Blue laser and method for generating high-brightness light beam

Abstract

The invention provides a blue laser and a method for generating a high-brightness light beam. The blue laser comprises a first light beam emitting and combining module, a second light beam emitting and combining module, a polarization beam combining module, a compression mirror group and an output module, wherein the polarization beam combining module, the compression mirror group and the output module are arranged in sequence; the first light beam emitting and combining module and the second light beam emitting and combining module each comprise a wedge-shaped prism and a secondary collimating lens, the wedge-shaped prisms are used for adjusting the fast axis divergence angle of at least part of light beams, and the secondary collimating lenses are used for reducing the slow axis divergence angle of the light beams. A high-brightness blue light laser with a wedge prism and a secondary collimating mirror is used, and light beams with non-ideal fast axis divergence angles and light beams with all slow axes are shaped, so that the area of condensed light spots of the light beams is reduced exponentially.

Description

Technical Field

[0001] The present invention relates to the technical field of lasers, and in particular to a blue laser and a method for generating a high-brightness light beam thereof. Background Art

[0002] The current 1KW blue laser has a low output brightness. The minimum output fiber of the 1KW blue laser that has been launched on the market is 600um, and the power density is about 3538w / mm 2 , only suitable for copper welding applications below 0.2mm or in conjunction with fiber laser multi-wavelength composite output.

[0003] The existing 1KW blue light laser has insufficient output brightness, which limits its application. The single-tube chip used has a large residual divergence angle and inconsistent fast and slow axes. The fast-axis beam is slightly contracted, and the slow-axis beam is slightly divergent. Ultimately, only a position with a larger focal point size can be selected as the fiber coupling position, which limits the output fiber core diameter size and power density. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the purpose of the present invention is to provide a blue light laser that uses a secondary collimator to optimize the divergent light beam on the slow axis, thereby reducing the divergence angle of the light beam and significantly reducing the size of the focused light spot; uses a wedge prism to shape the light beam with an undesirable fast axis divergence angle, thereby reducing the area of ​​the focused light spot by several times; and ultimately achieves a 1KW-400um fiber-coupled output.

[0005] The embodiments of the present invention are achieved through the following technical solutions:

[0006] A blue laser comprising:

[0007] A first light beam emission and combining module, a second light beam emission and combining module, a polarization beam combining module, a compression lens group and an output module for light beam output arranged in sequence;

[0008] The first light beam emission and combining module and the second light beam emission and combining module both include a wedge prism and a secondary collimator. The wedge prism is used to adjust the fast axis divergence angle of at least part of the light beam, and the secondary collimator is used to reduce the slow axis divergence angle of the light beam.

[0009] According to a preferred embodiment, the wedge-shaped prism half cuts into the fast-axis light beam, so that the fast-axis divergence angle of half of the light beam changes and the spot size in the fast-axis direction at the focal point changes.

[0010] According to a preferred embodiment, the secondary collimating mirror fully cuts into the slow-axis light beam, so that the slow-axis divergence angle of the light beam is reduced.

[0011] According to a preferred embodiment, the secondary collimating mirror is a cylindrical mirror, and the cylindrical mirror is arranged on the rear side of the wedge prism along the light beam output direction.

[0012] According to a preferred embodiment, the polarization beam combining module includes a wave plate and a beam combining mirror group for changing the polarization state of the light beam; a portion of the light beam is emitted by the first light beam emitting and combining module, is reflected by a reflector in turn, and is reflected by the beam combining mirror group to form a reflected light beam, and the reflected light beam is output toward the compression mirror group;

[0013] Part of the light beam is emitted by the second light beam emission and combining module, passes through the wave plate to change the polarization state of the light beam, and then enters the beam combining mirror group for refraction to form a refracted light beam. The refracted light beam overlaps with the reflected light beam in space and has the same output direction.

[0014] According to a preferred embodiment, the wedge-shaped prism includes an incident prism face and an exit prism face along the light beam output direction, wherein part of the light beam is incident vertically on the incident prism face, and the exit prism face is tilted relative to the incident prism face.

[0015] According to a preferred embodiment, the output module includes an aperture and a condenser, and the aperture and the condenser are arranged in sequence along the light beam output direction.

[0016] According to a preferred embodiment, the reflector is arranged at the output end of the first light beam emission and combining module, and is used to reflect the light beam output by the first light beam emission and combining module to the combining mirror group to form the emission light beam and output it overlapping with the refracted light beam.

[0017] According to a preferred embodiment, the beam combiner group includes a PBS beam combiner, and the wave plate is a 1 / 2 wave plate.

[0018] According to a preferred embodiment, it further comprises an optical fiber, which is arranged at the output end of the condenser lens and has a core diameter of 400 microns.

[0019] A method for generating a high-brightness light beam using a blue laser comprises the following steps:

[0020] The output light beam includes a fast axis beam and a slow axis beam. During the light beam output process, the wedge prism at least partially cuts into the fast axis beam, and the secondary collimator fully cuts into the slow axis beam. Finally, all the light beams are output through the output module to obtain a high-brightness light beam.

[0021] The wedge-shaped prism half cuts into the fast-axis beam.

[0022] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0023] Compared with the original 1KW blue laser, the blue laser designed in the present invention has a higher power density, which will greatly improve the processing performance of the KW-level blue laser.

[0024] A secondary collimator is used to optimize the divergent beam of the slow axis, so that the beam divergence angle is reduced and the size of the focused spot is also greatly reduced;

[0025] A wedge-shaped prism is used to shape some light beams with undesirable fast-axis divergence angles, reducing the area of ​​the focused light spot exponentially; ultimately achieving a 1KW-400um fiber-coupled output. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic diagram of the optical path layout of a blue laser provided in Example 1 of the present invention;

[0028] Figure 2 A schematic diagram comparing the optical path layout before and after the fast-axis beam optimization provided in Example 1 of the present invention;

[0029] Figure 3 A schematic diagram comparing the optical path layout before and after the slow-axis beam optimization provided in Example 1 of the present invention;

[0030] Figure 4 A schematic diagram of the optical path layout for the fast and slow axis beam optimization provided in Example 1 of the present invention;

[0031] Figure 5 A schematic diagram of a local optical path layout for fast-axis beam optimization provided in Example 1 of the present invention;

[0032] Figure 6 Schematic diagram of the light spot output before and after the fast axis beam optimization provided in Example 1 of the present invention;

[0033] Figure 7 Schematic diagram of the light spot output before the slow-axis beam is optimized according to Example 1 of the present invention;

[0034] Figure 8 Schematic diagram of the light spot output after the slow-axis beam is optimized according to Example 1 of the present invention;

[0035] Figure 9 This is a schematic diagram of the measured power and coupling efficiency data of a blue laser provided in Example 1 of the present invention.

[0036] Icons: 1. First beam emission and combining module; 2. Second beam emission and combining module; 3. Wave plate; 4. Beam combining lens group; 41. Reflector; 5. Compression lens group; 51. Wedge prism; 52. Secondary collimator; 6. Aperture; 7. Condenser. DETAILED DESCRIPTION

[0037] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention 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. Therefore, they cannot be understood as limiting the present invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] Example 1

[0041] Please refer to Figures 1 to 9 ,

[0042] In this embodiment, the fast-axis divergence angle is a key parameter of the laser, primarily describing the divergence of the laser beam along the fast axis. The fast axis refers to the direction of propagation of light within the laser perpendicular to the direction of the laser's emitted beam. The slow axis refers to the direction of propagation of light within the laser perpendicular to the fast axis. Therefore, the partial wedge-shaped prism 51 acts on the light beam along the fast axis, shaping the portion of the light beam with an undesirable fast-axis divergence angle, thereby reducing the area of ​​the focused spot exponentially; in other words, only a portion of the fast-axis light beam enters the wedge-shaped prism 51.

[0043] A blue light laser comprises: a first light beam emission and combining module 1, a second light beam emission and combining module, a polarization beam combining module arranged in sequence, a compression lens group, and an output module for light beam output; the first light beam emission and combining module 1 and the second light beam emission and combining module 2 both comprise a wedge prism 51 and a secondary collimator 52, the wedge prism 51 is used to adjust the fast-axis divergence angle of at least part of the light beam, and the secondary collimator 52 is used to reduce the slow-axis divergence angle of the light beam.

[0044] According to a preferred embodiment, the wedge-shaped prism 51 half cuts into the fast-axis light beam, so that the fast-axis divergence angle of half of the light beam changes and the spot size in the fast-axis direction at the focal point changes.

[0045] According to a preferred embodiment, the secondary collimator 52 fully cuts into the slow-axis light beam, thereby reducing the slow-axis divergence angle of the light beam.

[0046] According to a preferred embodiment, the secondary collimator 52 is a cylindrical mirror, which is arranged on the rear side of the wedge prism 51 along the light beam output direction. Figure 2 As shown, the half-cut form of the wedge prism 51 is set in the direction of light beam output, that is, half of the fast-axis light beam is half-incident on the wedge prism 51, and the other half of the fast-axis light beam is not incident on the wedge prism 51. It can also be understood that only half of the wedge prism 51 is in the direction of fast-axis light beam output. The wedge prism 51 of this solution cuts into half of the light beam. If the wedge prism 51 cuts into the entire light beam, that is, the full-cut form, the position of the overall light spot is moved. If the wedge prism 51 half-cuts into the light beam, a large light spot can be turned into a small light spot, thereby improving the focusing performance. Full-cut can be understood as the entire light beam being incident on the wedge prism 51. The wedge prism 51 of this application can be selected as a wedge prism 51 with a small angle, and the range of the small angle can be selected from 0-1°.

[0047] The secondary collimating lens 52 is a cylindrical lens, which is arranged at the rear side of the wedge prism 51 along the light beam output direction.

[0048] like Figure 3 as well as Figure 5 As shown, the secondary collimator 52 is set behind the wedge prism 51, and the slow axis light beam can all pass through the secondary collimator 52, so that the slow axis divergence angle of the light beam is reduced. Among them, the label A is the fast and slow axis integrated collimator, and the label B is the light beam. Figure 5 The direction of the arrow in the middle is the direction of the light beam. Figures 2 to 5 The light beams in the figure are emitted from bottom to top in the corresponding figure.

[0049] According to a preferred embodiment, the polarization beam combining module includes a wave plate 3 for changing the polarization state of the light beam and a beam combining module 4;

[0050] Part of the light beam is emitted by the first light beam emission and combination module 1 and is reflected by the reflector 41 and the beam combination lens group 4 in sequence to form a reflected light beam, which is output toward the compression lens group 5;

[0051] Part of the light beam is emitted by the second light beam emission and combining module 2, passes through the wave plate 3 to change the polarization state of the light beam, and then enters the beam combining lens group 4 for refraction to form a refracted light beam. The refracted light beam and the reflected light beam overlap in space and have the same output direction.

[0052] According to a preferred embodiment, the wedge prism 51 includes an incident prism face and an exit prism face along the light beam output direction, wherein part of the light beam is incident perpendicularly on the incident prism face, and the exit prism face is tilted relative to the incident prism face.

[0053] According to a preferred embodiment, the output module includes an aperture 6 and a condenser 7, and the aperture 6 and the condenser 7 are sequentially arranged along the light beam output direction.

[0054] According to a preferred embodiment, a reflector 41 is arranged at the output end of the first light beam emission and combining module 1, and is used to reflect the light beam output by the first light beam emission and combining module 1 to the combining lens group 4 to form an emission light beam and output it overlapping with the refracted light beam. The emission light beam and the refracted light beam overlap and are output to the compression lens group 5, and finally output to the optical fiber C by the output module, namely the aperture 6 and the converging lens 7.

[0055] According to a preferred embodiment, the beam combiner group 4 includes a PBS beam combiner, and the wave plate 3 is a 1 / 2 wave plate.

[0056] According to a preferred embodiment, an optical fiber C is further included. The optical fiber C is arranged at the output end of the condenser 7, and the core diameter of the optical fiber C is 400 microns.

[0057] Working principle of the present invention: Figure 1 This is the optical path layout diagram of the blue light laser. The blue light laser includes a first light beam emission combining module 1 and a second light beam emission combining module 2. The first light beam emission combining module 1 and the second light beam emission combining module 2 have the same structural distribution. The output end of the second light beam emission combining module 2 is provided with a wave plate for changing the polarization state of the light beam of the second light beam emission combining module 2 so that it can pass through the combining mirror group 4. In this embodiment, the second combining mirror in the combining mirror group 4 is a PBS combining mirror. The first light beam emission combining module 1 does not change the polarization state and is reflected at the PBS combining mirror. The light beam of the first light beam emission combining module 1 is reflected by the reflector 41 and then reflected again by the PBS combining mirror. The light beam of the second light beam emission combining module 2 is refracted onto the PBS combining mirror after passing through the wave plate 3. The combined light beam after passing through the PBS combining mirror is the spatial overlap of the reflected light beam and the refracted light beam, and the power is doubled. Figure 9 As shown, the power of an optical fiber with a core diameter of 400 microns can reach more than 1000W through the solution of this application, and the optical fiber coupling efficiency is 85%. The first beam emission and beam combination module 1 and the second beam emission and beam combination module 2 both have multiple blue light emission single tubes.

[0058] The first light beam emission and combination module 1 and the second light beam emission and combination module 2 are provided with a wedge prism 51 for reducing the fast axis spot size. The wedge prism 51 half cuts into the fast axis beam ( Figure 2 ), which changes the angle of half of the fast axis beam and changes the spot size in the fast axis direction at the focal point ( Figure 6 ), which will be beneficial for the final coupling into the 400um optical fiber. The slow axis beam passing through the wedge prism 51 does not change, and the slow axis beam is collimated twice by the slow axis secondary collimator 52 ( Figure 3 ), the secondary collimating mirror 52 is a cylindrical mirror, Figure 4 The dotted line portion is the slow axis secondary collimator 52, which reduces the residual divergence angle of the light beam in the slow axis direction, reduces the spot size after long-distance transmission, and reduces the size of the focused spot. Figure 8 As shown, it will be beneficial for spatial transmission and final coupling into 400um optical fiber for comparison. Figure 7 This is the actual measurement of the beam transmission size and the focusing spot without the slow axis secondary collimator 52. Figure 2 include Figure 2 The diagram on the left is similar to Figure 2 The diagram on the right, Figure 2 The left schematic diagram shows the focused spot of the fast axis beam before being optimized by the partial wedge prism 51. Figure 2 The schematic diagram on the right shows the focused spot of the fast-axis beam after being optimized by the partial wedge prism 51 . Figure 3 include Figure 3 The diagram on the left and Figure 3 The diagram on the right, Figure 3 The left diagram shows the focused spot of the slow axis beam before optimization by the secondary collimator 52. Figure 3 The schematic diagram on the right shows the focused spot of the slow-axis beam after being optimized by the secondary collimator 52 . Figure 4 This is the optical path layout diagram after the fast axis beam passes through the partial wedge prism 51 and the slow axis beam passes through the secondary collimator 52. The output power of this blue laser exceeds 1000W and can be coupled into a 400um optical fiber with a power density of about 7961W / mm 2 Compared with the original 1KW blue laser, the power density is increased by 2.25 times, which will greatly improve the processing performance of the KW-level blue laser.

[0059] A method for generating a high-brightness light beam using a blue laser comprises the following steps:

[0060] In this embodiment, the output light beam includes a fast-axis light beam and a slow-axis light beam. During the light beam output process, the wedge-shaped prism 51 half cuts into the fast-axis light beam of the light beam, and the secondary collimator 52 fully cuts into the slow-axis light beam of the light beam. Finally, all the light beams are output through the output module to obtain a high-brightness light beam.

[0061] The final total light beam includes half of the fast-axis light beam that passes through the wedge prism 51, half of the fast-axis light beam that does not pass through the wedge prism 51, and the slow-axis light beam adjusted by the secondary collimator 52. The secondary collimator 52 is a cylindrical lens.

[0062] The technical means disclosed in the solutions of the present invention are not limited to those disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above-mentioned technical features. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A blue laser, characterized in that: include: A first light beam emission and combining module, a second light beam emission and combining module, a polarization beam combining module, a compression lens group and an output module for light beam output arranged in sequence; The first light beam emission and combining module and the second light beam emission and combining module both include a wedge prism and a secondary collimator. The wedge prism is used to adjust the fast axis divergence angle of at least part of the light beam, and the secondary collimator is used to reduce the slow axis divergence angle of the light beam.

2. The blue laser according to claim 1, characterized in that The wedge-shaped prism half cuts into the fast-axis light beam, causing the fast-axis divergence angle of half of the light beam to change and changing the spot size in the fast-axis direction at the focusing point.

3. The blue laser according to claim 2, characterized in that The secondary collimating mirror completely cuts into the slow axis light beam, so that the slow axis divergence angle of the light beam is reduced.

4. The blue laser according to claim 3, characterized in that The secondary collimating mirror is a cylindrical mirror, and the cylindrical mirror is arranged on the rear side of the wedge prism along the light beam output direction.

5. The blue laser according to claim 3, characterized in that The polarization beam combining module includes a wave plate and a beam combining mirror assembly for changing the polarization state of the light beam; Part of the light beam is emitted by the first light beam emission and beam combining module, is reflected by the reflector in turn, and is reflected by the beam combining mirror group to form a reflected light beam, and the reflected light beam is output toward the compression mirror group; Part of the light beam is emitted by the second light beam emission and combining module, passes through the wave plate to change the polarization state of the light beam, and then enters the beam combining mirror group for refraction to form a refracted light beam. The refracted light beam overlaps with the reflected light beam in space and has the same output direction.

6. The blue laser according to claim 1, characterized in that The output module includes an aperture and a condenser, and the aperture and the condenser are arranged in sequence along the light beam output direction.

7. The blue laser according to claim 5, characterized in that The reflector is arranged at the output end of the first light beam emission and combination module, and is used to reflect the light beam output by the first light beam emission and combination module to the combination mirror group to form the emission light beam and output it overlapping with the refracted light beam.

8. The blue laser according to claim 6, characterized in that It also includes an optical fiber, which is arranged at the output end of the condenser, and the core diameter of the optical fiber is 400 microns.

9. A method for generating a high-brightness light beam using a blue laser, characterized in that: The method comprises the following steps: the output light beam includes a fast-axis light beam and a slow-axis light beam; during the light beam output process, a wedge-shaped prism at least partially cuts into the fast-axis light beam, a secondary collimator fully cuts into the slow-axis light beam, and finally all the light beams are output through an output module to obtain a high-brightness light beam.

10. The method for generating a high-brightness light beam using a blue laser according to claim 9, wherein: The wedge-shaped prism half cuts into the fast-axis beam.

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