16 are RTP crystals that respond to the first Q-switched drive 12 and the second Q-switched drive 15 to generate a maximum loss of 90% at 1064nm; the signal generator 14 is a signal generator 14 that generates a sequence pulse signal.

[0053] In some embodiments, after the laser reaches a stable state, it outputs a multi-wavelength mid-infrared sequence pulse laser with wavelengths of 3.8um, 3.9um, and 4.0um.

[0054] The multi-wavelength mid-infrared sequence pulse laser of the present invention uses sequence pulse laser to pump the fan-shaped PPLN crystal, and can generate sequence pulse laser with high repetition rate and high peak power. At the same time, through the angle control of the fast deflection mirror, a mid-infrared sequence pulse laser with multi-wavelength sequential output can be generated. The generated mid-infrared laser has the advantages of high repetition rate, high peak power, high conversion efficiency and multi-wavelength sequential emission. Due to the characteristics of high repetition rate, high peak power and multi-wavelength sequential output, the laser can effectively improve the application potential and application value of mid-infrared lasers in the above fields.

[0055] The multi-wavelength mid-infrared sequence pulse laser according to the embodiment of the present invention can obtain the following beneficial effects:

[0056] (1) The multi-wavelength mid-infrared sequential pulse laser in the present invention uses sequential pulse laser as a pump source to pump the fan-shaped PPLN crystal, and the obtained mid-infrared pulse laser has the advantages of high peak power, high repetition rate and high light-to-light conversion efficiency.

[0057] (2) The multi-wavelength mid-infrared sequential pulse laser in the present invention uses a fast deflection mirror to achieve periodic pumping of the fan-shaped PPLN crystal, and the obtained mid-infrared laser has the characteristics of multi-wavelength sequential output.

[0058] (3) The multi-wavelength mid-infrared sequential pulse laser in the present invention uses a sequential laser as a pump laser and combines a fast deflection mirror to periodically pump the fan-shaped PPLN crystal. The obtained mid-infrared laser has the advantages of high peak power (kilowatt level), high repetition rate (100kHz), high light-to-light conversion efficiency (wavelength>3.8um, light-to-light efficiency>10%) and multi-wavelength sequential output (wavelength switching time is kHz).

[0059] 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.

[0060] 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 multi-wavelength mid-infrared sequence pulse laser, characterized in that: The laser comprises a pump laser module, a laser Q-switching module, a beam control module and a mid-infrared laser module arranged along the optical path; 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 so that the continuous pump light forms a sequence pulse laser, and the sequence pulse laser is also used as the pump light of the mid-infrared laser module; The beam control module is used to perform beam shaping on the formed sequence pulse laser and control the action cycle between the sequence pulse laser and the mid-infrared laser module; The mid-infrared laser module is used to absorb the sequence pulse laser and form a multi-wavelength mid-infrared laser that is periodically output; The pump laser module includes a side pump laser, a first laser crystal, a polarizer, a half-wave plate, an input mirror and an output mirror arranged 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 first laser crystal is a neodymium-doped yttrium aluminum garnet crystal, and the neodymium-doped yttrium aluminum garnet crystal is a yttrium aluminum garnet crystal doped with 0.5% neodymium; The polarizer is used to control the polarization characteristics of the resonant cavity formed in the pump laser module to ensure that the output laser is polarized laser; The half-wave plate is used to control the polarization direction to ensure polarization matching between the fundamental frequency light and the laser Q-switching module, thereby generating maximum loss in the cavity; The input mirror is used as a reflector of the resonant cavity to ensure the gain effect of the laser; The output mirror is used as an output mirror of the resonant cavity to ensure the resonant gain of the laser.

2. The multi-wavelength mid-infrared sequence pulse laser according to claim 1, characterized in that: The side pump laser is used to output 808nm laser; The first laser crystal is used to output 1064nm near-infrared laser.

3. The multi-wavelength mid-infrared sequence pulse laser according to claim 2, characterized in that: The laser Q-switching module includes a first electro-optical Q-switching crystal, a first Q-switching driver, a second electro-optical Q-switching crystal, a second Q-switching driver and a signal generator; The first electro-optical Q-switched crystal is arranged in the optical path between the output mirror and the first laser crystal, and the first Q-switched driver is connected to the first electro-optical Q-switched crystal; The second electro-optical Q-switched crystal is arranged in the optical path between the half-wave plate and the input mirror, and the second Q-switched driver is connected to the second electro-optical Q-switched crystal; The signal generator is connected to the first Q-switched driver and the second Q-switched driver; Wherein, the signal generator is used to generate a sequence pulse signal; The first Q-switched driver is used to convert the sequence pulse signal generated by the signal generator into a high-voltage electrical signal to achieve drive control of the first electro-optical Q-switched crystal; The second Q-switched driver is used to convert the sequence pulse signal generated by the signal generator into a high-voltage electrical signal to achieve drive control of the second electro-optical Q-switched crystal; The first electro-optical Q-switched crystal and the second electro-optical Q-switched crystal are used to simultaneously generate controllable specific losses in the resonant cavity to ensure complete shutoff of the resonant cavity, thereby generating sequence pulse lasers.

4. The multi-wavelength mid-infrared sequence pulse laser according to claim 3, characterized in that: The beam control module comprises a focusing mirror, a first fast deflection mirror and a second fast deflection mirror arranged along the optical path; The focusing mirror is used to perform beam shaping on the sequence pulse laser generated after being processed by the laser Q-switching module, so as to achieve effective pumping of the mid-infrared laser module; The first fast deflection mirror is used to periodically adjust the transmission direction of the sequence pulse laser, so as to achieve periodic pumping of the mid-infrared laser module and obtain multi-wavelength mid-infrared sequence pulse laser; The second fast deflection mirror is used to realize the spatial output of the multi-wavelength mid-infrared laser excited by the mid-infrared laser module.

5. The multi-wavelength mid-infrared sequence pulse laser according to claim 4, characterized in that: The second fast deflection mirror is a controllable deflection mirror, and the beam control module also includes a deflection mirror controller connected to the second fast deflection mirror. The deflection mirror controller is used to generate a control signal and output it to the second fast deflection mirror. The second fast deflection mirror responds to the control signal to control the angle to achieve parallel emission.

6. The multi-wavelength mid-infrared sequence pulse laser according to claim 5, characterized in that: The mid-infrared laser module includes a second laser crystal, which is used to absorb pump light energy and output mid-infrared laser through optical parametric oscillation.

7. The multi-wavelength mid-infrared sequence pulse laser according to claim 6, characterized in that: The second laser crystal is a fan-shaped PPLN crystal, and the fan-shaped PPLN crystal is used to combine with the second fast deflection mirror and the deflection mirror controller to obtain a multi-wavelength mid-infrared laser.

8. The multi-wavelength mid-infrared sequence pulse laser according to claim 7, characterized in that: The fan-shaped PPLN crystal is a multi-period PPLN crystal coated on both sides, and the period is 29um / 29.5um / 30um. The input end is coated with 1064nm high transmittance and 1.4-1.6um and 3.6-4.5um high reflection, and the output end is coated with 1064nm high reflection, 1.4-1.6um high reflection and 3.6-4.5um, and the transmittance is 10%; The focusing lens is a positive lens with a focal length of f=200 mm; The output mirror is a flat mirror with a coating having a transmittance of 40% at 1064nm; The side pump laser is a 880nm semiconductor laser; The neodymium-doped yttrium aluminum garnet crystal is a yttrium aluminum garnet crystal doped with 0.5% neodymium; The polarizer is a polarization selective device; The half-wave plate is a plane mirror with a 1 / 2λ delay at 1064nm; The input mirror is a 1064nm high-reflection plane mirror; The first Q-switched driver and the second Q-switched driver are drivers for generating high voltage electricity; The first electro-optical Q-switched crystal and the second electro-optical Q-switched crystal are RTP crystals that generate a maximum loss of 90% at 1064nm in response to the first Q-switched drive and the second Q-switched drive; The signal generator is a signal generator that generates a sequence pulse signal.

9. The multi-wavelength mid-infrared sequence pulse laser according to any one of claims 1 to 8, characterized in that: After the laser reaches a stable state, it outputs multi-wavelength mid-infrared sequence pulse lasers with wavelengths of 3.8um, 3.9um, and 4.0um.

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