Laser homogenizing and amplifying optical device and optical equipment

Abstract

The invention provides a laser homogenizing and amplifying optical device and optical equipment. The laser homogenizing and amplifying optical device comprises a first-stage beam expanding assembly, a light beam diverging assembly and a second-stage beam expanding assembly which share the same optical axis and are sequentially arranged from the laser side to the imaging side. The first-stage beam expanding assembly is based on a convex lens or a combination of the convex lens, so that the diameter of a laser beam is amplified by M1 times; the light beam diverging assembly diverges and homogenizes the laser beams amplified by M1 times; and the second-stage beam expanding assembly is based on a convex lens or a combination of the convex lens, so that the diverged and homogenized laser beam is amplified by M2 times again. According to the invention, through the step-by-step and stage-by-stage processing design of primary amplification, homogenization and divergence and final secondary amplification, and through superposition of two-stage amplification, the total amplification factor of the light beam is M1 * M2, the energy distribution characteristic after homogenization is maintained, and the application requirements of large-size and high-uniformity laser beams are met.

Description

Technical Field

[0001] This invention relates to the field of optical equipment technology, and in particular to a laser homogenization and amplification optical device and optical equipment. Background Technology

[0002] With the development of infrared technology, the measurement of target infrared radiation characteristics is increasingly widely used in remote sensing, military, engineering, and many other fields. In laboratory or field measurements, studying the infrared reflection and transmission characteristics of materials requires a relatively stable, large-area, uniform infrared radiation source to illuminate the target. Similarly, when using infrared systems such as infrared thermal imagers to measure the radiation characteristics of targets, a uniform infrared radiation source is needed as a standard radiation source to calibrate the equipment. These applications typically place high demands on the spot size and uniformity of the infrared radiation source.

[0003] The size of the light spot, i.e., the effective area of ​​the infrared radiation source illuminating the target, is one of the key parameters affecting the measurement of the target's infrared radiation characteristics. Its rationality directly relates to the representativeness, completeness, and accuracy of the measurement results. When the radiation source spot is smaller than the target, the measurement signal only reflects the characteristics of a local area of ​​the target, resulting in the measurement results failing to represent the overall infrared characteristics of the target. To cover the entire target, "multi-point sampling" is required by scanning or moving the target. However, multiple sampling processes may introduce additional errors due to mechanical displacement and environmental interference, and it is difficult to ensure the consistency of each point when stitching data. When the radiation source spot is larger than the target, the spot will simultaneously illuminate the target and the surrounding background (such as the sample stage, air, support structure, etc.), causing the infrared radiation of the surrounding background to mix into the measurement signal, interfering with the extraction of the target's own characteristics.

[0004] Spot uniformity, or the consistency of energy / radiation intensity distribution of an infrared radiation source within the irradiated area, is one of the core factors affecting the measurement of a target's infrared radiation characteristics. Its quality directly impacts the accuracy, repeatability, and physical validity of the measurement results. Poor spot uniformity, such as energy distribution exhibiting strong energy at the center and weak energy at the edges, localized hotspots, or dark areas, will interfere with the extraction of average characteristics, even if the target itself is uniform. If the energy distribution of the spot is uneven, and the detector's detection area does not perfectly match the spot range, the calculated values ​​of "incident energy" or "reflected energy" will deviate from the true values. In scenarios requiring analysis of the target's spatial distribution characteristics (such as temperature field distribution captured by an infrared thermal imager), spot non-uniformity directly "contaminates" the target's apparent radiation distribution. For example, when a thermal imager measures a target's temperature field, if the energy at the center of the spot is too high, the apparent temperature of the target's central region will be higher, masking the target's true temperature gradient.

[0005] High-power infrared laser sources have advantages such as high radiation intensity and good monochromaticity. However, the laser spot size is too small, usually only a few millimeters in diameter. How to increase its size and achieve better uniformity is a challenge that needs to be solved when applying infrared laser sources to the measurement of the infrared radiation characteristics of targets. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a laser homogenization and amplification optical device and optical equipment to eliminate or improve one or more defects existing in the prior art.

[0007] In a first aspect, the present invention provides a laser homogenization and magnification optical device, comprising: a primary beam expander, a beam divergence component, and a secondary beam expander, arranged coaxially and sequentially from the laser side to the imaging side; the primary beam expander is based on a convex lens or a combination thereof, thereby magnifying the diameter of the laser beam by a factor of M1; the beam divergence component homogenizes the laser beam magnified by a factor of M1; and the secondary beam expander is based on a convex lens or a combination thereof, thereby further magnifying the homogenized laser beam by a factor of M2.

[0008] In some embodiments, the primary beam expander includes a first lens and a second lens, the first lens and the second lens being plano-convex lenses, the first lens having a convex surface as an incident surface and the second lens having a convex surface as an exit surface, the planes of the first lens and the second lens being arranged opposite to each other; the optical center distance between the first lens and the second lens is configured to be equal to the sum of the focal lengths of the two lenses, and M1 is equal to the ratio of the focal length of the second lens to that of the first lens.

[0009] In some embodiments, the beam divergence component includes an infrared diffuser, which is a circular thin sheet with frosted surfaces on both sides, and its diameter is not less than the diameter of the laser beam magnified by M1 times.

[0010] In some embodiments, the beam divergence component includes an infrared integrating rod, which is a cylindrical structure and the shape of its end face is set to be circular, square or rectangular according to the shape of the laser source or the target spot. When the beam diverging assembly includes an infrared diffuser, the infrared diffuser is disposed on either the incident surface side or the exit surface side of the infrared integrating bar, with the two disposed adjacent to each other.

[0011] In some embodiments, the incident surface of the infrared integrating rod is configured as a concave spherical surface, and the exit surface is configured as a plane; and / or, the incident surface of the infrared integrating rod is configured as a concave spherical surface, and the radius of curvature of the concave spherical surface is equal to the maximum radial dimension of the incident surface of the infrared integrating rod; and / or, the maximum radial dimension of the incident surface of the infrared integrating rod is configured to be not less than the diameter of the laser beam magnified by M1 times; and / or, the length of the infrared integrating rod is configured to be greater than 10 times its maximum radial dimension of the end face.

[0012] In some embodiments, the secondary beam expander includes a third lens, which is a positive meniscus lens having a concave surface as an incident surface and a convex surface as an exit surface.

[0013] In some embodiments, the third lens can be adjusted along the optical axis, with the adjustment range being between one and two focal lengths from the third lens of the beam diverging assembly.

[0014] In some embodiments, the infrared materials of each optical element in the primary beam expander, beam divergence assembly, and secondary beam expander are the same, such as silicon, germanium, zinc sulfide, or zinc selenide.

[0015] In some embodiments, the end faces of each optical element in the primary beam expander, beam divergence assembly, and secondary beam expander are coated with an infrared anti-reflection film.

[0016] In a second aspect, the present invention provides an optical device, including the aforementioned laser homogenization and amplification optical device, and further including an infrared laser.

[0017] The laser homogenization and amplification optical device and equipment in this embodiment of the invention employ a step-by-step, graded processing design of "initial amplification, then homogenization and divergence, and finally secondary amplification." Through the superposition of two stages of amplification, the total amplification factor of the laser beam is ultimately achieved to be M1×M2, while maintaining the energy distribution characteristics after homogenization, thus meeting the application requirements of large-size, highly uniform laser beams. This invention can effectively increase the laser spot size and solve the problem of insufficient uniformity in single amplification, making it suitable for laser application fields with strict requirements for both beam size and uniformity.

[0018] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows, and will also become apparent in part to those skilled in the art upon studying the description, or may be learned by practice of the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures specifically pointed out in the specification and drawings.

[0019] Those skilled in the art will understand that the objectives and advantages achievable with the present invention are not limited to those specifically described above, and that the above and other objectives achievable with the present invention will become clearer from the following detailed description. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, are not intended to limit the scope of the invention. The components in the drawings are not drawn to scale but are merely illustrative of the principles of the invention. For ease of illustration and description of certain parts of the invention, corresponding portions in the drawings may be enlarged, i.e., may appear larger relative to other components in an exemplary device actually manufactured according to the invention.

[0021] Figure 1 This is a schematic diagram of the structure of a laser homogenization and amplification optical device in one embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the optical path of a laser homogenization and amplification optical device according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of an infrared integrating rod in one embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the test points for the uniformity of the laser spot in a laser homogenization and magnification optical device according to an embodiment of the present invention.

[0025] Figure label: 1. First lens; 2. Second lens; 3. Infrared diffuser; 4. Infrared integrating bar; 5. Third lens. Detailed Implementation

[0026] 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 embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0027] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0028] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0029] It should also be noted that, unless otherwise specified, the term "connection" in this article can refer not only to a direct connection, but also to an indirect connection involving an intermediary.

[0030] In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar parts, or the same or similar steps.

[0031] Enhancing the size of infrared laser sources while maintaining good uniformity is a key challenge in measuring the infrared radiation characteristics of targets. To address the limitations of existing infrared laser sources in terms of spot size, which prevent direct application to target infrared radiation characteristic measurements, or the inability to achieve uniformity after beam amplification via lens refraction, this invention provides a laser homogenization and amplification optical device and equipment. This device can utilize commercially available high-power infrared lasers to form a large-area uniform infrared irradiation surface.

[0032] In a first aspect, the present invention provides a laser homogenization and amplification optical device, comprising: a primary beam expander, a beam divergence component, and a secondary beam expander, arranged coaxially and sequentially from the laser side to the imaging side. This laser homogenization and amplification optical device (or simply the device) can be positioned behind an infrared laser source, and through the synergistic effect of graded amplification and intermediate homogenization, it achieves an increase in the size and uniformity of the laser beam.

[0033] Specifically, the first-stage beam expander is based on a convex lens or a combination thereof, which magnifies the diameter of the laser beam by a factor of M1. This component initially changes the divergence diameter of the beam through the refraction of the lens, providing a base beam of suitable size for subsequent homogenization processing. The first-stage beam expander can also reduce the energy density in a timely manner, providing a safety margin for subsequent optical components.

[0034] The beam divergence component homogenizes the divergence of the laser beam magnified by M1 times. This component can break the non-uniform energy characteristics of the original Gaussian distribution of the laser and redistribute the beam energy in space through physical structures (such as optical elements with specific curvature, diffusers, or microstructure arrays), thereby achieving energy homogenization. This effectively suppresses the diffraction rings and edge attenuation caused by traditional single-lens magnification, laying a uniform foundation for the terminal beam spot. At the same time, it can also increase the divergence angle of the laser beam, laying the foundation for secondary amplification.

[0035] The secondary beam expander, based on a convex lens or a combination thereof, amplifies the diverged and homogenized laser beam by a factor of M². Guided by a telecentric or long focal length structure, the secondary beam expander performs secondary amplification, outputting a uniform illumination spot covering a large target. This satisfies the area requirements for measuring the infrared radiation characteristics of the target while avoiding uniformity degradation caused by amplification.

[0036] The laser homogenization and amplification optical device in this invention employs a step-by-step, graded processing design of "initial amplification, then homogenization and divergence, and finally secondary amplification." Through the superposition of these two amplification stages, the total beam magnification reaches M1×M2 while maintaining the homogenized energy distribution characteristics, meeting the application requirements of large-size, highly uniform laser beams. This invention effectively increases the laser spot size and solves the problem of insufficient uniformity in single amplification, making it suitable for laser applications with strict requirements for both beam size and uniformity.

[0037] In some embodiments, such as Figure 1 and Figure 2 As shown, the primary beam expander assembly includes a first lens 1 and a second lens 2. Both lenses are plano-convex lenses. The first lens 1 has a convex surface serving as its incident surface, and the second lens 2 has a convex surface serving as its exit surface. The planes of the first lens 1 and the second lens 2 are arranged opposite to each other. The optical center distance between the first lens 1 and the second lens 2 is configured to be equal to the sum of the focal lengths of the two lenses, i.e., d. 12 =f1+f2, M1 is equal to the focal length ratio of the second lens 2 to the first lens 1, that is, M1=f2 / f1. The diameter of the infrared laser beam after the first-stage beam expander is M1D0, where D0 is the initial diameter of the infrared laser beam.

[0038] In the above embodiment, the first lens 1 faces the light with a convex surface, undertaking the initial convergence of the light beam; the second lens 2 sends the light through a convex surface, completing the diameter magnification. The planes of the two lenses face each other, and the distance between their optical centers is strictly equal to the sum of their focal lengths, forming a focusless system. After the incident parallel beam is converged by the first lens 1, it is immediately re-collimated by the second lens 2; this not only ensures that the outgoing beam remains parallel, but also makes the beam expansion ratio determined by only a single parameter, the ratio of focal lengths, simplifying design and assembly.

[0039] In some embodiments, the beam divergence component includes an infrared diffuser 3, which is a circular thin sheet with frosted surfaces on both sides. Its diameter is not less than the diameter M1D0 of the laser beam magnified by M1 times, ensuring that the entire beam can cover its effective area. The double-sided frosted structure causes the incident beam to undergo two random scatterings during transmission, thereby rapidly homogenizing the energy distribution and introducing a controllable divergence angle. At the same time, the infrared diffuser 3 itself is thin (e.g., controlled between 0.5mm and 2mm), with a short additional optical path, and its aberration effect on the subsequent second-stage beam expander is negligible, maintaining a simple and stable overall structure.

[0040] In some embodiments, the beam divergence assembly includes an infrared integrating rod 4, which is a cylindrical structure. The shape of its end face is set to be circular, square, or rectangular according to the shape of the laser source or target spot, so as to directly match the subsequent optical channel or target surface contour. Since the refractive index of the material used in the infrared integrating rod 4 is much larger than that of air, a large amount of light entering the integrating rod will undergo total internal reflection when it is transmitted to the interface (incident end) on the side of the integrating rod. Light rays with different incident angles have different total internal reflection paths inside the integrating rod, and finally randomly superimpose at the exit end of the infrared integrating rod 4 to achieve homogenization.

[0041] In the above embodiments, if only the infrared integrating rod 4 is provided, a single cylindrical element can simultaneously complete homogenization and geometric shaping, resulting in a compact overall structure. It also boasts high internal total internal reflection utilization, fewer diffuse reflection stages, and high beam transmittance. The end face shape of the infrared integrating rod 4 directly determines the output beam profile, with steep edge transitions facilitating precise matching with subsequent secondary beam expanders.

[0042] Furthermore, in cases requiring a specific beam shape, the incident and exit ends of the infrared integrating rod 4 can be designed with different shapes. For example, the incident end can be circular, and the exit end can be square, rectangular, or elliptical. The beam shape transformation is achieved through multiple reflections or refractions within the integrating rod. After entering from the circular incident end, the infrared light gradually distributes evenly through the internal structure of the integrating rod, ultimately forming a square, rectangular, or elliptical beam output. This method is suitable for using most existing infrared laser sources, outputting a beam shape corresponding to the experimental target. In this embodiment, through continuous multiple total internal reflections within the rod, the light field is redistributed during transmission, ultimately forming a uniform beam with the desired contour at the exit end without requiring additional shaping elements.

[0043] Optionally, when the beam divergence assembly includes an infrared diffuser 3, the infrared diffuser 3 and an integrating rod are used in combination. The infrared diffuser 3 is disposed on either the incident surface or the exit surface of the infrared integrating rod 4, with the two adjacent to each other. The infrared diffuser 3 can be used to scatter and homogenize the laser, while the infrared integrating rod 4 can provide a more uniform distribution of light. The combined use of the two can effectively reduce non-uniform components in the beam and improve the imaging or illumination effect.

[0044] In some embodiments, the infrared integrating rod 4 can moderately converge the collimated beam after the first-stage beam expansion, causing it to undergo more total internal reflections within the rod, thereby improving homogenization. Specifically, the incident surface of the infrared integrating rod 4 is set as a concave spherical surface, and the exit surface is set as a plane. The concave spherical incident end allows the laser to diverge again when entering the infrared integrating rod 4. Compared with a plane end, the divergence of the concave spherical surface causes more light rays to enter the integrating rod at a larger angle. The larger the angle, the more times total internal reflection occurs in the propagation path, and finally, they are randomly superimposed at the exit end to achieve homogenization. If the incident surface of the infrared integrating rod 4 is set as a plane, there will be no increase in light divergence at that point. Light rays with small angles in the laser beam will pass straight through the infrared integrating rod 4, and the number of times total internal reflection occurs at slightly larger angles will be small. Therefore, the effect of random superposition is not obvious, the homogenization is not good enough, and it is difficult to meet the testing requirements. The exit end is kept as a plane to ensure that the outline of the output spot is clear and easy to align with the optical axis of the subsequent second-stage beam expansion.

[0045] Optionally, such as Figure 3 As shown, the incident surface of the infrared integrating rod 4 is set as a concave spherical surface, and the radius of curvature R of the concave spherical surface is equal to the maximum radial dimension D1 of the incident surface of the infrared integrating rod 4 (or Figure 3 (x is represented in the diagram). Setting the radius of curvature of the concave spherical surface to be equal to the maximum radial dimension of the incident surface of the infrared integrating rod 4 ensures that the laser beam diverges to the maximum extent when entering the integrating rod, allowing the beam to enter the integrating rod at a sufficiently large angle. This design optimizes the quality of the incident beam and enhances the uniformity of the beam as it passes through the integrating rod.

[0046] Optionally, the maximum radial dimension of the incident surface of the infrared integrating rod 4 is configured to be no less than the diameter of the laser beam magnified by M1 times. Here, the maximum radial dimension is set to the diameter of a circle or the diagonal length of a rectangle; that is, the maximum radial dimension D1 of the incident surface of the infrared integrating rod 4 is ≥ M1D0. This design ensures that the incident surface of the infrared integrating rod 4 can fully receive the laser beam after the first-stage beam expansion, and the beam quality remains stable.

[0047] Optionally, such as Figure 3 As shown, the length L of the infrared integrating rod 4 is configured to be greater than 10 times its maximum radial dimension at the end face, i.e., the length L1 of the infrared integrating rod 4 > 10D1. This design ensures that the infrared integrating rod 4 has sufficient length to complete the full integration and homogenization of the beam during beam propagation. A longer integrating rod provides a longer propagation path, allowing the laser to have sufficient optical path for scattering and mixing when passing through the integrating rod, thereby achieving a better homogenization effect. This design further reduces beam non-uniformity, ensuring a good uniform distribution in the final beam output. At the same time, by not using an excessively long infrared integrating rod 4, uniformity, boundary sharpness, and system compactness are balanced.

[0048] In some embodiments, the secondary beam expander assembly includes a third lens 5, which is a positive meniscus lens and has a concave surface as the incident surface and a convex surface as the exit surface. The lens faces the light with its concave surface and sends out the light with its convex surface, having both converging and diverging curvatures. Due to the combination of its concave and convex surfaces, when the incident light beam passes through the lens, the light beam will diverge and be redirected to a certain extent, so that the diameter of the light beam increases, meeting the requirements of the subsequent optical system. This arrangement can provide a low-distortion magnification effect within a large field of view, and at the same time, utilize the aberration self-compensation characteristics of the meniscus lens to reduce spherical aberration and coma, so that the output light beam can cover a large-aperture target surface while maintaining clear edges and no reduction in uniformity.

[0049] Furthermore, the third lens 5 can be arranged to be adjustable in the optical axis position, and its adjustment range is between one focal length and two focal lengths of the third lens 5 from the beam divergence assembly, that is, f3 < d3 < 2f3, where f3 is the focal length of the third lens 5. The third lens 5 uses the plane end face of the infrared integrating rod 4 as the secondary light source emission surface for magnifying imaging, and the magnification M2 = f3 / (d3 - f3), where the adjustment distance d3 is adjusted to obtain uniform infrared irradiation spots with different diameters at different distances behind the third lens 5.

[0050] This design can effectively change the size of the light spot to meet the measurement requirements of targets of different sizes. For example, when measuring a larger target, the position of the lens is adjusted to enlarge the light spot to adapt to the size of the target; when measuring a smaller target, the light spot is reduced to improve the focusing ability of the light beam.

[0051] Furthermore, the third lens 5 is installed in a manner that it can slide along the optical axis. For example, components such as a precision slide table with a guide rail and a screw rod, a sleeve and a locking screw type adjustment seat, a combination structure of a燕尾槽 (I'm not sure what this exactly is in English, it might be a specific mechanical structure name, so I'll keep it as is) and a differential drum can be used, and it can be manually adjusted, precisely adjusted by threads or driven electrically.

[0052] In some embodiments, the infrared materials of each optical element in the primary beam expander assembly, the beam divergence assembly, and the secondary beam expander assembly are the same. Using the same material can effectively eliminate the interface reflection loss and thermal expansion mismatch introduced by refractive index differences, simplify the coating process, and improve the transmittance and thermal stability of the entire device in a wide-band infrared environment.

[0053] Optionally, optical components can be made of materials such as silicon, germanium, zinc sulfide, or zinc selenide. Silicon is a common infrared material with good transmittance, especially in the mid-infrared band of 3-5µm. Germanium has high transmittance in the far-infrared band of 8-12µm, making it very effective in applications requiring processing long-wave infrared spectra. Zinc sulfide is a transparent infrared optical material suitable for applications with wavelengths from 0.5-12µm; it possesses not only good mechanical properties but also a low refractive index. Zinc selenide also exhibits excellent transmittance in most infrared bands, with high overall transmittance in the 0.5-22µm band and over 70% in the mid-infrared region of 3-12µm. After double-sided antireflective coating, the transmittance at 10.6µm can reach 99%, exhibiting extremely low absorption, high transmittance, and excellent laser resistance. In specific applications, appropriate materials can be selected based on requirements such as the infrared laser wavelength range, power, transmittance, and high-temperature resistance.

[0054] In some embodiments, the end faces of each optical element in the primary beam expander, beam divergence assembly, and secondary beam expander are coated with an infrared anti-reflection film. This film can be optimized for the operating wavelength of the selected material (silicon, germanium, zinc sulfide, or zinc selenide, etc.), significantly reducing interface reflection loss, improving overall transmittance, and reducing stray light and heat accumulation caused by multiple reflections, thus ensuring the brightness and uniformity of the system's output beam.

[0055] Optionally, the infrared antireflection coating may consist of one or more thin films, each with a precisely designed thickness and refractive index to achieve light interference within a specific wavelength range, thereby reducing reflection and enhancing transmission. For example, materials used in infrared antireflection coatings include, but are not limited to, alumina, magnesium fluoride, and calcium fluoride.

[0056] It is understood that the optical elements in the aforementioned embodiments are related to the wavelength of the infrared laser passing through the lens. When the wavelength of the infrared laser changes, the corresponding focal length of the lens will change, and the above distance constraint relationship needs to be recalculated according to the new focal length.

[0057] Example 1 The infrared laser uses a 60W carbon dioxide laser with a wavelength of 10.6μm±0.05μm and a beam diameter of 2mm.

[0058] First lens 1: Zinc selenide plano-convex lens, 5mm in diameter, focal length f1 = 8mm (10.6μm).

[0059] Second lens 2: Zinc selenide plano-convex lens, 10mm in diameter, focal length f2 = 24mm (10.6μm).

[0060] Infrared diffuser 3: Zinc selenide circular sheet, frosted on both sides, 8mm in diameter and 2mm in thickness.

[0061] Infrared integrating rod 4: a zinc selenide long cylinder with an end face diameter D1 = 6mm, a length L1 = 70mm, and a concave spherical radius of 6mm.

[0062] Third lens 5: Zinc selenide positive meniscus lens, diameter 50mm, edge thickness 3.50mm, center thickness 6.60mm, concave radius 69.40mm, convex radius 193.20mm, focal length f3 = 75mm (10.6μm).

[0063] The first lens 1, the second lens 2, the third lens 5, and the two end faces of the infrared integrating rod 4 are all coated with broadband infrared antireflection films, which have high transmittance in the range of 2~13μm.

[0064] The distance d between the optical centers of the first lens 1 and the second lens 2 12 = 32mm, beam magnification M1 = 3, the infrared laser will be expanded into a collimated beam with a diameter of 6mm after passing through the first and second lenses.

[0065] By keeping the distance parameters between the first lens 1, the second lens 2, and the infrared integrating rod 4 constant, and adjusting the position of the third lens 5 to change the distance d3, circular uniform infrared irradiation spots of different diameters can be obtained at different distances behind the third lens 5.

[0066] One application example: The distance from the optical center of the third lens 5 to the plane end face of the infrared integrating rod 4 is set to d3 = 82.2 mm. The infrared laser spot image formed after passing through the third lens 5 is located 856.25 mm behind it, with a spot diameter of 62.5 mm and a magnification of M2 = 10.42. At this time, the total magnification of the device reaches M≈31.

[0067] Another application example: The optical components are the same as in Embodiment 1 above. The distance from the optical center of the third lens 5 to the plane end face of the infrared integrating rod 4 is set to d3 = 76.35 mm. The infrared laser spot image formed after passing through the third lens 5 is located 4241.67 mm behind it, with a spot diameter of 333.3 mm and a magnification M2 = 55.5. At this time, the total magnification of the device reaches M≈166.

[0068] In the second application embodiment, a laser power meter was used to measure the laser power within a 333.3 mm diameter spot. Figure 4 The laser power results at each point of the test spot at the designated locations are as follows: Table 1. Power meter measurements at the light spot (mW) The uniformity of the light spot is calculated as follows: 8.3% Where P max Pmin These represent the maximum and minimum power values ​​at the light spot test points, respectively.

[0069] Secondly, the present invention also provides an optical device, including the aforementioned laser homogenization and amplification optical device, and further including an infrared laser. The original beam emitted by the infrared laser is directly output as a large-aperture, highly uniform infrared illumination spot after being processed in three stages by the laser homogenization and amplification optical device. This can meet the requirements for the area and uniformity of the target infrared radiation characteristics measurement in one go, without the need for additional homogenization accessories. The entire optical device is compact and easy to debug.

[0070] The laser homogenization and amplification optical device and optical equipment according to the embodiments of the present invention can achieve the following technical effects: (1) Unlike simply amplifying the laser beam, this invention incorporates an infrared diffuser into the optical path to diffuse and convert the laser beam. Simultaneously, a concave spherical surface is specially processed at the incident end of the infrared integrating rod to further diverge the laser beam. Through this dual conversion of light angles, the light output from the infrared laser or an infrared source with a narrow divergence angle is differentiated and diverged. Then, an infrared integrating rod is used to superimpose the diverged light beams with various incident angles within the integrating rod. The uniform output end face of the integrating rod serves as the secondary light source emission surface for magnification and imaging, ultimately forming a magnified, uniform, large-area infrared irradiation spot at a certain distance. (2) All optical elements in this invention are processed using the same special infrared material and coated with an infrared anti-reflection film on the end face to ensure that the optical elements have high infrared transmittance and a wide range of applicable infrared wavelengths. In actual use, different wavelengths of infrared lasers can be replaced as needed, and large-area uniform infrared irradiation spots of various wavelengths can be obtained through this device and optical equipment; (3) The device and optical equipment in this invention have high infrared transmittance, low infrared absorption, and high temperature resistance, which reduces the influence of the thermal effect of the infrared laser and can actually withstand laser power of up to tens of watts. (4) By adjusting the distance between key optical elements (third lens), the final spot diameter and uniformity can be adjusted, and the spot imaging distance (i.e. the working distance from the device to the test target) can be adjusted and adapted according to the application requirements.

[0071] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0072] In this invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or in place of features of other embodiments.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the embodiments of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser homogenization and amplification optical device, characterized in that, include: A primary beam expander, a beam divergence assembly, and a secondary beam expander are arranged coaxially and sequentially from the laser side to the imaging side. The primary beam expander is based on a convex lens or a combination thereof, which magnifies the diameter of the laser beam by a factor of M1. The beam divergence component makes the laser beam, after being magnified by M1 times, diverge and become uniform. The secondary beam expander is based on a convex lens or a combination thereof, which amplifies the diverged and homogenized laser beam by a factor of M2.

2. The laser homogenization and amplification optical device according to claim 1, characterized in that, The primary beam expander includes a first lens and a second lens, both of which are plano-convex lenses. The first lens has a convex surface as its incident surface, and the second lens has a convex surface as its exit surface. The planes of the first and second lenses are arranged opposite to each other. The optical center distance between the first and second lenses is configured to be equal to the sum of the focal lengths of the two lenses, and M1 is equal to the ratio of the focal length of the second lens to that of the first lens.

3. The laser homogenization and amplification optical device according to claim 1, characterized in that, The beam divergence component includes an infrared diffuser, which is a circular thin sheet with frosted surfaces on both sides, and its diameter is not less than the diameter of the laser beam magnified by M1 times.

4. The laser homogenization and amplification optical device according to claim 1, characterized in that, The beam divergence component includes an infrared integrating rod, which is a cylindrical structure, and the shape of its end face is set to be circular, square or rectangular according to the shape of the laser source or the target spot. When the beam diverging assembly includes an infrared diffuser, the infrared diffuser is disposed on either the incident surface side or the exit surface side of the infrared integrating bar, with the two disposed adjacent to each other.

5. The laser homogenization and amplification optical device according to claim 4, characterized in that, The incident surface of the infrared integrating bar is set as a concave spherical surface, and the exit surface is set as a plane; and / or, The incident surface of the infrared integrating bar is configured as a concave spherical surface, and the radius of curvature of the concave spherical surface is equal to the maximum radial dimension of the incident surface of the infrared integrating bar; and / or, The maximum radial dimension of the incident surface of the infrared integrating bar is configured to be not less than the diameter of the laser beam magnified by M1 times; and / or, The length of the infrared integrating rod is configured to be greater than 10 times its maximum radial dimension at the end face.

6. The laser homogenization and amplification optical device according to claim 1, characterized in that, The secondary beam expander includes a third lens, which is a positive meniscus lens with a concave surface as the incident surface and a convex surface as the exit surface.

7. The laser homogenization and amplification optical device according to claim 1, characterized in that, The third lens can be adjusted along the optical axis, and its adjustment range is between one and two focal lengths from the third lens of the beam diverging component.

8. The laser homogenization and amplification optical device according to claim 1, characterized in that, The infrared materials of each optical element in the primary beam expander, beam divergence assembly, and secondary beam expander are the same, using silicon, germanium, zinc sulfide, or zinc selenide.

9. The laser homogenization and amplification optical device according to claim 1, characterized in that, The end faces of each optical element in the primary beam expander, beam divergence assembly, and secondary beam expander are coated with an infrared anti-reflection film.

10. An optical device comprising a laser homogenizing and amplifying optical device as described in any one of claims 1-9, and further comprising an infrared laser.

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