Optical element for semiconductor laser and laser device
By designing the concave and convex shapes of the incident surface and exit surface and the aspherical lens structure, the problem of excessive distance in the optical components of semiconductor lasers is solved, and a compact laser device design and efficient laser radiation collimation effect are achieved.
Patent Information
- Application Number
- CN202280093213.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-04-22
- Filing Date
- 2022-12-08
- Publication Date
- 2024-12-31
AI Technical Summary
Among the existing semiconductor laser optical elements, the distance between the semiconductor laser exit surface and the slow-axis collimating lens exit surface is relatively large, resulting in a large amount of unused space when combining multiple laser devices, which affects the compactness of the device.
By designing that the incident surface part is partially concave and the exit surface part is partially projected, the distance between the semiconductor laser exit surface and the slow-axis collimating lens exit surface is significantly reduced, and compact and robust are achieved through transparent substrates and aspherical cylindrical lenses. optical component structure.
It effectively reduces the excess space in the shell, maintains a large effective focal length, and improves the collimation effect of laser radiation and beam shaping capabilities, and is suitable for compact laser device design.
Smart Images
Figure CN119234171A_ABST
Abstract
Description
[0001] Optical element for semiconductor laser, and laser device having the same
[0002] Based on the general concept of claim 1, the invention relates to an optical element for a semiconductor laser, in particular for a single-emission semiconductor laser, and to a laser device having such an optical element.
[0003] Optical elements and laser devices of the aforementioned kind are known. Figure 1 An example of a laser device having such an optical element is shown. Figure 1 The laser device shown comprises a single-emitting semiconductor laser 1 having an exit surface for emitting laser radiation 2. The laser radiation 2 propagating in the z direction has different divergences in a first direction x and a second direction y, the first direction x corresponding to the slow axis direction of the laser radiation 2 and the second direction y being located near Figure 1 The image plane of FIG. 2 extends in the direction of the fast axis of the laser radiation 2 and corresponds to the fast axis direction of the laser radiation 2. The divergence in the fast axis direction is significantly greater than the divergence in the slow axis direction.
[0004] according to Figure 1 The optical element shown comprises a fast-axis collimating lens 3 which is designed as a cylindrical lens, the cylindrical axis of which extends in a first direction x. Figure 1 Also shown is a slow axis collimating lens 4 having an incident surface 5 and an exit surface 6. The incident surface 5 is flat, and the exit surface 6 is configured as a convex cylindrical lens, whose cylindrical axis extends in the second direction y. The fast axis collimating lens 3 significantly reduces the divergence of the laser radiation 2 relative to the fast axis direction, or the laser radiation 2 is largely collimated in the fast axis direction. The slow axis collimating lens 4 significantly reduces the divergence of the laser radiation 2 relative to the slow axis direction, or the laser radiation 2 is largely collimated in the slow axis direction.
[0005] A disadvantage of such an optical element or such a laser device is that the distance ai between the exit surface of the semiconductor laser 1 and the exit surface 6 of the slow axis collimating lens 4 is relatively large. In the prior art, this distance ai is between 10 mm and 20 mm. If a plurality of such laser devices are combined in one housing, a large amount of unused space is present in the housing due to the large distance.
[0006] Based on this prior art, the object of the present invention is to provide an optical element and a laser device of the type mentioned at the outset which require less installation space.
[0007] This is achieved according to the invention by an optical element of the aforementioned type having the features of claim 1 and a laser device of the aforementioned type having the features of claim 10. The dependent claims relate to preferred embodiments of the invention.
[0008] Based on claim 1, it is provided that the incident surface is at least partially concave and the exit surface is at least partially convex. By such a design, the distance between the exit surface of the semiconductor laser and the exit surface of the slow axis collimating lens can be significantly reduced. For example, the distance between the exit surface of the semiconductor laser and the exit surface of the slow axis collimating lens can be between 3 mm and 15 mm, in particular between 5 mm and 11 mm, preferably between 7 mm and 8 mm. When a plurality of laser devices are combined in one housing, the excess space in the housing is reduced by the above configuration.
[0009] In another embodiment of the present invention, the slow axis collimating lens comprises a transparent substrate, on which an incident surface and an exit surface are formed, and in particular, the slow axis collimating lens is integrally formed. The above configuration makes the optical element relatively compact and strong.
[0010] In another embodiment of the present invention, the surface of the incident surface (15) or the concave portion thereof concave along the first direction (x) has an area smaller than the surface of the exit surface (16) or the convex portion thereof convex along the first direction (x), and the first direction (x) corresponds to the slow axis direction of the laser radiation (11) emitted from the semiconductor laser (10), wherein, specifically, the surface of the incident surface (15) or the concave portion thereof concave along the first direction (x) has an area between 0.3 and 0.7 times that of the surface of the exit surface (16) or the convex portion thereof convex along the first direction (x).
[0011] The effective focal length of the slow axis collimating lens formed by the incident surface and the exit surface can be between 5 mm and 50 mm, in particular between 10 mm and 30 mm, preferably between 13 mm and 20 mm, and exemplarily, the effective focal length is about 15 mm. The advantage of the optical element disclosed according to the present invention is that, although the distance between the exit surface of the semiconductor laser and the exit surface of the slow axis collimating lens is very small, for example 7 mm to 8 mm, a relatively large effective focal length, for example an effective focal length of about 15 mm, can be maintained. This is achieved by the concave incident surface, which expands the laser radiation impinging on the incident surface before the laser radiation is largely collimated by the convex exit surface.
[0012] In another embodiment of the present invention, the fast axis collimating lens is configured as a cylindrical lens, a cylindrical axis of which extends in the first direction.
[0013] In another embodiment of the present invention, both the incident surface (15) and the exit surface (16) of the slow axis collimating lens (14) are constructed as cylindrical lenses, and the cylindrical axes of the incident surface (15) and the exit surface (16) are parallel to each other, wherein the cylindrical axes of the incident surface (15) and the exit surface (16) extend along a second direction (y) perpendicular to the first direction (x), and at the same time, the second direction (y) corresponds to the fast axis direction of the laser radiation (11) emitted from the semiconductor laser (10).
[0014] Furthermore, the present invention also provides an embodiment in which the cross-section of the cylindrical geometric shape of the incident surface and / or the cross-section of the cylindrical geometric shape of the exit surface deviates from a circular shape, in particular, wherein the cylindrical lens forming the incident surface and / or the cylindrical lens forming the exit surface has an aspherical shape.
[0015] The circular deviation of the cylindrical geometric section of the incident surface is different from the circular deviation of the cylindrical geometric section of the exit surface.
[0016] The optical element (12) is designed to generate laser radiation (11) emerging from the exit surface (16) in such a way that a distributed intensity deviates from a uniform intensity distribution due to the aspherical shape of the entrance surface (15) and / or the exit surface (16). This allows the light distribution in the collimated laser radiation to be influenced by a targeted adjustment of the aspherical shape. This distribution can be improved compared to the prior art, thus also being advantageous for applications other than collimation. For example, fiber coupling of laser radiation can be achieved by concentrating the energy in the center of the fiber core to increase the efficiency. Furthermore, the arrangement of two cylindrical lenses in one optical component offers the possibility of beam shaping using a constant number of surfaces in the beam path.
[0017] According to claim 10, the laser device comprises a semiconductor laser, in particular a single-emission semiconductor laser, and the optical element provided by the present invention.
[0018] More features and advantages of exemplary embodiments of the present invention are disclosed below with reference to the accompanying drawings. The same reference numerals are used for the same or similar components and components having the same or similar functions.
[0019] Attached Figure 1 A schematic side view of a laser device in the prior art is shown;
[0020] Attached Figure 2 A schematic side view of a laser device in an embodiment of the present invention is shown.
[0021] A Cartesian coordinate system is shown in the figures, with the y direction extending perpendicularly to the drawing plane of the figures.
[0022] The device disclosed in the present invention does not necessarily have all the features described below. In addition, the device disclosed in the present invention may only have individual features of the following embodiments.
[0023] According to the attached Figure 2 The laser device shown comprises a semiconductor laser 10, in particular a single-emission semiconductor laser, having an exit surface for emitting laser radiation 11. The laser radiation 11 propagating along the z direction has different divergences in a first direction x and a second direction y, wherein the first direction x corresponds to the slow axis direction of the laser radiation 11 and the second direction y corresponds to the fast axis direction of the laser radiation 11. The divergence in the fast axis direction is significantly greater than the divergence in the slow axis direction. Figure 2 The optical element 12 disclosed in the present invention is also included. The optical element 12 includes a fast-axis collimating lens 13 configured as a cylindrical lens, whose cylindrical axis extends along the first direction x; the optical element 12 also includes a slow-axis collimating lens 14 having an incident surface 15 and an exit surface 16, wherein the incident surface 15 is configured as a concave cylindrical lens, and the exit surface 16 is configured as a convex cylindrical lens, and the cylindrical axes of the concave cylindrical lens and the convex cylindrical lens extend along the second direction y.
[0024] The fast axis collimating lens 13 significantly reduces the divergence of the laser radiation 11 relative to the fast axis direction, or in other words, the laser radiation 11 is largely collimated in the fast axis direction. The slow axis collimating lens 4 significantly reduces the divergence of the laser radiation 11 relative to the slow axis direction, or in other words, the laser radiation 11 is largely collimated in the slow axis direction.
[0025] In the x-direction, the concave entrance face 15 extends only approximately half as far as the exit face 16. Alternatively, in the x-direction, the concave entrance face 15 extends just as far as the exit face 16. However, since the beam of laser radiation 11 impinges on the entrance face 15 is relatively small, it may be sufficient to provide only a central portion of the entrance face with a given concave curvature.
[0026] An incident surface 15 and an exit surface 16 are formed on the slow axis collimating lens 14, wherein the slow axis collimating lens 14 is an integrally formed optical component. Both the incident surface 15 and the exit surface 16 have a cross section of a cylindrical geometry that deviates from a circular shape, and in particular, the cylindrical lens forming the incident surface 15 and the cylindrical lens forming the exit surface 16 have an aspherical shape. The deviation of the cross section of the cylindrical geometry of the incident surface 15 from the circular shape may be different from the deviation of the cross section of the cylindrical geometry of the exit surface 16 from the circular shape.
[0027] The distance between the emission surface of the semiconductor laser 1 and the emission surface 6 of the slow axis collimating lens 4 is between 7 mm and 8 mm.
Claims
1. An optical element (12) for a semiconductor laser (10), in particular for a single-emission semiconductor laser, the optical element (12) comprising a fast-axis collimating lens (13), the optical element (12) being configured to ensure that laser radiation (11) emitted from the semiconductor laser (10) passes through the fast-axis collimating lens (13), the optical element (12) further comprising a slow-axis collimating lens (14) having an entrance surface (15) and an exit surface (16), the optical element (12) being configured for this purpose such that the laser radiation (11) passing through the fast-axis collimating lens (13) enters the slow-axis collimating lens (14) through the entrance surface (15) and exits the slow-axis collimating lens (14) through the exit surface (16), wherein: The incident surface (15) is at least partially concave, and the exit surface (16) is at least partially convex.
2. The optical element (12) according to claim 1, characterized in that The collimating lens (14) comprises a transparent substrate on which the incident surface (15) and the exit surface (16) are formed, wherein the axis collimating lens (14) is an integral component.
3. The optical element (12) according to claim 1, characterized in that The surface of the incident surface (15) or the concave portion thereof concave along a first direction (x) is smaller than the surface of the exit surface (16) or the convex portion thereof convex along the first direction (x), and the first direction (x) corresponds to the slow axis direction of the laser radiation (11) emitted from the semiconductor laser (10), wherein, specifically, the surface of the incident surface (15) or the concave portion thereof concave along the first direction (x) has an area between 0.3 and 0.7 times that of the surface of the exit surface (16) or the convex portion thereof convex along the first direction (x).
4. The optical element (12) according to any one of claims 1 to 3, characterized in that The effective focal length of the slow axis collimating lens (14) formed by the incident surface (15) and the exit surface (16) is between 5 mm and 50 mm, in particular, between 10 mm and 30 mm, further, between 13 mm and 20 mm, preferably 15 mm.
5. The optical element (12) according to any one of claims 1 to 4, characterized in that The fast axis collimating lens (13) is configured as a cylindrical lens, the cylindrical axis of which extends along a first direction (x).
6. The optical element (12) according to any one of claims 1 to 5, characterized in that The incident surface (15) and the exit surface (16) of the slow axis collimating lens (14) are both constructed as cylindrical lenses, and the cylindrical axes of the incident surface (15) and the exit surface (16) are parallel to each other, wherein the cylindrical axes of the incident surface (15) and the exit surface (16) both extend along a second direction (y) perpendicular to the first direction (x), and the second direction (y) corresponds to the fast axis direction of the laser radiation (11) emitted from the semiconductor laser (10).
7. The optical element (12) according to claim 6, characterized in that The cross section of the cylindrical geometry of the incident surface (15) and / or the cross section of the cylindrical geometry of the exit surface (16) deviates from a circular shape, in particular, the cylindrical lens forming the incident surface (15) and / or the cylindrical lens forming the exit surface (16) has an aspherical shape.
8. The optical element (12) according to claim 7, characterized in that The circular deviation of the cylindrical geometric section of the incident surface (15) is different from the circular deviation of the cylindrical geometric section of the exit surface (16).
9. The optical element (12) according to any one of claims 7 or 8, characterized in that The optical element (12) is configured to generate laser radiation (11) emerging from an exit surface (16) in such a way that a distributed intensity deviating from a uniform intensity distribution is generated due to the aspherical shape of the entrance surface (15) and / or the exit surface (16).
10. A laser device comprising a semiconductor laser (10), in particular a single-emission semiconductor laser, and an optical element (12) according to any one of claims 1 to 9.
11. The laser device according to claim 10, characterized in that The semiconductor laser (10) has an exit surface for receiving laser radiation (11) generated by the semiconductor laser (10), wherein the exit surface of the semiconductor laser (10) is aligned with a slow axis collimating lens (14). The distance (a2) between the exit surfaces (16) is between 3 mm and 15 mm, in particular, between 5 mm and 11 mm, preferably, Between 7mm and 8mm.