A fast axis collimating lens and optical device having the same

Abstract

The application discloses a fast-axis collimating lens and an optical device with the same, and relates to the technical field of laser optical elements. The fast-axis collimating lens comprises a cylindrical base and a composite film layer arranged in sequence along the direction of incident light. The light-in surface of the cylindrical base is a plane, the light-out surface of the cylindrical base is a convex surface, and the radius of curvature of the cylindrical base is greater than 2.5 mm. The composite film layer comprises at least one high-refractive-index transmission film layer, and the refractive index of the high-refractive-index transmission film layer ranges from 1.8 to 2.4. The fast-axis collimating lens is used to realize the collimating function by the synergic design of the film layer and the base structure, the low-convexity base is matched with the high-refractive-index transmission film layer, the processing and integration are facilitated, and the optical and mechanical properties are effectively improved.

Description

Technical Field

[0001] This application relates to the field of laser optical element technology, and in particular to a fast-axis collimating lens and an optical device having the same. Background Technology

[0002] As a core optical component of semiconductor lasers, the fast-axis collimator (FAC) lens can suppress beam divergence along the fast axis, achieving efficient one-dimensional collimation control. To meet specific collimation power requirements, the fast-axis collimator lens in this technology employs a high-convexity structure, i.e., a small radius of curvature. By matching the refractive index of the substrate material with the surface shape, light deflection and collimation are achieved.

[0003] However, the fast-axis collimating lens with the above-mentioned structure has the following shortcomings in practical applications: First, it is difficult and costly to manufacture. It requires complex processes such as precision polishing and single-point diamond turning to achieve nanoscale surface roughness control. The small radius of curvature makes surface forming difficult, easily leading to surface errors, local bulges or depressions, reducing product yield and increasing manufacturing costs. Second, it has poor optical stability and weak damage resistance. The high convexity structure causes a significant difference in thickness between the lens center and edge. Under high-power laser irradiation, uneven heat distribution can cause severe thermal deformation, leading to curvature drift and compromising collimation accuracy. Simultaneously, the steep curved surface structure increases the incident angle of light at the interface. The differences exacerbate Fresnel reflection loss and make the edges prone to chipping or surface damage due to stress concentration during assembly and transportation; third, the choice of materials is limited and the adaptability is weak. That is, barium lanthanum-based high-refractive-index special glass needs to be used. These materials are expensive, and some high-refractive-index materials have problems such as severe dispersion and unstable thermo-optical coefficients. In broadband laser applications, they will cause chromatic aberration distortion, which limits their adaptability in multi-wavelength laser systems; fourth, the integration is hindered. That is, the high convexity structure makes it difficult to further reduce the size and thickness of the lens. In the scenario of miniaturization and high-density integration of laser modules, the large component size will limit the flexibility of optical path layout and cannot meet the design requirements of compact optical systems. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the related technologies, it is desirable to provide a fast-axis collimating lens and an optical device having the same, which is convenient for processing and integration and improves optical and mechanical performance.

[0005] In a first aspect, this application provides a fast-axis collimating lens, which includes a cylindrical substrate and a composite film layer arranged sequentially along the incident light direction; The incident surface of the cylindrical substrate is a plane, the emitting surface of the cylindrical substrate is a convex surface, and the radius of curvature of the cylindrical substrate is greater than 2.5 mm; the composite film layer includes at least one high refractive index transmission film layer, and the refractive index of the high refractive index transmission film layer is in the range of 1.8~2.4.

[0006] Optionally, in some embodiments of this application, the high refractive index transmission film is made of titanium oxide or niobium oxide.

[0007] Optionally, in some embodiments of this application, the composite film layer is deposited on the light-emitting surface of the cylindrical substrate by ion beam sputtering.

[0008] Optionally, in some embodiments of this application, the refractive index of the cylindrical substrate ranges from 1.45 to 1.6.

[0009] Optionally, in some embodiments of this application, the cylindrical substrate is made of fused silica or K9 optical glass.

[0010] Optionally, in some embodiments of this application, the operating wavelength of the cylindrical substrate is the same as the operating wavelength of the composite film layer, which is 808nm~1550nm.

[0011] Optionally, the total optical power of the fast-axis collimating lens described in some embodiments of this application... ,in Indicates the refractive index of air. Represents the refractive index of the cylindrical substrate. Indicates the refractive index of the composite film. The radius of curvature of the cylindrical base is represented by . This indicates the thickness of the composite film.

[0012] In a second aspect, this application provides an optical device, which includes the fast-axis collimating lens described in any one of the first aspects.

[0013] Optionally, in some embodiments of this application, the optical device described is a high-power laser, a laser processing device, or an optical communication device.

[0014] As can be seen from the above technical solutions, the embodiments of this application have the following advantages: This application provides a fast-axis collimating lens and an optical device having the same. By using a composite film layer containing at least one high-refractive-index transmission film layer to compensate for insufficient optical power of a low-convex substrate, the radius of curvature of the cylindrical substrate can be significantly increased, effectively reducing the difficulty of surface forming. Conventional precision machining processes can meet the surface accuracy requirements, improving product yield by more than 40%. The cylindrical substrate does not require special high-refractive-index glass, significantly reducing material costs and processing time. Simultaneously, the substrate thickness distribution is more uniform, thermal deformation under high-power laser irradiation is reduced by more than 60%, and the cylindrical curvature drift is within 0.01 μm. Because the composite film layer achieves refractive index gradient matching (air → film layer → substrate), Fresnel reflection loss can be reduced to below 1%, stray light interference is reduced, and beam M... 2 With a factor close to 1, the collimation accuracy error is ≤±1%, and the lens center thickness can be reduced by 20%~40%, making it more compact and facilitating miniaturization and high-density integration. Furthermore, the thermo-optical coefficients of the film and the substrate are matched through process optimization. There is no film peeling or substrate deformation within the operating temperature range of -20℃~80℃, making it suitable for high-power and wide-temperature applications. The mechanical stability is also improved accordingly, and the risk of edge cracking can be reduced by 50%, enhancing the resistance to damage during assembly and transportation. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A side view of the fast-axis collimating lens of this application is provided as an embodiment of this application; Figure 2 A side view of a fast-axis collimating lens provided in this application embodiment; Figure 3 This is a structural block diagram of an optical device provided in an embodiment of this application.

[0017] Figure label: 10 - Fast-axis collimating lens, 101 - Cylindrical substrate, 102 - Composite film, 20 - Optical device. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The following examples illustrate this. Figures 1 to 3 The fast-axis collimating lens and optical device having the same provided in the embodiments of this application are described in detail.

[0021] Please refer to Figure 1 This is a side view of a fast-axis collimating lens provided in an embodiment of this application. The fast-axis collimating lens 10 includes a cylindrical substrate 101 and a composite film layer 102 arranged sequentially along the incident light direction. The incident light surface of the cylindrical substrate 101 is planar, and the light emitting surface of the cylindrical substrate 101 is convex. The radius of curvature of the cylindrical substrate 101 is greater than 2.5 mm, that is, it adopts a plano-convex cylindrical structure, which has optical curvature only in the fast-axis direction and maintains planar characteristics in the slow-axis direction. The composite film layer 102 includes at least one high-refractive-index transmission film layer, and the refractive index of the high-refractive-index transmission film layer is in the range of 1.8 to 2.4.

[0022] Furthermore, in some embodiments of this application, for example, the refractive index range of the cylindrical substrate 101 is 1.45~1.6, and the substrate material includes, but is not limited to, fused silica or K9 optical glass, eliminating the need for special high-refractive-index glass and significantly reducing material costs and processing cycles. As another example, the material of the high-refractive-index transmission film includes, but is not limited to, titanium oxide or niobium oxide, with a film thickness uniformity error within 1 / 50 of the working wavelength. The composite film 102 is deposited on the light-emitting surface of the cylindrical substrate 101 using an ion beam sputtering process. This means that conventional precision machining processes can meet the surface accuracy requirements, effectively reducing the difficulty of curved surface forming and improving product yield by more than 40%. Simultaneously, the working wavelength of the cylindrical substrate 101 and the composite film 102 are the same, both ranging from 808nm to 1550nm. Another example is the total optical power of the fast-axis collimating lens 10. ,in This represents the refractive index of air, with a value of 1. Represents the refractive index of the cylindrical substrate. Indicates the refractive index of the composite film. The radius of curvature of the cylindrical base is represented by . The thickness of the composite film is indicated, which enables the high refractive index transmission film to be used as the core component for optical power control, and to work in conjunction with the cylindrical substrate to achieve collimation, thus solving the inherent defects of the high convexity structure.

[0023] For example, taking the collimation of a semiconductor laser with a wavelength of 808nm as an example, such as Figure 2 As shown, the high-convexity fast-axis collimating lens in the related technology has a base curvature radius of 2.5 mm, a base refractive index of 1.812, uses barium lanthanum glass, and has an optical power of 0.325 mm. -1 The fast-axis collimating lens 10 of this application can be made of fused silica substrate with a refractive index of 1.46 and a radius of curvature of 3.9 mm. The high-refractive-index transmission film is made of niobium pentoxide with a refractive index of 2.3 and a thickness of 156 μm, with a film thickness uniformity error ≤10 nm. Test results show that, under consistent optical power, the fast-axis collimating lens 10 of this application has a fast-axis collimation divergence angle ≤0.5 mrad, a transmission efficiency ≥98%, and a beam M... 2 With a factor of 1.05, the curvature drift in the thermal stability test (100W laser irradiation for 1 hour) is 0.008μm. All performance indicators reach or even exceed the level of high convexity fast axis collimating lenses in related technologies, and the convexity can be reduced by 35.9%, which facilitates processing and integration and effectively improves optical and mechanical properties.

[0024] In another aspect, embodiments of this application provide an optical device. Please refer to... Figure 3 This is a structural block diagram of an optical device provided in an embodiment of this application. The optical device 20 includes... Figure 1 In any of the corresponding embodiments, the fast-axis collimating lens 10, for example, the optical device 20 can be a high-power laser, a laser processing device, or an optical communication device, with the power of the high-power laser being above 100 watts.

[0025] It should be noted that the descriptions of the same content in this embodiment as in other embodiments can be found in the descriptions in other embodiments, and will not be repeated here.

[0026] The fast-axis collimating lens and optical device provided in this application compensate for the insufficient optical power of a low-convex substrate by using a composite film layer containing at least one high-refractive-index transmission film layer. This significantly increases the radius of curvature of the cylindrical substrate, effectively reducing the difficulty of surface forming. Conventional precision machining processes can meet the surface accuracy requirements, improving product yield by more than 40%. The cylindrical substrate does not require special high-refractive-index glass, greatly reducing material costs and processing cycles. At the same time, the substrate thickness distribution is more uniform, thermal deformation under high-power laser irradiation is reduced by more than 60%, and the cylindrical curvature drift is within 0.01 μm. Because the composite film layer achieves refractive index gradient matching (air → film layer → substrate), Fresnel reflection loss can be reduced to below 1%, stray light interference is reduced, and beam M... 2 With a factor close to 1, the collimation accuracy error is ≤±1%, and the lens center thickness can be reduced by 20%~40%, making it more compact and facilitating miniaturization and high-density integration. Furthermore, the thermo-optical coefficients of the film and the substrate are matched through process optimization. There is no film peeling or substrate deformation within the operating temperature range of -20℃~80℃, making it suitable for high-power and wide-temperature applications. The mechanical stability is also improved accordingly, and the risk of edge cracking can be reduced by 50%, enhancing the resistance to damage during assembly and transportation.

[0027] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0028] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A fast axis collimating lens characterized by, The fast-axis collimating lens (10) includes a cylindrical substrate (101) and a composite film layer (102) arranged sequentially along the incident light direction. The incident surface of the cylindrical substrate (101) is a plane, the emitting surface of the cylindrical substrate (101) is a convex surface, and the radius of curvature of the cylindrical substrate (101) is greater than 2.5 mm; the composite film layer (102) includes at least one high refractive index transmission film layer, and the refractive index of the high refractive index transmission film layer is in the range of 1.8~2.

4.

2. The fast axis collimating lens of claim 1, wherein, The high refractive index transmission film is made of titanium oxide or niobium oxide.

3. The fast axis collimating lens of claim 1, wherein, The composite film (102) is deposited on the light-emitting surface of the cylindrical substrate (101) by ion beam sputtering.

4. The fast axis collimating lens according to any one of claims 1 to 3, wherein, The refractive index of the cylindrical substrate (101) ranges from 1.45 to 1.

6.

5. The fast-axis collimating lens according to claim 4, characterized in that, The cylindrical substrate (101) is made of fused silica or K9 optical glass.

6. The fast-axis collimating lens according to claim 4, characterized in that, The operating wavelength of the cylindrical substrate (101) is the same as that of the composite film layer (102), both being 808nm~1550nm.

7. The fast-axis collimating lens according to any one of claims 1 to 3, characterized in that, The total optical power of the fast-axis collimating lens (10) ,in Indicates the refractive index of air. Represents the refractive index of the cylindrical substrate. Indicates the refractive index of the composite film. The radius of curvature of the cylindrical base is represented by . This indicates the thickness of the composite film.

8. An optical device, characterized in that, The optical device (20) includes the fast-axis collimating lens (10) according to any one of claims 1 to 7.

9. The optical device according to claim 8, characterized in that, The optical device (20) is a high-power laser, laser processing equipment or optical communication equipment.

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