A laser beam nesting type laser beam combining device for obtaining a stepped light intensity distribution

Abstract

The application discloses a light beam nesting type laser beam combining device for obtaining a stepped light intensity distribution. The light beam nesting type laser beam combining device comprises a first laser, a conical mirror, a slotted triangular prism and a second laser, and the first laser, the conical mirror and the slotted triangular prism are sequentially arranged from left to right. The second laser is arranged above the slotted triangular prism, and the laser beam output by the second laser is vertically incident on the slot surface of the slotted triangular prism. The conical mirror is used for transforming the laser beam emitted by the first laser into a circular ring laser beam with zero intermediate light intensity and gradually increasing along the radial direction. The slotted triangular prism is used for rotating the emission direction of the circular ring laser beam by 90 degrees to be parallel to the emission direction of the laser beam of the second laser, and does not change the light intensity distribution. The laser beam emitted by the second laser is transmitted through the slot surface of the slotted triangular prism, and is combined with the circular ring laser beam rotated by 90 degrees to form a nesting type laser beam.

Description

Technical Field

[0001] This invention belongs to the field of laser beam combining technology, specifically relating to a nested laser beam combining device for obtaining a stepped intensity distribution. Background Technology

[0002] A single laser can only output a single wavelength of laser light, and its output power cannot be increased indefinitely due to limitations in component performance, structural dimensions, and thermal effects. To obtain higher-power laser beams, laser beam combining technology is commonly used. Laser beam combining technology is widely applied in high-power laser components, two-photon imaging, multiphoton resonance ionization, laser pointing, laser welding, laser cladding, surface hardening, and many other fields. Coherent beam combining methods have specific requirements for laser wavelength, phase, and polarization parameters, making the technology complex, unstable, and technically challenging to implement at high output power. Incoherent beam combining, on the other hand, does not require controlling the consistency of wavelength, phase, and polarization parameters of each beam, has no requirements for the light source, and uses a relatively simpler device. The quality of the output beam depends primarily on the beam combining device, making it more reliable and practical.

[0003] A prior patent application with application number 201210078189.7 discloses a pulsed laser beam combining scheme, the schematic diagram of which is shown below. Figure 1 As shown in the diagram, 101-104 are lasers (output ends); 201-204 are plane mirrors, whose positions and angles are fixed, and 101-104 are placed corresponding to plane mirrors 201-204; 301 is a rotating reflecting prism. This scheme uses the rotation of a reflecting prism with at least one reflecting surface to reflect multiple pulsed laser beams onto each reflecting surface, achieving incoherent beam synthesis. However, this scheme has the following four shortcomings: First, the polyhedral mirror in this scheme is preferably a 60-facet mirror, which has a complex manufacturing process and requires a matching encoder. Precise control can only be achieved when the encoder acquires the orientation signal of the mirror; Second, the jitter of the reflected light generated when the mirror rotates continuously degrades the quality of the laser beam; Third, due to the rotation speed limitation of the rotating mirror, this device has certain requirements for the source laser, requiring the use of a low repetition frequency laser; Fourth, the source laser needs to be distributed in an arc shape around the reflecting rotating prism, which is complex and difficult to achieve. Summary of the Invention

[0004] In view of this, the present invention proposes a device for obtaining a nested laser beam combining beam with a stepped intensity distribution.

[0005] The nested laser beam combining device for obtaining a stepped intensity distribution includes: a first laser 1, a conical mirror 2, a slotted triangular prism 3, and a second laser 4, wherein:

[0006] The first laser 1, the conical mirror 2, and the slotted triangular prism 3 are placed sequentially from left to right;

[0007] The second laser 4 is placed above the slotted triangular prism 3, so that the laser beam it outputs is perpendicularly incident on the slotted surface of the slotted triangular prism 3.

[0008] The conical mirror 2 is used to transform the laser beam emitted by the first laser 1 into a ring-shaped laser beam with zero intensity in the middle and gradually increasing intensity in the radial direction.

[0009] The slotted triangular prism 3 is used to rotate the output direction of the annular laser beam by 90° to be parallel to the laser output direction of the second laser 4 without changing its light intensity distribution.

[0010] The laser beam emitted from the second laser 4 is transmitted through the slotted surface of the slotted triangular prism 3. The slotted triangular prism 3 does not change the emission path of the laser beam. The transmitted laser beam merges with the annular laser beam after being rotated 90° into a nested laser beam.

[0011] Among them, the first laser 1 and the second laser 4 are the light source lasers for the composite beam.

[0012] The first laser 1 and the second laser 4 have the same output power.

[0013] Among them, the first laser 1 and the second laser 4 are semiconductor-pumped 532nm fiber green lasers.

[0014] The conical mirror 2 is a lens with different front and rear cone angles.

[0015] The conical mirror 2 has a front cone angle θ1 of 40°, a rear cone angle θ2 of 60°, and a light-transmitting aperture of φ50mm.

[0016] The conical mirror 2 is a quartz lens.

[0017] The 45° inclined surface of the slotted triangular prism 3 is coated with a high-reflection film, and the slot surface is coated with a high-transmission film.

[0018] The grooved triangular prism 3 is made of fused silica.

[0019] This invention proposes a nested laser beam combiner for obtaining a stepped intensity distribution. This device can produce a high-power, stepped-energy beam with a central intensity approximately equal to that of one of the source lasers. The device does not require parameter consistency of the source lasers, and the combined beam can be used as the source laser for the next combining stage. That is, the device is not limited to two source lasers and can combine N (N≥2) laser beams to obtain a high-power laser beam. Furthermore, the device is simple to implement, exhibits no jitter and low loss during beam combining, and ensures good quality of the combined beam. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 This is a schematic diagram of a prior pulsed green laser beam combining device;

[0022] Figure 2 This is a schematic diagram of a beam nesting laser beam combiner that obtains a stepped light intensity distribution according to an embodiment of the present invention.

[0023] Figure 3 This is an intensity distribution diagram of a nested laser beam generated according to an embodiment of the present invention. Detailed Implementation

[0024] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0025] To illustrate the technical solution described in this invention, specific embodiments are described below.

[0026] Figure 2 This is a schematic diagram of a nested laser beam combiner for obtaining a stepped intensity distribution according to an embodiment of the present invention, as shown below. Figure 2 As shown, the nested laser beam combining device for obtaining a stepped intensity distribution includes: a first laser 1, a conical mirror 2, a slotted triangular prism 3, and a second laser 4, wherein:

[0027] The first laser 1, the conical mirror 2, and the slotted triangular prism 3 are placed sequentially from left to right;

[0028] The second laser 4 is placed above the slotted triangular prism 3, so that the laser beam it outputs is perpendicularly incident on the slotted surface of the slotted triangular prism 3.

[0029] Wherein, the first laser 1 and the second laser 4 are the light source lasers for the composite beam;

[0030] The conical mirror 2 is used to transform the laser beam emitted by the first laser 1 into a ring-shaped laser beam with zero intensity in the middle and gradually increasing intensity in the radial direction.

[0031] The slotted triangular prism 3 is used to rotate the output direction of the annular laser beam by 90° to be parallel to the laser output direction of the second laser 4 without changing its light intensity distribution.

[0032] The laser beam emitted from the second laser 4 is transmitted through the slotted surface of the slotted triangular prism 3. The slotted triangular prism 3 does not change the emission path of the laser beam. The transmitted laser beam merges with the annular laser beam after being rotated 90° into a nested laser beam.

[0033] In one embodiment of the present invention, the first laser 1 and the second laser 4 have the same output power. In addition, the present invention has no special requirements for other parameters such as wavelength, phase, and polarization of the first laser 1 and the second laser 4.

[0034] In one embodiment of the present invention, considering that green light has strong penetrating power, the first laser 1 and the second laser 4 can be selected as semiconductor-pumped 532nm fiber green lasers.

[0035] In one embodiment of the present invention, the conical mirror 2 is a lens with different front and rear cone angles.

[0036] In one embodiment of the present invention, the 45° inclined surface of the slotted triangular prism 3 is coated with a high-reflection film, and the slot surface is coated with a high-transmission film.

[0037] The working principle of the nested laser beam combining device for obtaining a stepped intensity distribution is as follows: When the Gaussian-distributed beam emitted from the first laser 1 is perpendicularly incident on the front cone angle of the conical mirror 2, it is equivalent to being incident on a negative conical mirror. At the cone tip, an axisymmetric beam distribution is formed along the axis, producing a cone-shaped hollow beam with the cone tip as the apex. This beam is then refracted by the rear conical surface of the conical mirror 2 to form a cylindrical parallel annular beam. Simultaneously, the second laser 4 is transmitted through the slotted surface of the slotted triangular prism 3 without changing the laser beam's exit path. The transmitted laser beam merges with the annular laser beam after being rotated 90° to form a nested laser beam. The synthesized nested laser beam exhibits a stepped intensity distribution, that is, the intensity is strongest at the center of the beam and decreases towards the edge of the beam.

[0038] In a specific embodiment of the present invention, the output power of the first laser 1 and the second laser 4 of the nested laser beam combining device is 50W; the conical lens 2 is a quartz lens with different front and rear cone angles, wherein the front cone angle θ1 is 40°, the rear cone angle θ2 is 60°, and the aperture is φ50mm; the slotted triangular prism 3 is made of fused silica, with an aperture of φ70mm, its 45° inclined surface is coated with a 532nm high reflectivity film (R>99%), and the slotted surface is coated with a 532nm antireflection film (T>99%). The intensity distribution of the synthesized beam formed by the nested laser beam combining device is as follows: Figure 3 As shown, the maximum power can reach approximately 100W.

[0039] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A nested laser beam combiner for obtaining a stepped intensity distribution, characterized in that, The device includes: a first laser (1), a conical mirror (2), a slotted triangular prism (3), and a second laser (4), wherein: The first laser (1), the conical mirror (2), and the slotted triangular prism (3) are placed sequentially from left to right; The second laser (4) is placed above the slotted triangular prism (3) so that the laser beam it outputs is perpendicularly incident on the slotted surface of the slotted triangular prism (3); The conical mirror (2) is used to transform the laser beam emitted by the first laser (1) into a circular laser beam with zero intensity in the middle and gradually increasing intensity in the radial direction. The conical mirror (2) is a lens with different front and rear cone angles. The slotted triangular prism (3) is used to rotate the output direction of the circular laser beam by 90° to be parallel to the laser output direction of the second laser (4) without changing its light intensity distribution. The laser beam emitted by the second laser (4) is transmitted through the slotted surface of the slotted triangular prism (3). The slotted triangular prism (3) does not change the emission path of the laser beam. The transmitted laser beam merges with the circular laser beam after being rotated 90° into a nested laser beam. Among them, the first laser (1) and the second laser (4) are the light source lasers for the composite beam.

2. The apparatus according to claim 1, characterized in that, The first laser (1) and the second laser (4) have the same output power.

3. The apparatus according to claim 1, characterized in that, The first laser (1) and the second laser (4) are semiconductor-pumped 532nm fiber green lasers.

4. The apparatus according to claim 1, characterized in that, The front cone angle of the conical mirror (2) The rear cone angle is 40°. The angle is 60°, and the aperture is [missing information]. mm.

5. The apparatus according to claim 4, characterized in that, The conical mirror (2) is a quartz lens.

6. The apparatus according to claim 1, characterized in that, The 45° inclined surface of the slotted triangular prism (3) is coated with a high-reflection film, and the slot surface is coated with a high-transmission film.

7. The apparatus according to claim 6, characterized in that, The grooved triangular prism (3) is made of fused silica.

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