WO2023236354A1

WO2023236354A1 - Reflective broadband integrator mirror and broadband optical fiber laser optical system

Info

Publication number: WO2023236354A1
Application number: PCT/CN2022/114206
Authority: WO
Inventors: 邵华江; 王伟; 李思佳
Original assignee: 上海嘉强自动化技术有限公司
Priority date: 2022-06-10
Filing date: 2022-08-23
Publication date: 2023-12-14
Also published as: CN114966925A

Abstract

A reflective broadband integrator mirror (100) and a broadband optical fiber laser optical system (10). The reflective broadband integrator mirror (100) is based on incident light from a point light source (20) and comprises a base body (110), wherein the base body (110) has a bottom face (111), a mirror face (112) and a symmetry plane (113); and the base body (110) is symmetrical about the symmetry plane (113). The mirror face (112) is inclined at a set acute angle (α) relative to the bottom face (111), and comprises at least three broadband curved surfaces (1121), which are concave, wherein the broadband curved surfaces (1121) pass through the symmetry plane (113) and are symmetrical about the symmetry plane (113); and every two adjacent broadband curved surfaces (1121) intersect and form an arc-shaped strip line (1122), focuses of all the arc-shaped strip lines (1122) are coplanar and form a focusing plane, and the focusing plane and the symmetry plane (113) are set in parallel and at an interval. Reflected light rays that are reflected by the mirror face (112) are focused towards a center to form a light spot. Since a plurality of reflected light rays reflected by the same arc-shaped strip line (1122) are symmetrical about the symmetry plane (113), the light spot has relatively good symmetry; in addition, by means of unidirectional flat-top homogenization, the light spot has relatively good overall homogeneity. The present invention has a simple optical path structure, less power loss, higher optical path stability, lower costs, and relatively good large-scale application prospects.

Description

Reflective broadband integrator mirror and broadband fiber laser optical system

Technical field

The invention relates to the technical field of laser beam shaping, and in particular to a reflective broadband integrator mirror and a broadband fiber laser optical system.

Background technique

Laser processing technologies such as laser cutting, welding, quenching, drilling, and micro-machining are widely used for their advantages of non-contact, fast processing speed, and excellent quality. Among them, broadband laser cladding, broadband laser quenching, and other broadband fiber laser processing process, which is very common in the industrial laser processing industry.

Broadband fiber laser processing technology usually requires the energy distribution of the laser beam to be shaped to achieve a flat-top distribution to ensure better surface effects and depth consistency. Currently, there are three types of spot shaping solutions: The first one is waveguide shaping, but due to its large light absorption, it is severely limited in high-power laser processing; the second one is transmissive lenses such as lens arrays, binary optical elements, and integral lenses. , because the material is hard and brittle fused quartz, the processing is difficult and the processing cost is high; the third option is a reflective broadband integrator mirror, which has the advantages of water cooling, good thermal conductivity, and the ability to withstand extremely high laser power. Power laser processing has advantages, but the existing reflective broadband integrator mirrors are all based on parallel beam incidence. The fiber-coupled output laser needs to collimate the divergent beam at the output point first, resulting in a more complex optical path structure and high power loss. The instability of the optical path is more prominent and the cost is higher.

Contents of the invention

Based on this, it is necessary to provide a reflective broadband integrator mirror and a broadband fiber laser optical system to solve the problem that the reflective broadband integrator mirror cannot handle the point light source beam.

The invention provides a reflective broadband integrator mirror based on the incident light of a point light source, including a base body. The base body has a bottom surface, a mirror surface and a symmetry surface. The base body is symmetrical about the symmetry plane, and the mirror surface It is inclined at a set acute angle with the bottom surface and includes at least three concave wide-band curved surfaces. The wide-band curved surfaces pass through the symmetry plane and are symmetrical about the symmetry plane. Two adjacent wide-band curved surfaces intersect. And an arc-shaped strip line is formed, and the focal points of all the arc-shaped strip lines are coplanar to form a focus plane, and the focus plane is parallel to and spaced apart from the symmetry plane.

In the above-mentioned reflective broadband integrator mirror, the point light source is set on the side of the mirror away from the bottom surface and shines onto the mirror in the direction toward the mirror. The incident light is distributed in a cone shape and is focused at the arc-shaped strip line. After reflection by the mirror, The reflected light is focused toward the center into a spot. Since the broadband curved surface is symmetrical about the symmetry plane, multiple reflected light rays reflected by the same arc-shaped strip line are symmetrical about the symmetry plane, thus making the spot symmetry better. All broadband curved surfaces are arranged in parallel and pass through the symmetry plane. All the arc-shaped strip lines are parallel and the focus points are coplanar, forming a focus plane parallel to the symmetry plane, so that the light spot is flat-topped and homogenized in one direction, and the overall uniformity is good. , and for fiber-coupled output lasers, only one of the above-mentioned reflective broadband integrator mirrors can achieve unidirectional flat-top homogenization shaping of point-emitted light. The optical path structure is simple, the power loss will be smaller, the optical path stability will be better, and the optical cost will be reduced. It will be relatively lower and has better prospects for large-scale application.

In one embodiment, the beam deflection angle a of the mirror is 30°-150°.

In the above-mentioned reflective broadband integrator mirror, the range of the beam deflection angle a of the mirror is limited to be suitable for application scenarios at different illumination positions.

In one embodiment, the set acute angle is 90°-a/2.

In the above-mentioned reflective broadband integrator mirror, by limiting the calculation formula of the set acute angle between the mirror surface and the bottom surface, and combining it with the beam deflection angle a of the mirror surface, the angle of inclination of the mirror surface relative to the bottom surface can be determined more conveniently and quickly, thereby making it easier to seat Body preparation.

In one embodiment, all of the broad-band curved surfaces form elliptical cross-sections on a cross-section parallel to the symmetry plane.

In the above-mentioned reflective broadband integrator mirror, by defining the cross-section shape of all broadband curved surfaces on the cross-section parallel to the symmetry plane, it can be more convenient and reliable to ensure that the focal points of all arc-shaped strip lines are coplanar and form a focus parallel to the symmetry plane. flat.

In one of the embodiments, the elliptical cross-section lines correspond to unequal intervals between the central broad bands of different broad band curved surfaces.

In the above-mentioned reflective broadband integrator mirror, by defining the cross-sectional dimensions of all broadband curved surfaces on the cross-section parallel to the symmetry plane, the unidirectional uniformity, overall uniformity and spot symmetry of the light spot are improved.

In one embodiment, the number of broadband curved surfaces is less than or equal to 50.

In the above-mentioned reflective broadband integrator mirror, by limiting the number range of broadband curved surfaces, the structure of the mirror surface is simplified and the preparation of the base body is facilitated while ensuring the one-way flat-top homogenization function.

In one embodiment, the number of broadband curved surfaces is 6-15.

In the above-mentioned reflective broadband integrator mirror, by further narrowing the number range of the broadband curved surfaces, the structure of the mirror can be further simplified and the production cost of the reflective broadband integrator mirror can be reduced.

In one embodiment, the distance between the focus plane and the symmetry plane is determined according to the following formula:

H＝F2*L2/(D+L2), (1);

D＝2*F1*tan(b), (2);

Where: H is the distance between the focus plane and the symmetry plane, F1 is the incident focal length, F2 is the exit focal length, D is the maximum spot size perpendicular to the symmetry plane on the mirror surface, L2 is the homogenized spot width, and b is The beam diverges half-angle.

In the above-mentioned reflective broadband integrator mirror, through formula (1), formula (2) and based on the known incident focal length F1, exit focal length F2, the maximum spot size D perpendicular to the symmetry plane on the mirror surface, the homogenized spot width L2, The beam divergence half angle b can more easily determine the distance between the focus plane and the symmetry plane, and then the base structure can be designed conveniently and quickly.

In one embodiment, a water-cooling channel is formed inside the base body, and the water inlet and outlet of the water-cooling channel are respectively opened on the bottom surface.

In the above-mentioned reflective broadband integrator mirror, by setting up a water-cooling channel and limiting the position of the water inlet and outlet of the water-cooling channel, it is conducive to cooling the base body, preventing the above-mentioned reflective broadband integrator mirror from being in a high temperature state for a long time, and improving the reflective Service life of broadband integrator mirrors.

In addition, the present invention also provides a broadband fiber laser optical system, including a point light source and a reflective broadband integrator mirror as described in any of the above technical solutions. The point light source is located at the incident focus of the reflective broadband integrator mirror. at.

In the above-mentioned broadband fiber laser optical system, the point light source is located at the incident focus of the reflective broadband integrator mirror. The light emitted by the point light source shines on the mirror in the direction toward the mirror. The incident light is distributed in a cone shape, and the arc-shaped strip line The reflected light after specular reflection is focused towards the center into a light spot. Since the broadband curved surface is symmetrical about the symmetry plane, multiple reflected light rays reflected by the same arc-shaped strip line are symmetrical about the symmetry plane, thus making The light spot has good symmetry. Since all the broadband curved surfaces are arranged in parallel and pass through the symmetry plane, all the arc-shaped strip lines are parallel and the focus points are coplanar, forming a focus plane parallel to the symmetry plane, so that the light spot is flat and uniform in one direction. ization, and the overall uniformity is good. Therefore, the above-mentioned broadband fiber laser optical system with a reflective broadband integrator mirror can realize unidirectional flat-top homogenization shaping of non-parallel beams. The optical path structure is simple, the power loss will be smaller, and the optical path stability Better, the optical cost will be relatively lower, and the prospects for large-scale application are better.

Description of the drawings

Figure 1 is a schematic structural diagram of a reflective broadband integrator mirror in an embodiment of the present invention;

Figure 2 is a cross-sectional view of the reflective broadband integrator mirror in Figure 1;

Figure 3 is a top view of the reflective broadband integrator mirror in Figure 1;

Figure 4 is a front view of the broadband fiber laser optical system along the light incident direction in one embodiment of the present invention;

Figure 5 is a cross-sectional view of the broadband fiber laser optical system in Figure 4 at the position of the symmetry plane;

Figure 6 is a schematic diagram of the light spot after one-way flat-top homogenization by a reflective broadband integrator mirror in an embodiment of the present invention;

7 is a cross-sectional view of a reflective broadband integrator mirror in another embodiment of the present invention.

Reference signs:

10. Broadband fiber laser optical system;

100. Reflective broadband integrating mirror; 110. Base; 111. Bottom surface; 112. Mirror surface; 1121. Broadband curved surface; 1122. Arc-shaped strip line; 1123. Elliptical cross-section; 113. Symmetry plane; 114. Water-cooling channel ; 1141. Water inlet; 1142. Water outlet; α, set acute angle;

20. Point light source; 21. Maximum light spot.

Detailed ways

In order to make the above objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, the present invention can be implemented in many other ways different from those described here. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axis" The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply the device or device referred to. Elements must have a specific orientation, be constructed and operate in a specific orientation and therefore are not to be construed as limitations of the invention.

In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

In the present invention, unless otherwise clearly stated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrated into one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interactive relationship between two elements, unless otherwise specified restrictions. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In the present invention, unless otherwise expressly stated and limited, a first feature being "on" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. touch. Furthermore, the terms "above", "above" and "above" the first feature is above the second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "below" and "beneath" the first feature to the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature has a smaller horizontal height than the second feature.

It should be noted that when an element is referred to as being "mounted" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is said to be "connected" to another element, it can be directly connected to the other element or there may also be intervening elements present. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation manner.

The technical solutions provided by the embodiments of the present invention will be introduced below with reference to the accompanying drawings.

As shown in Figures 1, 2, 3, 4 and 5, the present invention provides a reflective broadband integrator mirror 100 based on the incident light of the point light source 20. For flat-top homogenization shaping, in specific settings, the light cross-section of the point light source 20 is a regular spot shape, such as a circle, an ellipse, etc., and the energy distribution is a non-flat-top distribution. The point light source 20 can be a fiber-coupled laser. Other structural forms that can meet the requirements are also possible. The reflective broadband integrator mirror 100 includes a base body 110. The base body 110 is made of metal material, such as pure copper, aviation aluminum, etc. The shape of the base body 110 can be cylindrical, cubic, etc. Of course, the material and shape of the base body 110 It is not limited to this, and it can also be other structural forms that can meet the requirements.

The base body 110 has a bottom surface 111, a mirror surface 112 and a symmetry surface 113. The mirror surface 112 and the bottom surface 111 are inclined at a set acute angle α. The base body 110 is symmetrical about the symmetry surface 113. The mirror surface 112 includes at least three broadband curved surfaces 1121. The shape of the broadband curved surface 1121 is concave. When specifically set, the number of broadband curved surfaces 1121 can be 3, 4, 5, 10, 20, or more than 20. .

All broadband curved surfaces 1121 pass through the symmetry plane 113, and all broadband curved surfaces 1121 are symmetrical about the symmetry plane 113. Two adjacent broadband curved surfaces 1121 intersect, and an arc-shaped strip line 1122 is formed at the intersection position. In specific settings When , all the wide-band curved surfaces 1121 can be arranged parallel, and the arc-shaped strip lines 1122 can be parallel. The foci of all arc-shaped strip lines 1122 are coplanar, and these foci form a focus plane. The focus plane is parallel to the symmetry plane 113 , and is spaced apart from the symmetry plane 113 . In specific settings, the central axis of the incident beam and the central axis of the reflected beam form the central axis of the beam transmission of the mirror 112 , and the central axis of the beam transmission is parallel to the symmetry plane 113 .

As shown in Figures 4, 5 and 6, in the above-mentioned reflective broadband integrator mirror 100, the point light source 20 is disposed on the side of the mirror 112 away from the bottom surface 111 and irradiates the mirror 112 in the direction toward the mirror 112, and the incident light Distributed in a cone shape, it is focused at the arc-shaped strip line 1122. The reflected light reflected by the mirror 112 is focused toward the center into a light spot. Since the broadband curved surface 1121 is symmetrical about the symmetry plane 113, it passes through the same arc-shaped strip line. The multiple reflected light rays reflected by 1122 are symmetrical about the symmetry plane 113, which makes the spot symmetry better. Since all the broadband curved surfaces 1121 are arranged in parallel and pass through the symmetry plane 113, all the arc-shaped strip lines 1122 are parallel and the focus points are coplanar. A focusing plane parallel to the symmetry plane 113 is formed, so that the light spot is unidirectionally flat-topped and uniform, and the overall uniformity is good. For fiber-coupled output lasers, only one of the above-mentioned reflective broadband integrator mirrors 100 is needed to achieve point-emitting light. Unidirectional flat-top homogenization shaping has a simple optical path structure, smaller power loss, better optical path stability, relatively lower optical cost, and good prospects for large-scale application.

In order to adapt to different application scenarios, in a preferred embodiment, as shown in FIG. 5 , the beam deflection angle a of the mirror 112 may be 30°-150°. In specific settings, the beam deflection angle a of the mirror 112 is 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°. Of course, the beam deflection angle a of the mirror 112 does not Limited to the above values, it can also be other values in the range of 30°-150°.

In the above-mentioned reflective broadband integrator mirror 100, after the incident light is reflected by the broadband curved surface 1121, the deflection angle of the reflected light relative to the incident light is the beam deflection angle a of the mirror 112. At this time, the entire one-way flat-top homogenized and shaped The deflection angle of the spot position relative to the point light source 20 is the beam deflection angle a of the mirror 112, which is suitable for the illumination position forming an angle a with the point light source 20. By expanding the beam deflection angle a of the mirror 112, the above-mentioned reflective broadband integration can be The mirror 100 is applied to application scenarios with different illumination positions.

In order to facilitate the installation of the base 110, specifically, as shown in FIG. 2 and FIG. 7, the acute angle α may be set to 90°-a/2. In the above-mentioned reflective broadband integrator mirror 100, the beam deflection angle a of the mirror 112 is determined based on the given application scenario, and then the acute angle α can be set to 90°-a/2 according to the beam deflection angle a of the mirror 112. As a limiting condition, the angle of inclination of the mirror surface 112 relative to the bottom surface 111 can be determined more conveniently and quickly, thereby facilitating the installation of the base body 110 .

In order to simplify the structure of the mirror surface 112, specifically, the number of broadband curved surfaces 1121 may be less than or equal to 50. In the above-mentioned reflective broadband integrator mirror 100, the number of broadband curved surfaces 1121 is limited to a range of 3-50. For example, the mirror 112 has 30, 35, 40, 45 or 50 broadband surfaces. Curved surfaces 1121, so that on the basis of ensuring the one-way flat-top homogenization function, the number of broadband curved surfaces 1121 will not be too many and avoid problems such as the complicated installation method of the broadband curved surfaces 1121 in the mirror 112 and the narrow installation space, etc. Simplified The structure of the mirror surface 112 facilitates the preparation of the base body 110 . Specifically, the number of broadband curved surfaces 1121 may be 6-15. For example, there are 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 in the mirror surface 112. A broadband curved surface 1121 can further simplify the structure of the mirror 112, facilitate the preparation of the base 110, and reduce the production cost of the reflective broadband integrator mirror 100.

In order to facilitate the formation of the focal plane, in a preferred embodiment, as shown in FIG. 1 and FIG. 7 , all broad-band curved surfaces 1121 form elliptical cross-sections 1123 on cross-sections parallel to the symmetry plane 113 . In the above-mentioned reflective broadband integrator mirror 100, since all the broadband curved surfaces 1121 pass through the symmetry plane 113, all the broadband curved surfaces 1121 form elliptical cross-sections 1123 on the cross-sections parallel to the symmetry plane 113, so as to more conveniently and reliably ensure that all arcs The focal points of the strip lines 1122 are coplanar and form a focus plane parallel to the symmetry plane 113 .

In order to further improve the overall uniformity, specifically, the elliptical section lines 1123 correspond to the central broadbands of different broadband curved surfaces 1121 with unequal spacing, so as to make multiple reflected light rays reflected by the same elliptical section line 1123 uniform everywhere, and thus Improve the unidirectional uniformity of the light spot, the overall uniformity is better, and the symmetry of the light spot can be improved.

In order to facilitate the determination of the distance between the focus plane and the symmetry plane 113, as shown in Figures 4 and 5, in a preferred embodiment, the distance between the focus plane and the symmetry plane 113 is determined according to the following formula:

H＝F2*L2/(D+L2), (1);

D＝2*F1*tan(b), (2);

Where: H is the distance between the focus plane and the symmetry plane 113, F1 is the incident focal length, F2 is the exit focal length, D is the maximum spot 21 size perpendicular to the symmetry plane 113 on the mirror 112, L2 is the homogenized spot width, and b is The beam diverges half-angle.

In the above-mentioned reflective broadband integrator mirror 100, as shown in Figure 6, the point light source 20 with the beam divergence half angle b is at the incident focus, and the point divergent beam is incident on the mirror 112 with the incident focal length F1 and the exit focal length F2. , the incident beam undergoes spectroscopic reflection through the broadband curved surface 1121 and then is combined and superimposed. The combined and superimposed beam achieves spot energy homogenization in the direction of the focus plane parallel to the symmetry plane 113. The spot energy is distributed flat-top, and the homogenized spot length is L1; the incident beam passes through the broadband surface The arc-shaped strip line 1122 of the curved surface 1121 is focused, and the focusing plane will obtain a defocused light spot perpendicular to the symmetry plane 113. The light spot energy has a Gaussian distribution and the light spot width is L2. Therefore, based on the known incident focal length F1 and exit focal length F2, the maximum spot 21 size D perpendicular to the symmetry plane 113 on the mirror 112, the homogenized spot width L2, and the beam divergence half angle b, according to the above formula (1), formula ( 2) It is easier to determine the distance between the focus plane and the symmetry plane 113, and then design the structure of the base body 110 quickly and easily.

In order to improve the service life of the reflective broadband integrator mirror 100, as shown in FIG. 7, in a preferred embodiment, a water cooling channel 114 is formed inside the base 110, and the water inlet 1141 and the water outlet 1142 of the water cooling channel 114 are respectively opened in Bottom 111.

In the above-mentioned reflective broadband integrator mirror 100, the water inlet 1141 is used to introduce cooling water into the interior of the base body 110 to cool the base body 110, and the cooling water flows out through the water outlet 1142. In actual operation, the water-cooling channel 114 is connected to an external cooling water source. The cooling water flows into the water-cooling channel 114 through the water inlet 1141 and flows out through the water outlet 1142, which is beneficial to cooling the base 110 and avoids the long-term use of the reflective broadband integrator mirror 100. In a high temperature state, the service life of the reflective broadband integrator mirror 100 is improved.

As shown in Figures 4 and 5, the present invention also provides a broadband fiber laser optical system 10, which includes a point light source 20 and a reflective broadband integrator mirror 100 according to any of the above technical solutions. The point light source 20 is located in the reflective broadband integrator. The incident focus of the integrating mirror 100.

In the above-mentioned broadband fiber laser optical system 10, the point light source 20 is located at the incident focus of the reflective broadband integrator mirror 100. The light emitted by the point light source 20 irradiates the mirror 112 in the direction toward the mirror 112, and the incident light is distributed in a conical shape. Focused at the arc-shaped strip line 1122, the reflected light reflected by the mirror 112 is focused toward the center into a light spot. Since the broadband curved surface 1121 is symmetrical about the symmetry plane 113, multiple light beams reflected by the same arc-shaped strip line 1122 The reflected light is symmetrical about the symmetry plane 113, thus making the light spot more symmetrical. Since all the broadband curved surfaces 1121 are arranged in parallel and pass through the symmetry plane 113, all arc-shaped strip lines 1122 are parallel and the focus is coplanar, forming a symmetry plane 113. Parallel focusing planes can achieve one-way flat-top homogenization of the light spot, and the overall uniformity is better. Therefore, the above-mentioned broadband fiber laser optical system 10 with the reflective broadband integrator mirror 100 can achieve one-way flat-top homogenization of non-parallel light beams. Shaping, the optical path structure is simple, the power loss will be smaller, the optical path stability will be better, the optical cost will be relatively lower, and the prospects for large-scale application are better.

The technical features of the above-described embodiments can be combined in any way. To simplify the description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, All should be considered to be within the scope of this manual.

The above-mentioned embodiments only express several implementation modes of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the scope of protection of the patent of the present invention should be determined by the appended claims.

Claims

A reflective broadband integrator mirror, based on the incident light of a point light source, is characterized in that it includes a base body, the base body has a bottom surface, a mirror surface and a symmetry surface, the base body is symmetrical about the symmetry plane, and the mirror surface It is inclined at a set acute angle with the bottom surface and includes at least three concave wide-band curved surfaces. The wide-band curved surfaces pass through the symmetry plane and are symmetrical about the symmetry plane. Two adjacent wide-band curved surfaces intersect. And an arc-shaped strip line is formed, and the focal points of all the arc-shaped strip lines are coplanar to form a focus plane, and the focus plane is parallel to and spaced apart from the symmetry plane.
The reflective broadband integrator mirror according to claim 1, wherein the beam deflection angle a of the mirror surface is 30°-150°.
The reflective broadband integrator mirror according to claim 2, wherein the set acute angle is 90°-a/2.
The reflective broadband integrator mirror according to claim 1, characterized in that all the broadband curved surfaces form elliptical cross-sections on sections parallel to the symmetry plane.
The reflective broadband integrator mirror according to claim 4, wherein the elliptical cross-section lines correspond to central broadbands of different broadband curved surfaces with unequal spacing.
The reflective broadband integrator mirror according to claim 1, wherein the number of broadband curved surfaces is less than or equal to 50.
The reflective broadband integrator mirror according to claim 6, characterized in that the number of the broadband curved surfaces is 6-15.
The reflective broadband integrator mirror according to claim 1, wherein the distance between the focusing plane and the symmetry plane is determined according to the following formula:

H＝F2*L2/(D+L2), (1);

D＝2*F1*tan(b), (2);

Where: H is the distance between the focus plane and the symmetry plane, F1 is the incident focal length, F2 is the exit focal length, D is the maximum spot size perpendicular to the symmetry plane on the mirror surface, L2 is the homogenized spot width, b is The beam diverges half-angle.
The reflective broadband integrator mirror according to claim 1, wherein a water-cooling channel is formed inside the base body, and the water inlet and outlet of the water-cooling channel are respectively opened on the bottom surface.
A broadband fiber laser optical system, characterized by comprising a point light source and a reflective broadband integrator mirror as claimed in any one of claims 1 to 9, the point light source being located at the incident focus of the reflective broadband integrator mirror .