A wavelength tunable mid-infrared laser

Abstract

The application provides a wavelength-tunable mid-infrared laser, comprising, in sequence along an optical transmission direction: a full-solid-state multi-wavelength laser for outputting short-wave infrared pulse lasers of multiple different wavelengths; a standard component assembly with a rotation angle for selectively outputting the short-wave infrared pulse lasers; a coupling module for beam shaping of the short-wave infrared pulse lasers; a first acousto-optic deflection assembly for changing the transmission direction of the short-wave infrared pulse lasers and injecting the short-wave infrared pulse lasers into an optical parametric oscillator; the optical parametric oscillator for absorbing the short-wave infrared pulse lasers and outputting mid-infrared pulse lasers of multiple different wavelengths; and a second acousto-optic deflection assembly for synchronously deflecting the mid-infrared pulse lasers to realize the common-aperture coaxial output of the mid-infrared pulse lasers. The mid-infrared laser output by the mid-infrared laser has the advantages of wide spectral coverage, fast wavelength switching, high repetition frequency, wavelength coding and common-aperture coaxial output.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more specifically, to a wavelength-tunable mid-infrared laser. Background Technology

[0002] Mid-infrared lasers, situated within the atmospheric transmission window, have broad application prospects in various fields such as laser medicine, environmental monitoring, lidar, chemical remote sensing, and infrared countermeasures. A wavelength-tunable mid-infrared laser refers to a mid-infrared laser whose wavelength control unit can be adjusted according to requirements, making its output wavelength adjustable between 3 and 5 micrometers.

[0003] Currently, in the research of tunable mid-infrared lasers, infrared lasers based on periodically polarized lithium niobate crystals (PPLN crystals) are one of the key research areas. For example... Figure 1 The image shows a mid-infrared laser in the prior art, comprising a laser pump source 100, a first coupling system 101, a laser gain crystal 102, a second coupling system 103, a first resonant cavity mirror 104, a periodically polarized magnesium oxide-doped lithium niobate crystal (MgO:PPLN crystal) 105, a second resonant cavity 106, and a dichroic mirror 107 arranged along the optical path. Its main working principle is as follows: the laser pump source 100 excites the laser gain crystal 102 to generate a 1064nm continuous laser. Using the 1064nm continuous laser as the input light, it undergoes nonlinear frequency conversion through the multi-period MgO:PPLN crystal 105, thereby outputting a wavelength-tunable signal laser and an idler laser.

[0004] However, existing mid-infrared lasers still have many shortcomings:

[0005] First, the wavelength switching of the multi-wavelength mid-infrared laser output by the laser needs to be achieved by translating the PPLN crystal and adjusting the temperature of the PPLN crystal, which places high demands on the accuracy of the temperature control module of the optical parametric oscillator. In addition, during the light transmission process, translating the PPLN crystal is prone to crystal damage, which affects the output quality of the laser.

[0006] Second, the output laser is a continuous laser, resulting in extremely low peak power; moreover, the wavelength of the mid-infrared laser needs to be switched mechanically, which not only has a slow tuning speed, but also easily leads to misalignment of the resonant cavity inside the mid-infrared laser and deterioration of beam quality.

[0007] Third, this type of mid-infrared laser outputs multiple mid-infrared laser wavelengths without a common optical path, which limits the application of multi-wavelength mid-infrared lasers. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a wavelength-tunable mid-infrared laser that solves many problems such as high precision requirements for temperature control modules, easy damage caused by crystal movement, slow wavelength switching speed, and narrow tuning spectrum range.

[0009] This invention provides a wavelength-tunable mid-infrared laser, comprising the following components arranged sequentially along the light transmission direction:

[0010] An all-solid-state multi-wavelength laser is used to output short-wave infrared pulsed lasers of various wavelengths; wherein, the all-solid-state multi-wavelength laser includes an etalon assembly with a rotation angle for selectively outputting the short-wave infrared pulsed lasers;

[0011] A coupling module is used to perform beam shaping on the short-wave infrared pulsed laser.

[0012] The first acousto-optic deflection component is used to change the transmission direction of the short-wave infrared pulse laser and inject it into the optical parametric oscillator.

[0013] An optical parametric oscillator is used to absorb the short-wave infrared pulsed laser and output a variety of mid-infrared pulsed lasers of different wavelengths.

[0014] The second acousto-optic deflection component is used to synchronously deflect the mid-infrared pulsed laser, thereby achieving coaxial output of the mid-infrared pulsed laser with a common aperture.

[0015] Furthermore, the all-solid-state multi-wavelength laser also includes, in sequence along the optical transmission direction: a first resonant cavity mirror, a laser gain crystal, a polarizer, an acousto-optic Q-switching crystal, and a second resonant cavity mirror;

[0016] In addition, a pump source disposed on the side of the laser gain crystal, an acousto-optic driver connected to the acousto-optic Q-switched crystal, and a signal generator connected to the acousto-optic driver.

[0017] Furthermore, the etalon assembly is disposed between the acousto-optic Q-switched crystal and the second resonant cavity mirror.

[0018] Furthermore, the standard etalon assembly includes one or more standard etalons with different specifications and parameters.

[0019] Furthermore, the first acousto-optic deflection component includes a first acousto-optic deflector and a second acousto-optic deflector that are light-transmitting in the near-infrared band and are arranged sequentially along the light transmission direction.

[0020] The second acousto-optic deflection component includes a third acousto-optic deflector and a fourth acousto-optic deflector that are transmitted in the mid-infrared band and are arranged sequentially along the light transmission direction.

[0021] Furthermore, the mid-infrared laser also includes an angle rotator for controlling the rotation angle of the etalon assembly.

[0022] Furthermore, the standard etalon assembly is positioned above the angle rotator.

[0023] Furthermore, the mid-infrared laser also includes a control module for generating corresponding control signals and simultaneously transmitting them to the angle rotator, the first acousto-optic deflection component, and the second acousto-optic deflection component.

[0024] Furthermore, the optical parametric oscillator includes a third resonant cavity mirror, a nonlinear crystal, a temperature control module, and a fourth resonant cavity mirror.

[0025] Furthermore, the coupling module includes a negative lens and a positive lens.

[0026] In general, the technical solution conceived in this invention can achieve the following beneficial effects compared with the prior art:

[0027] (1) This invention provides a wavelength-tunable mid-infrared laser that does not require moving the position of the nonlinear crystal or a high-precision temperature control module. It only requires rotating the angle of the etalon and using multiple acousto-optic deflectors to deflect the angle of the pulsed laser. This not only avoids crystal damage caused by crystal movement, but also allows for high-speed switching of mid-infrared pulsed lasers of different wavelengths. The pulse repetition frequency is high and the wavelength tuning speed is fast. Compared with the method of using mechanical switching and temperature control, it can reach hundreds of kilohertz and above, with high tuning accuracy and less damage to the laser crystal.

[0028] (2) This invention provides a wavelength-tunable mid-infrared laser. The laser output by the all-solid-state multi-wavelength laser is a pulsed laser, which avoids the subsequent output of continuous laser and solves the problem of low peak power. In addition, since the output laser is a pulsed laser and multiple acousto-optic deflectors are used, mid-infrared lasers of various wavelengths can be output coaxially with the same aperture, which greatly expands the application range of mid-infrared pulsed lasers of various wavelengths.

[0029] (3) The present invention provides a wavelength-tunable mid-infrared laser, which realizes mid-infrared pulsed laser spectral information encoding by timing encoding through a control module, which greatly increases the practicality of the mid-infrared pulsed laser.

[0030] In summary, this invention provides a wavelength-tunable mid-infrared laser that does not require high temperature control of the crystal and is not easily damaged. The output mid-infrared pulsed laser has many advantages, such as high pulse repetition frequency, fast wavelength tuning speed, wide spectral range, high peak power, and coaxial output with common aperture. It is of great significance in expanding the practical application and scope of mid-infrared lasers. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of a mid-infrared laser in the prior art;

[0033] Figure 2 This is a schematic diagram of the structure of a wavelength-tunable mid-infrared laser provided by the present invention;

[0034] Figure 3 The present invention provides a signal timing diagram of an angle controller, a first acousto-optic deflector, a second acousto-optic deflector, a third acousto-optic deflector, and a fourth acousto-optic deflector for a wavelength-tunable mid-infrared laser. Figure 1 and the timing of the output laser pulses Figure 1 ;

[0035] Figure 4 The present invention provides a signal timing diagram of an angle controller, a first acousto-optic deflector, a second acousto-optic deflector, a third acousto-optic deflector, and a fourth acousto-optic deflector for a wavelength-tunable mid-infrared laser. Figure 2 and the timing of the output laser pulses Figure 2 ;

[0036] Figure 5 The present invention provides a signal timing diagram of an angle controller, a first acousto-optic deflector, a second acousto-optic deflector, a third acousto-optic deflector, and a fourth acousto-optic deflector for a wavelength-tunable mid-infrared laser. Figure 3 and the timing of the output laser pulses Figure 3 ;

[0037] 100 - Laser pump source; 101 - First coupling system; 102 - Laser gain crystal; 103 - Second coupling system; 104 - First resonant cavity mirror; 105 - Periodically polarized magnesium oxide-doped lithium niobate crystal (MgO:PPLN crystal); 106 - Second resonant cavity; 107 - Dichroic mirror;

[0038] 1-First resonant cavity mirror; 2-Laser gain crystal; 3-Pump source; 4-Polarizer; 5-Acousto-optic Q-switched crystal; 6-Acousto-optic driver; 7-Signal generator; 8-Ethernet assembly; 9-Angle controller; 10-Second resonant cavity mirror; 11-Coupled module; 12-First acousto-optic deflector; 13-Control module; 14-Second acousto-optic deflector; 15-Third resonant cavity mirror; 16-Nonlinear crystal; 17-Temperature control module; 18-Fourth resonant cavity mirror; 19-Third acousto-optic deflector; 20-Fourth acousto-optic deflector. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Furthermore, the technical features involved in the various embodiments described below can be combined with each other as long as they do not conflict with each other.

[0040] It should be noted that, in the description of the embodiments of the present invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, or circuit that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, or circuit. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, or circuit that includes said element.

[0041] The present invention provides a wavelength-tunable mid-infrared laser, comprising an all-solid-state multi-wavelength laser, a coupling module, a first acousto-optic deflection component, an optical parametric oscillator, and a second acousto-optic deflection component arranged sequentially along the optical transmission direction.

[0042] The all-solid-state multi-wavelength laser is used to output short-wave infrared pulsed lasers of various wavelengths, with a wavelength range of 1-2μm. The all-solid-state multi-wavelength laser includes a standard etalon assembly 8, which has a rotation angle and includes one or more standard etalons with different specifications and parameters, for selective output of short-wave infrared pulsed lasers.

[0043] As one embodiment of the present invention, such as Figure 2 As shown, the all-solid-state multi-wavelength laser also includes a first resonant cavity mirror 1, a laser gain crystal 2, a polarizer 4, an acousto-optic Q-switching crystal 5, and a second resonant cavity mirror 10 arranged sequentially along the optical transmission direction; as well as a pump source 3 disposed on the side of the laser gain crystal, an acousto-optic driver 6 connected to the acousto-optic Q-switching crystal 5, and a signal generator 7 connected to the acousto-optic driver 6.

[0044] It should be noted that the first resonant cavity mirror 1 serves as a reflector of the resonant cavity to ensure the laser gain effect; the laser gain crystal 2 is doped with rare earth ions and has two or more wavelength emission cross sections, used to absorb the laser energy from the pump source 3 and output short-wave infrared pulsed laser; the pump source 3 is used to output near-infrared pulsed laser and provide pumping laser energy to the laser gain crystal 2; the polarizer 4 is used to control the polarization characteristics of the resonant cavity formed in the pump source 3 to ensure that the output laser is polarized laser; the acousto-optic Q-switching crystal 5 is used to generate controllable specific losses in the resonant cavity to ensure complete shutdown of the resonant cavity; the acousto-optic driver 6 is used to receive the pulse signal generated by the signal generator 7 and generate a corresponding radio frequency signal to realize the driving control of the acousto-optic Q-switching crystal 5; the signal generator 7 is used to generate pulse signals; the second resonant cavity mirror 10 serves as the output mirror of the resonant cavity and is coated with a partially reflective film that matches the emission peak wavelength of the laser gain crystal 2 to ensure the resonant gain of the laser.

[0045] Furthermore, the etalon assembly 8 is disposed between the acousto-optic Q-switched crystal 5 and the second resonant cavity mirror 10, and includes one or more etalons with different specifications and parameters for selectively outputting short-wave infrared pulsed laser within the cavity.

[0046] As an embodiment of the present invention, the mid-infrared laser further includes an angle rotator 9 for controlling the rotation angle of the etalon assembly 8. It should be noted that the angle controller is a high-precision electronically controlled angle controller, capable of controlling the rotation of one or more etalons by different angles.

[0047] Furthermore, the standard fixture assembly 8 is positioned above the angle rotator 9; more specifically, the standard fixture assembly 8 comprises only one standard fixture with a thickness of 1 mm, positioned above the angle rotator 9.

[0048] The coupling module 11 is used to shape the short-wave infrared pulse laser beam. As an embodiment of the present invention, the coupling module 11 includes a negative lens and a positive lens to reduce the output short-wave infrared pulse laser beam and collimate it for output.

[0049] The first acousto-optic deflection component is used to change the transmission direction of the short-wave infrared pulsed laser and inject it into the optical parametric oscillator.

[0050] In other words, the first acousto-optic deflection component deflects the received short-wave infrared pulse lasers of different wavelengths, so that the short-wave infrared pulse lasers of different wavelengths are injected into the different polarization periods corresponding to the nonlinear crystal 16 in the optical parametric oscillator. As an embodiment of the present invention, the first acousto-optic deflection component includes a first acousto-optic deflector 12 and a second acousto-optic deflector 14 that are light-transmitting in the near-infrared band and arranged sequentially along the light transmission direction.

[0051] An optical parametric oscillator is used to absorb short-wave infrared pulsed laser light, generate optical parametric oscillations, and output mid-infrared pulsed laser light of various wavelengths.

[0052] As an embodiment of the present invention, the optical parametric oscillator includes a third resonant cavity mirror 15, a nonlinear crystal 16, a temperature control module 17, and a fourth resonant cavity mirror 18.

[0053] It should be noted that the third resonant cavity mirror 15 is coated with an antireflection coating covering all wavelengths of the all-solid-state multi-wavelength laser output, a high-reflection coating corresponding to the signal light wavelength, and a high-reflection coating corresponding to the idler light wavelength; the nonlinear crystal 16 is a multi-period MgO:PPLN crystal, with its two light-transmitting surfaces coated with an antireflection coating covering all wavelengths of the all-solid-state multi-wavelength laser output, a high-reflection coating corresponding to the signal light wavelength, and a high-reflection coating corresponding to the idler light wavelength; the temperature control module 17 is used to control the temperature of the nonlinear crystal 16, with a temperature control accuracy of 0.1K; the fourth resonant cavity mirror 18 is coated with a high-reflection coating covering all wavelengths of the all-solid-state multi-wavelength laser output, a high-reflection coating corresponding to the signal light wavelength, and an antireflection coating corresponding to the idler light wavelength.

[0054] The second acousto-optic deflection assembly is used to synchronously deflect the mid-infrared pulsed laser, thereby achieving coaxial output of the mid-infrared pulsed laser with a common aperture. As an embodiment of the present invention, the second acousto-optic deflection assembly includes a third acousto-optic deflector 19 and a fourth acousto-optic deflector 20 that are transmitted in the mid-infrared band and are arranged sequentially along the optical transmission direction.

[0055] As an embodiment of the present invention, the mid-infrared laser further includes a control module 13, which generates corresponding control signals and transmits them simultaneously to the angle rotator 8, the first acousto-optic deflection component and the second acousto-optic deflection component.

[0056] That is, the control module 13 is connected to the angle controller 9 and the first acousto-optic deflector 12, the second acousto-optic deflector 14, the third acousto-optic deflector 19, and the fourth acousto-optic deflector 20, respectively. The control module 13 is used to generate corresponding control signals and transmit the control signals synchronously to the angle controller 9, the first acousto-optic deflector 12, the second acousto-optic deflector 14, the third acousto-optic deflector 19, and the fourth acousto-optic deflector 20, respectively, so as to accurately and synchronously control the angle of the etalon assembly 8 and the sound field frequency on each acousto-optic deflector, so that short-wave infrared pulsed lasers of different wavelengths are injected into the corresponding nonlinear crystal 16 within different polarization periods to form optical parametric oscillations, and finally realize that the mid-infrared pulsed laser wavelength can be switched at high speed, with high repetition frequency, wide spectral range, wavelength can be encoded, and coaxial output with common aperture.

[0057] The mid-infrared laser proposed in this invention, during normal operation, is an all-solid-state multi-wavelength laser that outputs high-repetition-rate pump pulse lasers through acousto-optic Q-switching. By changing the angle of the etalon component 8, it selectively outputs short-wave infrared pulse lasers of different wavelengths. After passing through the first acousto-optic deflection component, different voltages are automatically adjusted based on different wavelengths, thereby causing the short-wave infrared pulse lasers to form different deflection angles. These are then input into different periods corresponding to the nonlinear crystal 16 to form optical parametric oscillations, outputting mid-infrared pulse lasers of different wavelengths. Finally, through the first acousto-optic deflection component, the mid-infrared pulse lasers of different wavelengths achieve coaxial output with the same aperture.

[0058] like Figure 2 As shown, in a preferred embodiment of the present invention, the mid-infrared laser includes, in sequence, a first resonant cavity mirror 1, a laser gain crystal 2, a pump source 3, a polarizer 4, an acousto-optic Q-switched crystal 5, an acousto-optic driver 6, a signal generator 7, an etalon assembly 8, a high-precision electrically controlled angle controller 9, a second resonant cavity mirror 10, a coupling module 11, a first acousto-optic deflector 12, a control module 13, a second acousto-optic deflector 14, a first resonant cavity mirror 15, a nonlinear crystal 16, a temperature control module 17, a second resonant cavity mirror 18, a third acousto-optic deflector 19, and a fourth acousto-optic deflector 20.

[0059] The first resonant cavity mirror 1 is coated with an 800-816nm antireflection film with a transmittance greater than 98%, a 1319nm high reflectivity film with a reflectivity greater than 99%, and a 1064nm high reflectivity film with a reflectivity greater than 99%.

[0060] The laser gain crystal 2 is a neodymium-doped yttrium aluminum garnet crystal, with anti-reflection coatings of 800-816 nm with a transmittance greater than 98% on both sides, an anti-reflection coating of 1319 nm with a transmittance greater than 98%, and an anti-reflection coating of 1064 nm with a transmittance greater than 98%.

[0061] Pump source 3 generates a pump laser with a center wavelength of 808nm.

[0062] Polarizer 4 can be any one of dichroic polarizer, thin film polarizer, reflective polarizer, birefringent polarizer, etc.

[0063] The acousto-optic Q-switched crystal 5 can transmit light in the 1–1.7 μm wavelength range.

[0064] The acousto-optic driver 6 is connected to the acousto-optic Q-switched crystal 5.

[0065] The signal generator 7 and the audio-visual driver 6 are connected.

[0066] The standard fixture assembly 8 includes a standard fixture with a thickness of 1 mm, which is placed on the angle controller 9.

[0067] Angle controller 9 is a high-precision electronically controlled angle controller. This high-precision electronically controlled angle controller is used to rapidly rotate the angle of the etalon assembly, enabling rapid switching between 1064nm and 1319nm wavelength lasers.

[0068] The second resonant cavity mirror 10 has a high-reflectivity film for 800-816nm laser with a reflectivity greater than 99% on both sides, a partial-reflectivity film for 1064nm laser with a transmittance of 15%, and a partial-reflectivity film for 1319nm laser with a transmittance of 10%.

[0069] The coupling module 11 includes a negative lens and a positive lens, which collimate and output the short-wave infrared pulse laser beam.

[0070] The first acousto-optic deflector 12 and the second acousto-optic deflector 14 both transmit light in the 1-2.1 μm band, and are used to synchronously deflect the direction of the output 1064 nm / 1319 nm wavelength laser, so that the laser after each deflection can be injected into the corresponding different polarization period in the nonlinear crystal (16).

[0071] Both the third acousto-optic deflector 19 and the fourth acousto-optic deflector 20 transmit light in the 3.1–4.9 μm band, and are used to synchronously deflect mid-infrared pulsed lasers of different wavelengths output by the optical parametric oscillator to achieve coaxial output with the same aperture.

[0072] The control module 13 generates corresponding control signals and synchronously loads the electrical signals onto the angle controller 9, the first acoustic-optical deflector 12, the second acoustic-optical deflector 14, the third acoustic-optical deflector 19, and the fourth acoustic-optical deflector 20.

[0073] The third resonant cavity mirror 15 is coated with anti-reflection films of 1064nm and 1319nm with a transmittance greater than 98%, a high-reflection film of 1.3-2.1μm with a reflectance greater than 99%, and a high-reflection film of 3-5μm with a reflectance greater than 99% on one side.

[0074] The nonlinear crystal 16 is a multi-period MgO:PPLN crystal with polarization periods of 29 μm, 30 μm and 31 μm, respectively; the light-transmitting surface is coated with an anti-reflection film of 1.0 to 2.1 μm with a transmittance greater than 98%, and an anti-reflection film of 3 to 5 μm with a transmittance greater than 98%.

[0075] The temperature is set to 330K in temperature control module 17.

[0076] The fourth resonant cavity mirror 18 is coated with a high-reflectivity film of 1064nm and 1319nm with a reflectivity greater than 99%, a high-reflectivity film of 1.3 to 2.1μm with a reflectivity greater than 99%, and an anti-reflection film of 3 to 5μm with a transmittance greater than 98%.

[0077] When the mid-infrared laser is working, the pump source 3 emits light, which excites the laser gain crystal 2 to generate stimulated emission, outputting lasers with center wavelengths of 1064nm and 1319nm. The signal generator 7 loads a pulse signal onto the acousto-optic driver 6, which in turn loads a radio frequency signal onto the acousto-optic Q-switched crystal 5, causing specific losses within the cavity, thereby generating high-repetition-rate pulsed lasers with center wavelengths of 1064nm and 1319nm.

[0078] When the control module 13 sends out different control signals, the signals synchronously loaded onto the first acoustic-optical deflector 12, the second acoustic-optical deflector 14, the third acoustic-optical deflector 19, and the fourth acoustic-optical deflector 20 will also be different, and thus the corresponding controls will also be different.

[0079] like Figure 3 As shown, when the control module 13 sends the first control signal, the angle controller 9 receives the first control signal and controls the rotation angle of the etalon assembly 8 to increase the intracavity loss of the 1064nm laser, so that only 1319nm pulsed laser is output.

[0080] The beam is then compressed and collimated by coupling module 11.

[0081] At the same time, the internal drives of the first acousto-optic deflector 12 and the second acousto-optic deflector 14 synchronously receive the corresponding first control signals. The internal drives generate radio frequency signals of corresponding frequencies: v11, v12, v13, v14, v15, and v16, respectively, and convert them into ultrasonic waves of specific frequencies. These ultrasonic waves are then loaded onto the internal crystals of the first acousto-optic deflector 12 and the second acousto-optic deflector 14, causing the 1319nm pulsed laser to deflect at different angles under the corresponding radio frequency signals.

[0082] Subsequently, 1319nm pulsed lasers deflected at different angles were injected into different polarization periods corresponding to the MgO:PPLN crystal 14, generating optical parametric oscillations, thereby outputting mid-infrared pulsed lasers with wavelengths of 4.78μm, 4.51μm, and 4.27μm.

[0083] Simultaneously, the internal drives of the third acousto-optic deflector 19 and the fourth acousto-optic deflector 20 synchronously receive the corresponding first control signals. The internal drives generate corresponding frequency radio frequency signals: v17, v18, v19, v20, v21, and v22, respectively, and convert them into ultrasonic waves of specific frequencies. These ultrasonic waves are then loaded onto the internal crystals of the third acousto-optic deflector 19 and the fourth acousto-optic deflector 20, respectively, causing mid-infrared lasers with wavelengths of 4.78μm, 4.51μm, and 4.27μm to be deflected. Ultimately, a mid-infrared pulsed laser with high-speed wavelength switching and coaxial output with a common aperture is achieved.

[0084] like Figure 4As shown, when the control module 13 sends out the second control signal, the angle controller 9 receives the second control signal and controls the rotation angle of the etalon assembly 8 to increase the intracavity loss of the 1319nm laser, so that only 1064nm pulsed laser output is produced.

[0085] The beam is then compressed and collimated by coupling module 11.

[0086] At the same time, the internal drives of the first acousto-optic deflector 12 and the second acousto-optic deflector 14 synchronously receive the corresponding second control signals. The internal drives generate radio frequency signals of corresponding frequencies: v21, v22, v23, v24, v25, and v26, respectively, and convert them into ultrasonic waves of specific frequencies. These ultrasonic waves are then loaded onto the internal crystals of the first acousto-optic deflector 12 and the second acousto-optic deflector 14, causing the 1064nm pulsed laser to deflect at different angles under the corresponding radio frequency signals.

[0087] Subsequently, 1064nm pulsed lasers deflected at different angles were injected into different polarization periods corresponding to the MgO:PPLN crystal 14, generating optical parametric oscillations, thereby outputting mid-infrared pulsed lasers with wavelengths of 3.97μm, 3.62μm, and 3.20μm.

[0088] Simultaneously, the internal drives of the third acousto-optic deflector 19 and the fourth acousto-optic deflector 20 synchronously receive the corresponding second control signals. The internal drives generate corresponding frequency radio frequency signals: v27, v28, v29, v30, v31, and v32, respectively, and convert them into ultrasonic waves of specific frequencies. These ultrasonic waves are then loaded onto the internal crystals of the third acousto-optic deflector 19 and the fourth acousto-optic deflector 20, respectively, causing mid-infrared lasers with wavelengths of 3.97μm, 3.62μm, and 3.20μm to be deflected. Ultimately, a mid-infrared pulsed laser with high-speed wavelength switching and coaxial output with a common aperture is achieved.

[0089] like Figure 5 As shown, by performing timing encoding control on the first and second control signals and repeating the above working principle, mid-infrared pulsed laser output with wavelength encoding of 3.97μm, 3.62μm, 3.20μm, 4.78μm, 4.51μm, and 4.27μm can be achieved. This working principle is the same as the one described above, and will not be repeated here.

[0090] In summary, the mid-infrared laser proposed in this invention not only eliminates the need for a high-precision temperature control module and minimizes damage to the laser crystal, but also possesses advantages such as a wide mid-infrared spectral coverage, fast wavelength switching speed, high repetition frequency, wavelength encoding capability, and coaxial output with common aperture, greatly expanding the practicality of mid-infrared lasers.

[0091] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0092] It should be understood that the embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0093] The foregoing description is merely an exemplary embodiment of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Those skilled in the art will readily conceive of embodiments of this disclosure upon considering the specification and practicing the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described herein. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

[0094] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wavelength-tunable mid-infrared laser, characterized in that, Including those arranged sequentially along the optical transmission direction: An all-solid-state multi-wavelength laser is used to output short-wave infrared pulsed lasers of various wavelengths; wherein, the all-solid-state multi-wavelength laser includes an etalon assembly with a rotation angle for selectively outputting the short-wave infrared pulsed lasers; A coupling module is used to perform beam shaping on the short-wave infrared pulsed laser. The first acousto-optic deflection component is used to change the transmission direction of the short-wave infrared pulse laser and inject it into the optical parametric oscillator; the first acousto-optic deflection component deflects the received short-wave infrared pulse lasers of different wavelengths, so that the short-wave infrared pulse lasers of different wavelengths are injected into the different polarization periods corresponding to the nonlinear crystal in the optical parametric oscillator; the nonlinear crystal is a multi-period MgO:PPLN crystal. An optical parametric oscillator is used to absorb the short-wave infrared pulsed laser and output mid-infrared pulsed lasers of various wavelengths; the optical parametric oscillator includes a third resonant cavity mirror, a nonlinear crystal, a temperature control module, and a fourth resonant cavity mirror; The second acousto-optic deflection component is used to synchronously deflect the mid-infrared pulsed laser to achieve coaxial output of the mid-infrared pulsed laser with a common aperture. The control module generates corresponding control signals and transmits them simultaneously to the angle rotator, the first acousto-optic deflection component, and the second acousto-optic deflection component. This enables precise synchronous control of the angle of the etalon component and the sound field frequency on each acousto-optic deflector, allowing short-wave infrared pulsed lasers of different wavelengths to be injected into different polarization periods corresponding to the nonlinear crystal, thus forming optical parametric oscillations.

2. A wavelength-tunable mid-infrared laser as described in claim 1, characterized in that, The all-solid-state multi-wavelength laser also includes, in sequence along the optical transmission direction: a first resonant cavity mirror, a laser gain crystal, a polarizer, an acousto-optic Q-switching crystal, and a second resonant cavity mirror; In addition, a pump source disposed on the side of the laser gain crystal, an acousto-optic driver connected to the acousto-optic Q-switched crystal, and a signal generator connected to the acousto-optic driver.

3. A wavelength-tunable mid-infrared laser as described in claim 2, characterized in that, The etalon assembly is disposed between the acousto-optic Q-switched crystal and the second resonant cavity mirror.

4. A wavelength-tunable mid-infrared laser as described in claim 1, characterized in that, The standard fixture assembly includes one or more standard fixtures with different specifications and parameters.

5. A wavelength-tunable mid-infrared laser as described in any one of claims 1 to 4, characterized in that, The first acousto-optic deflection component includes a first acousto-optic deflector and a second acousto-optic deflector that are light-transmitting in the near-infrared band and are arranged sequentially along the light transmission direction. The second acousto-optic deflection component includes a third acousto-optic deflector and a fourth acousto-optic deflector that are light-transmitting in the mid-infrared band and are arranged sequentially along the light transmission direction.

6. A wavelength-tunable mid-infrared laser as described in any one of claims 1 to 4, characterized in that, The mid-infrared laser also includes an angle rotator for controlling the rotation angle of the etalon assembly.

7. A wavelength-tunable mid-infrared laser as described in claim 6, characterized in that, The standard etalon assembly is positioned above the angle rotator.

8. A wavelength-tunable mid-infrared laser as described in claim 1, characterized in that, The coupling module includes a negative lens and a positive lens.

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