266 nm ultraviolet laser generation methods, apparatuses, systems, devices, and media

Abstract

The application provides a 266nm ultraviolet laser generation method, device, system, equipment and medium, and belongs to the technical field of lasers. The method comprises the following steps: determining a compensation position relationship of 266nm ultraviolet light in a nonlinear crystal; based on the compensation position relationship, a spatial modulation system is used to modulate 532nm laser light, and the modulated 532nm light field is introduced into the nonlinear crystal to obtain 266nm ultraviolet output laser; wherein a power density action area is formed along the axial direction in the nonlinear crystal, the transverse offset amount of the power density action area along the walk-off direction at each axial position conforms to the compensation position relationship, and the 266nm ultraviolet light generated at each axial position is located in the same preset target output area after walk-off propagation at the exit surface of the nonlinear crystal, so as to form 266nm ultraviolet output laser. The application improves the spatial coincidence degree of ultraviolet light components generated at different depths at the exit surface through active spatial precoding.

Description

Technical Field

[0001] This application relates to the field of laser technology, and in particular to a method, apparatus, system, device and medium for generating 266nm ultraviolet laser. Background Technology

[0002] 266nm ultraviolet lasers, due to their short wavelength and high single-photon energy, have important applications in cutting-edge fields such as precision machining, inspection, and micro / nano manufacturing. This wavelength laser is typically produced by frequency-doubled 1064nm laser to generate 532nm laser, which is then frequency-doubled again in a nonlinear crystal such as barium borate (BBO) to obtain 266nm ultraviolet light; this 266nm ultraviolet light is a fourth harmonic of the 1064nm fundamental frequency. The spatial walk-off effect during the 532nm to 266nm frequency conversion causes varying degrees of lateral displacement of the 266nm ultraviolet light generated at different crystal depths when it propagates to the crystal's exit surface. This spatial misalignment leads to problems such as widening and ellipticization of the output beam, reducing the output beam quality.

[0003] To address the above issues, common improvements include: placing a cylindrical mirror at the back end of the BBO to reshape the already output elliptical 266nm light spot; using a double BBO crystal, a flip crystal, or a polycrystalline structure to compensate for the walk-off; placing a cylindrical mirror or telescope assembly in front of the BBO to obtain an elliptical incident light spot, or using a dichroic mirror to filter out residual 532nm and 1064nm light.

[0004] These solutions improve the output beam morphology or purity to some extent, but the compensation targets are usually macroscopic compensations such as spot size, overall spot morphology at the output end, or crystal orientation. They cannot change the walk-off propagation process inside the crystal. When the 266nm ultraviolet light components generated at different depths of the crystal propagate to the exit surface, their spatial positions are still separate, and the problem of non-overlapping spatial positions has not been completely solved. Summary of the Invention

[0005] This application provides a method, apparatus, system, device, and medium for generating 266nm ultraviolet laser, aiming to solve the problem that existing macroscopic compensation methods for spatial walk-off effects cannot completely solve the problem of spatial non-overlapping positions.

[0006] In a first aspect, this application provides a method for generating 266nm ultraviolet laser, comprising: The compensation position relationship is determined based on the phase matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount. The main propagation direction of the nonlinear crystal is the axial direction. Based on the aforementioned compensation position relationship, a spatial modulation system is used to spatially modulate a 532nm laser, and the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser. A power density active region is formed within the nonlinear crystal along the aforementioned axis. The lateral offset of the power density active region at each of the aforementioned axial positions along the walk-off direction is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each of the aforementioned axial positions, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

[0007] As one embodiment, determining the compensation position relationship based on the phase-matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in a nonlinear crystal includes: The walk-off slope is determined based on the phase-matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal, and the walk-off slope is used to characterize the degree of spatial walk-off effect. Based on the walk-off slope, the center lateral position of the target output region, the axial length of the nonlinear crystal, and each of the axial positions, the lateral walk-off compensation amount at each of the axial positions is determined, and the compensation position relationship is constructed based on the mapping relationship between the axial position and the lateral walk-off compensation amount.

[0008] As one embodiment, the spatial modulation system includes a beam coding unit and an optical field transformation unit; The step of spatially modulating the 532nm laser using a spatial modulation system based on the compensated positional relationship includes: Based on the compensation position relationship, the walk-off compensation parameters are determined, and control commands are generated based on the walk-off compensation parameters; Depending on the type of the beam encoding unit, the beam encoding unit is driven, selected, or set according to the control command to generate an encoded 532nm light field; wherein, when the beam encoding unit is a programmable beam encoding unit, the beam encoding unit is driven according to the control command; when the beam encoding unit includes multiple preset light field encoding patterns or there are multiple prefabricated beam encoding units with different preset light field encoding patterns, a target light field encoding pattern or a target prefabricated beam encoding unit is selected according to the control command; when the beam encoding unit has adjustable optical parameters or adjustable installation parameters, the adjustable optical parameters or the adjustable installation parameters are set according to the control command. The encoded 532nm light field is input into the light field transformation unit to generate a converging light field, and the converging light field is used as the modulated 532nm light field.

[0009] As one embodiment, a post-shaping unit is provided downstream of the nonlinear crystal; The 266nm ultraviolet laser generation method further includes: The first sampling and monitoring of the 266nm ultraviolet light emitted from the nonlinear crystal was performed to obtain the spatial overlap parameter; If the spatial overlap parameter does not meet the first preset condition, the walk-off compensation parameter or control command is adjusted based on the spatial overlap parameter so that the spatial overlap parameter meets the first preset condition. The beam parameters are obtained by performing a second sampling and monitoring of the 266nm ultraviolet light emitted from the post-shaping unit. If the beam parameters do not meet the second preset condition, the system operating parameters are adjusted based on the beam parameters to make the beam parameters meet the second preset condition; the system operating parameters include the nonlinear conversion parameters of the nonlinear crystal, the walk-off compensation parameters, and the post-processing parameters of the post-shaping unit.

[0010] As one embodiment, the power density effective region is a discrete sub-foci array composed of multiple discrete sub-foci or a continuous focal trajectory extending along the axial direction; In the discrete sub-foci array, different discrete sub-foci correspond to different axial positions; in the continuous focal trajectory, the lateral offset is different at different axial positions.

[0011] As an example, when the power density operating region is the discrete sub-focus array, the generation of control commands based on the walk-off compensation parameters includes at least one of the following: Based on the walk-off compensation parameters, phase delay control commands are generated for the 532nm sub-beams corresponding to each of the discrete sub-foci, and the phase delay amounts are different for different discrete sub-foci; Based on the walk-off compensation parameters, different energy weights are assigned to the discrete sub-foci at different axial positions, and control commands corresponding to the energy weights are generated.

[0012] As one embodiment, determining the walk-off compensation parameters based on the compensation position relationship includes: When the beam encoding unit is a spatial light modulator, the target pixel grayscale image, target phase image, or target voltage matrix is ​​determined according to the compensation position relationship, and the target pixel grayscale image, the target phase image, or the target voltage matrix is ​​used as the walk-off compensation parameter; When the beam coding unit is a phase-type diffractive optical element, the number of the target light field coding pattern is determined according to the compensation position relationship, and the number is used as the walk-off compensation parameter; When the beam encoding unit is a freeform surface reflective optical element, the surface shape characterization parameters of the freeform surface reflective optical element are determined according to the compensation position relationship, and the surface shape characterization parameters are used as the walk-off compensation parameters. When the beam encoding unit is a microlens array, the focal length and center position of each microlens in the microlens array and the relay magnification of the light field transformation unit are determined according to the compensation position relationship, and the focal length, the center position and the relay magnification are used as the walk-off compensation parameters.

[0013] Secondly, this application also provides a 266nm ultraviolet laser generating device, comprising: The compensation position relationship determination module is used to determine the compensation position relationship based on the phase matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount. The main propagation direction of the nonlinear crystal is the axial direction. A spatial modulation module is used to spatially modulate a 532nm laser using a spatial modulation system based on the compensation position relationship, and to introduce the modulated 532nm light field into the nonlinear crystal to obtain a 266nm ultraviolet output laser. The nonlinear crystal forms a power density active region distributed along the axial direction. The lateral offset of the power density active region along the walk-off direction at each axial position is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each axial position, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

[0014] Thirdly, this application also provides a 266nm ultraviolet laser generation system, including the above-mentioned 266nm ultraviolet laser generation device, and a 532nm laser source, a spatial modulation system and a nonlinear crystal arranged sequentially along the optical path; The 266nm ultraviolet laser generating device is signal-connected to the spatial modulation system and is used to control the spatial modulation system to spatially modulate the 532nm laser output from the 532nm laser source, so that the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser.

[0015] Fourthly, this application also provides an electronic device, which includes a memory, a processor, a communication interface, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements any of the above-mentioned 266nm ultraviolet laser generation methods.

[0016] Fifthly, this application also provides a non-transitory computer-readable storage medium storing a computer program, which, when executed by a processor, implements any of the above-described 266nm ultraviolet laser generation methods.

[0017] Sixthly, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements any of the above-described 266nm ultraviolet laser generation methods.

[0018] This application provides a method, apparatus, system, device, and medium for generating 266nm ultraviolet laser. First, the compensation position relationship is determined. Then, based on the compensation position relationship, a 532nm laser is spatially modulated. The 532nm power density region is spatially pre-biased according to a 266nm walk-off amount, precisely achieving walk-off compensation at each axial position. This ensures that the 266nm ultraviolet light generated at different crystal depths, after walk-off propagation, is located within the same target output region at the exit surface. Compared to the passive compensation performed outside the crystal in existing technologies, the active spatial precoding of this application's embodiment helps reduce the broadening and ellipticization of the 266nm output spot caused by the walk-off effect, and improves the spatial overlap of ultraviolet light components generated at different depths at the exit surface. Simultaneously, by distributing the nonlinear interaction region along the entire crystal length, it also helps increase the effective interaction length under walk-off-constrained conditions and improves the energy proportion of the output ultraviolet light in the target spatial mode. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the 266nm ultraviolet laser generation system provided in this application; Figure 2 This is one of the flowcharts illustrating the 266nm ultraviolet laser generation method provided in this application; Figure 3 This is a schematic diagram illustrating the formation principle of a discrete sub-focal array within a nonlinear crystal when the beam encoding unit is a microlens array, as provided in this application. Figure 4 This is a schematic diagram of the energy weight distribution of the discrete subfocus array provided in this application; Figure 5 This is a schematic diagram of the continuous focal trajectory provided in this application; Figure 6This is a schematic diagram of the discrete sub-focal point array and continuous oblique focal line in a nonlinear crystal when the beam coding unit provided in this application is a phase-type diffractive optical element; Figure 7 This is the second schematic diagram of the 266nm ultraviolet laser generation method provided in this application; Figure 8 This is a schematic diagram of the 266nm ultraviolet laser generating device provided in this application; Figure 9 This is a schematic diagram of the structure of the electronic device provided in this application.

[0021] Figure label: 1: 1064nm laser source; 2: Frequency doubling module; 3: Beam encoding unit; 9: Optical field transformation unit; 4: Nonlinear crystal; 41: Walk-off direction; 42: 266nm outgoing overlapping region; 5: 266nm post-shaping unit; 6: Residual light separation unit; 63: 266nm main output; 64: Residual 532nm branch; 65: Residual 1064nm branch or bleed-out branch; 7: 266nm sampling monitoring unit; 8: Control unit; 301: Continuous oblique focal line; 302: Phase-type diffractive optical element; 303: Discrete subfocal array; 810: Compensation position relationship determination module; 820: Spatial modulation module; 910: Processor; 920: Communication interface; 930: Storage cavity; 840: Communication bus. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that, in the description of this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The terms "upper," "lower," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, without limiting the number of objects; for example, a first object can be one or more. Furthermore, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects have an "or" relationship.

[0025] The following description, in conjunction with the accompanying drawings, describes the 266nm ultraviolet laser generation method, apparatus, system, equipment, and medium provided in this application.

[0026] like Figure 1 As shown, the 266nm ultraviolet laser generation system provided in this application includes a 266nm ultraviolet laser generation device, and a 532nm laser source, a spatial modulation system, and a nonlinear crystal arranged sequentially along the optical path. The 266nm ultraviolet laser generation device is signal-connected to the spatial modulation system and is used to control the spatial modulation system to spatially modulate the 532nm laser output from the 532nm laser source, so that the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser.

[0027] Figure 1This is a schematic diagram of the 266nm ultraviolet laser generation system provided in this application. Figure 1 As shown, the 532nm laser source consists of a 1064nm laser source 1 and a frequency doubling module 2. The beam output from the 1064nm laser source 1 is used to generate a 532nm beam after passing through the frequency doubling module 2. The frequency doubling module 2 can be a lithium triborate (LBO) crystal or other frequency doubling crystals.

[0028] Understandably, the 532nm laser source can also be an independent light source that directly outputs 532nm wavelength laser light.

[0029] The nonlinear crystal 4 is used to convert the input 532nm laser frequency into 266nm ultraviolet light, which is a fourth harmonic of the 1064nm fundamental frequency. The nonlinear crystal 4 can be a BBO crystal.

[0030] The nonlinear crystal 4 is mounted on an angle adjustment mount and a temperature control mount. The angle adjustment mount is used to adjust the phase matching angle, and the temperature control mount is used to control the temperature of the nonlinear crystal to stabilize the phase matching condition. Understandably, the beam encoding unit 3 and the optical field transformation unit 9 can also be other components that can achieve the same function.

[0031] The spatial modulation system is the physical hardware that performs spatial modulation. For example... Figure 1 As shown, the spatial modulation system includes a beam encoding unit 3 and an optical field transformation unit 9. The beam encoding unit 3 and the optical field transformation unit 9 can be two independent physical components. In this structure, the beam encoding unit 3 outputs an encoded 532nm optical field, and the optical field transformation unit 9 transforms this encoded 532nm optical field and projects it onto a predetermined volume region inside the nonlinear crystal 4, i.e., the power density region. The optical field transformation can be Fourier transform, Fresnel propagation, 4f relay imaging transformation, cylindrical single-axis focusing transformation, freeform surface reflection transformation, etc. The optical field transformation unit 9 converts the phase, amplitude, or wavefront curvature distribution on the modulation surface into the coordinate distribution of the power density region inside the nonlinear crystal 4, ultimately forming a modulated 532nm optical field inside the nonlinear crystal 4.

[0032] In one possible implementation, the beam encoding unit 3 can be a phase-only diffractive optical element (DOE) or a spatial light modulator (SLM). The beam encoding unit 3 is mounted on an adjustable mount, which is used to precisely align the lateral position (x, y) and angle (pitch and deflection) of the phase-only DOE or spatial light modulator in the optical path with the incident 532nm beam.

[0033] The phase-type diffractive optical element can be a multi-step phase plate, a continuous relief phase plate, a kinoform phase element, or a composite phase grating formed on fused silica, ultraviolet-grade quartz, or other transparent substrates, with an operating wavelength designed at 532 nm. The spatial light modulator can be a reflective liquid crystal spatial light modulator, a transmissive liquid crystal spatial light modulator, a MEMS spatial light modulator, or a combination of a digital micromirror device and a phase modulation structure. For high average power applications, fixed phase-type diffractive optical elements or reflective freeform surface elements are preferred to improve the damage threshold.

[0034] In one possible implementation, the beam coding unit 3 can be a microlens array, with each microlens having a different focal length, position, or subsequent relay magnification, thereby dividing the 532nm beam into multiple sub-beams and forming corresponding power density action areas at different axial positions.

[0035] In one possible implementation, the beam coding unit 3 can employ a freeform surface reflecting optical element, and change the convergence position of light rays in different regions by using the surface shape characterization parameter W(x,y) of the reflecting surface to form a power density active region within the nonlinear crystal 4.

[0036] In one possible implementation, the light field transformation unit 9 can be a single lens, a tilted cylindrical focusing system, one or more 532nm anti-reflection focusing lenses, a reflective focusing mirror, an off-axis 4f imaging system, or a 4f relay system composed of two lenses. The distance between the two lenses in the 4f relay system is approximately the sum of their focal lengths. This relay system is used to relay the plane containing the beam encoding unit 3 to the target plane near the nonlinear crystal 4, and to change the lateral dimension of the focal array according to the relay magnification M. The power density region can be formed by placing the tilted cylindrical focusing system at a preset angle relative to the length direction of the nonlinear crystal 4, or by setting the object plane, image plane, or aperture plane of the off-axis 4f imaging system off-axis relative to the principal optical axis, causing the power density region within the nonlinear crystal to extend along the z-direction and be pre-biased in the lateral direction.

[0037] Building upon the above, the 266nm ultraviolet laser generation system also incorporates an adjustment mechanism for the optical field transformation unit 9. For example, when the tilted cylindrical focusing system or the 532nm anti-reflection focusing lens is moved along the optical axis, or when the distance between the two lenses of the 4f relay system is adjusted, the overall axial position of the power density action zone formed inside the nonlinear crystal 4 changes accordingly. When the focusing magnification of the optical field transformation unit 9 is adjusted, the lateral and axial spacing between the discrete sub-foci (one form of the power density action zone, see the description below) also changes accordingly. Thus, the adjustment mechanism allows the power density action zone to fall within the effective length range of the nonlinear crystal 4.

[0038] Understandably, the beam encoding unit 3 and the optical field transformation unit 9 can also be integrated into the same optical component, for example, by using a phase-type diffractive optical element that has both phase encoding and focusing functions, or by using a reflective element with freeform surface focusing function.

[0039] like Figure 1 As shown, the control unit 8 is used as the 266nm ultraviolet laser generating device. During system operation, the 266nm ultraviolet laser generating device first determines the compensation position relationship and generates corresponding control commands. Then, through a signal connection, the control commands are sent to the spatial modulation system. After receiving the control commands, the spatial modulation system spatially modulates the 532nm laser from the 532nm laser source and introduces the modulated 532nm light field into the nonlinear crystal 4, ultimately obtaining a 266nm ultraviolet output laser.

[0040] It should be noted that the physical process implemented in this embodiment does not involve tilting the 532nm beam along the walk-off direction of the nonlinear crystal 4. The main propagation direction of the 532nm incident beam can still be maintained corresponding to the phase-matching direction of the nonlinear crystal 4 or within its allowable angular range. This embodiment improves the beam quality of the 266nm ultraviolet output laser generated by the nonlinear crystal 4 by precisely controlling the positional distribution of the 532nm beam within the power density region inside the nonlinear crystal 4, thereby controlling the position of the 266nm ultraviolet light generated at different axial positions at the exit surface of the nonlinear crystal within a preset range, increasing spatial overlap.

[0041] Here, the axial direction refers to the main propagation direction of the 532nm laser within the nonlinear crystal 4, typically the length direction of the nonlinear crystal 4, defined as the z-axis. The walk-off direction refers to the transverse direction in which the 266nm ultraviolet light deviates from the main propagation direction due to the walk-off effect, defined as the y-axis. Figure 3 , Figure 5 and Figure 6 As shown.

[0042] The 266nm ultraviolet laser generating device controls the beam encoding unit 3 and the light field transformation unit 9 to ensure that the distribution of the 532nm light field actually formed in the nonlinear crystal 4 is consistent with the compensation position relationship determined according to its walk-off characteristics and phase matching characteristics. This forms a power density action zone inside the nonlinear crystal that is consistent with the compensation position relationship, so that walk-off compensation is obtained at different axial positions (i.e., different crystal depths). Finally, the 266nm ultraviolet light generated at different axial positions is located in the same preset target output area at the exit surface of the nonlinear crystal after walk-off propagation, which improves the spatial overlap of the 266nm ultraviolet laser output.

[0043] This application embodiment utilizes a 266nm ultraviolet laser generating device to perform logic control on the spatial modulation system. A power density region distributed along the axial direction according to the walk-off compensation position relationship is actively constructed inside the nonlinear crystal. This ensures that the 532nm power density region inside the nonlinear crystal is no longer concentrated in a single fixed lateral position, but rather that walk-off compensation and compensation position relationships are consistent at different axial positions. Consequently, the 266nm ultraviolet light generated at different axial positions, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal. This improves the spatial overlap of 266nm ultraviolet light generated at different depths at the exit surface, thereby effectively improving the output beam quality.

[0044] The following is Figure 1 The 266nm ultraviolet laser generation system shown is used as an example to illustrate the 266nm ultraviolet laser generation method and 266nm ultraviolet laser generation device provided in this application.

[0045] It should be noted that the 266nm ultraviolet laser generation method provided in this application embodiment is based on a 266nm ultraviolet laser generation device. The 266nm ultraviolet laser generation method can spatially pre-bias the 532nm power density region within the nonlinear crystal by a 266nm walk-off amount, so that the 266nm ultraviolet light generated at different axial positions (i.e., crystal depth) is located in the same target output region at the emission surface. This helps to reduce the spatial non-overlap caused by the nonlinear crystal walk-off, reduce the output beam broadening and ellipticization, and improve the output beam quality.

[0046] This application describes the 266nm ultraviolet laser generation method using a 266nm ultraviolet laser generation device as an example.

[0047] Figure 2 This is one of the flowcharts illustrating the 266nm ultraviolet laser generation method provided in this application. For example... Figure 2 As shown, the 266nm ultraviolet laser generation method provided in this application includes: S210: The compensation position relationship is determined based on the phase-matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount, wherein the main propagation direction of the nonlinear crystal is the axial direction.

[0048] S220: Based on the aforementioned compensation position relationship, a spatial modulation system is used to spatially modulate the 532nm laser, and the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser. Specifically, a power density active region is formed within the nonlinear crystal along the aforementioned axial direction. The lateral offset of the power density active region along the walk-off direction at each of the aforementioned axial positions is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each of the aforementioned axial positions, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

[0049] Specifically, phase matching characteristics are a fundamental physical condition for the efficient nonlinear frequency conversion process, determining the optimal operating angle and temperature of the crystal. Lateral walk-off characteristics describe the propagation trajectory of 266nm ultraviolet light within the crystal. The compensation position relationship is essentially a mapping rule or functional relationship guiding subsequent spatial modulation; it precisely specifies that at each axial position z of the nonlinear crystal 4, the energy of the 532nm laser needs to be guided to a corresponding lateral position y(z) to compensate for subsequent walk-off displacement.

[0050] After determining the compensation positional relationship, the spatial modulation system is used to spatially modulate the input 532nm laser beam based on this relationship, such as phase modulation, imaging modulation, microlens array focusing, or reflection wavefront modulation. Specifically, after receiving the control command, the spatial modulation system performs a preset, non-uniform modulation on the wavefront of the 532nm incident beam to form a modulated 532nm light field. Subsequently, this modulated 532nm light field is introduced into the nonlinear crystal 4.

[0051] Due to precise spatial modulation, the modulated 532nm light field within the nonlinear crystal 4 is not simply focused into a single point, nor does it propagate at an overall tilt. Instead, it forms an axially distributed power density region within the crystal, pre-biased in the walk-off direction. This power density region is a spatial region where the 532nm light intensity or power density is significantly higher than the surrounding area, effectively driving second-order nonlinear polarization and efficiently generating 266nm ultraviolet light. The morphology of the power density region can be multiple discrete energy concentration points distributed along the axial direction, such as... Figure 3 , Figure 4 The discrete sub-foci shown Figure 6 The discrete sub-focal array 303 shown can also have a power density region that is a continuous focal trajectory extending along the axial direction, such as... Figure 5 Continuous pre-biased focal lines and Figure 6The continuous oblique focal line 301 is shown. Here, the continuous focal trajectory is not the overall propagation direction of the 532nm beam, but rather the spatial position trajectory of the 532nm high power density region within the nonlinear crystal. The lateral position y(z) of the power density region at different axial positions z along the walk-off direction is strictly consistent with the compensation position, used for accurate walk-off compensation.

[0052] Finally, when the modulated 532nm light field passes through the nonlinear crystal 4, the 532nm photons are converted into 266nm photons at different axial positions within the power density region. Since the generation positions have been precisely pre-biased, the lateral bias at the generation point of the 266nm ultraviolet light generated near the crystal's incident end (smaller z-value), which requires a longer propagation distance and results in a larger walk-off displacement, is relatively larger; conversely, the lateral bias at the generation point of the 266nm ultraviolet light generated near the crystal's exit end (larger z-value), which has a shorter subsequent propagation distance and a smaller walk-off displacement, is correspondingly smaller. Thus, the 266nm ultraviolet light generated at different axial positions, after undergoing different walk-off propagation distances, ultimately converges at the exit surface of the nonlinear crystal 4 into the same pre-defined target output region, such as... Figure 4 , Figure 5 and Figure 6 The common emission region in the laser beam forms a high-quality 266nm ultraviolet output laser.

[0053] This application first determines the compensation position relationship, and then spatially modulates the 532nm laser based on the compensation position relationship. The 532nm power density region is spatially pre-biased according to a 266nm walk-off amount, and walk-off compensation is precisely achieved at each axial position. This ensures that the 266nm ultraviolet light generated at different crystal depths, after walk-off propagation, is located in the same target output region at the exit surface. Compared with the passive compensation performed outside the crystal in the prior art, the active spatial precoding of this application helps to reduce the broadening and ellipticization of the 266nm output spot caused by the walk-off effect, and improves the spatial overlap of ultraviolet light components generated at different depths at the exit surface. At the same time, by distributing the nonlinear interaction region along the entire length of the crystal, it is also beneficial to increase the effective interaction length under walk-off-limited conditions and improve the energy proportion of the output ultraviolet light in the target spatial mode.

[0054] In one possible implementation, step S210, determining the compensation position relationship based on the phase-matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal, includes: S2110: Determine the walk-off slope based on the phase-matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The walk-off slope is used to characterize the degree of spatial walk-off effect.

[0055] The walk-off slope can be determined in the following two ways: a. Parameter calculation method: This method is based on theoretical calculations using known physical parameters. Specifically, based on the material properties of the nonlinear crystal 4, its cutting angle, current operating temperature, operating wavelength, and the refractive indices of the 532nm and 266nm lasers at a specific phase-matching angle, the phase-matching and walk-off characteristics are determined, thus establishing the walk-off angle between the energy flow direction of the 266nm ultraviolet light and its wave vector direction. Then take the departure angle. The tangent value is used as the walk-off slope. ,Right now At the walk-off angle In cases where the value is small, it can also be approximated. .

[0056] b. Calibration Method: This method obtains the actual effective walk-off slope of the system through experimental measurement. In a specific calibration procedure, firstly, the angle of the nonlinear crystal 4 is adjusted to maximize the output power of the 266nm ultraviolet light. At this point, the main propagation direction of the 532nm laser is in the phase-matching direction. Based on this, by fine-tuning the position of the 532nm laser incident on the incident surface of the nonlinear crystal 4, the lateral direction in which the centroid of the 266nm emitted light spot is most sensitive to movement is observed and determined; this direction is the walk-off direction. Subsequently, the lateral displacement of the centroid of the 266nm emitted light spot corresponding to different axial positions of the 532nm laser within the nonlinear crystal 4 is recorded. and the corresponding axial propagation distance Finally, the actual walk-off slope was obtained through calculation. .

[0057] S2120: Based on the walk-off slope, the center lateral position of the target output region, the axial length of the nonlinear crystal, and each of the axial positions, determine the lateral walk-off compensation amount at each of the axial positions, and construct the compensation position relationship based on the mapping relationship between the axial position and the lateral walk-off compensation amount.

[0058] Assuming the axial position of the incident end of the nonlinear crystal 4 is z=0, and the axial position of the exit end is z=L (i.e., the axial length is L), and a pre-defined common exit region is defined. The center horizontal position is For the case where the power density region is a continuous focal trajectory, assuming the lateral coordinate of the axial position z in the power density region along the walk-off direction is... For the case where the power density region is a discrete sub-focus array, assuming the axial position of the i-th discrete sub-focus is... The lateral coordinate in the departure direction is .

[0059] For any axial position inside the nonlinear crystal 4 Its horizontal coordinate in the continuous focal trajectory is With horizontal position The relationship is: The horizontal coordinate in the discrete subfocus array is With horizontal position The relationship is: .in, This represents the lateral displacement at the axial position z. and The allowable deviation, not exceeding half the width of the common launch zone, represents minor errors that may exist during manufacturing and assembly. Therefore, the lateral run-off compensation is... (Continuous focal trajectory) or (Discrete subfocal array), axial position After lateral walk-off compensation, the generated 266nm laser beam is positioned within the common emission region at the exit surface of the nonlinear crystal 4. (Continuous focal trajectory) or (Discrete sub-focus array) to improve spatial overlap. Therefore, the closer the axial position is to the incident end of the nonlinear crystal, the longer the 266nm ultraviolet light generated at that axial position travels to the exit end, and the greater the walk-off. Therefore, the corresponding 532nm power density focus needs to be pre-biased more in the walk-off direction.

[0060] Finally, the mapping relationship between all axial positions and their corresponding lateral walk-off compensation amounts, or the mapping relationship between all axial positions and their corresponding lateral coordinates of the power density action zone, is combined to form the compensation position relationship.

[0061] The embodiments of this application first determine the walk-off slope, and then determine the lateral walk-off amount at each axial position based on the walk-off slope. Based on the positional relationship between the lateral walk-off amount and the common exit region, the lateral walk-off compensation amount is determined, thereby determining the compensation positional relationship. This makes the compensation positional relationship a quantitative indicator with a physical basis, which significantly improves the accuracy of subsequent spatial modulation.

[0062] In one possible implementation, S220, the spatial modulation system includes a beam coding unit 3 and an optical field transformation unit 9, such as... Figure 1 As shown.

[0063] Based on the above, in S220, the step of spatially modulating the 532nm laser using a spatial modulation system based on the compensated positional relationship includes: S2210: Determine the walk-off compensation parameters based on the compensation position relationship, and generate control commands based on the walk-off compensation parameters.

[0064] The walk-off compensation parameters are specific parameters determined based on the compensation position relationship and can be understood and executed by the beam coding unit. Therefore, the walk-off compensation parameters are different for different beam coding units. For example, in an embodiment where the beam coding unit is a spatial light modulator, the walk-off compensation parameters are pixel grayscale images, phase images, or voltage matrices.

[0065] Control commands may include control commands related to phase delay, control commands related to energy weight, control commands related to the slope of the continuous focus trajectory, and control commands related to the coordinates of the discrete sub-focuses of the discrete sub-focus array.

[0066] S2220: Based on the type of the beam encoding unit, drive, select, or set the beam encoding unit according to the control command to generate an encoded 532nm light field.

[0067] Upon receiving the control command, the beam coding unit spatially modulates the incident 532nm laser, which typically has a flat wavefront, thereby generating a coded 532nm light field with a non-flat wavefront carrying preset coding information. Spatial modulation includes applying modulation to the incident light field such as spatial phase, phase delay, amplitude, ray angle, or wavefront curvature. Specifically, when the beam coding unit is a programmable beam coding unit such as a spatial light modulator, the control command is used to drive the beam coding unit to load the target pixel grayscale image, target phase image, or target voltage matrix; when the beam coding unit includes multiple phase-type diffractive optical elements with different preset light field coding patterns, the control command is used to select the target phase-type diffractive optical element; when the beam coding unit has adjustable optical parameters or adjustable installation parameters, the control command is used to set the corresponding parameters. For phase-type diffractive optical elements, freeform surface reflective optical elements, or microlens arrays with fixed parameters, the control command can be used as an offline selection, manufacturing, or assembly command to select or set a beam coding unit with target coding characteristics.

[0068] S2230: Input the encoded 532nm light field into the light field transformation unit to generate a converging light field, and use the converging light field as the modulated 532nm light field.

[0069] The optical field transformation unit performs optical transformation on the encoded 532nm optical field, transforming it from a collimated or near-collimated state into a converging optical field that is propagating to different target points inside the nonlinear crystal. This converging optical field is the modulated 532nm optical field.

[0070] After the modulated 532nm light field is introduced into the nonlinear crystal, local power density peaks are formed at various axial positions within the nonlinear crystal, thereby forming the power density active region.

[0071] The following uses a phase-type diffractive optical element as an example to illustrate the change in the optical field before and after spatial modulation. For a phase-type diffractive optical element, assume the incident 532nm light field is... Complex transmittance of beam encoding unit 3 It can be represented as ,in For amplitude modulation function, It is a spatial phase modulation function. It is the imaginary unit.

[0072] After passing through beam encoding unit 3, the generated encoded 532nm light field It can be represented as The encoded 532nm light field is then propagated and transformed by the light field transformation unit 9, converting the phase, amplitude, or wavefront curvature distribution on the modulation surface into the coordinate distribution of the power density action region inside the nonlinear crystal 4, ultimately forming a 532nm light field inside the nonlinear crystal 4. It can be represented as , where H represents the propagation operator from the modulation surface to a point in the internal space of the nonlinear crystal 4. A right-handed Cartesian coordinate system is established for the nonlinear crystal 4. ,in, The direction is the length direction of the nonlinear crystal 4, and is the same as the main propagation direction of the 532nm incident beam; The direction is the projection of the 266nm ultraviolet light walk-off direction onto a cross section perpendicular to the z-direction; The direction is perpendicular to direction and Direction. By direction and The plane formed by the directions is the walk-off plane. By designing a spatial phase modulation function, a 532nm optical field can be generated inside the nonlinear crystal 4. A local peak is formed at a predetermined location to create the desired power density region.

[0073] The modulation process in this application embodiment is not simply to enlarge the 532nm light spot or passively correct the 266nm light spot at the output end, but to actively and accurately precode the nonlinear generation region inside the nonlinear crystal.

[0074] In this embodiment, the compensation position relationship is first converted into walk-off compensation parameters corresponding to the beam encoding unit, and the walk-off compensation parameters are converted into control commands, so that the beam encoding unit encodes the 532nm light field, and the modulated 532nm light field is obtained through the transformation of the light field transformation unit, so as to accurately obtain the power density active region when the light field is introduced into the nonlinear crystal. This process accurately converts the abstract compensation position relationship into the actual three-dimensional light intensity distribution inside the nonlinear crystal, ensuring the effective execution of the walk-off compensation scheme.

[0075] In one possible implementation, the power density effective region is a discrete sub-foci array composed of multiple discrete sub-foci or a continuous focal trajectory extending along the axis. In the discrete sub-foci array, different discrete sub-foci correspond to different axial positions; in the continuous focal trajectory, the lateral offset is different at different axial positions.

[0076] Specifically, the shape of the power density active region can be designed as a discrete sub-focus array or a continuous focus trajectory, depending on application requirements, the type of beam encoding unit used, and the desired energy distribution characteristics. Regardless of whether a discrete sub-focus array or a continuous focus trajectory is used, the core design idea is to physically realize the aforementioned compensation positional relationship. The beam encoding unit encodes the 532nm laser wavefront according to the selected shape, ultimately forming a preset intensity distribution within the nonlinear crystal.

[0077] Compared to continuous focus trajectories, discrete subfocus arrays facilitate individual control of power density, phase, and energy distribution at each axial position, making them suitable for optimizing the conversion region under high-power conditions. A discrete subfocus array comprises multiple discrete subfocuses. (Reference) Figure 3 The discrete subfocus array shown and Figure 6 The illustrated embodiment of the discrete sub-focus array 303 shows multiple discrete sub-focuses distributed within the nonlinear crystal. In this embodiment, the energy of the 532nm laser is intentionally divided and focused onto a series of spatially separated, high-energy-density points. In this discrete sub-focus array, different discrete sub-focuses correspond to different axial positions. The array is not a two-dimensional lattice located on a single plane, but rather a three-dimensional structure extending along an axial direction, such as... Figure 3 As shown, each sub-foci , , ... The spatial coordinates are respectively expressed as , , ... An axially distributed array of discrete subfoci ensures that the nonlinear transformation process can occur over the entire or most of the effective length of the crystal.

[0078] refer to Figure 5 The continuous pre-biased focal line shown and Figure 6 The continuous oblique focal line 301 shown is a continuous focal trajectory. In the embodiment of the continuous focal trajectory, the energy of the 532nm laser is smoothly distributed along a spatial trajectory, rather than concentrated at discrete points, and the lateral offset varies at different axial positions. The continuous focal trajectory is not parallel to the axial direction, but rather has a predetermined, usually varying, angle with the axial direction.

[0079] It should be noted that some beam coding units 3 can only be encoded as discrete sub-foci arrays, such as microlens arrays. Each microlens or group of microlenses in a microlens array can correspond to a discrete sub-foci, such as... Figure 3 The sub-foci shown , , ... .

[0080] Some beam coding units 3 can be encoded as continuous focal trajectories or as discrete subfocal arrays. Examples include phase-type diffractive optical elements, spatial light modulators, and freeform surface reflective optical elements. The following uses phase-type diffractive optical elements and freeform surface reflective optical elements as examples to illustrate the formation principle of power density action regions of different shapes.

[0081] like Figure 6 As shown, the phase-type diffractive optical element (DOE) 302 integrates the functions of a beam encoding unit and a light field transformation unit, so the modulated 532nm light field output from the phase-type diffractive optical element 302 directly enters the BBO crystal. A continuous oblique focal line 301 or a discrete sub-focal point array 303 is achieved by loading or solidifying different phase functions into the phase-type diffractive optical element 302.

[0082] In one possible implementation, when the phase-type diffractive optical element 302 is loaded or fabricated as a continuously varying cylindrical / axial phase function, the 532nm beam forms a continuous oblique focal line 301 within the BBO crystal; when the phase-type diffractive optical element 302 is loaded or fabricated as multiple sub-lens phases, multiple diffraction order phases, or multiple partitioned phases, the 532nm beam forms multiple discrete sub-foci within the BBO crystal, namely a discrete sub-foci array 303.

[0083] In one possible implementation, the phase function is designed as a superposition or multiplexing of multiple sub-lens phases, multiple blazed grating phases, and multiple phase bias terms, so that the i-th diffraction order or the i-th sub-region is focused onto one of the sub-foci. At point ), a discrete sub-focal array 303 can be formed; the phase function can be designed as a focal length or cylindrical phase that changes continuously along one direction, so that the axial and lateral positions of the focal points change continuously with the incident aperture coordinates, thus forming a continuous oblique focal line 301.

[0084] For freeform surface reflecting optical elements, the surface shape characterization parameters of their reflection This is used to provide different local normal directions and optical path compensations for different incident regions. If the surface shape characterization parameters... If the surface shape is smooth and continuous, then the modulated 532nm light field can form a continuous oblique focal line 301 within the BBO crystal; if the surface shape characterization parameters If the surface is partitioned or segmented, and each partition has a different curvature or tilt angle, then each partition can form a corresponding discrete subfoci, thus forming a discrete subfoci array 303.

[0085] When using a continuous focus trajectory, it can be regarded as the limit when the subfocal spacing tends to be continuous, and the continuous focus trajectory can be expressed in integral form. : ,in For continuous axial variables along the length direction of the nonlinear crystal, The magnitude weights are the corresponding positions on the continuous trajectory. For the corresponding phase coding quantity, This represents the field distribution of a single subfoci. It is the imaginary unit.

[0086] In the discrete focus array scheme, the complex amplitude of the target focus array can be written as a superposition of multiple sub-focuses: ;in Indicates the first The magnitude weight of individual focal points Indicates the first Phase encoding amount of each sub-focal point.

[0087] The beam encoding unit 3, consisting of phase-type diffractive optical elements, spatial light modulators, microlens arrays, or freeform mirrors, approximates the actual light field within the nonlinear crystal 4. .

[0088] In this embodiment, the power density action region includes two specific geometric forms: a discrete sub-focal array and a continuous oblique focal line. The discrete sub-focal array facilitates independent and fine-tuning of each nonlinear generation region, while the continuous focal trajectory can form a smoother internal heat distribution in high-power applications. The two forms of power density action region enhance the application flexibility and universality, and can be optimized and selected according to different hardware conditions and performance requirements, thereby more effectively compensating for the space walk-off effect.

[0089] In one possible implementation, when the power density operating region is a discrete sub-focus array, the generation of control commands based on the walk-off compensation parameters includes at least one of the following: Based on the walk-off compensation parameters, phase delay control commands are generated for the 532nm sub-beams corresponding to each of the discrete sub-foci, and the phase delay amounts are different for different discrete sub-foci; Based on the walk-off compensation parameters, different energy weights are assigned to the discrete sub-foci at different axial positions, and control commands corresponding to the energy weights are generated.

[0090] Even if the 266nm ultraviolet light components generated by the discrete sub-foci achieve spatial overlap at the exit surface, if an uncontrolled phase difference exists between them, superposition interference will occur, potentially reducing the energy proportion in the target spatial mode and thus reducing the energy coupled into the target spatial mode. Based on this consideration, in this embodiment, a preset phase delay is applied to the 532nm sub-beams corresponding to each discrete sub-foci during spatial modulation. Specifically, the generated phase delay control command causes the beam encoding unit to add an additional phase delay to each sub-beam while splitting and focusing the 532nm beam. The determination of the phase delay must satisfy the following phase compensation relationship: ; in, Because of the The phase term introduced into the 266nm optical field is due to the phase delay of a 532nm sub-beam. It is the first The cumulative phase term related to each subfoci and phase mismatch, when the phase mismatch is approximately constant. It can be approximated as or Specifically, it depends on the selection of the phase reference plane; the phase mismatch varies with the axial position. When changing, This can be represented as an integral term along the corresponding propagation path. ;in It can be represented as Or the equivalent mismatch amount selected according to the actual phase matching definition. It is the geometric propagation distance of 266nm ultraviolet light within the crystal from the generation location to the emission surface. It is the wave vector magnitude or equivalent propagation constant of 266nm ultraviolet light in a nonlinear crystal, which can be expressed as: ,in The effective refractive index of 266nm ultraviolet light in a nonlinear crystal. It is the vacuum wavelength of 266nm ultraviolet light. It is the desired common phase reference value at the target output region; It is an integer used to indicate that phases differing by an integer multiple of 2π can be considered as being in phase.

[0091] By constraining this phase compensation relationship, the 266nm ultraviolet light generated at different axial positions can have a preset phase relationship at the nonlinear crystal emission surface, so that the phase difference of each 266nm component in the target output region is within a preset range, achieving in-phase superposition.

[0092] Phase delay can be implemented by: writing a specific phase grayscale value to a spatial light modulator, applying a voltage to an adjustable phase plate, switching the encoding region of a prefabricated phase-type diffractive optical element, or adjusting the optical path difference of a partitioned delay plate. For a fixed phase-type diffractive optical element implementation, the phase delay can be pre-fixed during the design and manufacturing of the phase-type diffractive optical element; for a programmable spatial light modulator implementation, the phase delay can be updated in real time in closed-loop control.

[0093] During high-power operation, ultraviolet absorption and local temperature rise within the nonlinear crystal are significant factors affecting system stability. If most of the 266nm ultraviolet light is generated early at the crystal tip and needs to propagate a long distance within the crystal, its accumulated absorption and heat load will increase significantly. Based on this consideration, embodiments of this application assign non-uniform energy weights to discrete sub-foci at different axial positions. The energy weights are the peak power density at 532nm, the integrated power, or their normalized values ​​at each sub-foci.

[0094] Specifically, the generated control commands correspond to the energy weights of each sub-focus, with different energy weights for different sub-focuses. The energy weight control commands adjust the discrete sub-focuses (such as those near the exit end of the nonlinear crystal) to... Figure 4 The 532nm energy weights corresponding to sub-focuses 4 and 5 in the image are greater than those of discrete sub-focuses closer to the incident end (such as...). Figure 4 The energy weights of sub-foci 1 and sub-foci 2 in the equation.

[0095] The allocation of energy weights can include: changing the diffraction efficiency or grayscale weight of the corresponding sub-region of the spatial light modulator; changing the blaze depth or duty cycle of each diffraction order in the design of phase-type diffractive optical elements; setting variable attenuators, combinations of polarizers and half-wave plates, or liquid crystal attenuation units in each sub-beam channel; or changing the incident energy of each sub-foci by the area of ​​the microlens aperture, the area of ​​the freeform surface partition, and the distribution of the incident beam landing point.

[0096] This application embodiment achieves coherent combining of 266nm ultraviolet light generated at different axial positions at the exit surface by applying phase compensation to the discrete sub-foci. This helps reduce target mode coupling loss caused by phase mismatch, thereby improving the coherence and energy concentration of the final output beam. By setting non-uniform energy weights, especially setting higher weights in the region near the exit end, the long-distance propagation of early-generated 266nm ultraviolet light within the nonlinear crystal is reduced to a certain extent. This can reduce ultraviolet absorption and local thermal load under high-power operating conditions and improve system output stability.

[0097] In one possible implementation, determining the walk-off compensation parameters based on the compensation position relationship includes: When the beam encoding unit is a spatial light modulator, the target pixel grayscale image, target phase image, or target voltage matrix is ​​determined according to the compensation position relationship, and the target pixel grayscale image, the target phase image, or the target voltage matrix is ​​used as the walk-off compensation parameter; When the beam coding unit is a phase-type diffractive optical element, the number of the target light field coding pattern is determined according to the compensation position relationship, and the number is used as the walk-off compensation parameter; When the beam encoding unit is a freeform surface reflective optical element, the surface shape characterization parameters of the freeform surface reflective optical element are determined according to the compensation position relationship, and the surface shape characterization parameters are used as the walk-off compensation parameters. When the beam encoding unit is a microlens array, the focal length and center position of each microlens in the microlens array and the relay magnification of the light field transformation unit are determined according to the compensation position relationship, and the focal length, the center position and the relay magnification are used as the walk-off compensation parameters.

[0098] A spatial light modulator is a dynamic optical element composed of a large number of independently addressable pixel units, capable of real-time modulation of the beam wavefront based on the input electrical signal. A two-dimensional digital matrix can be calculated using a reverse optics design algorithm based on the compensation position relationship. This digital matrix can be a target pixel grayscale image, a target phase image, or a target voltage matrix. This digital matrix is ​​used as walk-off compensation parameters to generate control commands, which are then loaded onto the pixel surface of the spatial light modulator. Each pixel on the spatial light modulator applies a precise phase delay to the portion of the 532nm beam passing through it based on its assigned grayscale or voltage value, obtaining an encoded 532nm light field. After passing through the light field transformation unit, the phase distribution on the pixel surface is converted into a discrete sub-focus array within a nonlinear crystal. The 266nm ultraviolet laser generator can adjust the lateral position, axial position, phase delay, and energy weight of the sub-focuses by updating the grating period, quadratic phase coefficient, local phase bias, and grayscale weight in the phase image, respectively.

[0099] A phase-type diffractive optical element is a static, purely phase-based element whose surface microstructure pattern is fixed during the design and manufacturing stage. The phase-type diffractive optical element in this embodiment is a selectable or switchable diffractive optical element system. This system can include multiple pre-fabricated diffractive optical elements, or a single diffractive optical element may have multiple different coded regions engraved on it. Each element or region corresponds to a unique target light field coded pattern number. Based on the above, when determining the walk-off compensation parameters based on the compensation position relationship, the most suitable target light field coded pattern number under the current operating condition can be determined from a preset database or lookup table according to the compensation position relationship. This number is the walk-off compensation parameter. Subsequently, a corresponding control command is generated based on this number to drive a mechanical device (such as a rotating disk or translation stage) to select the corresponding diffractive optical element or switch to the corresponding coded region, thereby achieving spatial modulation.

[0100] A freeform surface reflective optical element is a mirror whose surface shape is neither spherical nor rotationally symmetric. Its continuously smooth and complex surface shape can precisely and asymmetricly modulate the wavefront of the incident beam. For a freeform surface reflective optical element, the surface shape characterization parameter W(x,y) of its reflecting surface is used to provide different local normal directions and optical path compensations for different incident regions. Therefore, by using the surface shape characterization parameter as the walk-off compensation parameter and generating corresponding control commands based on the surface shape characterization parameter, the freeform surface reflective optical element can be controlled to encode the 532nm light field in different ways. Alternatively, corresponding control commands can be generated based on the geometric parameters of the freeform surface reflective optical element, such as the movement parameters of the displacement stage, tilt stage, or zoom mechanism, to change the incident beam landing point and effective focal length.

[0101] Microlens arrays can split a complete incident beam into multiple sub-beams, with each microlens or group of microlenses corresponding to a discrete sub-focal point. If the... The center coordinates of each microlens are Focal length is and through the multiplier When a relay system is imaged into a nonlinear crystal, the lateral coordinate of its corresponding subfoci can be approximated as: axial position The focal length of the microlens can be determined. The image distance of the relay system and the position of the nonlinear crystal are jointly determined. Therefore, by selecting microlenses with different center positions and focal lengths, discrete sub-focal points distributed along the length of the nonlinear crystal can be formed. Alternatively, based on the geometric parameters of the microlens array, such as the movement parameters of the displacement stage, tilt stage, or zoom mechanism, corresponding control commands can be generated to change the incident beam landing point and effective focal length.

[0102] Based on the above, when determining the walk-off compensation parameters based on the compensation position relationship, the required geometric parameters of each microlens in the microlens array can be determined as walk-off compensation parameters. These geometric parameters may include: the focal length of each microlens, which mainly determines the axial position of its corresponding sub-focal point within the nonlinear crystal; the center position of each microlens in the array, which mainly determines the lateral coordinates of its corresponding sub-focal point within the nonlinear crystal; and the relay magnification of the subsequent optical field transformation unit, which is used to scale the size of the original focal array formed by the microlens array to adjust the lateral and axial spacing between the sub-focal points, thereby ensuring that the entire discrete sub-focal point array can accurately fall within the effective length range of the nonlinear crystal.

[0103] This application provides specific forms of walk-off compensation parameters when spatial light modulators, phase-type diffractive optical elements, freeform surface reflective optical elements, and microlens arrays are used as beam coding units, providing a basis for flexible selection of beam coding units between different operating modes.

[0104] Under high-power or long-term operation conditions, factors such as temperature changes and mechanical vibrations in the laser system may cause the preset walk-off compensation parameters to deviate from their optimal state, thereby affecting the quality and stability of the output beam. Based on this consideration, in one possible implementation, a post-shaping unit is provided downstream of the nonlinear crystal.

[0105] Based on the above, such as Figure 7 As shown, the 266nm ultraviolet laser generation method further includes: S230: Perform a first sampling and monitoring of the 266nm ultraviolet light emitted from the nonlinear crystal to obtain spatial overlap parameters; S240: If the spatial overlap parameter does not meet the first preset condition, adjust the walk-off compensation parameter or control command based on the spatial overlap parameter so that the spatial overlap parameter meets the first preset condition. S250: Perform a second sampling and monitoring of the 266nm ultraviolet light emitted from the post-shaping unit to obtain beam parameters; S260: If the beam parameters do not meet the second preset condition, adjust the system operating parameters based on the beam parameters to make the beam parameters meet the second preset condition. The system operating parameters include the nonlinear conversion parameters of the nonlinear crystal, the walk-off compensation parameters, and the post-processing parameters of the post-shaping unit.

[0106] like Figure 1 As shown, in the 266nm ultraviolet laser generation system, a 266nm post-shaping unit 5 is provided downstream of the nonlinear crystal 4 for further fine-tuning and optimizing the spot shape of the 266nm ultraviolet light. In one possible implementation, the 266nm post-shaping unit 5 is a cylindrical lens group or an ultraviolet beam expander group.

[0107] Meanwhile, the 266nm ultraviolet laser generation system also includes a residual light separation unit 6 and a 266nm sampling and monitoring unit 7. The residual light separation unit 6 is located downstream of the 266nm post-shaping unit 5 and is used to separate the 266nm main output 63, the residual 532nm branch 64, and the residual 1064nm branch or bleeder branch 65. The residual 1064nm light can enter the bleeder branch or optical trap, and the residual 532nm light can enter the monitoring branch. The residual light separation unit 6 can be a dual-color mirror group and optical trap with high reflectivity or high transmittance at 266nm and different reflection / transmission characteristics at 532nm and 1064nm.

[0108] The 266nm sampling and monitoring unit 7 can sample and monitor the light beam at two or more locations in the optical path. Figure 1 In the 266nm ultraviolet laser generation system, the 266nm sampling and monitoring unit 7 is used to sample and monitor the 266nm main output 63 (i.e., the subsequent 266nm ultraviolet light). The 266nm ultraviolet light generated by the nonlinear crystal 4 is shaped by the 266nm post-shaping unit 5 and then enters the residual light separation unit 6. The residual 532nm and / or 1064nm are separated into the corresponding branches, and the 266nm main output enters the output optical path and is sampled by the 266nm sampling and monitoring unit 7.

[0109] Understandably, a 266nm sampling and monitoring unit 7 can also be set at the output end of the nonlinear crystal 4 to sample and monitor the 266nm ultraviolet light output by the nonlinear crystal 4.

[0110] Specifically, the 266nm sampling monitoring unit 7 can be one or more of a 266nm sampling mirror, an ultraviolet spot detector, a power detector, a pointing detector, or a wavefront detector. The 266nm sampling mirror is used to extract a small proportion of sampled light from the 266nm main optical path. The ultraviolet spot detector is used to obtain a two-dimensional spot image. The image is used to calculate the beam width, ellipticity, and centroid position. A power detector outputs an electrical signal corresponding to the average power or pulse energy at 266 nm. A pointing detector, either a position-sensitive detector or a four-quadrant detector, is used to obtain the pointing drift of the beam centroid over time. A wavefront detector, either a Shack-Hartmann wavefront sensor or a shearing interference wavefront sensor, is used to obtain the wavefront slope or wavefront aberration.

[0111] The beam width can be calculated from the second moment, for example... , ,in Let R be the centroid of the light spot. The ellipticity R can be derived from the two eigenvalues ​​of the second-order moment matrix. and Sure: The direction drift can be calculated from the deviation of the centroid coordinates over time or the deviation Δx relative to the reference position. c Δy c This indicates the power P of 266nm ultraviolet light. 266 Can be made by P 266 =C p ·V p Alternatively, it can be calculated using the detector calibration coefficients, where Cp is the calibration coefficient of the power detector and Vp is the voltage signal output by the power detector. The wavefront slope can be directly measured by the wavefront sensor, and the wavefront distribution can be obtained by integrating the local slope.

[0112] After the nonlinear crystal 4 exits and before the 266nm shaping unit 5, the first sampling and monitoring of the 266nm ultraviolet light is performed. The obtained spatial overlap parameters may include one or more of the following: 266nm spot width, ellipticity, power, pointing or wavefront information.

[0113] If these spatial coincidence parameters are not within the preset range, they do not meet the requirements. For example, if the light spot is too wide in the walk-off direction, it indicates a decrease in internal spatial coincidence. In this case, based on the spatial coincidence parameter, the walk-off compensation parameter or control command is adjusted to ensure the optimality of the internal focal array under different operating conditions and improve the spatial coincidence of 266nm ultraviolet light generated at different depths inside the nonlinear crystal at the exit surface. The adjustment parameters include the slope κ of the continuous focal trajectory and the coordinates (z) of the discrete sub-foci. i ,y i Phase delay of sub-beams i Energy weight w of discrete subfocus i And the focusing position. For example, adjusting the phase diagram loaded by the phase-type diffraction optical element or switching the coding pattern of the phase-type diffraction optical element to re-optimize the focal array distribution inside the crystal until the spatial coincidence parameter is restored to the ideal state.

[0114] In one possible implementation, this can be achieved by constructing an evaluation function J = α(R - R0). 2 +β(W-W0) 2 +γ(1-P 266 / P0) 2 +ηD 2 To determine whether the spatial overlap parameters meet the requirements, where W is the beam width in the target direction and P... 266 Let be the power of 266nm ultraviolet light, D be the centroid or wavefront deviation of the light spot, R0, W0, and P0 be the target values ​​corresponding to ellipticity, spot width, and power, and α, β, γ, and η be weighting coefficients. By changing the parameter vector q={κ,y i ,z i , i ,w i To reduce the evaluation function J, the spatial overlap parameter that is outside the preset range is brought into the preset range. Specifically, the parameter vector q can be updated using scanning optimization or gradient iteration, for example, q(k+1)=q(k)-μ· J / q, where μ is the step size; alternatively, a lookup table method can be used to select the initial parameter vector q based on the pre-calibrated walk-off slope ρ, the length L of the nonlinear crystal, the input power, and the temperature, and then fine-tune the parameter vector q based on the real-time sampling and monitoring results.

[0115] After passing through the 266nm shaping unit 5, the final output 266nm ultraviolet light undergoes a second sampling and monitoring. Specifically, the final beam parameters, such as output power P266 and direction shift Δx, are obtained through a power detector, a pointing detector, or a wavefront sensor. c Δy cThe beam parameters, such as wavefront slope or wavefront aberration, are then assessed to determine if they meet the final application requirements. If not, for example, if the output power decreases or the pointing drifts, the system operating parameters are adjusted based on these beam parameters to ensure that the final output beam quality meets all requirements. These system operating parameters may include: nonlinear conversion parameters of the nonlinear crystal, such as optimizing the phase matching angle of the nonlinear crystal by adjusting the temperature control seat or angle adjustment seat; walk-off compensation parameters, such as fine-tuning the axial position of the individual focal arrays within the crystal; and post-processing parameters of the post-shaping unit, such as adjusting the spacing or angle of the cylindrical mirror group. Furthermore, the ratio of the monitored residual 532nm light intensity to the 266nm output power can be used to assist in determining the deviation of the phase matching state and make corresponding adjustments.

[0116] This application embodiment ensures that the 266nm ultraviolet light generated at different axial positions reaches the expected spatial overlap and output beam quality when it reaches the exit surface of the nonlinear crystal through walk-off propagation by sampling and monitoring the 266nm ultraviolet light of the pre-stage and post-stage stages and making corresponding adjustments. This transforms the static compensation scheme into a dynamic and adaptive optimization system, improving the output stability and reliability of the entire laser system in high-power or complex environments, enabling it to continuously provide high-quality 266nm ultraviolet laser.

[0117] Based on the above, this application also provides a 266nm ultraviolet laser generating apparatus. The 266nm ultraviolet laser generating apparatus and the aforementioned 266nm ultraviolet laser generating method can be referred to and correspond to each other.

[0118] As an example, such as Figure 8 As shown, the 266nm ultraviolet laser generating device includes: The compensation position relationship determination module 810 is used to determine the compensation position relationship based on the phase matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount. The main propagation direction of the nonlinear crystal is the axial direction. The spatial modulation module 820 is used to spatially modulate the 532nm laser using a spatial modulation system based on the compensation position relationship, and to introduce the modulated 532nm light field into the nonlinear crystal to obtain a 266nm ultraviolet output laser. The nonlinear crystal forms a power density active region distributed along the axial direction. The lateral offset of the power density active region at each axial position along the walk-off direction is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each axial position, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

[0119] This application first determines the compensation position relationship, and then spatially modulates the 532nm laser based on the compensation position relationship. The 532nm power density region is spatially pre-biased according to a 266nm walk-off amount, and walk-off compensation is precisely achieved at each axial position. This ensures that the 266nm ultraviolet light generated at different crystal depths, after walk-off propagation, is located in the same target output region at the exit surface. Compared with the passive compensation performed outside the crystal in the prior art, the active spatial precoding of this application helps to reduce the broadening and ellipticization of the 266nm output spot caused by the walk-off effect, and improves the spatial overlap of ultraviolet light components generated at different depths at the exit surface. At the same time, by distributing the nonlinear interaction region along the entire length of the crystal, it is also beneficial to increase the effective interaction length under walk-off-limited conditions and improve the energy proportion of the output ultraviolet light in the target spatial mode.

[0120] Figure 9 This is a schematic diagram of the structure of the electronic device provided in this application, such as... Figure 9 As shown, the electronic device may include: a processor 910, a communication interface 920, a memory 930, and a communication bus 940, wherein the processor 910, the communication interface 920, and the memory 930 communicate with each other via the communication bus 940. The processor 910 can be connected to the 266nm ultraviolet laser generation system via the communication interface 920 and can call the logic instructions in the memory 930 to implement the 266nm ultraviolet laser generation method of any of the above embodiments, the method including: The compensation position relationship is determined based on the phase matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount. The main propagation direction of the nonlinear crystal is the axial direction. Based on the aforementioned compensation position relationship, a spatial modulation system is used to spatially modulate a 532nm laser, and the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser. A power density active region is formed within the nonlinear crystal along the aforementioned axis. The lateral offset of the power density active region at each of the aforementioned axial positions along the walk-off direction is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each of the aforementioned axial positions, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

[0121] Furthermore, the logical instructions in the aforementioned memory 930 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0122] On the other hand, this application also provides a computer program product, the computer program product including a computer program stored on a non-transitory computer-readable storage medium, the computer program including program instructions, which, when executed by a computer, implement the 266nm ultraviolet laser generation method provided in the above embodiments, the method including: The compensation position relationship is determined based on the phase matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount. The main propagation direction of the nonlinear crystal is the axial direction. Based on the aforementioned compensation position relationship, a spatial modulation system is used to spatially modulate a 532nm laser, and the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser. A power density active region is formed within the nonlinear crystal along the aforementioned axis. The lateral offset of the power density active region at each of the aforementioned axial positions along the walk-off direction is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each of the aforementioned axial positions, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

[0123] In another aspect, this application also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the 266nm ultraviolet laser generation method provided in the above embodiments, the method comprising: The compensation position relationship is determined based on the phase matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount. The main propagation direction of the nonlinear crystal is the axial direction. Based on the aforementioned compensation position relationship, a spatial modulation system is used to spatially modulate a 532nm laser, and the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser. A power density active region is formed within the nonlinear crystal along the aforementioned axis. The lateral offset of the power density active region at each of the aforementioned axial positions along the walk-off direction is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each of the aforementioned axial positions, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

[0124] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0125] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for generating 266nm ultraviolet laser, characterized in that, include: The compensation position relationship is determined based on the phase matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount. The main propagation direction of the nonlinear crystal is the axial direction. Based on the aforementioned compensation position relationship, a spatial modulation system is used to spatially modulate a 532nm laser, and the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser. A power density active region is formed within the nonlinear crystal along the aforementioned axis. The lateral offset of the power density active region at each of the aforementioned axial positions along the walk-off direction is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each of the aforementioned axial positions, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

2. The method for generating 266nm ultraviolet laser according to claim 1, characterized in that, The determination of the compensation position relationship based on the phase-matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in a nonlinear crystal includes: The walk-off slope is determined based on the phase-matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal, and the walk-off slope is used to characterize the degree of spatial walk-off effect. Based on the walk-off slope, the center lateral position of the target output region, the axial length of the nonlinear crystal, and each of the axial positions, the lateral walk-off compensation amount at each of the axial positions is determined, and the compensation position relationship is constructed based on the mapping relationship between the axial position and the lateral walk-off compensation amount.

3. The method for generating 266nm ultraviolet laser according to claim 1, characterized in that, The spatial modulation system includes a beam coding unit and an optical field transformation unit; The step of spatially modulating the 532nm laser using a spatial modulation system based on the compensated positional relationship includes: Based on the compensation position relationship, the walk-off compensation parameters are determined, and control commands are generated based on the walk-off compensation parameters; According to the type of the beam encoding unit, the beam encoding unit is driven, selected or set according to the control command to generate an encoded 532nm light field; The encoded 532nm light field is input into the light field transformation unit to generate a converging light field, and the converging light field is used as the modulated 532nm light field.

4. The 266nm ultraviolet laser generation method according to claim 3, characterized in that, A post-shaping unit is provided downstream of the nonlinear crystal; The 266nm ultraviolet laser generation method further includes: The first sampling and monitoring of the 266nm ultraviolet light emitted from the nonlinear crystal was performed to obtain the spatial overlap parameter; If the spatial overlap parameter does not meet the first preset condition, the walk-off compensation parameter or control command is adjusted based on the spatial overlap parameter so that the spatial overlap parameter meets the first preset condition. The beam parameters are obtained by performing a second sampling and monitoring of the 266nm ultraviolet light emitted from the post-shaping unit. If the beam parameters do not meet the second preset condition, the system operating parameters are adjusted based on the beam parameters to make the beam parameters meet the second preset condition; the system operating parameters include the nonlinear conversion parameters of the nonlinear crystal, the walk-off compensation parameters, and the post-processing parameters of the post-shaping unit.

5. The 266nm ultraviolet laser generation method according to claim 3, characterized in that, The power density effective region is either a discrete sub-foci array composed of multiple discrete sub-foci or a continuous focal trajectory extending along the axial direction. In the discrete sub-foci array, different discrete sub-foci correspond to different axial positions; in the continuous focal trajectory, the lateral offset is different at different axial positions.

6. The method for generating 266nm ultraviolet laser according to claim 5, characterized in that, When the power density operating region is the discrete sub-focus array, the generation of control commands based on the walk-off compensation parameters includes at least one of the following: Based on the walk-off compensation parameters, phase delay control commands are generated for the 532nm sub-beams corresponding to each discrete sub-foci, and the phase delay amounts are different for different discrete sub-foci; Based on the walk-off compensation parameters, different energy weights are assigned to the discrete sub-foci at different axial positions, and control commands corresponding to the energy weights are generated.

7. A 266nm ultraviolet laser generating device, characterized in that, include: The compensation position relationship determination module is used to determine the compensation position relationship based on the phase matching characteristics and lateral walk-off characteristics of 266nm ultraviolet light in the nonlinear crystal. The compensation position relationship characterizes the correspondence between the axial positions of the nonlinear crystal and the corresponding lateral walk-off compensation amount. The main propagation direction of the nonlinear crystal is the axial direction. A spatial modulation module is used to spatially modulate a 532nm laser using a spatial modulation system based on the compensation position relationship, and to introduce the modulated 532nm light field into the nonlinear crystal to obtain a 266nm ultraviolet output laser. The nonlinear crystal forms a power density active region distributed along the axial direction. The lateral offset of the power density active region along the walk-off direction at each axial position is the lateral walk-off compensation amount corresponding to that axial position in the compensation position relationship. The 266nm ultraviolet light generated at each axial position, after walk-off propagation, is located within the same preset target output region at the exit surface of the nonlinear crystal, thus forming the 266nm ultraviolet output laser.

8. A 266nm ultraviolet laser generation system, characterized in that, It includes the 266nm ultraviolet laser generating device according to claim 7, and a 532nm laser source, a spatial modulation system and a nonlinear crystal arranged sequentially along the optical path; The 266nm ultraviolet laser generating device is signal-connected to the spatial modulation system and is used to control the spatial modulation system to spatially modulate the 532nm laser output from the 532nm laser source, so that the modulated 532nm light field is introduced into the nonlinear crystal to obtain a 266nm ultraviolet output laser.

9. An electronic device, the electronic device comprising a memory, a processor, a communication interface, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the 266nm ultraviolet laser generation method as described in any one of claims 1 to 6.

10. A non-transitory computer-readable storage medium, wherein a computer program is stored on the non-transitory computer-readable storage medium, characterized in that, When the computer program is executed by the processor, it implements the 266nm ultraviolet laser generation method as described in any one of claims 1 to 6.

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