Feedback type multi-wavelength space laser shaping and amplifying structure based on layered frequency doubling crystal

Abstract

The invention belongs to the technical field of laser, and discloses a feedback type multi-wavelength space laser shaping and amplifying structure based on a layered frequency doubling crystal, which is characterized in that a laser source unit comprises one or more lasers, and a selective frequency doubling unit comprises a 50 / 50 space optical beam splitter, a non-frequency doubling optical path, a frequency doubling optical path and a space optical coupler. The non-frequency doubling light path only passes through one optical switch, the frequency doubling light path passes through one optical switch, one layered frequency doubling crystal module and one multi-wavelength filter, and the feedback laser shaping unit comprises a three-port one-way transmission device, a multi-wavelength waveform shaping device and a total reflection mirror device. The multi-wavelength gain amplification unit comprises a gain amplifier based on a layered gain medium module and a multi-wavelength filter, and the output end of the laser source unit is in butt joint with the input end of the selective frequency doubling unit. The device is simple in structure, high in expansibility, suitable for being used in a space laser application system, and capable of modulating laser frequency, improving multi-wavelength laser waveforms and improving multi-wavelength laser output energy.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, specifically relating to a feedback-type multi-wavelength spatial laser shaping and amplification structure based on a layered frequency doubling crystal. Background Technology

[0002] With the further development of modern information technology, the future trend of intelligent optoelectronic devices towards multi-wavelength, multi-element, multi-functional, and multi-platform applications has become inevitable. Especially in the field of optoelectronic detection and sensing, as long-distance multi-wavelength, multi-element, and multi-functional composite systems become a key development focus, high-power, high-beam-quality dual-wavelength and even multi-wavelength laser sources have become an urgent need for the development of optoelectronic detection technology. In fact, dual-wavelength and even multi-wavelength lasers have important applications in important fields such as optical communication, optical computing, fine laser spectroscopy, laser color printing, interferometric rainbow holography, photodynamic medicine, environmental monitoring, lidar, laser remote sensing, and optoelectronic countermeasures.

[0003] In the field of traditional solid-state and gas lasers, frequency doubling, amplification, and waveform shaping of lasers are often limited to single-wavelength lasers. Multi-wavelength lasers are typically difficult to process using a single system. In other words, to obtain a dual-wavelength or multi-wavelength laser composed of a fundamental and frequency-doubled beam with higher power and better waveform, the common practice is to first frequency-double, amplify, and shape the single-wavelength laser, and then combine the beams. The drawback of this approach is that each single-wavelength laser has its own independent optical path structure, and the subsequent multi-source laser beam combining optical path structure results in a complex and large multi-wavelength laser optical path structure with a large number of components and high cost, which is detrimental to subsequent system applications. Summary of the Invention

[0004] (a) Purpose of the invention The purpose of this invention is: (1) to improve the problem of limited waveform shaping and amplification of multi-wavelength pulsed lasers in traditional laser application systems, and to make the waveform of multi-wavelength pulsed lasers as close to Gaussian as possible, thereby solving the problem that the peak power of the amplifier output laser is limited and the single pulse energy is limited due to the distortion of the multi-wavelength pulsed laser waveform and its deviation from the Gaussian shape, resulting in poor application effect; (2) to solve the problem of simultaneously realizing the frequency up-conversion, power compensation and amplification of multi-wavelength lasers in the same system.

[0005] (II) Technical Solution To address the aforementioned technical problems, this invention provides a feedback-based multi-wavelength spatial laser shaping and amplification structure based on a layered frequency-doubling crystal. The structure includes: a laser source unit, a selective frequency-doubling unit, a feedback-based laser shaping unit, and a multi-wavelength gain amplification unit. The laser source unit includes one or more lasers. The selective frequency-doubling unit includes a 50 / 50 spatial optical beam splitter, a non-frequency-doubled optical path, a frequency-doubled optical path, and a spatial optical coupler. The non-frequency-doubled optical path passes through only one optical switch, while the frequency-doubled optical path passes through an optical switch, a layered frequency-doubling crystal module, and a multi-wavelength filter. The feedback-based laser shaping unit includes a three-port unidirectional transmission device, a multi-wavelength waveform shaping device, and a total reflection mirror. The device, the multi-wavelength gain amplification unit, includes a gain amplifier based on a layered gain dielectric module and a multi-wavelength filter. The output of the laser source unit is connected to the input of the selective frequency doubling unit. The output of the selective frequency doubling unit is connected to port ① of the three-port unidirectional transmission device in the feedback laser shaping unit. Port ② of the three-port unidirectional transmission device is connected to one end of the multi-wavelength waveform shaping device. Port ③ of the three-port unidirectional transmission device is connected to the input of the multi-wavelength gain amplification unit. The laser output from the laser source unit undergoes selective frequency conversion by the selective frequency doubling unit, then undergoes Gaussian shaping of the waveform twice by the feedback laser shaping unit, and finally the multi-wavelength gain amplification unit achieves compensation and amplification of laser power or energy.

[0006] Specifically, depending on the requirements of laser waveform shaping and power amplification, there are one or N (N≥2) feedback laser shaping units and multi-wavelength gain amplification units; the laser first-stage shaping and amplification structure includes one feedback laser shaping unit and one multi-wavelength gain amplification unit to achieve two Gaussian shapings of the laser waveform, as well as one compensation and amplification of the laser power or energy; the laser N-stage shaping and amplification structure includes N feedback laser shaping units and N multi-wavelength gain amplification units to achieve 2Nth Gaussian shapings of the laser waveform, as well as Nth compensation and amplification of the laser power or energy.

[0007] The laser output is a single wavelength or a multi-wavelength laser, and the output wavelength range is 280nm-2μm.

[0008] The optical switches in the non-frequency-doubled optical path and the frequency-doubled optical path of the selective frequency-doubled unit can control the transmission of laser light with a wavelength range of 280nm-2μm. These two optical switches are selectively turned on or off, giving the selective frequency-doubled unit three switching connection modes: (1) Both optical switches are turned on and connected simultaneously; (2) The optical switch in the non-frequency doubling optical path is open and connected, while the optical switch in the frequency doubling optical path is closed; (3) The optical switch in the non-frequency doubling optical path is closed, and the optical switch in the frequency doubling optical path is opened and connected.

[0009] The three switching connection modes correspond to three output laser modes. When it is the first connection mode, the selective frequency doubling unit coupling output is a mixed multi-wavelength output laser consisting of the fundamental frequency light of the laser output and the frequency-doubled light converted by the layered frequency doubling crystal module. When it is the second connection mode, the selective frequency doubling unit coupling output is the fundamental frequency light of the laser output. When it is the third connection mode, the selective frequency doubling unit coupling output is the frequency-doubled light converted by the layered frequency doubling crystal module.

[0010] The layered frequency doubling crystal module consists of a crystal layering slot and one or more frequency doubling crystal blocks. If one or more wavelengths of laser light need to be frequency doubled, one or more corresponding frequency doubling crystal blocks are inserted into the crystal layering slot to form a layered frequency doubling crystal combination.

[0011] The crystal layering groove is designed with a length of 24.7cm, a width of 10cm, and a height of 10cm. A base plate is designed at the bottom of the crystal layering groove, with dimensions of 24.7cm in length, 10cm in width, and 1cm in height. Two baffles are designed at each end of the crystal layering groove, with dimensions of 1cm in length, 1cm in width, and 9cm in height. Parallel to the baffles at both ends of the crystal layering groove, 18 longitudinal partitions are designed along the longitudinal direction of the crystal layering groove, with each pair of partitions positioned parallel to each other, dividing the entire crystal layering groove into 10 identical small grooves. Each partition has dimensions of 3mm in length, 1cm in width, and 9cm in height, and each groove has dimensions of 2cm in length, 10cm in width, and 9cm in height. The entire crystal layering groove can accommodate 10 frequency doubling crystal blocks.

[0012] The dimensions of each frequency doubling crystal block are designed to be 2cm long, 10cm wide, and 10cm high. Each frequency doubling crystal block can transmit laser light with a wavelength range of 280nm-2μm. However, each frequency doubling crystal only doubles the frequency of one wavelength of laser light. For laser light with a wavelength other than the corresponding frequency doubling wavelength, in addition to a certain power loss, it does not produce frequency conversion, wavelength transformation, or gain amplification.

[0013] In the feedback laser shaping unit, the three-port unidirectional transmission device is a polarizing beam splitter (PBS) or a beam splitter, and the applicable wavelength range is 280nm-2μm.

[0014] The multi-wavelength waveform shaping device is applicable to wavelengths ranging from 280nm to 2μm. It can simultaneously optimize and modulate the waveforms of lasers with multiple center wavelengths. As a bidirectional transmission device, the waveform shaper can achieve Gaussian shaping of the laser waveform regardless of which end the laser is input from, thereby improving the input laser waveform.

[0015] The total reflection mirror device is a space total reflection mirror with an applicable wavelength range of 280nm-2μm and a reflection efficiency of 99.9%.

[0016] The multi-wavelength gain amplification unit includes a layered gain dielectric module, an optical coupler, and multiple pump sources.

[0017] The layered gain medium module consists of a gain medium layering slot and one or more gain medium blocks. If it is necessary to amplify the gain of one or more wavelength lasers, one or more corresponding gain medium blocks are inserted into the gain medium layering slot to form a layered gain medium combination.

[0018] The gain dielectric layering groove is designed with a length of 34.7cm, a width of 10cm, and a height of 10cm. A base plate is designed at the bottom of the groove, with dimensions of 34.7cm in length, 10cm in width, and 1cm in height. Two baffles are designed at each end of the groove, with dimensions of 1cm in length, 1cm in width, and 9cm in height. Parallel to the baffles at both ends of the groove, 18 longitudinal partitions are designed along the longitudinal direction of the groove, with each pair of partitions positioned parallel to each other, dividing the groove into 10 identical smaller grooves. Each partition has dimensions of 3mm in length, 1cm in width, and 9cm in height, and each groove has dimensions of 3cm in length, 10cm in width, and 9cm in height. The entire gain dielectric layering groove can accommodate 10 gain dielectric blocks.

[0019] The gain medium blocks are designed to be 3cm long, 10cm wide, and 10cm high. The gain medium blocks are solid gain crystals or hollow glass cubes filled with gain gas. Each gain medium block can transmit lasers with a wavelength range of 280nm-2μm. However, each gain medium block only amplifies the gain of one wavelength of laser. For lasers with non-corresponding gain wavelengths, in addition to a certain power loss, no gain amplification, frequency conversion, wavelength conversion, or waveform conversion is generated.

[0020] The number and output wavelength of the pump sources correspond to the number and wavelength of the laser beams output from port ③ of the three-port unidirectional transmission device and entering the gain amplifier.

[0021] There are two multi-wavelength filters. One is located in the selective frequency doubling unit frequency doubling optical path, after the layered frequency doubling crystal module, and is used to lock the center wavelength corresponding to all frequency doubling crystals and filter out other stray light other than these center wavelengths. The other is located in the multi-wavelength gain amplification unit, after the gain amplifier, and is used to lock the center wavelength corresponding to all gain dielectric blocks and filter out other stray light other than these center wavelengths.

[0022] The laser beam is always incident perpendicular to the longitudinal section of the frequency doubling crystal block and the gain medium block.

[0023] In the entire optical path, the laser energy output by the previous device is less than the laser energy threshold that the next adjacent device can withstand.

[0024] (III) Beneficial Effects The feedback-based multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal provided by the above technical solution has the following advantages: (1) A composite function of selective frequency upconversion of multi-wavelength laser, waveform modulation and shaping of multi-wavelength laser, gain amplification of multi-wavelength laser and filtering of multi-wavelength laser is realized through a set of optical structures, which provides a new idea for realizing the shaping and amplification of multi-wavelength fundamental frequency light, or frequency doubling light, or fundamental frequency light-frequency doubling light.

[0025] (2) This invention solves the problem that the peak power of the output laser of the amplifier is limited due to the waveform distortion of the pulsed laser, which deviates far from the Gaussian type. The invention can improve the single pulse energy of the laser by Gaussian shaping of the laser waveform and enhance the laser application effect.

[0026] (3) It breaks through the bottleneck of the previous method of frequency doubling a single wavelength laser and then using laser beam combining to achieve multi-wavelength frequency doubling laser output, making the way to obtain multi-wavelength frequency doubling laser more concise.

[0027] (4) It breaks through the bottleneck of previous single-wavelength laser gain amplification and provides a new approach for simultaneous gain of multi-wavelength lasers.

[0028] (5) Simple structure and easy to build. The optical path structure is simple to connect and easy to implement.

[0029] (6) High scalability and flexibility. The number of frequency doubling crystal blocks, gain dielectric blocks and multi-wavelength waveform shaping devices can be increased or decreased as needed.

[0030] (7) Economical and cost-effective. The components used in this structure are relatively inexpensive. In particular, for the laser first-stage modulation and shaping structure, the number of components is less than that of the previous laser modulation, shaping and amplification structure, thus saving costs. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a feedback-based multi-wavelength first-order solid or gas space laser shaping and amplification structure based on a layered frequency doubling crystal.

[0032] Figure 2 This is a schematic diagram of a feedback-based multi-wavelength secondary solid or gas space laser shaping and amplification structure based on a layered frequency doubling crystal.

[0033] Figure 3This is a schematic diagram of a feedback-based multi-wavelength three-level solid or gas space laser shaping and amplification structure based on a layered frequency doubling crystal.

[0034] Figure 4 This is a schematic diagram of the crystal layered groove structure and dimensions.

[0035] Figure 5 This is a front view of a layered frequency doubling crystal module designed for three-wavelength frequency doubling.

[0036] Figure 6 This is a front view of a layered frequency doubling crystal module designed for single-wavelength frequency doubling.

[0037] Figure 7 This is a side view of a layered frequency doubling crystal module.

[0038] Figure 8 This is a schematic diagram of the gain dielectric layered trench structure and dimensions.

[0039] Figure 9 This is a front view of a layered gain dielectric module for six-wavelength gain amplification.

[0040] Figure 10 This is a front view of a layered gain dielectric module for dual-wavelength gain amplification.

[0041] Figure 11 This is a side view of the layered gain dielectric module.

[0042] Figure 12 This is a schematic diagram of a crystal layered groove structure. Detailed Implementation

[0043] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0044] To obtain a simple optical path structure capable of simultaneously performing multi-wavelength frequency doubling, amplification, and shaping, this invention designs an optical path structure that can simultaneously perform multi-wavelength laser frequency up-conversion, laser waveform Gaussian shaping, and laser power or energy amplification to obtain high-power, high-quality laser output by mixing the fundamental frequency and frequency harmonics of multiple wavelengths. (It should be noted that the single-wavelength or multi-wavelength mentioned in this invention refers to the center wavelength.) Laser frequency doubling is a nonlinear optical process that doubles the frequency of a laser, thereby halving its wavelength. When fundamental frequency light with frequency ω passes through a nonlinear crystal BBO, LBO, or CLBO, second harmonic generation (SHG) occurs, producing light with a frequency of 2ω, i.e., frequency-doubled light. Below are some common laser types and their associated wavelength frequency doubling: (1) The 1064 nm laser output from the Nd:YAG laser can be reduced to 532 nm by passing through a KTP crystal. Sometimes, it can also be further processed by LBO or CLBO crystals to produce 355 nm or 266 nm ultraviolet light.

[0045] (2) The 770nm potassium (K) laser, 795nm rubidium (Rb) laser and 895nm cesium (Cs) laser output by the Ti:Sapphire tunable laser can be used to obtain the second harmonic 385nm, 397nm and 447nm lasers after passing through a BBO crystal (barium β-borate) or an LBO crystal (lithium triborate).

[0046] Laser waveform shaping primarily utilizes methods such as introducing appropriate filtering, delay, and amplitude adjustment into the circuit to alter the waveform of the laser pulse signal. Typical devices include laser pulse clippers, which are all-solid-state laser pulse clipping systems employing high-speed photoelectric Q-switches with rise and fall times as fast as 3ns. This makes them ideal for laser pulse waveform shaping, laser pulse chopping, laser pulse clipping, regenerative amplifier switching, mode-locked pulse gating, cavity emptying, and Q-switching applications. Laser pulse clippers offer advantages such as reliability, minimal radiated noise, solid-state operation, and high-voltage switching, making them suitable for both internal and external cavity applications. Typical specifications for laser pulse clippers are as follows: (1) 250nm~2200nm (DKDP Pockel cell is suitable for 300-1320nm, BBO Pockel cell is suitable for 250-1320nm, RTP Pockel cell is suitable for 500-2200nm).

[0047] (2) Optical rise time, fall time: ~3ns (10mm diameter DKDP Pockels cell).

[0048] (3) Optical pulse width: ~8ns to 1us.

[0049] (4) Repetition frequency: 1Hz~2500Hz.

[0050] Laser gain amplification is primarily based on stimulated emission, amplifying optical signals by exciting atoms or molecules in a medium. A laser amplifier typically contains a gain medium (such as a solid, liquid, or gas) that can transition to higher energy levels under external optical excitation. When the incident laser interacts with these excited atoms or molecules, stimulated emission occurs, generating photons with the same frequency, coherent phase, and direction as the input laser, thus amplifying the optical signal. The structure of a laser gain amplifier is basically similar to that of a laser oscillator, except that the former does not require a laser resonant cavity system; the input laser radiation is usually amplified in a single pass through the gain medium within the amplifier to achieve single-pass traveling-wave amplification.

[0051] Based on the principles of spatial laser frequency doubling, waveform shaping, and gain amplification, and drawing upon current advancements in optoelectronic devices both domestically and internationally, this invention departs from traditional multi-wavelength laser implementation methods. It is the first to design and integrate a flexible optical path structure that combines layered frequency doubling, layered gain amplification, multi-wavelength feedback waveform shaping, and filtering. This achieves simultaneous frequency doubling, waveform shaping, power amplification, and filtering of multiple wavelengths of laser light. The following sections will describe the key innovations of this invention: (1) A layered frequency doubling crystal module structure with an effective size was designed for multi-wavelength laser frequency doubling in optical paths. Traditional frequency doubling optical paths typically only double the frequency of a single wavelength laser, while this module is designed to achieve multi-wavelength frequency doubling. The structure incorporates crystal layering grooves, allowing multiple frequency doubling crystals to be carried within the optical path.

[0052] For multi-wavelength lasers, the effective frequency doubling of lasers with different wavelengths and powers requires different frequency doubling crystal thicknesses. If the crystal thickness is too small, the frequency doubling will be insufficient, and if the crystal thickness is too large, the laser power attenuation will be too large. In order to meet the effective frequency doubling of lasers with different wavelengths and effectively control the influence of laser power attenuation of different wavelengths, through comprehensive calculation, the thickness of the frequency doubling crystal is selected to be 2cm, and the width and height are both 10cm.

[0053] Therefore, the specific structure and dimensions of the crystal layered slot are designed as follows: The entire crystal layered slot is required to have 10 slots, so a total of 11 baffles are needed. The thickness of the two layers (four baffles) at both ends is designed to be 1cm. To minimize air gaps, the thickness of the nine baffles in the middle is designed to be 0.3cm. The thickness of each slot is calculated based on a 2cm thickness for the frequency doubling crystal. Therefore, the total length of the crystal layered slot should be: 10×2cm + 2×1cm + 9×0.3cm = 24.7cm. Furthermore, to ensure sufficient passage of multi-wavelength laser light through the layered frequency doubling crystal module, the crystal layered slot is designed with a width of 10cm and a height of 10cm. The base of the crystal layered slot is 24.7cm long, 10cm wide, and 1cm high. The two layers (four baffles) at both ends are 1cm long, 1cm wide, and 9cm high. The nine layers (eighteen baffles) in the middle are 0.3cm long, 1cm wide, and 9cm high. Figure 12 As shown in Figures I and II.

[0054] (2) A feedback laser shaping unit structure was designed for simultaneous shaping of multi-wavelength laser waveforms in the optical path. Multi-wavelength laser waveform shapers typically use specific optical components, such as gratings, prisms, and filters, along with optical, electronic, and digital control mechanisms, to precisely control and adjust the waveform of multi-wavelength lasers to achieve shaping. These components can selectively reflect, transmit, or modulate lasers of different wavelengths, thereby adjusting the waveform. Furthermore, multi-wavelength laser waveform shapers may utilize digital or analog modulation techniques to finely control the intensity, frequency, and phase characteristics of the laser. In this way, multi-wavelength laser waveform shapers can output laser beams with specific waveforms and spectral characteristics according to application requirements.

[0055] (3) A layered gain dielectric module structure with effective size was designed for multi-wavelength laser power amplification in optical paths. Traditional gain amplifiers typically only amplify the gain of single-wavelength lasers, but this modular design enables multi-wavelength laser gain amplification. The structure incorporates layered gain medium slots, allowing multiple gain medium blocks to be accommodated within the optical path.

[0056] For multi-wavelength lasers, the thickness of the gain medium required for effective gain amplification varies for different wavelengths. The power attenuation of different wavelengths of lasers varies when passing through the non-gain medium. If the gain medium thickness is too small, the laser power amplification will be insufficient. If the gain medium thickness is too large, the power attenuation of non-corresponding wavelengths will be too large. In order to meet the effective gain amplification of different wavelength lasers and effectively control the attenuation effect of different wavelength lasers, through comprehensive calculation, the thickness of the gain medium block is selected to be 3cm, and the width and height are both 10cm.

[0057] Therefore, the specific structure and dimensions of the gain dielectric layered trench are designed as follows: The entire gain dielectric layered trench has 10 slots, requiring a total of 11 baffles. The thickness of the two layers (four baffles at each end) is designed to be 1cm. To minimize air gaps, the thickness of the nine baffles in the middle is designed to be 0.3cm. The thickness of each slot is calculated based on a gain dielectric block thickness of 3cm. Therefore, the total length of the crystal layered trench should be: 10 × 3cm + 2 × 1cm + 9 × 0.3cm = 34.7cm. Furthermore, to ensure sufficient passage of multi-wavelength laser light through the layered gain dielectric module, the crystal layered trench is designed with a width of 10cm and a height of 10cm. The base of the crystal layered trench is 34.7cm long, 10cm wide, and 1cm high. The two layers (four baffles at each end) are 1cm long, 1cm wide, and 9cm high. The nine layers (eighteen baffles) in the middle are 0.3cm long, 1cm wide, and 9cm high. Figure 12 As shown in Figures III and IV.

[0058] (4) Design a multi-wavelength laser filter structure for filtering multi-wavelength lasers in the optical path. A multi-wavelength laser filter is a device capable of filtering lasers of multiple center wavelengths. Its principle is based on designing multiple narrow-band filtering channels within a wide wavelength range. Each narrow-band channel corresponds to a specific gain, which in turn corresponds to a specific laser wavelength. Therefore, each filtering channel can filter a specific wavelength of laser light. By integrating multiple narrow-band filtering channels into a single design, simultaneous filtering of multiple wavelengths of laser light can be achieved. Multi-wavelength laser filters are commonly used in LiDAR systems, laser cutting, laser painting, and other fields.

[0059] Figure 1 , Figure 2 and Figure 3 The figures illustrate a feedback-based multi-wavelength, first-, second-, and third-stage solid-state or gas-based space laser shaping and amplification structure based on a layered frequency-doubling crystal. The specific units, modules, and devices are shown below: Laser source unit 1, selective frequency doubling unit 2, first-stage feedback laser shaping unit 3, first-stage multi-wavelength gain amplification unit 4, laser 5, 50 / 50 spatial optical beam splitter 6, optical switch 7, optical switch 8, layered frequency-doubling crystal module 9, multi-wavelength filter 10, spatial optical coupler 11, PBS 12, multi-wavelength laser pulse clipper 13, total reflection mirror 14, gain amplifier 15, multi-wavelength filter 16, second-stage feedback laser shaping unit 17, second-stage multi-wavelength gain amplification unit 18, PBS 19, multi-wavelength laser pulse clipper 20, total reflection mirror 21, gain amplifier 22, multi-wavelength filter 23, third-stage feedback laser shaping unit 24, third-stage multi-wavelength gain amplification unit 25, PBS 26. Multi-wavelength laser pulse clipper 27. Total reflection mirror 28. Gain amplifier 29. Multi-wavelength filter 30.

[0060] Figure 4 The diagram shows the structure and dimensions of the crystal layered groove. Figure 5 The image shown is a front view of a layered frequency doubling crystal module for three-wavelength frequency doubling. Figure 6 The image shown is a front view of a layered frequency doubling crystal module for single-wavelength frequency doubling. Figure 7 The diagram shown is a side view of the layered frequency doubling crystal module, where the components are specifically represented as: crystal layering groove 31 and frequency doubling crystal block 32.

[0061] Figure 8 The diagram shows the structure and dimensions of the gain dielectric layered trench. Figure 9 The image shown is a front view of a layered gain dielectric module for six-wavelength gain amplification. Figure 10 The image shown is a front view of a layered gain dielectric module for dual-wavelength gain amplification. Figure 11 The diagram shown is a side view of the layered gain dielectric module, where the devices are specifically represented as: gain dielectric layered slot 33 and gain dielectric block 34.

[0062] 1. Taking a feedback-type six-wavelength three-level alkali metal laser shaping and amplification structure based on a layered frequency doubling crystal as an example, refer to... Figure 3 , Figure 5 and Figure 9 The specific embodiments of the present invention will be described in detail below.

[0063] Laser 5 is a potassium-rubidium-cesium (K-Rb-Cs) three-wavelength alkali metal vapor laser. During operation, laser 5 outputs a mixed three-wavelength laser at 770nm (K laser), 795nm (Rb laser), and 895nm (Cs laser). A frequency-doubled BBO crystal block for the 770nm, 795nm, and 895nm wavelengths is pre-inserted into the crystal layering groove 31. When optical switches 7 and 8 are simultaneously activated, half of the laser beam, after passing through optical switch 7, remains at 770nm, 795nm, and 895nm. The other half, after passing through optical switch 8, is frequency-doubled by the layered frequency-doubled crystal module 9 to obtain a three-wavelength laser at 385nm, 397nm, and 447nm. This laser beam is then locked at 385nm after passing through a three-wavelength filter 10. The three wavelength lasers of 5nm, 397nm, and 447nm are filtered out and output. The spatial optical coupler 11 is coated to transmit three wavelength lasers of 770nm, 795nm, and 895nm, while reflecting three wavelength lasers of 385nm, 397nm, and 447nm. Therefore, after the two beams are coupled by the spatial optical coupler 11, a six-wavelength alkali metal laser with wavelengths of 770nm, 795nm, 895nm, 385nm, 398nm, and 448nm is obtained. These six wavelengths of laser light enter from port ① of PBS 12 and exit from port ② of PBS 12. The multi-wavelength laser pulse clipper 13 and the total reflection mirror 14 are two devices that can process these six wavelengths of laser light. The multi-wavelength laser pulse clipper 13 has a laser transmission channel for these six wavelengths and can perform Gaussian shaping on the waveform of these six wavelengths of laser light. After the waveform is shaped, the six wavelengths of laser light are reflected by 99.9% through the total reflection mirror 14 and enter the multi-wavelength laser pulse clipper 13 again for secondary waveform shaping. At this time, the polarization characteristics of the above six wavelengths of laser light have changed by π / 2. Therefore, after the six wavelengths of laser light are output from the multi-wavelength laser pulse clipper 13, they are output through port ③ of PBS 12 and then the power is compensated and amplified by the gain amplifier 15. The layered gain medium module inside the gain amplifier 15 consists of a gain medium layering slot 33 and a gain medium block 34. In this specific embodiment, there are six gain medium blocks, which respectively amplify the gain of six wavelengths: 770nm, 795nm, 895nm, 385nm, 398nm, and 448nm. The amplified laser light is then filtered out by a six-wavelength filter 16 to lock the laser light with center wavelengths of 770nm, 795nm, 895nm, 385nm, 398nm, and 448nm.

[0064] Following the above method, after two-stage waveform shaping and power amplification, and three-stage waveform shaping and power amplification, a total of six-wavelength alkali metal laser outputs of 770nm, 795nm, 895nm, 385nm, 398nm, and 448nm were obtained, which underwent a total of six waveform shapings and three energy / power amplifications.

[0065] 2. Taking a feedback-type dual-wavelength three-stage solid-state laser shaping and amplification structure based on a layered frequency-doubling crystal as an example, refer to... Figure 3 , Figure 6 and Figure 10 The specific implementation methods are described in detail.

[0066] Laser 5 is an Nd:YAG solid-state laser. During operation, laser 5 outputs a single-wavelength laser at 1064nm. A frequency-doubled KTP crystal block 32, designed for the 1064nm wavelength, is pre-inserted into the crystal layered slot 31. When optical switches 7 and 8 are simultaneously activated, half of the 1064nm laser beam remains 1064nm after passing through optical switch 7. The other half of the 1064nm laser beam passes through optical switch 8 and is then frequency-doubled by the layered frequency-doubled crystal module 9 to obtain a 532nm wavelength laser. This 532nm wavelength laser is then locked by a multi-wavelength filter 10, and other stray light is filtered out before output, resulting in a frequency-doubled laser in the 532nm band. The spatial optical coupler 11, through coating treatment, can transmit the 1064nm wavelength laser while simultaneously reflecting the 532nm wavelength laser. Therefore, when the two beams are coupled simultaneously through the spatial optical coupler 11, a dual-wavelength laser output with wavelengths of 1064nm and 532nm is obtained. These wavelengths of laser light enter from port ① of PBS 12 and exit from port ② of PBS 12. The multi-wavelength laser pulse clipper 13 and the total reflection mirror 14 are two devices that can process 1064nm and 532nm wavelength laser light. The multi-wavelength laser pulse clipper 13 has a transmission channel for these two wavelengths of laser light and can perform Gaussian shaping on the waveforms of the 1064nm and 532nm laser light. The shaped dual-wavelength laser light is reflected by 99.9% through the total reflection mirror 14 and then enters the multi-wavelength laser pulse clipper 13 again for secondary waveform shaping. At this time, the polarization characteristics of the 1064nm and 532nm dual-wavelength laser light have changed by π / 2. Therefore, after the two wavelengths of laser light are output from the multi-wavelength laser pulse clipper 13, they are output through port ③ of PBS 12 and then power-compensated and amplified by the gain amplifier 15. The layered gain medium module inside the gain amplifier 15 consists of a gain medium layered slot 33 and a gain medium block 34. In this specific embodiment, there are two gain medium blocks, which respectively amplify the gain of lasers with wavelengths of 1064nm and 532nm. The amplified laser is then filtered out for stray light by a multi-wavelength filter 16 to lock the dual-wavelength laser with center wavelengths of 1064nm and 532nm.

[0067] Following the above method, after two-stage waveform shaping and power amplification, and three-stage waveform shaping and power amplification, a dual-wavelength laser output of 1064nm and 532nm is obtained, which has undergone a total of six waveform shapings and three energy / power amplifications.

[0068] As can be seen from the above technical solution, the present invention has the following significant features: (1) Frequency modulation, waveform modulation and shaping and power amplification of multi-wavelength lasers can be achieved simultaneously through a set of spatial optical path structures.

[0069] (2) Improved laser waveform.

[0070] (3) Simultaneously achieve frequency modulation of multiple wavelength lasers.

[0071] (4) Simultaneously achieve gain amplification of multiple wavelength lasers.

[0072] (5) The structure is simple and easy to build.

[0073] (6) It has strong scalability and flexibility.

[0074] (7) Economical and affordable.

[0075] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural exchanges made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A feedback-based multi-wavelength spatial laser shaping and amplification structure based on a layered frequency doubling crystal, characterized in that, include: The system comprises a laser source unit, a selective frequency doubling unit, a feedback laser shaping unit, and a multi-wavelength gain amplification unit. The laser source unit includes one or more lasers. The selective frequency doubling unit includes a 50 / 50 spatial optical beam splitter, a non-frequency-doubled optical path, a frequency-doubled optical path, and a spatial optical coupler. The non-frequency-doubled optical path passes through an optical switch. The frequency-doubled optical path passes through an optical switch, a layered frequency-doubled crystal module, and a multi-wavelength filter. The feedback laser shaping unit includes a three-port unidirectional transmission device, a multi-wavelength waveform shaping device, and a total reflection mirror device. The multi-wavelength gain amplification unit includes a layered gain medium-based module... The laser source unit consists of a gain amplifier and a multi-wavelength filter. The output of the laser source unit is connected to the input of the selective frequency multiplier unit. The output of the selective frequency multiplier unit is connected to port ① of the three-port unidirectional transmission device in the feedback laser shaping unit. Port ② of the three-port unidirectional transmission device is connected to one end of the multi-wavelength waveform shaping device. Port ③ of the three-port unidirectional transmission device is connected to the input of the multi-wavelength gain amplifier unit. The laser output from the laser source unit undergoes selective frequency conversion by the selective frequency multiplier unit, then undergoes Gaussian shaping of the waveform twice by the feedback laser shaping unit, and finally undergoes compensation and amplification of laser power or energy by the multi-wavelength gain amplifier unit.

2. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 1, characterized in that, Depending on the requirements of laser waveform shaping and power amplification, there may be one or N feedback laser shaping units and multi-wavelength gain amplification units, where N≥2. One feedback laser shaping unit and one multi-wavelength gain amplification unit form a first-stage laser shaping and amplification structure, realizing two Gaussian shapings of the laser waveform and one compensation and amplification of the laser power or energy. N feedback laser shaping units and N multi-wavelength gain amplification units form an N-stage laser shaping and amplification structure, realizing 2Nth-order Gaussian shaping of the laser waveform and Nth-order compensation and amplification of the laser power or energy.

3. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 1 or 2, characterized in that, The laser outputs a single-wavelength or multi-wavelength laser, with an output wavelength range of 280nm-2μm.

4. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 1 or 2, characterized in that, The optical switches in the non-frequency-doubled optical path and the frequency-doubled optical path of the selective frequency-doubled unit control the transmission of laser light with a wavelength range of 280nm-2μm. The two optical switches are selectively turned on or off, giving the selective frequency-doubled unit three switching connection modes: 1) Both optical switches are turned on and connected simultaneously; 2) The optical switch in the non-frequency-doubled optical path is open and connected, while the optical switch in the frequency-doubled optical path is closed; 3) The optical switch in the non-frequency-doubled optical path is closed, and the optical switch in the frequency-doubled optical path is open and connected; The three switching connection modes correspond to three output laser modes. When it is the first connection mode, the selective frequency doubling unit coupled output is a mixed multi-wavelength output laser consisting of the fundamental frequency light of the laser output and the frequency-doubled light converted by the layered frequency doubling crystal module. When it is the second connection mode, the selective frequency doubling unit coupled output is the fundamental frequency light of the laser output. When it is the third connection mode, the selective frequency doubling unit coupled output is the frequency-doubled light converted by the layered frequency doubling crystal module.

5. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 1 or 2, characterized in that, The layered frequency doubling crystal module consists of a crystal layering slot and one or more frequency doubling crystal blocks. To double the frequency of one or more wavelength lasers, one or more corresponding frequency doubling crystal blocks are inserted into the crystal layering slot to form a layered frequency doubling crystal combination.

6. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 5, characterized in that, The crystal layering groove is designed with a length of 24.7cm, a width of 10cm, and a height of 10cm. A base plate is designed at the bottom of the crystal layering groove, with dimensions of 24.7cm in length, 10cm in width, and 1cm in height. Two baffles are designed at each end of the crystal layering groove, with dimensions of 1cm in length, 1cm in width, and 9cm in height. Along the longitudinal direction of the crystal layering groove, parallel to the baffles at both ends, 18 longitudinal partitions are designed, with each pair of partitions positioned parallel to each other, dividing the entire crystal layering groove into 10 identical small grooves. Each partition has dimensions of 3mm in length, 1cm in width, and 9cm in height, and each groove has dimensions of 2cm in length, 10cm in width, and 9cm in height. The entire crystal layering groove can accommodate 10 frequency doubling crystal blocks.

7. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 6, characterized in that, The dimensions of each frequency doubling crystal block are designed to be 2cm long, 10cm wide, and 10cm high. Each frequency doubling crystal block can transmit laser light with a wavelength range of 280nm-2μm. However, each frequency doubling crystal only doubles the frequency of one wavelength of laser light and does not produce frequency conversion, wavelength transformation, or gain amplification for laser light with wavelengths other than the corresponding frequency doubling wavelength.

8. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 7, characterized in that, The multi-wavelength waveform shaping device is applicable to a wavelength range of 280nm-2μm and can simultaneously optimize and modulate the waveform of lasers with multiple center wavelengths. It is also a bidirectional transmission device, so the waveform shaper can achieve Gaussian shaping of the laser waveform regardless of which end the laser is input from.

9. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 8, characterized in that, The multi-wavelength gain amplification unit includes a layered gain medium module, an optical coupler, and multiple pump sources. The layered gain medium module consists of a gain medium layering slot and one or more gain medium blocks. When amplifying the gain of one or more wavelength laser inputs, one or more corresponding gain medium blocks are inserted into the gain medium layering slot to form a layered gain medium combination. The gain medium layering slot is designed with a length of 34.7cm, a width of 10cm, and a height of 10cm. A base plate is designed at the bottom of the gain medium layering slot, with dimensions of 34.7cm in length, 10cm in width, and 1cm in height. Two baffles are designed at each end of the gain medium layering slot, with dimensions of 1cm in length, 1cm in width, and 9cm in height. Along the longitudinal direction of the gain medium layering groove, parallel to the baffles at both ends, there are 18 longitudinal partitions, with each pair of partitions positioned parallel to each other, dividing the entire gain medium layering groove into 10 identical small grooves. Each partition has dimensions of 3mm in length, 1cm in width, and 9cm in height, and each groove has dimensions of 3cm in length, 10cm in width, and 9cm in height. The entire gain medium layering groove can accommodate 10 gain medium blocks. The gain medium blocks are all designed to be 3cm in length, 10cm in width, and 10cm in height. The gain medium blocks are solid gain crystals or hollow glass cubes filled with gain gas. Each gain medium block can transmit laser light with a wavelength range of 280nm-2μm. Each gain medium block only amplifies the gain of one wavelength of laser light and does not produce gain amplification, frequency conversion, wavelength transformation, or waveform transformation.

10. The feedback-type multi-wavelength spatial laser shaping and amplification structure based on layered frequency doubling crystal as described in claim 9, characterized in that, There are two multi-wavelength filters. One is located in the selective frequency doubling unit frequency doubling optical path, after the layered frequency doubling crystal module, and is used to lock the center wavelength corresponding to all frequency doubling crystals and filter out other stray light other than these center wavelengths. The other is located in the multi-wavelength gain amplification unit, after the gain amplifier, and is used to lock the center wavelength corresponding to all gain dielectric blocks and filter out other stray light other than these center wavelengths.

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