Macroenergy optical parametric oscillator and mid-far infrared optical parametric oscillator

Abstract

The embodiment of the invention provides a large-energy optical parametric oscillator, in particular to a middle and far infrared optical parametric oscillator. The large-energy optical parametric oscillator comprises a pump light emitting module, a frequency conversion module, a spectrum beam combining module and an output coupling mirror which are sequentially arranged along an optical path, wherein the pump light emitting module is used for emitting multiple beams of pump light with preset wavelengths to the frequency conversion module; the frequency conversion module comprises a plurality of optical parametric frequency conversion modules, and the optical parametric frequency conversion modules are used for converting the received pump light into parametric light; the spectrum beam combination module is used for performing spectrum beam combination on the multiple beams of parametric light generated by the frequency conversion module to form combined light and transmitting the combined light to the output coupling mirror; and the output coupling mirror is used for reflecting one part of the combined light back to each optical parametric frequency conversion module to form feedback oscillation and outputting the other part of the combined light. According to the macro-energy optical parametric oscillator, macro-energy parametric light with high light beam quality is output by utilizing a simple optical device combination.

Description

Technical Field

[0001] The present invention relates to the technical field of high-energy optical parametric oscillators, and in particular to a high-energy optical parametric oscillator and a mid- and far-infrared optical parametric oscillator. Background Art

[0002] An optical parametric oscillator is a device that uses nonlinear optical effects to generate laser light of a specific wavelength, while a high-energy optical parametric oscillator is a device that can generate higher energy output (such as providing high-brightness laser light). High-energy optical parametric oscillators have important applications in materials science, spectroscopy, medicine, and military.

[0003] The existing high-energy parametric light technologies mainly include Optical Parametric Oscillator (OPO) and Optical Parametric Amplifier (OPA). Among them, the output energy of Optical Parametric Oscillator (OPO) is limited by crystal gain and device damage threshold. To achieve high-energy parametric light output, the Optical Parametric Amplifier (OPA) requires not only a high-energy fundamental frequency pump light, but also a seed signal light with high beam quality, and the two beams need to be matched in time and space, which increases the complexity of the entire experimental device to a certain extent. Summary of the invention

[0004] The present invention provides a high-energy optical parametric oscillator, especially a mid-to-far infrared optical parametric oscillator, to solve the defect that the optical parametric oscillator in the prior art cannot output high-energy parametric light, and realizes the output of high-energy parametric light with high beam quality by combining simple optical devices.

[0005] In a first aspect, an embodiment of the present invention provides a high-energy optical parametric oscillator, comprising: a pump light transmitting module, a frequency conversion module, a spectrum combining module and an output coupling mirror arranged in sequence along an optical path; wherein: The pump light transmitting module is used to transmit multiple beams of pump light of preset wavelength to the frequency conversion module; wherein the wavelengths of the multiple beams of pump light are the same; The frequency conversion module comprises a plurality of optical parametric frequency conversion modules, and the optical parametric frequency conversion modules are used to convert the received pump light into parametric light; wherein the multiple beams of pump light emitted by the pump light transmitting module are input into the plurality of optical parametric frequency conversion modules one by one, and the wavelengths of the parametric light output by different optical parametric frequency conversion modules are different; The spectral beam combining module is used to perform spectral beam combining on the multiple parametric light beams output by the frequency conversion module to form a combined light beam, and transmit the combined light beam to the output coupling mirror; The output coupling mirror is used to reflect a part of the combined light beam back to each of the optical parametric frequency conversion modules to form feedback oscillation, and output the other part of the combined light beam.

[0006] In a possible implementation, the optical parametric frequency conversion module includes an optical parametric high reflector and an optical parametric frequency conversion crystal sequentially arranged along the optical path; The frequency conversion module, the spectrum combining module and the output coupling mirror together constitute an optical parametric oscillator cavity.

[0007] In a possible implementation, the optical parametric high reflector of the optical parametric oscillator cavity is coated with a first anti-reflection film and a high reflective film, wherein the transmittance of the first anti-reflection film to the pump light is greater than 95%, and the wavelength of the high reflective film covers the wavelength of the parametric light.

[0008] In a possible embodiment, the spectral beam combining module includes an optical transformation element and a diffractive optical element arranged in sequence along the optical path, wherein the optical transformation element is used to transmit multiple beams of the parametric light to the same position of the diffractive optical element; and the diffractive optical element is used to perform spectral beam combining on the multiple beams of the parametric light and transmit the obtained combined light to the output coupling mirror.

[0009] In a possible implementation, the optical transformation element is a lens, the diffractive optical element is a grating, and the diffractive optical element is located at a focal plane of the optical transformation element.

[0010] In a possible implementation, according to a preset incident angle formula, the parametric light is incident on the diffractive optical element at a preset incident angle, wherein the preset incident angle calculation formula is as follows: Where λ is the wavelength of the parametric light band, d is the groove spacing of the diffractive optical element, α is the incident angle, and β is the diffraction angle.

[0011] In a possible implementation, the output coupling mirror is coated with a second anti-reflection film, and the transmittance of the second anti-reflection film to one of the signal light and the idler light is greater than 95%, and the transmittance to the other light is 10% to 80%.

[0012] In a possible implementation, the pump light transmitting module includes a plurality of pump laser transmitters corresponding one-to-one to the optical parametric frequency conversion modules.

[0013] In a possible implementation manner, the multiple optical parametric oscillator cavities of the optical parametric frequency conversion module are arranged in a straight line with equal intervals.

[0014] In a second aspect, an embodiment of the present invention provides a mid- and far-infrared optical parametric oscillator, including the above first aspect and / or various possible implementations of the first aspect.

[0015] The high-energy optical parametric oscillator provided by the present invention comprises: a pump light transmitting module, a frequency conversion module, a spectrum combining module and an output coupling mirror which are sequentially arranged along an optical path, wherein the pump light transmitting module transmits a plurality of pump lights of preset wavelengths to the frequency conversion module; the frequency conversion module comprises a plurality of optical parametric frequency conversion modules, and the optical parametric frequency conversion module is used to convert the received pump lights into parametric lights; wherein the plurality of pump lights emitted by the pump light transmitting module are input into the plurality of optical parametric frequency conversion modules one by one, the wavelengths of the plurality of pump lights are the same, and the wavelengths of the parametric lights output by different optical parametric oscillator cavities are different; the spectrum combining module is used to perform spectrum combining on the plurality of parametric lights generated by the frequency conversion module, and transmit the obtained combined light to the output coupling mirror; the output coupling mirror is used to reflect a part of the combined light back to each optical parametric frequency conversion module along the original path to form feedback oscillation, and output the other part of the combined light. It can be seen that the technical solution provided by the present invention outputs multiple beams of parametric light of different wavelengths through multiple optical parametric frequency conversion modules, and uses a spectral beam combining module to combine multiple beams of parametric light of different wavelengths into a combined beam of light, so the beam quality of the parametric light after spectral beam combining is basically the same as the beam quality of a single beam of parametric light (i.e., the parametric light outputted separately by each optical parametric frequency conversion module). The combined parametric light (combined light) is output through an output coupling mirror, and the combined light contains the beam energy of multiple single beams of parametric light, so that the energy can be effectively concentrated and output, that is, the output combined parametric light has greater energy than that of a single beam of parametric light. Part of the combined light (combined parametric light) is returned to the optical parametric frequency conversion module, so that the optical parametric frequency conversion module can start and continue to oscillate at a specific wavelength. At the same time, the high-energy optical parametric oscillator adopts a modular structure. This modular structure makes it easy to inspect, repair or replace a single module when the oscillator device fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is one of the optical path schematic diagrams of the high-energy optical parametric oscillator provided by the present invention; Figure 2 This is the second optical path schematic diagram of the high-energy optical parametric oscillator provided by the present invention; Figure 3This is the third optical path schematic diagram of the high-energy optical parametric oscillator provided by the present invention; Figure 4 This is the fourth optical path schematic diagram of the high-energy optical parametric oscillator provided by the present invention; Reference numerals: 1: Pump light emission module; 11: Pump laser transmitter; 2: Frequency conversion module; 21: Optical parametric frequency conversion module; 211: Optical parametric high reflector; 212: Optical parametric frequency conversion crystal; 3: Spectral beam combining module; 31: Optical transformation element; 32: Diffraction optical element; 4: Output coupling mirror. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Optical parametric oscillators (OPOs) and optical parametric amplifiers (OPAs) are devices based on nonlinear optical effects. They use specific nonlinear media (such as certain types of crystals) to achieve frequency conversion of light waves. Optical parametric oscillators (OPOs) use nonlinear crystals as working media to convert laser wavelengths to other wavelengths through second-order nonlinear polarization (three-wave interaction). They have the advantages of flexible output wavelength conversion, wide tuning range, good beam quality, and simple and compact structure. However, in optical parametric oscillators (OPOs), crystals are a very critical component. It is located on the propagation path of light and is the core element for realizing the optical parametric oscillation process. The gain characteristics of the crystal determine the energy conversion efficiency from pump light to signal light and idler light. The gain of the crystal is limited. During the optical parametric oscillation process, when the energy of the signal light and idler light increases to a certain extent, the output energy reaches a limited state because the crystal gain can no longer support further energy conversion. At the same time, as the energy of the pump light increases, the light intensity inside the crystal will also increase. When the light intensity reaches the damage threshold of the crystal, the crystal will be damaged (such as cracks), so the pump light energy cannot be increased indefinitely, thus limiting the energy output by the optical parametric oscillator. The working principle of the optical parametric amplifier (OPA) is to use the parametric amplification process in the nonlinear medium. When a beam of high-intensity pump light and a beam of weaker signal light propagate in the same direction through the nonlinear medium, the energy of the pump light is partially transferred to the signal light, resulting in an increase in the amplitude of the signal light, and at the same time, a new light wave with a frequency that is the sum or difference of the pump light is generated, namely, the idler light. Therefore, the optical parametric amplifier not only requires a high-energy fundamental frequency pump light to achieve high-energy parametric light output, but also requires a seed signal light with high beam quality, and the two beams need to be matched in time and space, which increases the complexity of the entire device to a certain extent.

[0020] In combination with the above content, it can be seen that in the prior art, there is a technical problem that a parametric optical oscillator with a simple structure cannot output high-energy parametric light.

[0021] The high-energy optical parametric oscillator provided by the present invention solves the technical problem that a parametric optical oscillator with a simple structure cannot output high-energy parametric light by means of a technical means of spectrally combining multiple beams of parametric light into one beam of light for output.

[0022] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0023] Figure 1 This is one of the optical path schematic diagrams of the high-energy optical parametric oscillator provided by the present invention, such as Figure 1 As shown, the high-energy optical parametric oscillator includes: a pump light emission module 1, a frequency conversion module 2, a spectrum combining module 3 and an output coupling mirror 4 which are sequentially arranged along the optical path.

[0024] The pump light transmitting module 1 is used to transmit multiple beams of pump light with preset wavelengths to the frequency conversion module 2. The wavelengths of the multiple beams of pump light are the same.

[0025] The pump light may be a baseband pump light of a preset wavelength required to generate optical parametric frequency conversion.

[0026] Exemplarily, the fundamental frequency pump light may be continuous light, quasi-continuous light or pulsed light, wherein the pulse width of the pulsed light may include millisecond, microsecond, nanosecond, picosecond, or femtosecond level pulses. The preset wavelength of the fundamental frequency pump light may be 532nm, 1064nm, or 2100nm, etc.

[0027] Exemplarily, the preset wavelength of the fundamental frequency pump light may be 532 nm, 1064 nm, or 2100 nm.

[0028] The frequency conversion module 2 includes a plurality of optical parametric frequency conversion modules 21, and the optical parametric frequency conversion modules 21 are used to convert the received pump light into parametric light. The multiple pump light beams emitted by the pump light transmitting module 1 are input into the plurality of optical parametric frequency conversion modules 21 one by one, and the wavelengths of the parametric light output by different optical parametric frequency conversion modules 21 are different.

[0029] Among them, the number of beams of baseband pump light emitted by the pump light transmitting module 1 is equivalent to the number of frequency conversion modules 2. One beam of baseband pump light corresponds to the input of one optical parametric frequency conversion module 21, and outputs one beam of parametric light. The optical parametric frequency conversion module 21 can convert a baseband pump light of one frequency into a coherent output of signal light and idler light, and the sum of the frequencies of the two is equal to the frequency of the pump light. The signal light wavelength λs and the idler light wavelength λi output by an optical parametric frequency conversion module 21 satisfy 1 / λp=1⁄λs+1 / λi, where λp is the pump light wavelength. Different optical parametric frequency conversion modules 21 output different wavelengths of signal light and different wavelengths of idler light. However, the wavelengths of parametric light (signal light and idler light) output by different optical parametric frequency conversion modules 21 belong to the same wavelength band.

[0030] The spectral beam combining module 3 is used for spectrally combining the multiple beams of parametric light generated by the frequency conversion module 2 to form a combined light beam, and transmitting the combined light beam to the output coupling mirror 4 .

[0031] It is understandable that spectral beam combining is a beam synthesis technology that combines multiple laser beams with a certain spectral interval into one beam to increase the output power (energy) while maintaining the beam quality as much as possible. The spectral beam combining module 3 can use the different offsets of components of different wavelengths in multiple beams of parametric light according to the principle of spectral beam combining, and finally make these components propagate in the same direction to achieve spectral beam combining.

[0032] The spectral beam combining module 3 spectrally combines the parametric lights of different wavelengths generated by the different optical parametric frequency conversion modules 21 of the frequency conversion module 2 into a combined beam of light (parametric light). The beam quality of the combined beam is basically the same as the beam quality of the single parametric light output by each optical parametric frequency conversion module 21. However, the energy of the combined beam is the accumulation of multiple single parametric lights, thereby achieving the output of high-energy parametric light while maintaining the beam quality of the final output parametric light. At the same time, spectral beam combining does not require the synthesized light beam to have temporal coherence, which helps to achieve stable operation at high power levels.

[0033] The output coupling mirror 4 is used to reflect a part of the combined light beam back to each optical parametric frequency conversion module 21 along the original path, and output the other part of the combined light beam.

[0034] It is understandable that returning part of the parametric light to the optical parametric frequency conversion module 21 is to establish and maintain feedback of the oscillation process, which is crucial for the startup and stable operation of the oscillation cavity. The optical parametric frequency conversion module 21 relies on the parametric process in the nonlinear crystal to convert the pump light into signal light and idler light. In this process, the energy of the pump light is divided into two parts, forming signal light and idler light, which are usually interdependent and need to meet the conditions of energy conservation and momentum conservation. Returning part of the parametric light to the nonlinear crystal can ensure that a stable three-wave mixing state can be maintained between the pump light, signal light and idler light. In this way, the efficiency of parametric conversion can be maximized, so that the optical parametric frequency conversion module can start and continue to oscillate at a specific wavelength. Without proper feedback, even if the nonlinear crystal and pump light conditions meet the requirements, oscillation is difficult to establish because the initial intensity of the signal and idler light is not enough to self-enhance through the nonlinear process. The returned parametric light can also help stabilize the oscillation process and reduce frequency drift caused by fluctuations in pump light intensity or temperature changes.

[0035] The high-energy optical parametric oscillator provided in this embodiment can relatively flexibly change the wavelength of the output parametric light by adjusting the relevant parameters of the optical parametric frequency conversion module 21. Multiple optical parametric frequency conversion modules 21 can generate parametric light of different wavelengths, and combine the light through the spectrum combining module 3, so that the energy can be effectively gathered and output. In some applications that require high-energy lasers, such as laser cutting of thick metal materials, high energy output can improve cutting speed and quality. Finally, the output coupling mirror 4 reflects a part of the combined light back to each optical parametric frequency conversion module 21 along the original path. This energy feedback mechanism helps to increase the light energy density in the cavity. During the optical parametric oscillation process, higher energy density can improve the conversion efficiency, so that more pump light energy is converted into parametric light energy, thereby further improving the overall energy output. At the same time, the high-energy optical parametric oscillator adopts a modular structure. This modular structure makes it easy to inspect, repair or replace a single module when the oscillator device fails. At the same time, if it is necessary to upgrade the equipment, for example, to increase the power of the pump light emission module 1 or to improve the performance of the frequency conversion module 2, the corresponding modules can be replaced or improved more conveniently.

[0036] Figure 2 This is the second optical path schematic diagram of the high energy optical parametric oscillator provided by the present invention, such as Figure 2 As shown, the high energy optical parametric oscillator comprises: a pump light emission module 1, a frequency conversion module 2, a spectrum combining module 3 and an output coupling mirror 4 which are sequentially arranged along the optical path. The functions of the above optical devices are similar to those of the above Figure 1 The functions of the optical devices are the same and will not be described again here.

[0037] In this embodiment, the optical parametric frequency conversion module 21 includes an optical parametric high reflector 211 and an optical parametric frequency conversion crystal 212 arranged in sequence along the optical path. It should be noted that the frequency conversion module 2 (including multiple optical parametric frequency conversion modules 21), the spectrum combining module 3 and the output coupling mirror 4 together constitute an optical parametric oscillator cavity.

[0038] Among them, the optical parametric high reflector 211 is a reflector with very high optical reflectivity within a specific wavelength or wavelength range, such as a plane mirror. The optical parametric frequency conversion crystal 212 is a place to realize the frequency conversion of pump light to signal light and idle light. The signal light and idle light can be realized within a specific wavelength range by adjusting the angle of the crystal or using different types of crystals. Here, the optical parametric high reflector 211 has an extremely high reflectivity for the specific wavelengths of the signal light and idle light generated by the optical parametric frequency conversion module 21, while allowing the wavelength of the pump light to pass. In this way, it can be ensured that the signal light and idle light propagate back and forth in the optical parametric frequency conversion crystal 212, and accumulate energy through the parametric amplification process until a sufficient threshold is reached to achieve self-oscillation.

[0039] In a possible implementation, the optical parametric high reflector 211 of the optical parametric frequency conversion module 21 is coated with a first anti-reflection film and a high reflective film, wherein the transmittance of the first anti-reflection film to the pump light (baseband pump light) is greater than 95%, and the wavelength of the high reflective film covers the wavelength of the parametric light.

[0040] It can be understood that the wavelength of the high-reflection film on the optical parametric high-reflection mirror 211 covers the wavelength of the parametric light, that is, the wavelength of the high-reflection film is equivalent to the wavelength of the signal light and the idler light output by the optical parametric high-reflection mirror 211, and the reflectivity of the high-reflection film is greater than 99.8%.

[0041] In a possible implementation, the optical parametric high reflector 211 may be a plane mirror. The optical parametric frequency conversion crystal 212 includes but is not limited to a lithium triborate (LBO) crystal, a potassium titanyl phosphate (KTP) crystal, a periodically poled lithium niobate (PPLN) crystal, and a zinc germanium phosphide (ZGP) crystal.

[0042] For example, Figure 2 As shown, the frequency conversion module 2 of the high-energy optical parametric oscillator can be provided with two optical parametric frequency conversion modules 21. The high-energy optical parametric oscillator includes: a pump light transmitting module 1 that emits two beams of fundamental frequency pump light, the fundamental frequency pump light having a repetition frequency of 10 kHz, a pulse width of 52 ns, and a wavelength of 2.09µm. The optical parametric high-reflection mirrors 211 of the two optical parametric frequency conversion modules 21 are both plane mirrors, the surfaces of which are coated with a 2.09µm first anti-reflection film and a high-reflection film, and the wavelengths of the two beams of parametric light output from the two optical parametric frequency conversion modules 21 are different, but are within the range of 6.45µm-6.47µm. The wavelengths of the high-reflection films coated on the surfaces of the corresponding two plane mirrors are different, and the wavelengths of the high-reflection films coated on the surfaces of the two plane mirrors are respectively consistent with the wavelengths of the idler light output by the optical parametric frequency conversion module 21. The two beams of parametric light are spectrally combined into one beam of light by the subsequent spectral combining module 3 and then transmitted to the output coupling mirror 4, which returns part of the combined light to the optical parametric frequency conversion module 21 along the original path. In this way, the two optical parametric high-reflection mirrors 211 cooperate with the output coupling mirror 4 to complete the oscillation of the parametric light.

[0043] Figure 3 This is the third optical path schematic diagram of the high energy optical parametric oscillator provided by the present invention, such as Figure 3 As shown, the high energy optical parametric oscillator comprises: a pump light emission module 1, a frequency conversion module 2, a spectrum combining module 3 and an output coupling mirror 4 which are sequentially arranged along the optical path. The functions of the above optical devices are similar to those of the above Figure 1The functions of the optical devices are the same and will not be described again here.

[0044] In this embodiment, the spectral beam combining module 3 includes an optical transformation element 31 and a diffraction optical element 32 arranged in sequence along the optical path, wherein the optical transformation element 31 is used to transmit multiple beams of parametric light to the same position of the diffraction optical element 32; the diffraction optical element 32 is used to perform spectral beam combining on the multiple beams of parametric light and transmit the obtained combined light to the output coupling mirror 4.

[0045] Exemplarily, the optical transformation element 31 is a lens, the diffractive optical element 32 is a grating, and the diffractive optical element 32 is located at the focal plane of the optical transformation element 31 .

[0046] It is understandable that the optical transformation element 31 can be a lens for light convergence such as a ball lens or a ball lens group. The diffractive optical element 32 is a grating that can effectively merge light beams of multiple wavelengths into a high-quality light beam, such as a multilayer dielectric grating or a volume Bragg grating with a line density higher than 1000 lines / mm. The lens can focus multiple beams of parametric light so that these beams converge at the same position of the diffractive optical element 32. This helps to concentrate the scattered light beams into a smaller area, making it convenient for the diffractive optical element 32 to perform spectral beam combining on these light beams. The lens can also adjust the shape of the light beam to a certain extent, so that the light beam entering the diffractive optical element 32 has a suitable spot size and shape to meet the requirements of the diffractive optical element 32 for spectral beam combining. The grating can recombine the light of different wavelengths in multiple beams of parametric light according to the principle that light of different wavelengths has different diffraction angles, so that they are spatially synthesized into a beam of light. The grating can effectively separate and recombine light of different wavelengths, thereby realizing the function of spectral beam combining, and finally synthesize multiple beams of parametric light into a beam of light to be emitted to the surface of the output mirror. Parametric light incident at different angles will converge to the focal plane after being focused by the lens. Placing the diffractive optical element 32 at the focal plane can accurately process these light beams and accurately combine them in space and spectrum, which helps to improve the efficiency and accuracy of beam combination and reduce the divergence and energy loss of the light beam.

[0047] In a possible implementation, the parametric light includes signal light and idler light, the output coupling mirror is coated with a second anti-reflection film, and the second anti-reflection film has a transmittance greater than 95% for one of the signal light and the idler light and a transmittance of 10% to 80% for the other.

[0048] It can be understood that the second anti-reflection film on the output coupling mirror partially transmits one of the signal light and the idler light, that is, the non-transmitted part of the parametric light is returned to the optical parametric conversion module 21. The second anti-reflection film can allow the selected transmitted signal light or idler light to be transmitted as much as possible, and the return ratio of the returned parametric light is set by adjusting the transmittance of the second anti-reflection film.

[0049] In a possible implementation, according to a preset incident angle formula, the parametric light is incident on the diffractive optical element 32 at a preset incident angle, wherein the preset incident angle calculation formula is as follows: In the formula, is the wavelength of the parametric light band, is the groove pitch of the diffractive optical element 32, is the incident angle, is the diffraction angle.

[0050] It can be understood that λ is the wavelength of the parametric light band, which here refers to the wavelength of the signal light or idler light returned to the optical parametric frequency conversion module 21. Within the maximum separation angle range of the grating to ensure the diffraction power, the incident angle and diffraction angle of the corresponding parametric light and the grating can be determined, and then the inclination angle of the diffraction optical element 32 can be determined. The inclination angle is the angle between the diffraction surface of the diffraction optical element 32 and the parametric light incident on its surface. The correct inclination angle can ensure that the propagation direction, energy distribution, etc. of the light meet the expected requirements, so that within the maximum separation angle range of the grating to ensure the diffraction power, it means within this specific angle range. The grating can most effectively separate light of different parameters (such as different wavelengths, etc.) and make the diffracted light have sufficient power.

[0051] For example, Figure 3As shown, the frequency conversion module of the high-energy optical parametric oscillator can be provided with three optical parametric frequency conversion modules 21. The high-energy optical parametric oscillator includes: a pump light transmitting module 1 that emits three beams of fundamental frequency pump light, the fundamental frequency pump light has a repetition frequency of 1 kHz, a pulse width of 15 ns, and a wavelength of 532nm. The surfaces of the optical parametric high-reflection mirrors 211 in the three optical parametric frequency conversion modules 21 are all coated with a 532nm first anti-reflection film and a high-reflection film, and the wavelengths of the three signal lights (idle light) output by the three optical parametric frequency conversion modules 21 are different, but in the range of 991nm-1010nm. The wavelength of the high-reflection film of each optical parametric frequency conversion module 21 is consistent with the wavelength of the signal light output by each optical parametric frequency conversion module 21. The optical parametric frequency conversion crystals 212 in the three optical parametric frequency conversion modules 21 are all LBO crystals, the size of the LBO crystal is 5mm×5mm×60mm, and the size of the light-through openings on both sides is 5mm×5mm. The LBO crystals all meet the first type of phase matching, with matching angles θ=90°, φ=0°. The LBO crystals are equipped with a crystal temperature control device with an accuracy of 0.1°C for adjusting the temperature. The crystal temperature is adjusted by the temperature control device so that the output band of the three signal light beams λs generated is 991nm-1010nm, but the wavelengths are different. The combined parametric light is transmitted to the output coupling mirror 4, which reflects the combined parametric light part back to the optical parametric frequency conversion module 21 along the original path, and the rest is output from the output coupling mirror 4. The output coupling mirror 4 is coated with a film with a predetermined reflectivity for the output signal light 991-1010nm.

[0052] Figure 4 This is the fourth optical path schematic diagram of the high energy optical parametric oscillator provided by the present invention, such as Figure 4 As shown, the high-energy optical parametric oscillator includes: a pump light emission module 1, a frequency conversion module 2, a spectrum combining module 3 and an output coupling mirror 4 which are sequentially arranged along the optical path.

[0053] The functions of the above optical devices are similar to those mentioned above. Figure 1 The functions of the optical devices are the same and will not be described again here.

[0054] In this embodiment, the frequency conversion module 2 includes n (more than three) optical parametric frequency conversion modules 21, and the multiple optical parametric frequency conversion modules 21 are arranged in a straight line with equal spacing. The optical parametric frequency conversion module 21 includes an optical parametric high reflector 211 and an optical parametric frequency conversion crystal 212 arranged in sequence along the optical path. The spectral beam combining module 3 includes an optical conversion element 31 and a diffractive optical element 32 arranged in sequence along the optical path. The functions of the above optical devices are the same as those described above. Figure 2 and 3 The functions of the optical devices are the same and will not be described again here.

[0055] The multiple optical parametric frequency conversion modules 21 are arranged in parallel in sequence according to the wavelength, and the multiple optical parametric frequency conversion modules 21 jointly generate parallel lasers with equal spacing, so as to generate parametric light with different wavelengths but in the same wavelength band.

[0056] It is understandable that the inline arrangement can achieve a high degree of integration in a limited space, making it easier to build a miniaturized optical parametric oscillator. The equally spaced arrangement helps optimize the spatial overlap of pump light and signal light in nonlinear media and improve conversion efficiency.

[0057] In a possible implementation, the pump light transmitting module 1 includes a plurality of pump laser transmitters 11 corresponding one-to-one to the optical parametric frequency conversion modules 21 .

[0058] It is understandable that multiple optical parametric frequency conversion modules 21 and corresponding pump laser emitters 11 provide a redundant backup function. If one of the optical parametric frequency conversion modules 21 or the pump laser emitter 11 fails, the other components can still continue to work and will not cause the entire system to be completely paralyzed. At the same time, the pump energy can be flexibly allocated between different optical parametric frequency conversion modules 21 according to actual needs. In some application scenarios, some frequency conversion modules may need to output more energy. By adjusting the power and other parameters of the corresponding pump laser emitter 11, it is possible to achieve a reasonable distribution of energy between different modules and improve energy utilization efficiency.

[0059] The mid-infrared optical parametric oscillator provided in this embodiment includes the above Figures 1 to 4 The high energy optical parametric oscillator in the embodiment has similar implementation principles and technical effects, which will not be described in detail in this embodiment.

[0060] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-energy optical parametric oscillator, characterized in that: include: The pump light emission module, frequency conversion module, spectrum combining module and output coupling mirror are arranged in sequence along the optical path; wherein, The pump light transmitting module is used to transmit multiple beams of pump light of preset wavelength to the frequency conversion module; wherein the wavelengths of the multiple beams of pump light are the same; The frequency conversion module comprises a plurality of optical parametric frequency conversion modules, and the optical parametric frequency conversion modules are used to convert the received pump light into parametric light; wherein the multiple beams of pump light emitted by the pump light transmitting module are input into the plurality of optical parametric frequency conversion modules one by one, and the wavelengths of the parametric light output by different optical parametric frequency conversion modules are different; The spectral beam combining module is used to perform spectral beam combining on the multiple parametric beams generated by the frequency conversion module to form a combined beam, and transmit the combined beam to the output coupling mirror; The output coupling mirror is used to reflect a part of the combined light beam back to each of the optical parametric frequency conversion modules to form feedback oscillation, and output the other part of the combined light beam.

2. The high energy optical parametric oscillator according to claim 1, characterized in that: The optical parametric frequency conversion module includes an optical parametric high reflector and an optical parametric frequency conversion crystal arranged in sequence along the optical path; The frequency conversion module, the spectrum combining module and the output coupling mirror together constitute an optical parametric oscillator cavity.

3. The high-energy optical parametric oscillator according to claim 2, characterized in that: The optical parametric high reflector is coated with a first anti-reflection film and a high reflective film, wherein the transmittance of the first anti-reflection film to the pump light is greater than 95%, and the wavelength of the high reflective film covers the wavelength of the parametric light.

4. The high-energy optical parametric oscillator according to claim 1, characterized in that: The spectral beam combining module includes an optical transformation element and a diffractive optical element arranged in sequence along the optical path, wherein the optical transformation element is used to transmit multiple beams of the parametric light to the same position of the diffractive optical element; the diffractive optical element is used to perform spectral beam combining on the multiple beams of the parametric light and transmit the obtained combined light to the output coupling mirror.

5. The high-energy optical parametric oscillator according to claim 4, characterized in that: The optical conversion element is a lens, the diffractive optical element is a grating, and the diffractive optical element is located at a focal plane of the optical conversion element.

6. The high-energy optical parametric oscillator according to claim 4, characterized in that: According to a preset incident angle formula, the parametric light is incident on the diffractive optical element at a preset incident angle, wherein the preset incident angle calculation formula is as follows: In the formula, is the wavelength of the parametric light band, d is the groove spacing of the diffractive optical element, is the incident angle, is the diffraction angle.

7. The high-energy optical parametric oscillator according to claim 1, characterized in that: The parametric light includes signal light and idler light. The output coupling mirror is coated with a second anti-reflection film. The transmittance of the second anti-reflection film to one of the signal light and the idler light is greater than 95%, and the transmittance to the other is 10% to 80%.

8. The high energy optical parametric oscillator according to any one of claims 1 to 7, characterized in that: The pump light transmitting module includes a plurality of pump laser transmitters corresponding one to one to the optical parametric frequency conversion modules.

9. The high energy optical parametric oscillator according to any one of claims 1 to 7, characterized in that: The multiple optical parametric oscillator cavities of the optical parametric frequency conversion module are arranged in a straight line with equal spacing.

10. A mid-to-far infrared optical parametric oscillator, characterized in that: A high-energy optical parametric oscillator comprising any one of claims 1 to 9.

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