An irregular pulse train laser emission control system and method

Abstract

The present invention relates to the field of laser technology, and provides an irregular pulse train laser emission control system and method, which coordinately control two electro-optic crystals in a seed light oscillation cavity and an optical parametric oscillation cavity respectively. First, a plurality of time series are set through a delay controller, which are respectively used to obtain pulse train seed laser and mid-infrared pulse train parametric laser. In each of the plurality of time series, the turn-on times of the two electro-optic crystals are adjusted to obtain pulse train seed laser outputs with different time intervals, and then an irregular mid-infrared pulse train parametric laser output is obtained. Furthermore, the technical problem in the prior art that the pulse intervals generated by a pulse train laser system are usually fixed and are easily detected and recognized is overcome, a faster and more efficient irregular pulse train operation is provided, the start-up time of the laser system is reduced, and the anti-detection performance of the output laser signal is improved.

Description

Technical Field

[0001] The present invention generally relates to the field of laser technology, and particularly relates to an irregular pulse train laser emission control system and method. Background Art

[0002] Laser technology has a wide range of applications in many fields, including communication, medical treatment, material processing, and military applications. A laser is the core component of a laser system, and its performance directly affects the performance of the entire system.

[0003] In some applications, it is necessary to emit a laser with multiple pulses in an extremely short time to achieve specific goals. For example, in military applications, a pulsed laser system that can be quickly started and launched can be used to excite specific targets or perform target recognition. In addition, in the medical field, pulsed laser can precisely cut biological tissues and perform various minimally invasive surgeries. Therefore, pulsed laser has broad application prospects.

[0004] Traditional laser systems are usually subject to some limitations, making it difficult to achieve pulsed train operations with quick start and launch. Some of these problems include: traditional laser systems require a certain amount of time to start up and stabilize, which results in a startup time delay between pulses, limiting the speed and efficiency of pulsed train operations; the output pulse train frequency of traditional pulsed train laser systems is in the kHz range, and it is difficult to achieve a pulse train output at the MHz level; the pulse intervals generated by traditional pulsed train laser systems are usually fixed, making them easy to be detected and recognized.

[0005] Therefore, it is necessary to develop an irregular pulse train laser emission control system to overcome the problems of startup time delay and easy detection and recognition of traditional laser systems, provide faster and more efficient irregular pulse train operations, reduce the startup time of the laser system, and improve the anti-detection ability of the output laser signal. Summary of the Invention

[0006] The following refers to Figures 1 to 4 to describe an irregular pulse train laser emission control system provided by an embodiment of the present invention. As Figure 1 shown, an irregular pulse train laser emission control system includes a seed light oscillation optical path, an optical parametric oscillation optical path, and an emission control device 16. Among them,

[0007] The seed light oscillation optical path includes a pump source 1, a transmission optical fiber 2, a coupling lens barrel 3, a first cavity mirror 4, a laser crystal 5, a first electro-optic crystal 6, a first polarizer 7, and a second cavity mirror 8. Among them,

[0008] The pump source 1 is connected to the coupling lens barrel 3 through the transmission optical fiber 2. Along the optical path behind the coupling lens barrel 3, a first cavity mirror 4, a laser crystal 5, a first electro-optic crystal 6, a first polarizer 7, and a second cavity mirror 8 are sequentially arranged;

[0009] The first polarizer 7 can transmit P-polarized laser while reflecting S-polarized laser, or the first polarizer 7 can transmit S-polarized laser while reflecting P-polarized laser;

[0010] The first polarizer 7 is arranged at 45° along the optical path direction for changing the propagation direction of the optical path;

[0011] The second cavity mirror 8 is arranged in the reflection direction of the first polarizer 7;

[0012] The optical parametric oscillation optical path is arranged in the transmission direction of the first polarizer 7 so that the seed light generated by the seed light oscillation optical path can enter the optical parametric oscillation optical path;

[0013] The optical parametric oscillation optical path includes a third cavity mirror 9, an MgO:PPLN crystal 10, a fourth cavity mirror 11, a fifth cavity mirror 12, a second electro-optic crystal 13, a sixth cavity mirror 14, and a second polarizer 15; among them,

[0014] The third cavity mirror 9 is arranged in the transmission direction of the first polarizer 7;

[0015] Behind the third cavity mirror 9, the MgO:PPLN crystal 10, the fourth cavity mirror 11, the fifth cavity mirror 12, the second electro-optic crystal 13, the second polarizer 15, and the sixth cavity mirror 14 are sequentially arranged along the optical path;

[0016] The third cavity mirror 9, the fourth cavity mirror 11, the fifth cavity mirror 12, and the sixth cavity mirror 14 form an eight-shaped optical parametric oscillation cavity;

[0017] The MgO:PPLN crystal 10 is arranged between the third cavity mirror 9 and the fourth cavity mirror 11;

[0018] The second electro-optic crystal 13 and the second polarizer 15 are arranged between the fifth cavity mirror 12 and the sixth cavity mirror 14;

[0019] The second polarizer 15 can transmit P-polarized laser while reflecting S-polarized laser, or the second polarizer 15 can transmit S-polarized laser while reflecting P-polarized laser;

[0020] The second polarizer 15 and the second electro-optic crystal 13 are arranged at 45° along the optical path direction for emitting mid-infrared parametric light;

[0021] The upper end faces of the first electro-optic crystal 6 and the second electro-optic crystal 13 are both attached to metal electrodes, and the lower end faces of the first electro-optic crystal 6 and the second electro-optic crystal 13 are both grounded;

[0022] The emission control device 16 includes a processor 16-1, a delay controller 16-2, a first high-voltage module 16-3, and a second high-voltage module 16-4; among them,

[0023] The processor 16-1 is electrically connected to the delay controller 16-2, and the delay controller 16-2 is electrically connected to the pump source 1, the first high-voltage module 16-3, and the second high-voltage module 16-4 respectively;

[0024] The first high-voltage module 16-3 is electrically connected to the upper end face of the first electro-optic crystal 6, and the second high-voltage module 16-4 is electrically connected to the upper end face of the second electro-optic crystal 13.

[0025] In one embodiment, the pump source 1 is an 808nm pulsed pump source, the laser crystal 5 is an a-axis cut Nd:YVO4 crystal, the polarization period of the MgO:PPLN crystal 10 is 29.8μm, the first electro-optic crystal 6 is an RTP electro-optic crystal, and the second electro-optic crystal 13 is an LN crystal.

[0026] In one embodiment, the first mirror 4 is coated with a 1064nm total reflection film, the second mirror 8 is coated with a 1064nm total reflection film, the third mirror 9 is coated with a 1064nm antireflection film and a 2.7 - 4.5μm total reflection film, and the fourth mirror 11, the fifth mirror 12, and the sixth mirror 14 are all coated with a 2.7 - 4.5μm total reflection film.

[0027] According to another aspect of the present invention, an irregular pulse train laser emission control method is disclosed, which applies the above-mentioned irregular pulse train laser emission control system. The control method includes:

[0028] Set the time series of the delay controller 16-2 to 0 - t1, t1 - t2, t2 - t3;

[0029] Within the 0 - t1 time series, the processor 16-1 in the emission control device 16 controls the delay controller 16-2 to turn on the pump source 1, and the pump source 1 emits pump light that enters the coupling lens barrel 3 through the transmission optical fiber 2;

[0030] The pump light enters the laser crystal 5 after passing through the coupling lens barrel 3 and then through the first mirror 4;

[0031] The seed light emitted after the laser crystal 5 is excited is P-type linearly polarized light. The polarization state of the seed light does not change after passing through the first electro-optic crystal 6. At this time, the seed light can pass through the first polarizer 7 and transmit out of the seed light oscillation cavity;

[0032] At time t', the emission control device 16 controls the delay controller 16-2 to turn on the first high-voltage module 16-3 through the processor 16-1. The first high-voltage module 16-3 provides a 1 / 2 wavelength voltage to both ends of the first electro-optic crystal 6;

[0033] Where 0 < t' < t1;

[0034] The seed light becomes S-type linearly polarized light after passing through the first electro-optic crystal 6. At this time, the seed light cannot pass through the first polarizer 7 by transmission, but is reflected by the first polarizer 7 and transmitted to the second cavity mirror 8;

[0035] The seed light is reflected by the second cavity mirror 8 and oscillates in the seed light oscillation cavity, accumulating the number of photons in the seed light oscillation cavity;

[0036] At time t1, when the number of photons in the cavity reaches the maximum value, the emission control device 16 controls the delay controller 16-2 to turn off the first high-voltage module 16-3 through the processor 16-1, so that the voltage at both ends of the first electro-optic crystal 6 is 0. At this time, the seed light is P-type linearly polarized light, and the seed light can pass through the first polarizer 7 and transmit out of the seed light oscillation cavity;

[0037] The seed light enters the optical parametric oscillation cavity, undergoes nonlinear frequency conversion through the MgO:PPLN crystal 10, and obtains 3.8 μm mid-infrared parametric light. The mid-infrared parametric light is P-type linearly polarized light. At this time, the mid-infrared parametric light can pass through the second polarizer 15;

[0038] Repeat the operations in the 0 - t1 time sequence within the t1 - t2 time sequence to obtain multiple seed lights, and continuously accumulate the seed lights in the optical parametric oscillation cavity;

[0039] Within the t2 - t3 time sequence, when the second high-voltage module 16-4 is not turned on, the mid-infrared parametric light is P-type linearly polarized light. At this time, the mid-infrared parametric light cannot be reflected by the second polarizer 15;

[0040] At time t'', the emission control device 16 controls the delay controller 16-2 to turn on the second high-voltage module 16-4 through the processor 16-1. The second high-voltage module 16-4 provides a 1 / 2 wavelength voltage to both ends of the second electro-optic crystal 13;

[0041] wherein, t2 < t’’ < t3;

[0042] The mid-infrared parametric light becomes S-type linearly polarized light after passing through the second electro-optic crystal 13. At this time, the mid-infrared parametric light cannot pass through the second polarizer 15 for transmission, but is reflected by the second polarizer 15 and then exits, obtaining mid-infrared pulsed train parametric laser output;

[0043] Adjust the values of t1, t2, and t3, change the 0 - t1 time sequence, t1 - t2 time sequence, and t2 - t3 time sequence, and further change the pulsed train time interval;

[0044] Adjust the values of t’ and t’’, change the turn-on durations of the first high-voltage module 16 - 3 and the second high-voltage module 16 - 4, so as to obtain irregular mid-infrared pulsed train parametric laser output.

[0045] As Figure 3 shown is the time-domain schematic diagram of the seed light output, wherein Figure 3 (a) is the waveform time sequence diagram of the pump source 1. Within the 0 - t1 time sequence, the pump source 1 emits pump light; Figure 3 (b) is the voltage time sequence diagram at both ends of the first electro-optic crystal 6, Figure 3 (c) is the seed light pulse time sequence diagram. With the turn-on of the first high-voltage module 16 - 3 at the moment t’, a seed light pulse sequence is output. Within the t1 - t2 time sequence, the process within the 0 - t1 time sequence is repeated to obtain pulsed train seed laser output.

[0046] As Figure 4 shown is the time-domain schematic diagram of the mid-infrared parametric light output, Figure 4 (a) is the voltage time sequence diagram at both ends of the second electro-optic crystal 13, Figure 4 (b) is the mid-infrared pulse time sequence diagram. Within the t2 - t3 time sequence, with the turn-on of the second high-voltage module 16 - 4 at the moment t’’, irregular mid-infrared pulsed train parametric laser is output.

[0047] Beneficial effects

[0048] The present invention coordinates and controls two electro-optic crystals in a seed light oscillation cavity and an optical parametric oscillation cavity respectively. First, a delay controller is used to set multiple time sequences, which are respectively used to obtain a pulsed train seed laser and a mid-infrared pulsed train parametric laser. In multiple time sequences, the turn-on times of the two electro-optic crystals are adjusted respectively to obtain pulsed train seed laser outputs with different time intervals, and then an irregular mid-infrared pulsed train parametric laser output is obtained. Furthermore, the technical problem in the prior art that the pulse intervals generated by a pulsed train laser system are usually fixed and are easily detected and recognized is overcome, a faster and more efficient irregular pulsed train operation is provided, the startup time of the laser system is reduced, and the anti-detection performance of the output laser signal is improved.

[0049] It should be understood that the content described in the summary of the invention section is not intended to limit the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In conjunction with the accompanying drawings and with reference to the following detailed description, the above and other features, advantages, and aspects of the embodiments of the present invention will become more apparent. In the drawings, the same or similar reference numerals denote the same or similar elements, where

[0051] Figure 1 is a schematic diagram of an irregular pulsed train laser emission system;

[0052] Figure 2 is a schematic diagram of an emission control device of an irregular pulsed train laser emission system;

[0053] Figure 3 is a time domain schematic diagram of seed light output;

[0054] Figure 4 is a time domain schematic diagram of mid-infrared parametric light output;

[0055] In the figure, the structural components denoted by each reference numeral are:

[0056] 1. Pump source; 2. Transmission optical fiber; 3. Coupling lens barrel; 4. First cavity mirror; 5. Laser crystal; 6. First electro-optic crystal; 7. First polarizer; 8. Second cavity mirror; 9. Third cavity mirror; 10. MgO:PPLN crystal; 11. Fourth cavity mirror; 12. Fifth cavity mirror; 13. Second electro-optic crystal; 14. Sixth cavity mirror; 15. Second polarizer; 16. Emission control device; 16-1. Processor; 16-2. Delay controller; 16-3. First high-voltage module; 16-4. Second high-voltage module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0058] In addition, the term "and / or" in this text is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0059] Next, refer to Figures 1 to 4 to describe an irregular pulse train laser emission control system provided by an embodiment of the present invention. As Figure 1 shown, an irregular pulse train laser emission control system includes a seed light oscillation optical path, an optical parametric oscillation optical path, and an emission control device 16. Among them,

[0060] The seed light oscillation optical path includes a pump source 1, a transmission optical fiber 2, a coupling lens barrel 3, a first cavity mirror 4, a laser crystal 5, a first electro-optic crystal 6, a first polarizer 7, and a second cavity mirror 8. Among them,

[0061] The pump source 1 is connected to the coupling lens barrel 3 through the transmission optical fiber 2. The first cavity mirror 4, the laser crystal 5, the first electro-optic crystal 6, the first polarizer 7, and the second cavity mirror 8 are sequentially arranged along the optical path behind the coupling lens barrel 3.

[0062] The first polarizer 7 can transmit P-polarized laser while reflecting S-polarized laser, or the first polarizer 7 can transmit S-polarized laser while reflecting P-polarized laser.

[0063] The first polarizer 7 is arranged at 45° along the optical path direction for changing the propagation direction of the optical path.

[0064] The second cavity mirror 8 is arranged in the reflection direction of the first polarizer 7.

[0065] The optical parametric oscillation optical path is arranged in the transmission direction of the first polarizer 7 so that the seed light generated by the seed light oscillation optical path can enter the optical parametric oscillation optical path.

[0066] The optical parametric oscillation optical path includes a third cavity mirror 9, a MgO:PPLN crystal 10, a fourth cavity mirror 11, a fifth cavity mirror 12, a second electro-optic crystal 13, a sixth cavity mirror 14, and a second polarizer 15; among them,

[0067] The transmission direction of the first polarizer 7 is set for the third cavity mirror 9;

[0068] After the third cavity mirror 9, the MgO:PPLN crystal 10, the fourth cavity mirror 11, the fifth cavity mirror 12, the second electro-optic crystal 13, the second polarizer 15, and the sixth cavity mirror 14 are arranged in sequence along the optical path;

[0069] The third cavity mirror 9, the fourth cavity mirror 11, the fifth cavity mirror 12, and the sixth cavity mirror 14 form an eight-shaped optical parametric oscillation cavity;

[0070] The MgO:PPLN crystal 10 is arranged between the third cavity mirror 9 and the fourth cavity mirror 11;

[0071] The second electro-optic crystal 13 and the second polarizer 15 are arranged between the fifth cavity mirror 12 and the sixth cavity mirror 14;

[0072] The second polarizer 15 can transmit P-polarized laser while reflecting S-polarized laser, or the second polarizer 15 can transmit S-polarized laser while reflecting P-polarized laser;

[0073] The second polarizer 15 is arranged at 45° along the optical path direction with the second electro-optic crystal 13 for emitting mid-infrared parametric light;

[0074] The upper end surfaces of the first electro-optic crystal 6 and the second electro-optic crystal 13 are both attached to metal electrodes, and the lower end surfaces of the first electro-optic crystal 6 and the second electro-optic crystal 13 are both grounded;

[0075] The emission control device 16 includes a processor 16-1, a delay controller 16-2, a first high-voltage module 16-3, and a second high-voltage module 16-4; among them,

[0076] The processor 16-1 is electrically connected to the delay controller 16-2, and the delay controller 16-2 is electrically connected to the pump source 1, the first high-voltage module 16-3, and the second high-voltage module 16-4 respectively;

[0077] The first high-voltage module 16-3 is electrically connected to the upper end surface of the first electro-optic crystal 6, and the second high-voltage module 16-4 is electrically connected to the upper end surface of the second electro-optic crystal 13.

[0078] In one embodiment, the pump source 1 is an 808 nm pulsed pump source, the laser crystal 5 is an a-axis cut Nd:YVO4 crystal, the polarization period of the MgO:PPLN crystal 10 is 29.8 μm, the first electro-optic crystal 6 is an RTP electro-optic crystal, and the second electro-optic crystal 13 is an LN crystal.

[0079] In one embodiment, the first mirror 4 is coated with a 1064 nm total reflection film, the second mirror 8 is coated with a 1064 nm total reflection film, the third mirror 9 is coated with a 1064 nm antireflection film and a 2.7 - 4.5 μm total reflection film, and the fourth mirror 11, the fifth mirror 12, and the sixth mirror 14 are all coated with a 2.7 - 4.5 μm total reflection film.

[0080] According to another aspect of the present invention, a method for controlling the emission of an irregular pulse train laser is disclosed. The method applies the above-mentioned irregular pulse train laser emission control system, and the control method includes:

[0081] Set the time sequence of the delay controller 16 - 2 to 0 - t1, t1 - t2, t2 - t3;

[0082] Within the time sequence of 0 - t1, the processor 16 - 1 in the emission control device 16 controls the delay controller 16 - 2 to turn on the pump source 1, and the pump source 1 emits pump light that enters the coupling lens barrel 3 through the transmission optical fiber 2;

[0083] The pump light enters the first mirror 4 through the coupling lens barrel 3 and then enters the laser crystal 5;

[0084] The seed light emitted after the laser crystal 5 is excited is P-type linearly polarized light. The polarization state of the seed light does not change after passing through the first electro-optic crystal 6. At this time, the seed light can pass through the first polarizer 7 and transmit out of the seed light oscillation cavity;

[0085] At time t’, the emission control device 16 controls the delay controller 16 - 2 to turn on the first high-voltage module 16 - 3 through the processor 16 - 1, and the first high-voltage module 16 - 3 provides a 1 / 2 wavelength voltage to both ends of the first electro-optic crystal 6;

[0086] Where 0 < t’ < t1;

[0087] The seed light becomes S-type linearly polarized light after passing through the first electro-optic crystal 6. At this time, the seed light cannot pass through the first polarizer 7 for transmission, but is reflected by the first polarizer 7 and transmitted to the second mirror 8;

[0088] The seed light oscillates in the seed light oscillation cavity after being reflected by the second cavity mirror 8, and the number of photons is accumulated in the seed light oscillation cavity;

[0089] At time t1, the number of photons in the cavity reaches the maximum value. The emission control device 16 controls the delay controller 16-2 through the processor 16-1 to turn off the first high-voltage module 16-3, so that the voltage across the first electro-optic crystal 6 is 0. At this time, the seed light is P-type linearly polarized light, and the seed light can pass through the first polarizer 7 and transmit out of the seed light oscillation cavity;

[0090] The seed light enters the optical parametric oscillation cavity and undergoes nonlinear frequency conversion through the MgO:PPLN crystal 10 to obtain 3.8-μm mid-infrared parametric light. The mid-infrared parametric light is P-type linearly polarized light, and at this time, the mid-infrared parametric light can pass through the second polarizer 15;

[0091] Repeat the operations in the 0-t1 time sequence within the t1-t2 time sequence to obtain multiple seed lights, and make the seed lights continuously accumulate in the optical parametric oscillation cavity;

[0092] Within the t2-t3 time sequence, when the second high-voltage module 16-4 is not turned on, the mid-infrared parametric light is P-type linearly polarized light, and at this time, the mid-infrared parametric light cannot be reflected by the second polarizer 15;

[0093] At time t'', the emission control device 16 controls the delay controller 16-2 through the processor 16-1 to turn on the second high-voltage module 16-4, and the second high-voltage module 16-4 provides a 1 / 2 wavelength voltage across the second electro-optic crystal 13;

[0094] Among them, t2 < t'' < t3;

[0095] The mid-infrared parametric light becomes S-type linearly polarized light after passing through the second electro-optic crystal 13. At this time, the mid-infrared parametric light cannot pass through the second polarizer 15 by transmission, but is reflected by the second polarizer 15 and exits, obtaining mid-infrared pulsed train parametric laser output;

[0096] Adjust the values of t1, t2, and t3, change the 0-t1 time sequence, t1-t2 time sequence, and t2-t3 time sequence, and further change the pulsed train time interval;

[0097] Adjust the values of t' and t'', change the on-time of the first high-voltage module 16-3 and the second high-voltage module 16-4, so as to obtain irregular mid-infrared pulsed train parametric laser output.

[0098] As Figure 3The following is a schematic diagram of the time domain of the seed light output, where Figure 3 (a) is a waveform timing diagram of the pump source 1. Within the time sequence of 0 - t1, the pump source 1 emits pump light; Figure 3 (b) is a voltage timing diagram across the first electro - optic crystal 6, Figure 3 (c) is a seed light pulse timing diagram. With the turn - on of the first high - voltage module 16 - 3 at the moment t’, a seed light pulse sequence is output. Within the time sequence of t1 - t2, the process within the 0 - t1 time sequence is repeated to obtain a pulsed - train seed laser output.

[0099] As Figure 4 shown, the following is a schematic diagram of the time domain of the mid - infrared parametric light output, Figure 4 (a) is a voltage timing diagram across the second electro - optic crystal 13, Figure 4 (b) is a mid - infrared pulse timing diagram. Within the time sequence of t2 - t3, with the turn - on of the second high - voltage module 16 - 4 at the moment t’’, an irregular mid - infrared pulsed - train parametric laser is output.

[0100] In the description of this specification, terms such as "connection", "installation", "fixation", etc. should all be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific situation.

[0101] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0102] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An irregular pulse train laser emission control system, comprising a seed light oscillation optical path, an optical parametric oscillation optical path, and an emission control device, wherein, The seed light oscillation optical path includes a pump source, a transmission optical fiber, a coupling lens barrel, a first cavity mirror, a laser crystal, a first electro-optic crystal, a first polarizer, and a second cavity mirror; wherein, The pump source is connected to the coupling lens barrel through the transmission optical fiber, and the first cavity mirror, the laser crystal, the first electro-optic crystal, the first polarizer, and the second cavity mirror are sequentially arranged along the optical path behind the coupling lens barrel; The first polarizer can transmit P-polarized laser while reflecting S-polarized laser, or the first polarizer can transmit S-polarized laser while reflecting P-polarized laser; The first polarizer is arranged at 45° along the optical path direction for changing the propagation direction of the optical path; The second cavity mirror is arranged in the reflection direction of the first polarizer; The optical parametric oscillation optical path is arranged in the transmission direction of the first polarizer so that the seed light generated by the seed light oscillation optical path can enter the optical parametric oscillation optical path; The optical parametric oscillation optical path includes a third cavity mirror, a MgO:PPLN crystal, a fourth cavity mirror, a fifth cavity mirror, a second electro-optic crystal, a sixth cavity mirror, and a second polarizer; wherein, The third cavity mirror is arranged in the transmission direction of the first polarizer; Behind the third cavity mirror, the MgO:PPLN crystal, the fourth cavity mirror, the fifth cavity mirror, the second electro-optic crystal, the second polarizer, and the sixth cavity mirror are sequentially arranged along the optical path; The third cavity mirror, the fourth cavity mirror, the fifth cavity mirror, and the sixth cavity mirror form an eight-shaped optical parametric oscillation cavity; The MgO:PPLN crystal is arranged between the third cavity mirror and the fourth cavity mirror; The second electro-optic crystal and the second polarizer are arranged between the fifth cavity mirror and the sixth cavity mirror; The second polarizer can transmit P-polarized laser while reflecting S-polarized laser, or the second polarizer can transmit S-polarized laser while reflecting P-polarized laser; The second polarizer and the second electro-optic crystal are arranged at 45° along the optical path direction for emitting mid-infrared parametric light; The upper end surfaces of the first electro-optic crystal and the second electro-optic crystal are both attached to metal plates, and the lower end surfaces of the first electro-optic crystal and the second electro-optic crystal are both grounded; The emission control device includes a processor, a delay controller, a first high-voltage module, and a second high-voltage module; wherein, The processor is electrically connected to the delay controller, and the delay controller is electrically connected to the pump source, the first high-voltage module, and the second high-voltage module respectively; The first high-voltage module is electrically connected to the upper end surface of the first electro-optic crystal, and the second high-voltage module is electrically connected to the upper end surface of the second electro-optic crystal; The opening durations of the first high-voltage module and the second high-voltage module are used to obtain irregular pulse train parametric laser output.

2. An irregular pulse train laser emission control method, using an irregular pulse train laser emission control system as described in claim 1, comprising: Set the time series of the delay controller to 0 - t1, t1 - t2, t2 - t3; Within the time series of 0 - t1, control the delay controller through the processor in the emission control device to turn on the pump source, and the pump source emits pump light that enters the coupling lens barrel through the transmission optical fiber; The pump light enters the first cavity mirror through the coupling lens barrel and then enters the laser crystal; The seed light emitted after the laser crystal is excited is P - type linearly polarized light. The polarization state of the seed light does not change after passing through the first electro - optic crystal. At this time, the seed light can pass through the first polarizer and transmit out of the seed light oscillation cavity; At time t’, the emission control device controls the delay controller to turn on the first high - voltage module through the processor, and the first high - voltage module provides a voltage of 1 / 2 wavelength to both ends of the first electro - optic crystal; Where 0 < t’ < t1; The seed light becomes S - type linearly polarized light after passing through the first electro - optic crystal. At this time, the seed light cannot pass through the first polarizer but is reflected by the first polarizer and transmitted to the second cavity mirror; The seed light is reflected by the second cavity mirror and oscillates in the seed light oscillation cavity, and the number of photons is accumulated in the seed light oscillation cavity; At time t1, the number of photons in the cavity reaches the maximum value. The emission control device controls the delay controller to turn off the first high - voltage module through the processor, so that the voltage at both ends of the first electro - optic crystal is 0. At this time, the seed light is P - type linearly polarized light, and the seed light can pass through the first polarizer and transmit out of the seed light oscillation cavity; The seed light enters the optical parametric oscillation cavity, undergoes nonlinear frequency conversion through the MgO:PPLN crystal, and obtains 3.8 - μm mid - infrared parametric light. The mid - infrared parametric light is P - type linearly polarized light. At this time, the mid - infrared parametric light can pass through the second polarizer; Repeat the operations within the time series of 0 - t1 within the time series of t1 - t2 to obtain multiple seed lights and continuously accumulate the seed lights in the optical parametric oscillation cavity; Within the time series of t2 - t3, when the second high - voltage module is not turned on, the mid - infrared parametric light is P - type linearly polarized light. At this time, the mid - infrared parametric light cannot be reflected by the second polarizer; At time t’’, the emission control device controls the delay controller to turn on the second high - voltage module through the processor, and the second high - voltage module provides a voltage of 1 / 2 wavelength to both ends of the second electro - optic crystal; Where t2 < t’’ < t3; The mid - infrared parametric light becomes S - type linearly polarized light after passing through the second electro - optic crystal. At this time, the mid - infrared parametric light cannot pass through the second polarizer but is reflected by the second polarizer and emits out, obtaining mid - infrared pulsed train parametric laser output; Adjust the values of t1, t2, and t3, change the time series of 0 - t1, t1 - t2, and t2 - t3, and thus change the pulsed train time interval.

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