An irradiance simulation light source device

Abstract

The present application relates to the technical field of optical design, and specifically provides a kind of irradiance simulation light source device, laser, first beam expander lens group and shaping module are sequentially arranged along optical path;Laser is used to emit Gaussian beam;First beam expander lens group includes first group of lenses, second group of lenses and third group of lenses, adjust the axial spacing between first group of lenses and second group of lenses to carry out first beam expansion to Gaussian beam, adjust the axial spacing between second group of lenses and third group of lenses to carry out first collimation to Gaussian beam;Shaping module includes first free-form surface lens and second free-form surface lens, first free-form surface lens converts Gaussian beam into uniform intensity beam, and second free-form surface lens carries out second collimation to uniform intensity beam.The present application can form uniform irradiance light spot at target working distance, and uniform irradiance light spot has the advantages of high uniformity, high stability and high collimation, and is suitable for solar global irradiance calibration and other radiation metrology field.

Description

Technical Field

[0001] This invention belongs to the field of optical design technology, and in particular relates to an irradiance simulation light source device. Background Technology

[0002] The sun is the energy source of Earth's climate system and plays a vital role in Earth's environment and life activities. Total Solar Irradiance (TSI) is a key physical quantity characterizing the solar radiation energy reaching the top of Earth's atmosphere, and therefore one of the important input parameters in Earth's climate models. TSI is the main external energy driving Earth's radiation energy balance, photosynthesis, surface photochemical reactions, meteorological and climate formation, and the global hydrological cycle. Its changes are directly related to the stable operation of Earth's ecosystems and have a continuous and profound impact on the survival and health of humans and other organisms.

[0003] TSI calibration is a crucial step in the development of solar radiation measurement instruments. The obtained calibration coefficients are one of the error sources in the solar radiation measurement chain, and calibration uncertainty directly affects TSI measurement uncertainty. To unify the global solar radiation scale, in the late 1970s, the World Radiation Centre (WRC) in Davos, Switzerland, adopted fifteen absolute radiometers of nine types as the World Standard Group (WSG), using the weighted average measurement results as the WRR. The WRC holds an international field calibration every five years, with the WSG and national solar radiometers simultaneously observing ground-based solar radiation to transmit the WRR benchmark. Due to the influence of WRR uncertainty, ground-based solar radiation stability, and vacuum-air inequivalence, the field calibration uncertainty traced back to WRR is only 0.3%. With the increasing demands for data quality in major fields such as global climate change research, extreme weather prediction, and high-resolution space observation, the need for high precision in aerospace remote sensing data is becoming increasingly prominent. Existing field calibration methods traced back to WRR are insufficient to meet the stringent requirement of 0.05% uncertainty in total solar irradiance measurement in international climate change research.

[0004] Cryoradiometers are a globally recognized primary standard for optical radiation metrology. Based on near-ideal blackbody absorption in low-temperature environments and the principle of precise electrical substitution measurement, they directly trace optical radiation power to an electrical power reference, theoretically achieving extremely high absolute accuracy. Using cryoradiometers as the reference source for optical radiation measurement fundamentally solves the problem of insufficient absolute accuracy of reference sources in traditional calibration systems, providing a direct and reliable traceability path for solar absolute radiometers. However, a key technical bottleneck in constructing an irradiance calibration link based on cryoradiometers in the laboratory lies in the lack of a suitable irradiance simulation light source. Therefore, it is urgent to study a method for obtaining an irradiance calibration light source that can achieve high uniformity and high stability.

[0005] To achieve direct comparison between solar radiation measurement instruments and cryogenic radiometers, the Lab of Atmospheric and Space Physics (LASP) developed the Solar Radiation Calibration Facility (TSI Radiometer Facility, TRF), achieving a nominal calibration uncertainty of 0.03%. This method utilizes a highly stable laser source, employing a two-dimensional scanning galvanometer to rapidly scan the incident laser source, achieving uniform superposition of Gaussian beams. The rapid scanning galvanometer uses an optomechanical scanning method, with a mechanical device driving the deflection of the reflected beam, thus moving the laser beam within its working range. Its mechanical component consists of a beam deflector composed of X and Y scanning heads, equipped with tiny reflecting mirrors. The reflection angle is controlled by a marking program to achieve beam positioning and scanning. However, the TRF device acquires illuminance using a rapid scanning galvanometer, making the systematic error introduced by time equivalence difficult to assess. Summary of the Invention

[0006] In view of this, the present invention aims to provide an irradiance simulation light source device, which achieves diameter adjustment and first collimation of light through three sets of lenses in the first beam expander group; the first freeform surface lens of the shaping module converts the Gaussian beam into a uniform intensity beam, and the uniform intensity beam is collimated for the second time by the second freeform surface lens; the converging lens and collimating lens of the second beam expander group achieve the second beam expansion and the third collimation of the uniform intensity beam.

[0007] To achieve the above objectives, the technical solution created by this invention is implemented as follows: The present invention provides an irradiance simulation light source device, comprising: a laser, a first beam expander group and a shaping module arranged sequentially along the optical path; Lasers are used to emit Gaussian beams; The first beam expander group includes: a first group of lenses, a second group of lenses, and a third group of lenses. Adjusting the axial distance between the first group of lenses and the second group of lenses is used for the first beam expansion of the Gaussian beam; adjusting the axial distance between the second group of lenses and the third group of lenses is used for the first collimation of the Gaussian beam. The shaping module includes: a first freeform surface lens and a second freeform surface lens; the design formula for the shaping module is expressed as: ; in: For about , , , and The function, for The second-order partial derivative, for The second-order partial derivative, for and The mixed partial derivatives, For Gaussian beams in The amplitude distribution function at that location, u and v Let be the coordinates of the Gaussian beam's position within the optical path cross-section. Let x be the x-coordinate of the incident surface. The vertical coordinate of the incident surface is... Let be the amplitude distribution function of the target surface. For the Gaussian beam radius parameter, Let be the radius of curvature of the incident wavefront. Let be the radius of curvature of the incident wavefront in the u direction. Let be the radius of curvature of the incident wavefront in the v direction. The boundary of the incident surface, For the target surface boundary, The x-coordinate of the target surface, The vertical coordinate of the target surface; The first freeform lens converts the Gaussian beam into a uniform intensity beam, which is then collimated a second time by the second freeform lens to form a uniform irradiance spot at the target working distance.

[0008] Preferably, the laser is a monochromatic laser.

[0009] Preferably, it also includes a laser power stabilizer and a spatial filter, which are arranged sequentially between the laser and the first beam expander group. The laser power stabilizer is used to suppress power fluctuations in the Gaussian beam, and the spatial filter is used to filter out stray wavefront components in the Gaussian beam.

[0010] Preferably, the Gaussian beam is in Amplitude distribution function at point Represented as: ; in: Let z be the radius of the light spot at point z on the optical path. Let be the waist radius of the Gaussian beam. The maximum amplitude of the Gaussian beam. u and v Let be the coordinates of the Gaussian beam's position within the optical path cross-section. Let x be the x-coordinate of the incident surface. The vertical coordinate of the incident surface; Preferably, the first group of lenses, the second group of lenses, and the third group of lenses are all ultraviolet fused silica lenses.

[0011] Preferably, the first beam expander group adopts a Galilean structure. Preferably, it also includes a second beam expander group, which includes a converging lens and a collimating lens. The converging lens and the collimating lens are sequentially arranged along the optical path at the output end of the shaping module. The converging lens and the collimating lens are used to perform a second beam expansion and a third collimation on the uniform intensity beam.

[0012] Preferably, the focal length of the converging lens and the focal length of the collimating lens are scaled proportionally according to the specific target working distance.

[0013] Preferably, the second beam expander group is set using Kohler illumination, and the axial distance between the converging lens and the collimating lens is equal to the sum of the focal lengths of the converging lens and the collimating lens.

[0014] Preferably, the first group of lenses, the second group of lenses, and the third group of lenses are integrated into a precision mechanical lens barrel by means of an air gap.

[0015] Compared with the prior art, the present invention can achieve the following beneficial effects: This application employs a freeform shaping lens to precisely control the wavefront and redistribute the intensity of Gaussian distributed light, overcoming the inherent defect of uneven intensity distribution after simple beam expansion of traditional monochromatic lasers, and achieving a highly uniform irradiance distribution on the target surface.

[0016] This application introduces an active power stabilization control system, which incorporates a laser power stabilizer. This stabilizer effectively suppresses instantaneous fluctuations and long-term drift in the laser's output intensity, ensuring the temporal stability of the irradiance. Furthermore, using a laser as the light source provides an irradiance level significantly higher than that of a halogen tungsten lamp.

[0017] This application combines spatial filtering technology to purify the light wavefront. The spatial filtering technology is achieved through a spatial filter, and a second beam expander group is designed to maintain good collimation while expanding the large aperture light beam. This meets the long working distance requirements of irradiance simulation light sources used in laboratory vacuum common-path calibration systems.

[0018] The TRF calibration device of LASP in the United States acquires irradiance light source by rapidly scanning galvanometers. The systematic error introduced by time equivalence is difficult to evaluate. However, the irradiance simulation light source device of this application establishes a spatially uniform irradiance simulation light source based on Gaussian beam shaping technology of freeform surfaces. The systematic error introduced by it can be evaluated experimentally. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1This is a diagram illustrating the composition of an irradiance simulation light source device provided according to an embodiment of the present invention; Figure 2 This is a diagram of the first beam expander assembly provided according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a shaping module provided according to an embodiment of the present invention; Figure 4 This is a diagram of the second beam expander assembly provided according to an embodiment of the present invention.

[0020] The reference numerals in the figures include: 1. Laser power stabilizer; 2. Spatial filter; 3. First beam expander group; 4. Shaping module; 5. Converging lens; 6. Collimating lens; 7. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; the relevant operations can be fully understood based on the description in the specification and general technical knowledge in the art.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] Please see Figures 1 to 4 In one embodiment of the present invention, an irradiance simulation light source device based on freeform surface shaping and two beam expansions is provided, wherein the following components are arranged sequentially along the optical path: a laser 1, a first beam expander group 4 and a shaping module 5; Laser 1 is used to emit a Gaussian beam; The first beam expander group 4 includes: a first group of lenses, a second group of lenses, and a third group of lenses. The axial spacing between the first group of lenses and the second group of lenses is adjusted to perform the first beam expansion of the Gaussian beam; the axial spacing between the second group of lenses and the third group of lenses is adjusted to perform the first collimation of the Gaussian beam. Shaping module 5 includes: a first freeform surface lens and a second freeform surface lens; the design formula for shaping module 5 is expressed as: ; in: For about , , , and The function, for The second-order partial derivative, for The second-order partial derivative, for and The mixed partial derivatives, For Gaussian beams in The amplitude distribution function at that location, u and v Let be the coordinates of the Gaussian beam's position within the optical path cross-section. Let x be the x-coordinate of the incident surface. The vertical coordinate of the incident surface is... Let be the amplitude distribution function of the target surface. For the Gaussian beam radius parameter, Let be the radius of curvature of the incident wavefront. Let be the radius of curvature of the incident wavefront in the u direction. Let be the radius of curvature of the incident wavefront in the v direction. The boundary of the incident surface, For the target surface boundary, The x-coordinate of the target surface, The vertical coordinate of the target surface; The first freeform lens converts the Gaussian beam into a uniform intensity beam, which is then collimated a second time by the second freeform lens to form a uniform irradiance spot at the target working distance.

[0027] The components arranged sequentially along the optical path are: laser 1, laser power stabilizer 2, spatial filter 3, first beam expander group 4, shaping module 5, converging lens 6, and collimating lens 7.

[0028] In this system, laser 1 serves as the light source, emitting a Gaussian beam. A laser power stabilizer 2 and a spatial filter 3 are sequentially installed at the output end of laser 1. Both the laser power stabilizer 2 and the spatial filter 3 are used to denoise the Gaussian beam. Specifically, the laser power stabilizer 2 suppresses power fluctuations and long-term drift in the Gaussian beam. The spatial filter 3 filters out high-frequency stray wavefront components from the Gaussian beam. After passing through the laser power stabilizer 2 and the spatial filter 3, the Gaussian beam is collimated and then incident on the first beam expander group 4.

[0029] The size of the collimated beam output by the spatial filter 3 varies slightly depending on the pinhole of the spatial filter 3 and the selection of the collimating lens behind it. In conventional designs, to fully ensure the wavefront purification effect, the diameter of the output beam is mostly 2-3 mm, and generally does not exceed 3 mm. However, the shaping module 5 has strict requirements on the incident beam size (approximately 10 mm at 1 / e² intensity), so the first beam expander group 4 is still required to complete the parameter matching of the Gaussian beam size.

[0030] Please see Figure 2 The first beam expander group 4 adopts a Galilean structure and includes three lens groups. The light beam passes through these three lens groups sequentially. These three lens groups are: a first lens group, a second lens group, and a third lens group. All three lenses are ultraviolet fused silica lenses and are integrated within a precision mechanical lens barrel via air gaps. Along the optical path, the first lens group (a convex lens) is fixed at the front, the second lens group (a movable compensating lens) is in the middle, and the third lens group (a movable concave lens) is at the rear.

[0031] The Gaussian beam passes sequentially through the first, second, and third lens groups. Adjusting the axial distance between the first and second lens groups continuously changes the magnification of the first beam expander group 4, adjusting the beam diameter from 2-3 mm to 10 mm to match the incident size requirements of the shaping module 5. Adjusting the axial distance between the second and third lens groups finely controls the divergence angle of the output beam, achieving initial collimation and ensuring the beam enters the shaping module 5 as parallel light. Through the independent coordination of these two adjustment functions, independent optimization of the beam diameter and collimation angle is achieved, ensuring the beam meets the subsequent incident requirements of the shaping module 5 in both size and collimation.

[0032] Through the above configuration, the first beam expander group 4 can continuously adjust the output beam diameter and divergence angle within a certain range, thereby flexibly adapting to different models of shaping modules 5 and the incident condition requirements under different working conditions. This avoids one-time matching only for a single fixed-specification lens, significantly improving the versatility and scalability of the entire light source system. The first beam expander group 4 only undertakes the incident condition adaptation function and has no other additional optical functions. Its design is entirely dedicated to optimizing the performance of the shaping module 5.

[0033] Please see Figure 3 The shaping module 5 is located at the exit end of the first beam expander group 4, and includes a first freeform surface lens and a second freeform surface lens arranged sequentially along the optical path.

[0034] The beam emitted by laser 1 has an amplitude distribution function that is Gaussian. Within the cross-section at position z, the Gaussian beam exhibits... The amplitude distribution function at point is expressed as: ; in: Let z be the radius of the light spot at point z on the optical path. Let be the waist radius of the Gaussian beam. The maximum amplitude of the Gaussian beam. u and v Let be the coordinates of the Gaussian beam's position within the optical path cross-section. Let x be the x-coordinate of the incident surface. The vertical axis represents the incident plane. This amplitude distribution results in energy concentration in the central region of the beam and a sharp attenuation of energy at the edges, failing to meet the requirements for uniform illumination. Even after being expanded by the first beam expander group 4, the laser amplitude still belongs to the Gaussian beam, leading to uneven light intensity distribution. Gaussian beams are difficult to meet the requirements for uniform illumination in high-precision irradiance calibration or irradiance comparison experiments.

[0035] Freeform lenses, due to their high degree of design freedom, allow for precise control of the beam propagation path and simultaneous manipulation of the phase and intensity distribution of the incident beam, thus achieving a fine redistribution of beam energy. By rationally designing the profile of the freeform lens, a Gaussian beam can be transformed into a uniform intensity beam. Currently, the widely used double-freeform optical design method is based on the Monge-Ampère equations, typically constructed and solved in cylindrical coordinates. However, this method is constrained by geometric constraints at the vertices in cylindrical coordinates, which somewhat limits its design flexibility and applicability. Furthermore, achieving the beam boundary at the incident surface requires careful consideration. The light rays on Ω1 are precisely deflected by the shaping system to the boundary of the illuminance distribution on the target surface. For Ω2, corresponding boundary conditions (BC) need to be introduced into the Monge-Ampère equations. Therefore, the design formula for shaping module 5 is expressed as: ; in: For about , , , and The function, for The second-order partial derivative, for The second-order partial derivative, for and The mixed partial derivatives, For Gaussian beams in The amplitude distribution function at that location, u andv Let be the coordinates of the Gaussian beam's position within the optical path cross-section. Let x be the x-coordinate of the incident surface. The vertical coordinate of the incident surface is... Let be the amplitude distribution function of the target surface. For the Gaussian beam radius parameter, Let be the radius of curvature of the incident wavefront. Let be the radius of curvature of the incident wavefront in the u direction. Let be the radius of curvature of the incident wavefront in the v direction. The boundary of the incident surface, For the target surface boundary, The x-coordinate of the target surface, The vertical coordinate of the target surface is given by the equation, which describes the energy redistribution process and energy conservation relationship during beam shaping.

[0036] The collimated beam (10mm in diameter, Gaussian distribution) emitted from the first beam expander group 4 enters the first freeform lens, exhibiting a beam intensity distribution that is strong at the center and weak at the edges. The beam then passes sequentially along its path through the shaping module 5, which consists of the first and second freeform lenses, ultimately forming a uniform irradiance spot on the target surface on the right. Point P on the first freeform lens and point Q on the second freeform lens correspond to the coordinates (u,v) of a ray on the incident surface and the coordinates of the point where the beam lands on the target surface, respectively. The mapping relationship between the two lenses is as follows: the first freeform lens redistributes the intensity of the incident beam to the corresponding position on the target surface according to the preset mapping relationship, achieving uniform intensity distribution; then, the second freeform lens corrects and collimates the beam propagation direction, ensuring that the beam exiting the target surface remains parallel and spatially uniform. The synergistic effect of the two freeform lenses shapes the incident beam (10mm in diameter, Gaussian distribution) into a collimated, uniform intensity beam. After passing through the shaping module 5, an output beam with a diameter of approximately 15mm, 90% uniformity, and a divergence angle of 0.2° can be obtained.

[0037] In this embodiment, the incident wavefront refers to the wavefront when the Gaussian beam enters the shaping module 5. After collimation by the first beam expander group 4, the incident wavefront is approximately a planar wavefront with a radius of curvature of [missing information]. R It tends towards infinity. When there is a small residual curvature on the incident wavefront... and They represent u direction and v The radius of curvature of the incident wavefront in the direction; , It can be measured using a wavefront sensor.

[0038] Please see Figure 4The second beam expander group includes a converging lens 6 and a collimating lens 7. This second beam expander group is located at the output end of the shaping module 5 and is used to perform a second beam expansion and a third collimation on the uniform intensity beam emitted from the shaping module 5. The second beam expander group is arranged using Kohler illumination. The focal length of the converging lens 6 is 200mm, and the focal length of the collimating lens 7 is 500mm. They are positioned along the optical path with a distance strictly equal to the sum of their focal lengths (700mm), ensuring that the rear focal point of the former and the front focal point of the latter are precisely coincident in space, thus completing the Kohler illumination arrangement. The uniform intensity beam emitted from the shaping module 5 enters the converging lens 6, is converged by the converging lens 6, and then enters the collimating lens 7. The collimating lens 7 performs a third collimation on the uniform intensity beam before outputting it, and the diameter of the output beam is larger than the diameter of the input beam, achieving the second beam expansion. The above configuration effectively improves the uniformity and collimation characteristics of the emitted beam, forming a uniform irradiance spot at the target working distance. In this embodiment, the target working distance is 3m, and a uniform irradiance spot with a uniformity of over 98% can be generated at the target working distance of 3m.

[0039] It should be noted that the focal length parameters of 200mm and 500mm mentioned above are only a preferred embodiment of the present invention. In practical engineering applications, the focal length parameters of the two lenses can be scaled proportionally according to the specific target working distance requirements. For example, when the target working distance increases from 3m to 6m, the focal lengths of the converging lens 6 and the collimating lens 7 can be increased to 400mm and 1000mm respectively by the same proportion to maintain the collimation and uniformity of the beam at a more distant target working distance.

[0040] The working process of the irradiance simulation light source device is as follows: The Gaussian beam emitted by laser 1 is suppressed by laser power stabilizer 2 to suppress power fluctuations, and then enters spatial filter 3 to filter out stray wavefront components; the filtered collimated beam is injected into the first beam expander group 4, and the axial distance between the first group of lenses and the second group of lenses is adjusted to expand the Gaussian beam for the first time (beam diameter 10mm); the axial distance between the second group of lenses and the third group of lenses is adjusted to collimate the Gaussian beam for the first time; then it is injected into the shaping module 5, and the first freeform surface lens converts the Gaussian beam into a uniform intensity beam, and the second freeform surface lens collimates it for the second time to form a uniform intensity beam; finally, the second beam expander group composed of converging lens 6 and collimating lens 7 performs a second beam expansion and a third collimation, forming a uniform irradiance spot with a uniformity of better than 98% at a target working distance of 3m, and its output stability is better than 0.01% / 2h.

[0041] As an optional embodiment, the first beam expander group 4 may also adopt a Keplerian beam expander structure or other equivalent beam expander structures instead of a Galilean structure; the second beam expander group may also adopt other equivalent uniform illumination methods instead of a Kohler illumination method.

[0042] In summary, the above description is merely a preferred embodiment of this specification and is not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.

[0043] The systems, apparatuses, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, a computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0044] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover 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. Without further limitation, 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.

[0045] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

Claims

1. An irradiance simulation light source device, characterized in that, The following components are arranged sequentially along the optical path: a laser, a first beam expander group, and a shaping module; The laser is used to emit a Gaussian beam; The first beam expander group includes: a first group of lenses, a second group of lenses, and a third group of lenses. Adjusting the axial distance between the first group of lenses and the second group of lenses is used to perform the first beam expansion of the Gaussian beam; adjusting the axial distance between the second group of lenses and the third group of lenses is used to perform the first collimation of the Gaussian beam. The shaping module includes: a first freeform surface lens and a second freeform surface lens; the design formula of the shaping module is expressed as: ； in: For about , , , and The function, for The second-order partial derivative, for The second-order partial derivative, for and The mixed partial derivatives, For the Gaussian beam in The amplitude distribution function at that location, u and v Let be the coordinates of the Gaussian beam's position within the optical path cross-section. Let x be the x-coordinate of the incident surface. The vertical coordinate of the incident surface is... Let be the amplitude distribution function of the target surface. For the Gaussian beam radius parameter, Let be the radius of curvature of the incident wavefront. Let be the radius of curvature of the incident wavefront in the u direction. Let be the radius of curvature of the incident wavefront in the v direction. The boundary of the incident surface, For the target surface boundary, The x-coordinate of the target surface, The vertical coordinate of the target surface; The first freeform lens converts the Gaussian beam into a uniform intensity beam, which is then collimated a second time by the second freeform lens to form a uniform irradiance spot at the target working distance.

2. The irradiance simulation light source device according to claim 1, characterized in that, The laser is a monochromatic laser.

3. The irradiance simulation light source device according to claim 1, characterized in that, It also includes a laser power stabilizer and a spatial filter, which are arranged sequentially between the laser and the first beam expander group. The laser power stabilizer is used to suppress power fluctuations in the Gaussian beam, and the spatial filter is used to filter out stray wavefront components in the Gaussian beam.

4. The irradiance simulation light source device according to claim 1, characterized in that, The Gaussian beam in Amplitude distribution function at point Represented as: ； in: Let z be the radius of the light spot at point z on the optical path. Let be the waist radius of the Gaussian beam. The maximum amplitude of the Gaussian beam. u and v Let be the coordinates of the Gaussian beam's position within the optical path cross-section. Let x be the x-coordinate of the incident surface. The vertical coordinate of the incident surface is given.

5. The irradiance simulation light source device according to claim 1, characterized in that, The first group of lenses, the second group of lenses, and the third group of lenses are all ultraviolet fused silica lenses.

6. The irradiance simulation light source device according to claim 1, characterized in that, The first beam expander group adopts a Galilean structure.

7. The irradiance simulation light source device according to claim 1, characterized in that, It also includes a second beam expander group, which includes a converging lens and a collimating lens. The converging lens and the collimating lens are sequentially arranged along the optical path at the output end of the shaping module. The converging lens and the collimating lens are used to perform a second beam expansion and a third collimation on a uniform intensity beam.

8. The irradiance simulation light source device according to claim 7, characterized in that, The focal lengths of the converging lens and the collimating lens are scaled proportionally according to the target working distance.

9. The irradiance simulation light source device according to claim 7, characterized in that, The second beam expander group is set up using Kohler illumination, and the axial distance between the converging lens and the collimating lens is equal to the sum of the focal lengths of the converging lens and the collimating lens.

10. The irradiance simulation light source device according to claim 1, characterized in that, The first group of lenses, the second group of lenses, and the third group of lenses are integrated into a precision mechanical lens barrel by means of an air gap.

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