A semiconductor laser light homogenization technology and module

Abstract

The invention discloses a semiconductor laser / bar module shaping and homogenizing technology and a manufacturing method. Small grooves of micro-nano size are manufactured on the surface of an existing optical lens. The depth and direction of the small grooves are randomly distributed, and the direction of laser diffraction by the small grooves is randomly distributed. A uniform slurry is formed by mixing micro-nano structured grinding powder and a corrosive solution in a certain proportion. The slurry is dripped on the center position of the upper surface of the substrate to form a semicircular ellipsoidal slurry droplet to manufacture a homogenizing ellipsoidal mirror. The homogenizing ellipsoidal mirror is fixedly installed before the light-emitting point of the semiconductor laser. After all the laser beams radiated from the laser output port pass through the homogenizing ellipsoidal mirror, they become small beams with uniform divergence angles and irradiate a local point on the laser radiation surface. The laser radiation energy of the point is the superposition of the energy distribution of all the laser beams radiated from the laser output port, thereby realizing laser homogenization. The invention has high system integration, simple manufacturing method and low cost.

Description

Technical Field

[0001] The present invention relates to semiconductor laser application technology, mainly to a semiconductor laser shaping packaging technology, and in particular to a beam shaping and homogenizing technology and a homogenizing module based on micro-nano optical structure and controlled corrosion. The homogenizing module outputs a uniform small-beam divergence laser beam for irradiating a target. Background Art

[0002] Semiconductor lasers are engineered commercial laser devices. The elliptical far-field spot distribution of the semiconductor laser output beam needs to be further shaped and homogenized before it can be used to illuminate distant targets. It is usually collimated using a cylindrical lens group or a microlens array, and then homogenized to meet the need for uniform illumination. This step-by-step shaping optical structure has limitations on the small / miniaturized design of semiconductor laser systems and does not match the small size of semiconductor lasers.

[0003] The geometric optical design concept of this cylindrical lens or microlens array has the problem of uneven local structural stress caused by heat concentration, which affects the beam stability of the semiconductor laser output; the surface reflection of the cylindrical lens can easily cause damage to the semiconductor laser chip, so the cylindrical lens cannot be too close to the semiconductor laser output window. The fast axis of the semiconductor laser output makes the aperture of the collimating cylindrical lens much larger than the size of the semiconductor laser output window, which limits the large-scale integration of semiconductor lasers.

[0004] Diffractive optical devices are often used to homogenize parallel laser beams output by solid lasers and gas lasers on the irradiated surface within a certain image distance range. Diffractive optical devices have regular patterns of micro-nano structures and are expensive to manufacture. The thermal effect of laser irradiation causes the laser wavelength magnitude of the regular pattern to change, affecting the local homogenization effect of the laser on the irradiated surface.

[0005] Patent application number 202010728798.7 A semiconductor laser beam combining technology discloses a semiconductor laser diffraction beam combining technology. On the side wall of the bare optical fiber, a diffraction grating with a width equivalent to the laser wavelength is etched perpendicular to the optical axis of the optical fiber. The laser is coupled to the bare optical fiber core through the diffraction grating and output from both ends of the bare optical fiber. Summary of the invention

[0006] The purpose of the present invention is to overcome the limitation of mass integration of semiconductor lasers caused by step-by-step shaping and homogenization of the output beam of semiconductor lasers at present, and to improve the uniformity and stability of the distribution of semiconductor laser spots.

[0007] The first technical problem to be solved by the present invention is to provide a homogenizing microlens to overcome the large size of the optical structure of the existing semiconductor laser step-by-step shaping. The homogenizing microlens is a small groove of micro-nano size made on the surface of the existing optical lens. The depth and direction of the small groove are randomly distributed, and the direction of laser diffraction by the small groove is randomly distributed. After all the laser beams radiated from the laser output port pass through the homogenizing microlens, they are irradiated to a local point on the laser radiation surface. The laser radiation energy at this point is a random superposition of the energy distribution of all the laser beams radiated from the laser output port, obeys the normal distribution, and realizes laser homogenization.

[0008] The second technical problem to be solved by the present invention is to provide a homogenizing ellipsoidal mirror for shaping the elliptical laser spot output by the semiconductor laser into a laser spot uniformly distributed at a small angle. The homogenizing ellipsoidal mirror is an optical ellipsoidal mirror with small grooves of micro-nano size made on the surface. The optical ellipsoidal mirror has different curvature radii in the XY directions. The ratio of the curvature radii in the XY directions matches the fast-axis beam divergence angle of the semiconductor laser. The small curvature radius corresponds to the fast-axis direction of the laser output by the semiconductor laser, and the large curvature radius corresponds to the slow-axis direction of the laser output by the semiconductor laser, so as to collimate and homogenize the laser output by the semiconductor laser.

[0009] The third technical problem to be solved by the present invention is to provide a semiconductor laser shaper for shaping and homogenizing the laser beam output by a semiconductor laser, including a homogenizing ellipsoidal mirror and a semiconductor laser. The homogenizing ellipsoidal mirror is fixedly placed before the light-emitting point of the semiconductor laser. After the output laser passes through the homogenizing ellipsoidal mirror, it becomes a small beam with uniform divergence angle to irradiate the target.

[0010] The fourth technical problem to be solved by the present invention is to provide a homogenizing module for shaping and homogenizing the laser beam output by a semiconductor laser bar, including a homogenizing ellipsoidal mirror array and a semiconductor laser bar module. The spacing between all the homogenizing ellipsoidal mirrors in the homogenizing ellipsoidal mirror array is the same as the spacing between the light-emitting points of the semiconductor laser bar module. The homogenizing ellipsoidal mirror array is fixedly placed before the light-emitting points of several semiconductor laser bar modules. The laser output from each light-emitting point becomes a small beam with uniform divergence angle after passing through the homogenizing ellipsoidal mirror to irradiate the target.

[0011] The fifth technical problem to be solved by the present invention is to provide a homogenized ellipsoid mirror processing method based on controlled chemical corrosion for the production of homogenized ellipsoid mirrors, the processing method involves materials: a substrate, abrasive powder of a micro-nano structure, and a corrosion solution, the substrate is a flat optical glass, the abrasive powder of the micro-nano structure and the corrosion solution are mixed into a uniform slurry in a certain proportion, the substrate is placed flat, the slurry is dripped on the center of the upper surface of the substrate to form a semi-spherical slurry droplet, most of the abrasive powder in the slurry droplet is deposited on the center of the upper surface of the substrate, and the density of the abrasive powder gradually decreases along the radial direction, and the slurry Most of the etching solution flows to the periphery of the hemispherical slurry droplet, forming a large proportion of etching solution in the periphery and a small proportion of etching solution in the center; after standing for a certain period of time, randomly distributed micro-nanostructure grooves are etched in the center of the upper surface of the substrate, and the etching depth gradually increases along the radial direction, the slurry is washed away, and a homogenized spherical mirror is made on the upper surface of the substrate, the substrate is turned over and placed flat, and the process of making the homogenized spherical mirror is repeated to make homogenized spherical mirrors on both sides of the substrate to form a homogenized microlens; the slurry is dripped along one direction on the center of the upper surface of the substrate to form a hemispherical slurry droplet, and a homogenized ellipsoidal mirror is made in the same way.

[0012] The present invention has the following advantages:

[0013] The present invention adopts a surface micro-nano structure of a homogenized microlens, so that the surface reflection is diffuse reflection at a micro-nano scale, reducing the laser energy reflected to the light-emitting point of the semiconductor laser and in the same direction as the laser resonant cavity, greatly reducing the probability of laser resonance caused by the reflected light on the lens surface, reducing the damage to the laser chip, and extending the service life of the semiconductor laser;

[0014] The present invention adopts a homogenized ellipsoid mirror, which reduces the volume of the semiconductor laser emission system and optimizes the beam quality;

[0015] The present invention adopts a homogenized ellipsoid mirror array, so that the volume of the collimation system of the array-type semiconductor laser module is reduced and the stability of the beam quality is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Homogenizing Ellipsoid

[0017] Figure 2 Semiconductor Laser Shaper

[0018] Figure 3 Homogenizing ellipsoidal mirror array DETAILED DESCRIPTION

[0019] The preferred embodiment 1 is the production of a homogenized ellipsoid mirror 1, and provides a processing method for a homogenized ellipsoid mirror 1 based on controlled chemical corrosion. The processing method involves materials: a substrate 2, a micro-nano structured grinding powder, and a corrosion solution. The substrate 2 is a flat K9 optical glass. The micro-nano structured grinding powder is preferably a micro-nano particle size aluminum oxide Al2O3 powder. The corrosion solution is preferably a hydrofluoric acid solution. The aluminum oxide Al2O3 powder and the hydrofluoric acid solution are mixed in a certain proportion to form a uniform slurry 3. The substrate 2 is placed flat, and the slurry 3 is dropped on the center of the upper surface of the substrate 2 to form a semi-spherical slurry 3 drop. Most of the grinding powder in the slurry 3 drops is deposited on the center of the upper surface of the substrate 2, and the grinding The density of the abrasive powder gradually decreases in the radial direction, and most of the etching solution in the slurry 3 flows to the periphery of the semi-spherical slurry droplet 3, forming a large proportion of the peripheral etching solution and a small proportion of the central etching solution; after standing for a certain period of time, randomly distributed micro-nano structure grooves are etched in the center of the upper surface of the substrate 2, and the etching depth gradually increases along the radial direction, the slurry 3 is washed away, and a homogenized spherical mirror is made on the upper surface of the substrate, the substrate 2 is turned over and placed flat, and the manufacturing process of the homogenized spherical mirror is repeated to make homogenized spherical mirrors on both sides of the substrate 2 to form a homogenized microlens; the slurry 3 is dripped on the center of the upper surface of the substrate 2 in one direction to form 3 drops of semi-spherical slurry, and a homogenized ellipsoidal mirror 1 is manufactured using the homogenized microlens method.

[0020] Preferred embodiment 2 is a semiconductor laser shaper, comprising a homogenizing ellipsoidal mirror 1 and a semiconductor laser 4. The homogenizing ellipsoidal mirror 1 is fixedly placed before the light-emitting point of the semiconductor laser 4. The surface of the homogenizing ellipsoidal mirror 1 before the light-emitting point of the semiconductor laser 4 is a surface of small grooves randomly distributed in micro-nano sizes. After passing through the homogenizing ellipsoidal mirror 1, the semiconductor laser outputs a small beam with uniform divergence angle to irradiate the target.

Claims

1. A semiconductor laser homogenization method, Features: Small grooves of micro-nano size are made on the surface of the existing optical lens to form a homogenizing micro-lens. The depth and direction of the small grooves are randomly distributed, and the direction of laser diffraction by the small grooves is randomly distributed. After all the laser beams radiated from the laser output port pass through the homogenizing micro-lens, they are irradiated to a local point on the laser radiation surface. The laser radiation energy at this point is a random superposition of the energy distribution of all the laser beams radiated from the laser output port, and obeys a normal distribution, thereby realizing laser homogenization. The step of making small grooves of micro-nano size on the surface of the existing optical lens comprises: The micro-nano structured abrasive powder and the corrosive solution are mixed in a certain proportion to form a uniform slurry; The optical lens is placed flat, and the slurry is dripped on the center of the upper surface of the optical lens to form a semi-spherical slurry drop; most of the abrasive powder in the slurry drop is deposited on the center of the upper surface of the optical lens, and the density of the abrasive powder gradually decreases along the radial direction, and most of the corrosive solution in the slurry flows to the periphery of the semi-spherical slurry drop, forming a large proportion of the corrosive solution in the periphery and a small proportion of the corrosive solution in the center; After standing for a certain period of time, randomly distributed micro-nanostructured small grooves are etched in the center of the upper surface of the optical lens, and the corrosion depth gradually increases along the radial direction; The slurry is washed off, and a homogenized spherical mirror is made on the upper surface of the optical lens. The optical lens is turned over and placed flat, and the manufacturing process of the homogenized spherical mirror is repeated to make homogenized spherical mirrors on both sides of the optical lens to form a homogenized microlens.

2. The semiconductor laser homogenization method according to claim 1, Features: The micro-nano structured grinding powder is aluminum oxide with micro-nano particle size, and the etching solution is a hydrofluoric acid solution.

3. A homogenizing ellipsoid mirror, used for collimating and homogenizing the laser output from a semiconductor laser, comprising an optical ellipsoid mirror, wherein the optical ellipsoid mirror has different curvature radii in the XY direction, and the ratio of the curvature radii in the XY direction matches the fast axis and slow axis beam divergence angle of the semiconductor laser, wherein the small curvature radius corresponds to the fast axis direction of the laser output from the semiconductor laser, and the large curvature radius corresponds to the slow axis direction of the laser output from the semiconductor laser, Features: Small grooves of micro-nano size are made on the surface of the optical ellipsoid mirror; the depth and direction of the small grooves are randomly distributed, and the direction of laser diffraction by the small grooves is randomly distributed; The step of making micro-nano-sized small grooves on the surface of the optical ellipsoid mirror comprises: The micro-nano structured abrasive powder and the corrosive solution are mixed in a certain proportion to form a uniform slurry; The optical ellipsoid mirror is placed flat, and the slurry is dripped on the center of the upper surface of the optical ellipsoid mirror to form a semi-spherical slurry drop; most of the abrasive powder in the slurry drop is deposited on the center of the upper surface of the optical ellipsoid mirror, and the density of the abrasive powder gradually decreases along the radial direction, and most of the corrosive solution in the slurry flows to the periphery of the semi-spherical slurry drop, forming a large proportion of the corrosive solution in the periphery and a small proportion of the corrosive solution in the center; After standing for a certain period of time, randomly distributed micro-nanostructured small grooves are etched in the center of the upper surface of the optical ellipsoid mirror, and the corrosion depth gradually increases along the radial direction; The slurry is washed off, and a homogenized spherical mirror is made on the upper surface of the optical ellipsoid mirror. The optical ellipsoid mirror is turned over and placed flat, and the manufacturing process of the homogenized spherical mirror is repeated to make homogenized spherical mirrors on both sides of the optical ellipsoid mirror to form a homogenized ellipsoid mirror.

4. The homogenizing ellipsoidal mirror according to claim 3, Features: The micro-nano structured grinding powder is aluminum oxide with micro-nano particle size, and the etching solution is a hydrofluoric acid solution.

5. A semiconductor laser shaper, Features: It comprises the homogenizing ellipsoid mirror and semiconductor laser as described in claim 3 or 4, wherein the homogenizing ellipsoid mirror is fixedly placed before the light-emitting point of the semiconductor laser, and the output laser becomes a small beam with uniform divergence angle after passing through the homogenizing ellipsoid mirror to irradiate the target.

6. A light homogenization module, Features: It comprises a homogenizing ellipsoidal mirror array and a semiconductor laser bar module. The spacing between all the homogenizing ellipsoidal mirrors in the homogenizing ellipsoidal mirror array is the same as the spacing between the light-emitting points of the semiconductor laser bar module. The homogenizing ellipsoidal mirror array is fixedly placed before the light-emitting points of several semiconductor laser bar modules. The laser output from each light-emitting point becomes a small beam with uniform divergence angle after passing through the homogenizing ellipsoidal mirror to irradiate the target. The homogenizing ellipsoidal mirror array comprises a plurality of homogenizing ellipsoidal mirrors as described in claim 3 or 4.

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