Compact nonreciprocal spatial light modulation system
Through the compact non-reciprocal spatial light modulation system, the combination of beam expansion collimation system, polarization beam splitting element, deflection optical rotating element and reflective spatial light modulator is solved, and the energy utilization and light field modulation accuracy of the reflective spatial light modulator are achieved, achieving efficient light energy utilization and compact optical path design.
Patent Information
- Application Number
- CN202510650855.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2025-08-08
AI Technical Summary
The existing reflective spatial light modulators have low global energy utilization and insufficient light field modulation accuracy, and loose optical path structure, resulting in beam wavefront distortion.
A compact non-reciprocal spatial light modulation system is adopted, including a beam-expanded collimation system, a polarization beam splitting element, a deflected rotation element and a reflective spatial light modulator. Through optical path design and rotation matching of polarization direction, light utilization and modulation accuracy are improved.
The global energy utilization rate of the optical path has been improved to more than 90%, the optical field modulation accuracy has been improved, and the optical path volume has been reduced by 40%.
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Figure CN120447235A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical fields of laser processing and holographic imaging, and in particular to a compact non-reciprocal spatial light modulation system. Background Art
[0002] A spatial light modulator (SLM) is an optical device that controls the phase and amplitude distribution of a light beam through electrical signals. It is widely used in laser shaping, holographic imaging, adaptive optics, and other fields. It can be divided into a transmissive type, in which light passes through the device, and a reflective type, in which light is reflected by the device surface.
[0003] In the prior art, when a reflective spatial light modulator uses a non-polarizing beamsplitter plate (NPBS) solution, the light must pass through the NPBS twice. The first pass has a transmittance of 50%, and the second pass has a reflectance of 50%. The final theoretical transmittance is only 25% of the incident light, resulting in a theoretical global energy utilization rate of only 25% for the modulated optical path. Furthermore, when a reflective spatial light modulator uses an oblique incidence scheme, it can cause wavefront distortion (such as coma and astigmatism), thereby reducing the accuracy of light field modulation. Furthermore, to avoid the obstruction of incident / reflected light by excessively large lateral dimensions of the component, the incident / reflection segments of the optical path must be extended, resulting in an overly loose optical path structure.
[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention
[0005] To address the above problems, the present application provides a compact non-reciprocal spatial light modulation system that can increase the theoretical value of the global energy utilization rate of the modulated optical path from 25% to more than 90%, and improve the light field modulation accuracy, while reducing the volume by more than 40%.
[0006] To achieve the purpose of this application, this application provides the following technical solutions:
[0007] The present application provides a compact non-reciprocal spatial light modulation system, comprising a beam expansion and collimation system, a polarization beam splitter, a deflection rotator, and a reflective spatial light modulator, which are sequentially arranged along an optical path;
[0008] The beam expansion and collimation system is used to expand the incident light beam into a collimated light beam with higher parallelism;
[0009] The polarization beam splitting element is used to split the light beam according to the polarization direction;
[0010] The deflection rotator is used to rotate the polarization direction of the light beam passing through the reflective spatial light modulator under the action of a magnetic field, so that the polarization direction of the light beam incident from the deflection rotator to the reflective spatial light modulator is consistent with the modulatable polarization direction of the reflective spatial light modulator, and the polarization direction of the light beam incident from the deflection rotator to the polarization beam splitting element is matched with the reflection axis of the polarization beam splitting element;
[0011] The reflective spatial light modulator is used to perform phase or amplitude modulation on an incident light beam and then reflect the light beam.
[0012] In a possible implementation, the beam expansion and collimation system includes: a first convex lens and a second convex lens; the distance between the first convex lens and the second convex lens is the sum of the focal lengths of the first convex lens and the second convex lens.
[0013] In a possible implementation, the beam expansion and collimation system further includes an aperture, which is arranged at an intermediate focal plane between the first convex lens and the second convex lens.
[0014] In a possible implementation, the beam expansion and collimation system further includes a vacuum chamber, and an intermediate focal plane between the first convex lens and the second convex lens is located in the vacuum chamber.
[0015] In a possible implementation, the polarization beam splitting element is any one of a polarization beam splitter and a polarization beam splitter cube.
[0016] In a possible implementation, the polarization beam splitting element is coated with a high damage threshold anti-reflection film.
[0017] In a possible implementation, the deflection optical rotation element is a 45° optical rotation Faraday rotator.
[0018] In a possible implementation, the reflective spatial light modulator operates in a normal incidence reflection mode, and the polarization direction of the modulated light beam is the same as the polarization direction of the light beam incident on the reflective spatial light modulator from the deflection rotator element.
[0019] In a possible implementation, the compact non-reciprocal spatial light modulation system further includes: a processing objective lens, configured to focus the light beam carrying modulation information of the reflective spatial light modulator onto a workpiece.
[0020] In a possible implementation, the reflective spatial light modulator modulates information and further includes: a linearly polarized laser for emitting a polarized laser beam.
[0021] The technical solution provided by this application may have the following beneficial effects:
[0022] The compact non-reciprocal spatial light modulation system provided by the present application can improve light utilization by cooperating with a beam expansion and collimation system, a polarization beam splitter, a deflection rotator, and a reflective spatial light modulator, thereby increasing the theoretical value of the global energy utilization of the modulated light path from 25% to over 90%. Furthermore, it can eliminate off-axis aberrations at strictly vertical incidence and improve the accuracy of light field modulation. At the same time, the optical path folding design of the present application can reduce the volume by over 40%.
[0023] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present application and do not constitute a limitation of the present application. Obviously, the drawings described below are only some embodiments of the present disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work.
[0025] Figure 1 A schematic diagram of the structure of a compact non-reciprocal spatial light modulation system provided in an embodiment of the present application;
[0026] Figure 2 A schematic structural diagram of a compact non-reciprocal spatial light modulation system beam expansion and collimation system provided in an embodiment of the present application.
[0027] Reference numerals:
[0028] 100, optical path, 110, first optical path, 111, second optical path;
[0029] 200, beam expansion and collimation system, 210, first convex lens; 220, second convex lens; 230, aperture; 240, vacuum chamber;
[0030] 300, polarization beam splitter; 400, deflection rotator; 500, reflective spatial light modulator; 600, processing objective lens; 700, workpiece; 800, linearly polarized laser. DETAILED DESCRIPTION
[0031] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0032] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus their repeated description will be omitted.
[0033] This exemplary embodiment first provides a compact non-reciprocal spatial light modulation system. Figures 1 to 2 As shown in , the compact non-reciprocal spatial light modulation system includes a beam expansion and collimation system 200, a polarization beam splitter 300, a deflection rotator 400, and a reflective spatial light modulator 500, which are sequentially arranged along an optical path 100;
[0034] The beam expansion and collimation system 200 is used to expand the incident light beam into a collimated light beam with higher parallelism;
[0035] The polarization beam splitting element 300 is used to split the light beam according to the polarization direction;
[0036] The deflection rotator 400 is used to rotate the polarization direction of the light beam passing through the reflective spatial light modulator 500 under the action of a magnetic field, so that the polarization direction of the light beam incident from the deflection rotator 400 to the reflective spatial light modulator 500 is consistent with the modulatable polarization direction of the reflective spatial light modulator 500, and the polarization direction of the light beam incident from the deflection rotator 400 to the polarization beam splitting element 300 is matched with the reflection axis of the polarization beam splitting element 300.
[0037] The reflective spatial light modulator 500 is used to spatially modulate and reflect an incident light beam.
[0038] With the above technical solution, the laser beam can be expanded and collimated by the beam expansion and collimation system 200 and then incident on the polarization beam splitting element 300. At this time, the polarization direction of the incident light beam does not match the reflection axis of the polarization beam splitting element 300. Therefore, the light beam passes through the polarization beam splitting element 300 and is incident on the deflection rotator 400. The deflection rotator 400 rotates the polarization direction of the light beam to match the polarization direction modulated by the reflective spatial light modulator 500. The light beam is then incident on the reflective spatial light modulator 500 for spatial modulation and is reflected back to the deflection rotator 400. The deflection rotator 400 rotates the polarization direction of the light beam to match the reflection axis of the polarization beam splitting element 300. The light beam is then incident on the polarization beam splitting element 300. At this time, the polarization direction of the light beam matches the reflection axis. The polarization beam splitting element 300 reflects the light beam and outputs it for use in subsequent processing optical paths.
[0039] In a possible implementation, the beam expansion and collimation system 200 includes: a first convex lens 210 and a second convex lens 220 ; the distance between the first convex lens 210 and the second convex lens 220 is the sum of the focal lengths of the first convex lens 210 and the second convex lens 220 .
[0040] It should be noted that the beam expansion and collimation system 200 can use a Kepler beam expander composed of two convex lenses to expand and collimate the light beam; if the light beam energy is low and there is little stray light, a Galilean beam expander can also be used.
[0041] Optionally, the beam expansion and collimation system 200 further includes an aperture 230 , which is disposed at an intermediate focal plane between the first convex lens 210 and the second convex lens 220 .
[0042] It can be understood that the stop 230 is inserted at the intermediate focal plane to filter out stray light.
[0043] Optionally, the beam expansion and collimation system 200 further includes a vacuum chamber 240 , and an intermediate focal plane between the first convex lens 210 and the second convex lens 220 is located in the vacuum chamber 240 .
[0044] It can be understood that by increasing the spatial optical power density to more than 10 13 W / cm 2 When the optical power is high, the intermediate focal plane is placed in the vacuum cavity to avoid the optical path being disturbed by plasma caused by the breakdown of the photoelectric field in the air under high instantaneous power.
[0045] In a possible implementation, the polarization beam splitting element 300 is any one of a polarization beam splitter and a polarization beam splitter cube.
[0046] It should be noted that any polarization beam splitting element that does not introduce additional errors in the polarization transmission selection process may be selected.
[0047] Optionally, the polarization beam splitting element 300 is coated with a high damage threshold anti-reflection film.
[0048] It should be noted that by coating a high damage threshold anti-reflection film, its optical performance and durability are improved to meet the working requirements of the device in a high-energy laser environment.
[0049] In a possible implementation, the deflection optical rotation element 400 is a 45° optical rotation Faraday rotator.
[0050] It can be understood that the light beam efficiently transmitted through the polarization beam splitting element 300 is rotated 45° by the 45° optical rotation Faraday rotator, so that the polarization direction of the light beam is consistent with the polarization direction modulated by the reflective spatial light modulator 500. The light beam then reflected by the reflective spatial light modulator 500 is rotated again by the 45° optical rotation Faraday rotator by 45°, for a total rotation of 90°, so that the polarization direction of the light beam matches the reflection axis of the polarization beam splitting element 300.
[0051] In a possible implementation, the reflective spatial light modulator 500 operates in a normal incidence reflection mode, and the polarization direction of the modulated light beam is the same as the polarization direction of the light beam incident on the reflective spatial light modulator 500 from the deflection rotator 400 .
[0052] It is understandable that the incident light and the reflected light of the reflective spatial light modulator 500 are both perpendicularly incident, and the reflective spatial light modulator 500 can be any reflective spatial light modulator as long as the polarization of the light field does not change during the modulation process.
[0053] In a possible implementation, the compact non-reciprocal spatial light modulation system further includes: a processing objective lens 600 for focusing the light beam carrying the modulation information of the reflective spatial light modulator 500 onto the workpiece 700 .
[0054] It is understandable that the specifications and types of the processing objective lens 600 and the workpiece 700 can be adjusted according to processing requirements and processing scenarios.
[0055] In a possible implementation, the compact non-reciprocal spatial light modulation system further includes: a linearly polarized laser 800 for emitting a polarized laser beam.
[0056] It can be understood that the linearly polarized laser 800 is used to emit P-polarized light, such as horizontally polarized light.
[0057] Working principle:
[0058] The linearly polarized laser 800 emits polarized light (e.g., horizontally polarized light). After beam expansion and spatial filtering by the aperture in the beam expansion and collimation system 200, the light is efficiently transmitted through the polarization beam splitter 300. After being rotated 45° by the deflection rotator 400, the polarization direction is aligned with the polarization direction of the modulated light of the reflective spatial light modulator, and the light is incident perpendicularly to the target surface of the reflective spatial light modulator. The reflected light, which carries the modulation information of the reflective spatial light modulator, is rotated a second time by the deflection rotator 400 by a cumulative 90°. The polarization direction matches the reflection axis of the polarization beam splitter 300 and is efficiently reflected and output for use in the subsequent processing optical path.
[0059] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and 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 understood as a limitation on this application.
[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.
[0061] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.
[0062] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.
[0063] In the description of this specification, the descriptions with reference to the terms "in one possible embodiment", "further", "exemplary", "specific example", or "optional" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.
[0064] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the inventions claimed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art that are not claimed herein. The description and examples are to be considered merely as exemplary, and the true scope and spirit of the present application are indicated by the appended claims.
Claims
1. A compact non-reciprocal spatial light modulation system, characterized in that: It includes a beam expansion and collimation system, a polarization beam splitter, a deflection rotator, and a reflective spatial light modulator that are sequentially arranged along the optical path; The beam expansion and collimation system is used to expand the incident light beam into a collimated light beam with higher parallelism; The polarization beam splitting element is used to split the light beam according to the polarization direction; The deflection rotator is used to rotate the polarization direction of the light beam passing through the reflective spatial light modulator under the action of a magnetic field, so that the polarization direction of the light beam incident from the deflection rotator to the reflective spatial light modulator is consistent with the modulatable polarization direction of the reflective spatial light modulator, and the polarization direction of the light beam incident from the deflection rotator to the polarization beam splitting element is matched with the reflection axis of the polarization beam splitting element; The reflective spatial light modulator is used to perform phase or amplitude modulation on an incident light beam and then reflect the light beam.
2. The compact non-reciprocal spatial light modulation system according to claim 1, wherein: The beam expansion and collimation system includes: a first convex lens and a second convex lens; the distance between the first convex lens and the second convex lens is the sum of the focal lengths of the first convex lens and the second convex lens.
3. The compact non-reciprocal spatial light modulation system according to claim 2, wherein: The beam expansion and collimation system further includes an aperture, which is arranged at an intermediate focal plane between the first convex lens and the second convex lens.
4. The compact non-reciprocal spatial light modulation system according to claim 2, wherein: The beam expansion and collimation system further includes a vacuum chamber, and an intermediate focal plane between the first convex lens and the second convex lens is located in the vacuum chamber.
5. The compact non-reciprocal spatial light modulation system according to claim 1, wherein: The polarization beam splitting element is any one of a polarization beam splitter and a polarization beam splitter cube.
6. The compact non-reciprocal spatial light modulation system according to claim 1, wherein: The polarization beam splitting element is coated with a high damage threshold anti-reflection film.
7. The compact non-reciprocal spatial light modulation system according to claim 1, wherein: The deflection optical rotation element is a 45° optical rotation Faraday rotator.
8. The compact non-reciprocal spatial light modulation system according to claim 1, wherein: The reflective spatial light modulator operates in a vertical incidence reflection mode, and the polarization direction of the modulated light beam is the same as the polarization direction of the light beam incident on the reflective spatial light modulator from the deflection rotator element.
9. The compact non-reciprocal spatial light modulation system according to claim 1, wherein: Also includes: The processing objective lens is used to focus the light beam carrying the modulation information of the reflective spatial light modulator on the workpiece.
10. The compact non-reciprocal spatial light modulation system according to claim 1, wherein: Also includes: Linearly polarized laser, used to emit polarized laser beam.