Beam shaping method and system of laser

Abstract

The invention provides a beam shaping method and system of a laser, and relates to the technical field of bar packaging, the method adopts a curved surface shaping piece with one surface being a free-form surface to shape a fast axis beam of the bar laser, and the molded surface of the curved surface shaping piece is fitted by adjusting a Zernike polynomial, so that the fast axis beam of the bar laser is shaped. And the wave aberration of the curved surface shaping piece after fitting accords with a preset value, so that the square light spots generated by the bars of the shaped stacked laser have uniform light intensity distribution and sharp edges, and the problems that in the prior art, the quality of light beams of the stacked laser is poor, and an existing optical shaping method needs multiple times of shaping and is high in difficulty are solved.

Description

Technical Field

[0001] This application relates to the field of bar packaging technology, and particularly to a method and system for beam shaping of a laser. Background Art

[0002] Smile is a phenomenon existing in bar lasers, which is mainly reflected in that each light-emitting point is not on the same horizontal line. This is a phenomenon caused by the warping of the wafer itself or packaging stress. The value of Smile is defined as the difference between the center of the highest light-emitting point and the center of the lowest light-emitting point. Its value can be 0 - 10 . When collimating a bar with a large Smile using an aspherical FAC, the light-emitting points not on the same horizontal plane are off-axis, as Figure 1 and Figure 2 shown. Figure 1 For a bar laser with a Smile value of 10 , the spot after collimation is shown. Figure 2 The collimated spot is thick and has a trailing shadow. This will seriously affect the beam quality of the stacked array output, and further increase the difficulty of secondary shaping of the subsequent optical system.

[0003] In the prior art, in order to obtain a uniform square spot output with a larger output power, multiple bars need to be combined into a stacked array. Since the fast-axis divergence angle of the LD semiconductor laser is large and the light intensity is Gaussian distributed, the output surface size of the stacked array is large and the uniformity is poor. In addition, the Smile effect of the bar itself also greatly affects the beam quality. In order to achieve a usable effect, a relatively complex optical shaping system is often required to meet the usable technical indicators. This not only increases the volume of the entire system, but also requires more cost and complex debugging processes.

[0004] As Figure 3 shown is the light intensity distribution curve of the fast axis of the bar. The fast axis of the bar laser is typically Gaussian distributed, and the slow axis is super-Gaussian distributed. This non-uniform light intensity distribution with unclear edges cannot be used in most applications. Therefore, a more complex secondary shaping system is required to transform it into a flat-top beam, as Figure 4 shown. Figure 4 This is the light intensity distribution curve of the flat-top beam. In the scientific research field, it is required that the edge of the flat-top distribution is sharpest. Therefore, a tertiary shaping system will be added, which increases the volume of the stacked array system, makes the cost more expensive and the process more difficult.

[0005] In summary, in the prior art, the stacked lasers applied to the scientific research pump source and the medical beauty industry all have a relatively complex post-channel optical shaping system. In the scientific research industry, if a bar stack with a large Smile effect is encountered, the shaping system will be more expensive and the debugging process will be more difficult, such as using multiple fast-axis collimators and slow-axis collimators. If the Smile effect is reduced from the chip packaging process, the yield will be relatively low. In the medical beauty industry, there are high requirements for the size and uniformity of the light spot, which makes it necessary to design a more complex optical shaping system to achieve this, such as using a light guide cone to homogenize the light spot, but this method is limited by the emission area and volume of the bar stack, and the light spot uniformity is relatively poor when using a lens group. Therefore, in the prior art, there are still many problems to be solved for the light spot shaping of bar stacks with a large Smile effect. Summary of the Invention

[0006] The purpose of this application is to provide a method and system for beam shaping of a laser to improve the technical problems proposed in the background art.

[0007] For the above purpose, this application provides the following technical solutions: In the first aspect of this application, a method for beam shaping of a laser is provided. The laser includes a bar to be shaped and a curved surface shaping member arranged corresponding to the bar to be shaped. The method includes: According to the Smile characteristics of the bar to be shaped, adjust the spherical aberration term coefficient and coma term coefficient of the Zernike polynomial of the curved surface shaping member to be in the first preset range and the second preset range respectively. The first preset range and the second preset range are determined based on the Smile characteristics of the bar to be shaped. According to the adjusted Zernike polynomial, fit the free surface of the curved surface shaping member so that the wavefront aberration of the curved surface shaping member after fitting is less than a preset value; Set the determined curved surface shaping member in the light emitting direction of the bar to be shaped. The curved surface shaping member is used to shape the beam in the fast axis direction of the bar to be shaped.

[0008] Further, the simulated value of the wavefront aberration is expressed as:

[0009] where W is the wavefront aberration of the curved surface shaping member after adjusting the spherical aberration term coefficient and the coma term coefficient of the Zernike polynomial, and the unit is ; is the refractive index, is the number of light emitting points of the bar to be shaped, is the normalized value of the incident height of the chief ray of different fields of view of the curved surface shaping member at the aperture stop; 、 is a coefficient, with the same meaning as the coefficient of the Zernike polynomial mentioned above. Here is , is A8.

[0010] Preferably, the simulated wavefront aberration value of the surface shaping part after fitting is less than a preset value, and the preset value is 0.89λ, where λ is the calibration wavelength of the surface shaping part, and the unit is .

[0011] Furthermore, the Zernike polynomial is:

[0012] Among them, is the optical surface sag, is the surface base part of the surface shaping part, where is the conic coefficient, is the curvature of the free surface of the surface shaping part, is the radius height in the optical axis direction of the surface shaping part; is the Zernike polynomial part, is the Zernike polynomial coefficient, is the Zernike polynomial term, is the number of terms of the Zernike polynomial term, is the normalized value of the incident height of the chief ray at different fields of view at the aperture stop, = r / (D / 2), D is the entrance pupil diameter, is the argument.

[0013] Preferably, adjust the coefficient of the eighth term of the Zernike polynomial part so that the edge softening factor of the bar to be shaped after being shaped by the surface shaping part is within a third preset range, that is, adjust the coefficient to be within 0.00001~0.005.

[0014] Preferably, adjust the coefficient of the ninth term of the Zernike polynomial part so that the spot uniformity of the bar to be shaped after being shaped by the surface shaping part is within a fourth preset range, that is, adjust the coefficient to be within 0.01~0.05.

[0015] Furthermore, according to the fast-axis divergence angle of the bar to be shaped, determine the curvature of the surface base part of the surface shaping part of the Zernike polynomial, the entrance pupil diameter D, and the conic coefficient .

[0016] Preferably, in the Smile feature of the bar to be shaped, the Smile value is 5~20 .

[0017] Preferably, the substrate of the surface shaping member is quartz glass.

[0018] The second aspect of the present application provides a beam shaping system for a laser, which is applied to the method described in the first aspect of the present application. The system includes: A stacked array laser, including a plurality of bars to be shaped arranged in a first direction, where the first direction is perpendicular to the arrangement direction of a plurality of single-tube laser chips in the bars to be shaped; A surface shaping member, which is arranged in the light emitting direction of the bars to be shaped. The surface shaping member includes a free surface and an incident plane. The free surface is located on the side away from the bars to be shaped; the incident plane is located on the side close to the bars to be shaped.

[0019] The beam shaping method for a laser provided by the present application can at least achieve the following technical effects: In view of the Smile effect of the bar laser, the free surface of the surface shaping member is fitted by Zernike polynomials, and the wave aberration of the surface shaping member after fitting is less than a preset value. Thus, by adjusting the micro-curvature of the free surface of the surface shaping member, the spherical aberration and coma aberration of different normalized entrance pupil apertures are adjusted to weaken or eliminate the influence brought by the Smile effect of the laser, so that the shaped light spot has a uniform light intensity distribution and clear and sharp edges. The method provided by the present invention has the advantages of high beam quality, controllable spot size, simple shaping method, easy implementation, cost reduction, small volume of the optical shaping system, and compact structure. Description of the Drawings

[0020] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 Schematic diagram of the collimated light spot of the bar laser with a Smile value of 10 provided in the background art section of the present application ; Figure 2 Schematic diagram of the coma aberration caused by off-axis light emitting points provided in the background art section of the present application Figure 3 Schematic diagram of the light intensity distribution curve of the bar fast axis provided in the background art section of the present application Figure 4Schematic diagram of the light intensity distribution curve of the bar-top flat beam provided in the background art section of this application; Figure 5 Schematic diagram of the process flow of a beam shaping method for a laser provided in the embodiment section of this application; Figure 6 Schematic diagram of the curved Smile arrangement provided in the embodiment section of this application; Figure 7 Schematic diagram of the cross-sectional contour of the curved surface shaping part provided in the embodiment section of this application; Figure 8 Schematic diagram of the overall structure of the curved surface shaping part provided in the embodiment section of this application; Figure 9 Schematic diagram of the structure of a beam shaping system for a laser provided in the embodiment section of this application; Figure 10 Schematic diagram of the light spot after the bar to be shaped is shaped by the curved surface shaping part provided in the embodiment section of this application; Figure 11 Schematic diagram of the fast-axis light intensity distribution after the bar to be shaped is shaped by the curved surface shaping part provided in the embodiment section of this application; Figure 12 Schematic diagram of the wavefront aberration with partial defocus, spherical aberration and coma when using a collimated beam to test the curved surface shaping part provided in the embodiment section of this application; Figure 13 Schematic diagram of the overall optical path after the stacked array laser is shaped by the curved surface shaping part provided in the embodiment section of this application; Figure 14 Schematic diagram of the light spot after the stacked array laser is shaped by the curved surface shaping part provided in the embodiment section of this application; Figure 15 Schematic diagram of the fast-axis light intensity distribution curve of the shaped light spot provided in the embodiment section of this application; Figure 16 Schematic diagram of the light spot of the stacked array laser after being shaped by ordinary FAC in the prior art provided in the embodiment section of this application; Figure 17 Schematic diagram of the fast-axis light intensity distribution of the stacked array laser after being shaped by ordinary FAC in the prior art provided in the embodiment section of this application; Reference numerals: 1. Bar to be shaped; 2. Curved surface shaping part; 21. Free curved surface; 22. Incident plane. Detailed implementation manners The technical solutions of this application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of this application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the protection scope of this application.

[0022] In an embodiment of the present application, by providing a method for beam shaping of a laser, the free surface of a surface shaping member is fitted by Zernike polynomials, so as to adjust the spherical aberration and coma of different normalized entrance pupil apertures by adjusting the micro-curvature of the free surface of the surface shaping member, so as to weaken or eliminate the influence brought by the Smile effect of the laser, so that the square light spot obtained after shaping has a uniform light intensity distribution and sharp edges. According to Figure 5 As shown, a method for beam shaping of a laser provided in this embodiment, the laser includes a bar to be shaped and a surface shaping member arranged corresponding to the bar to be shaped, and specifically includes the following steps: Step S100: According to the Smile characteristics of the bar 1 to be shaped, adjust the spherical aberration term coefficient and coma term coefficient of the Zernike polynomial of the surface shaping member 2 to be in a first preset range and a second preset range respectively, where the first preset range and the second preset range are respectively determined based on the Smile characteristics of the bar 1 to be shaped. According to the adjusted Zernike polynomial, fit the free surface 21 of the surface shaping member 2, so that the wavefront aberration of the surface shaping member 2 after fitting is less than a preset value; Step S200: Arrange the determined surface shaping member 2 in the light emitting direction of the bar 1 to be shaped, and the surface shaping member 2 is used to shape the beam in the fast axis direction of the bar 1 to be shaped.

[0023] Specifically, in step S100, the Zernike polynomial is expressed as the following formula (1): (1) In formula (1), is the sag of the optical surface, is the surface base part of the surface shaping member 2, where is the conic coefficient, is the curvature of the free surface 21 of the surface shaping member 2, is the radius height in the optical axis direction of the surface shaping member; is the Zernike polynomial part, is the Zernike polynomial coefficient, is the Zernike polynomial term, is the number of terms of the Zernike polynomial term, is the normalized value of the incident height of the chief ray of different fields of view at the aperture stop, = r / (D / 2), D is the entrance pupil diameter, is the argument.

[0024] Specifically, the Smile shapes of the bars 1 to be shaped are all curved, and their shapes are as Figure 6Since the fast-axis divergence angle of the bar is relatively large and the light intensity is Gaussian-distributed, the Smile effect also greatly affects the beam quality. Therefore, in this embodiment, a curved surface shaper 2 is used to actively control the beam characteristics of the bar 1 to be shaped in the direction perpendicular to the semiconductor junction plane (i.e., the fast-axis direction) to solve its inherent problems of large divergence angle and Gaussian distribution, as Figure 9 shown. In this embodiment, the free surface 21 of the curved surface shaper 2 is linearly fitted in the form of the standard Zernike polynomial described by formula (1) so that its wavefront aberration meets the preset value. If the fitting result does not meet the preset value, the curvature of the curved surface base part of the curved surface shaper 2 in the Zernike polynomial (1) is changed and the conic coefficient , and repeated simulations and corrections are performed to make the fitting result meet the requirements of the preset value. Based on the curved surface shaper 2 that meets the requirements after fitting, the beam in the fast-axis direction of the bar 1 to be shaped is shaped. Among them, the free surface refers to an optical surface with any combination of curvatures.

[0025] Specifically, during implementation, according to the fast-axis divergence angle of the bar 1 to be shaped, the curvature of the curved surface base part of the curved surface shaper 2 in the Zernike polynomial (1) is determined respectively and the entrance pupil diameter D. Preferably, if the fast-axis divergence angle of the curved surface shaper is , and the entrance pupil diameter is D, then according to the curvature is calculated, where is the focal length of the device, is the curvature; according to , according to the relationship between the curvature , the entrance pupil diameter D, and the fast-axis divergence angle , the entrance pupil diameter D is calculated. In formula (1), the conic coefficient is set by oneself.

[0026] Furthermore, in step S100, the spherical aberration term coefficient and coma term coefficient of the Zernike polynomial are adjusted respectively according to the Smile value and Smile shape of the bar 1 to be shaped. In the Zernike polynomial part of formula (1), the eighth term is the coma term that affects the spot edge softening factor (Spot Edge Softening Factor SEA: the ratio of the width between 90% and 10% of the maximum laser energy density to the corresponding laser beam aperture size), and the ninth term is the spherical aberration term that affects the spot uniformity. Therefore, in this embodiment, the first 9 terms are taken in the Zernike polynomial part, and omitting the calculation of the remaining terms can greatly save calculation time and reduce the difficulty of surface processing. In order to make the beam of a single bar 1 to be shaped into a flat-top beam after being shaped by the free surface 21 of the curved surface shaper 2, it is necessary to control the spherical aberration value of different normalized entrance pupil diameters, that is, the ninth term Coefficient (When this coefficient is 0, it means no spherical aberration is generated, but at this time, an appropriate spherical aberration needs to be deliberately introduced to make the illuminance uniform after shaping), and at the same time, control the eighth term Coefficient of off-axis coma aberration value to obtain a lower edge softening factor ( When it is 0, it means no coma aberration is generated, but when applied to a bar array, an appropriate coma aberration also needs to be deliberately introduced so that there are no spikes in the overlapping part of the adjacent bars to be shaped after shaping).

[0027] Optionally, according to the specific Smile value and shape of the bar 1 to be shaped, adjust the coefficient of the eighth term in the Zernike polynomial part in formula (1) , so that the coefficient of the coma aberration term is within the second preset range of 0.00001 to 0.005, so that the edge softening factor of the bar to be shaped after being shaped by the surface shaping member is within the third preset range, and the third preset range is "the edge softening factor is less than 5%"; adjust the coefficient of the ninth term in the Zernike polynomial part in formula (1) , so that the coefficient of the spherical aberration term is within the first preset range of 0.01 to 0.05, so that the spot uniformity of the bar to be shaped after being shaped by the surface shaping member is within the fourth preset range, and the fourth preset range is "the spot uniformity > 95%". In this application, by adjusting the coefficient of the eighth term and the coefficient of the ninth term of the Zernike polynomial, the influence brought by the Smile effect of the bar to be shaped is weakened or eliminated.

[0028] Optionally, the Smile value of the bar 1 to be shaped is 5 to 20 , so this embodiment can solve the beam shaping of a bar laser with a large Smile value.

[0029] Further, the design of the free surface 21 of the surface shaping member 2 adopts computer software-assisted calculation and fitting, and uses the simulated value of wave aberration to test the fitting effect. Wave aberration is the aberration introduced due to surface shape error. According to the vector wave aberration theory, the wave aberration of an optical system is the sum of the contributions of the wave aberrations of each independent surface shape. Then, the aberrations introduced by the eighth and ninth terms in the Zernike polynomial (1) of a single surface shaping member 2 can be expressed as the following formula (2): (2) In formula (2), W is the wave aberration of the surface shaping member after adjusting the coefficient of the eighth term and the coefficient of the ninth term of the Zernike polynomial, and the unit is ; is the refractive index, is the number of light-emitting points of the bar to be shaped 1, is the normalized value of the incident height of the chief rays of different fields of view of the surface shaping member at the aperture stop; 、 is a coefficient, and its meaning is the same as the coefficient of the Zernike polynomial. Here, is , is 。

[0030] Further, in step S100, the surface profiles corresponding to the coefficients of the terms in different Zernike polynomials are inconsistent, and the wavefront aberration is also inconsistent. In this embodiment, through fitting, the wavefront aberration of the surface shaping member 2 is made less than a preset value, and the preset value is 0.89λ, where λ is the calibration wavelength of the surface shaping member, and the unit is 。Preferably, in this embodiment, λ = 0.633 ,and the preset value is obtained based on the redundancy (tolerance) of the spherical aberration coefficient and coma coefficient of the Zernike polynomial. When the wavefront aberration of the surface shaping member 2 after fitting satisfies the preset value, the square light spot emitted by the bar 1 to be shaped after shaping has a uniform light intensity distribution and sharp edges.

[0031] Preferably, the substrate of the surface shaping member 2 is quartz glass.

[0032] Preferably, the size of the surface shaping member 2 is designed according to the size of the bar 1 to be shaped, and specifically satisfies: the length of the surface shaping member 2 is greater than the length of the bar 1 to be shaped, and the cylindrical height of the surface shaping member 2 is designed based on the fast-axis divergence angle of the bar 1 to be shaped. The schematic cross-sectional profile of the surface shaping member 2 is as shown in Figure 7 shown, and the schematic overall structure is as shown in Figure 8 shown.

[0033] Based on the beam shaping method of a laser provided in the first aspect of this embodiment, the second aspect of this embodiment also provides a beam shaping system of a laser, as shown in Figure 9 shown, and specifically includes: Stacked array laser, including a plurality of bars 1 to be shaped arranged in a first direction, where the first direction is perpendicular to the arrangement direction of a plurality of single laser chips in the bar 1 to be shaped; Surface shaping member 2, the surface shaping member 2 includes a free surface 21 and an incident plane 22, and the surface shaping member 2 is arranged in the light-emitting direction of the bar 1 to be shaped. Among them, the free surface 21 is located on the side away from the bar 1 to be shaped, the incident plane 22 is located on the side close to the bar 1 to be shaped, and the first direction is perpendicular to the light-emitting direction.

[0034] Preferably, the horizontal distance between the curved surface shaping member 2 and the bar 1 to be shaped is equal to the focal length value of the curved surface shaping member 2.

[0035] Specifically, the bars 1 to be shaped of the stacked laser are arranged vertically, and each of the curved surface shaping members 2 is arranged corresponding to one of the bars 1 to be shaped.

[0036] Optionally, the wavelength of a single bar 1 to be shaped can be 700 - 1000 nm, the number of light emitting points of each bar can be 10 - 65, the bar length is 10 mm, the fast axis divergence angle can be 50 - 70°, and the slow axis divergence angle can be 8 - 15°.

[0037] Optionally, the distance between the bars 1 to be shaped in the first direction can be 0.5 mm - 5 mm, and the distance between each of the curved surface shaping members 2 in the first direction can be optionally 0.5 - 5 mm.

[0038] Embodiment 1 Based on the beam shaping method and system of a laser provided in the above specific embodiments, this embodiment gives a specific example of beam shaping of a stacked laser, and the repeated parts will not be described again.

[0039] In this embodiment, the stacked laser is composed of five bars 1 to be shaped distributed in the first direction, where the first direction is perpendicular to the arrangement direction of multiple single - tube laser chips in the bar 1 to be shaped. Among them, the wavelength of the bar 1 to be shaped is 808 nm, the number of light emitting points of each bar 1 to be shaped is 10, the bar length is 10 mm, the fast axis divergence angle is 70°, the slow axis divergence angle is 10°, the distance between each bar 1 to be shaped in the first direction is 1.5 mm, and the Smile value of a single bar 1 to be shaped is 10 and the bar shapes are all curved. A curved surface shaping member 2 is arranged perpendicular to the plane where the light emitting points are located and extending in the X - axis direction for each bar 1 to be shaped for beam shaping. The base of the curved surface shaping member 2 is quartz glass, with dimensions of 1 mm * 0.5 mm * 12 mm.

[0040] Based on the bar 1 to be shaped with the above Smile value of 10 the curved surface shaping member 2 is designed, and the eighth - term coefficient of the Zernike polynomial part in formula (1) is adjusted to be 0.000273, and the ninth - term coefficient is 0.01477, and the free - form surface 21 of the curved surface shaping member 2 is fitted. The radius of curvature of the curved surface shaping member 2 is - 0.48; the focal length is 0.6 mm; = 10 (the number of light-emitting points of the bar to be shaped is 10), the number of single-tube laser chips of a single bar to be shaped is 10, and 1 single-tube laser chip is 1 light-emitting point. The curved surface shaper 2 shapes the light beams emitted from the 10 light-emitting points. The curved surface shaper 2 includes parts that shape the light beams emitted from the 10 light-emitting points respectively. At this time, after the curved surface shaper 2 with the above parameters shapes the light beam of a single bar to be shaped 1, the output light spot of the single bar to be shaped 1 is as Figure 10 shown, and the fast-axis light intensity distribution is as Figure 11 shown.

[0041] A collimated light beam is used to test the curved surface shaper 2. The wavefront aberration with partial defocus, spherical aberration, and coma is as Figure 12 shown. The wavefront aberration value is calculated based on the aforementioned formula (2) to obtain W = 0.67λ, which meets the requirements of the aforementioned preset value.

[0042] The above-mentioned curved surface shaper 2 is respectively applied to a stack laser composed of 5 bars to be shaped 1. The overall optical path diagram is as Figure 13 shown, the shaped light spot is as Figure 14 shown, and the fast-axis light intensity distribution curve is as Figure 15 shown. The uniformity of this light spot > 95%, the edge softening factor < 5%, and only one set of optical shaping devices is used. In the prior art, the light spot of a stack laser shaped by a common aspherical FAC is as Figure 16 shown, and the light intensity distribution is as Figure 17 shown. The existing scheme is greatly affected by Smile, and there are serious virtual images at both ends of the light spot. And the uniformity is poor < 80%, and the edge softening factor is large > 15%. Therefore, by comparison, it can be seen that the design scheme provided in this embodiment improves the light spot uniformity and edge softening factor of the stack laser.

[0043] The embodiments of the present invention achieve the following technical effects: 1. In response to the Smile effect of the bar stack laser, the free surface of the curved surface shaper is fitted by the Zernike polynomial. Thus, by adjusting the micro-curvature of the free surface of the curved surface shaper, the spherical aberration and coma of different normalized pupil apertures are adjusted to weaken or eliminate the influence brought by the Smile effect of the bar laser, so that the shaped square light spot has a uniform light intensity distribution and sharp edges, and the edge softening factor is small and the light spot uniformity is high; 2. The light spot shaping method provided in this application has the advantages of high beam quality, controllable light spot size, simple shaping method, easy implementation, cost reduction, small volume of the optical shaping system, and compact structure. One-time shaping can meet the requirements of the light spot distribution and beam quality of the stack laser. It has low cost and low process difficulty, and can be used in the scientific research and medical industries.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A beam shaping method for a laser, characterized in that, The laser includes a bar to be shaped and a curved surface shaping member arranged corresponding to the bar to be shaped. The method includes: According to the Smile feature of the bar to be shaped, adjusting the spherical aberration term coefficient and coma term coefficient of the Zernike polynomial of the curved surface shaping member to be respectively within a first preset range and a second preset range, where the first preset range and the second preset range are respectively determined based on the Smile feature of the bar to be shaped. According to the adjusted Zernike polynomial, fitting the free surface of the curved surface shaping member so that the wavefront aberration of the curved surface shaping member after fitting is less than a preset value; Arranging the determined curved surface shaping member in the light emitting direction of the bar to be shaped, and the curved surface shaping member is used for shaping the light beam in the fast axis direction of the bar to be shaped.

2. A beam shaping method for a laser according to claim 1, characterized in that, The simulated value of the wavefront aberration is expressed as: Among them, W is the wave aberration of the surface shaping component after adjusting the spherical aberration coefficient and the coma aberration coefficient of the Zernike polynomial, with the unit of ; is the refractive index, is the number of light-emitting points of the bar to be shaped, is the normalized value of the incident height of the chief ray of different fields of view of the surface shaping component at the aperture stop; , are coefficients, and their meanings are the same as those of the coefficients of the Zernike polynomial. Here is , is A8.

3. A method for beam shaping of a laser according to claim 2, characterized in that, After fitting, the simulated numerical value of the wave aberration of the surface shaping part is less than a preset value, and the preset value is 0.89λ, where λ is the calibration wavelength of the surface shaping part, and the unit is .

4. A method for beam shaping of a laser according to claim 1, characterized in that, The Zernike polynomial is: Among them, is the sag of the optical surface, is the surface base part of the surface shaping part, where is the conic coefficient, is the curvature of the free surface of the surface shaping part, is the radius height in the optical axis direction of the surface shaping part; is the Zernike polynomial part, is the Zernike polynomial coefficient, is the Zernike polynomial term, is the number of terms of the Zernike polynomial term, is the normalized value of the incident height of the chief ray at different fields of view at the aperture stop, = r / (D / 2), D is the entrance pupil diameter, is the argument.

5. A beam shaping method for a laser according to claim 4, characterized in that Adjust the coefficient of the eighth term of the Zernike polynomial part so that the edge softening factor of the bar to be shaped after being shaped by the surface shaping part is within a third preset range, that is, adjust the coefficient of the coma term It is in the range of 0.00001 to 0.

005.

6. A beam shaping method for a laser according to claim 4, characterized in that, Adjust the coefficient of the ninth term of the Zernike polynomial part so that the spot uniformity of the bar to be shaped after being shaped by the surface shaper is within the fourth preset range, that is, adjust the coefficient of the spherical aberration term It is between 0.01 and 0.

05.

7. A beam shaping method for a laser according to claim 4, characterized in that, Determine the curvature of the surface base part of the surface shaping part of the Zernike polynomial according to the fast-axis divergence angle of the bar to be shaped , the entrance pupil diameter D, and the conic coefficient .

8. A beam shaping method for a laser according to claim 1, characterized in that, In the Smile feature of the bar to be shaped, the Smile value is 5 to 20 .

9. A beam shaping method for a laser according to claim 1, characterized in that, The substrate of the curved surface shaping member is quartz glass.

10. A beam shaping system for a laser, characterized in that, The system is applied to the method according to any one of claims 1 to 9, and includes: A stacked laser, including a plurality of bars to be shaped arranged along a first direction, where the first direction is perpendicular to the arrangement direction of a plurality of single-tube laser chips in the bar to be shaped; A curved surface shaping member, the curved surface shaping member is arranged in the light emitting direction of the bar to be shaped, the curved surface shaping member includes a free surface and an incident plane, the free surface is located on the side away from the bar to be shaped; the incident plane is located on the side close to the bar to be shaped.

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