CN218122373U - Device for improving quality of slow axis light beam of semiconductor laser - Google Patents

Abstract

The utility model discloses a device for improving the quality of slow axis light beam of a semiconductor laser, which comprises a phase delay plate, a parallelogram prism and a prism A with a right triangle or right trapezoid cross section; the prism A, the phase delay sheet and the parallelogram prism are jointed to form a right-angle trapezoidal prism B; the prism A comprises a first right-angle surface, a second right-angle surface and an inclined surface which are sequentially intersected, the included angle between the inclined surface and the second right-angle surface is 45 degrees, and the inclined surface is attached to the phase delay sheet or the parallelogram prism. The utility model discloses the collimation facula size of semiconductor laser's slow axis direction folds the compression, and its fast axis direction facula size remains unchanged. The BPP of the folded and compressed laser in the slow axis direction is reduced, and the beam quality is improved.

Description

Device for improving quality of slow axis light beam of semiconductor laser

Technical Field

The utility model relates to a laser technical field, in particular to improve device of semiconductor laser slow axis beam quality.

Background

At present, a high-power edge-emitting semiconductor laser has the advantages of high electro-optic conversion efficiency, small volume, long service life, low cost and the like, so that the high-power edge-emitting semiconductor laser has wide application prospects in the fields of laser radars, industrial lasers and the like. Edge-emitting semiconductor lasers have many advantages, but the greatest disadvantage is their poor beam quality. The active area of a common single-tube edge emitting semiconductor laser is flat, the size of the active area in the fast axis direction is usually 1um or several um, the divergence angle of laser reaches about 50 degrees, and the laser is close to single-mode distribution; the size of the active region in the slow axis direction is usually several tens um to several hundreds um, the divergence angle of the laser reaches about 10 degrees, and the distribution is multimode. Edge-emitting semiconductor lasers generally need to be shaped by an optical system before being used. The beam quality of current semiconductor lasers can be expressed by a product of optical parameters (BPP), which is defined as half the product of the beam waist radius of the spot and the far field divergence angle (full angle) of the beam. A smaller BPP value indicates a better beam quality of the laser. In the edge emitting semiconductor laser, the BPP value of light in the slow axis direction is very high, which means that the beam quality is poor, and the beam quality in the fast axis direction is good, so that the light in the slow axis direction needs to be improved in practical application. In general, when laser light passes through an optical system composed of optical elements such as an ideal lens and a mirror, that is, when there is no aberration, the BPP value of the laser light is kept constant. Therefore, the conventional beam shaping system cannot reduce the BPP value of the slow axis direction light of the edge-emitting semiconductor laser, and cannot improve the beam quality.

SUMMERY OF THE UTILITY MODEL

The utility model provides a device for improving the quality of the slow axis light beam of the semiconductor laser, which solves the technical problems existing in the prior art.

The utility model discloses a solve the technical scheme that technical problem that exists among the well-known technique took and be: a device for improving the slow axis beam quality of a semiconductor laser comprises a phase delay plate, a parallelogram prism and a prism A with a right-angled triangle or right-angled trapezoid cross section; the prism A, the phase delay sheet and the parallelogram prism are jointed to form a right-angle trapezoidal prism B; the prism A comprises a first right-angle surface, a second right-angle surface and an inclined surface which are sequentially intersected, the included angle between the inclined surface and the second right-angle surface is 45 degrees, and the inclined surface is attached to the phase delay sheet or the parallelogram prism.

Furthermore, the parallelogram prism, the phase retardation plate and the prism A are attached by adopting an optical cement or gluing method.

Further, the prism a, the phase retarder and the parallelogram prism are sequentially attached.

Further, a direction which is perpendicular to the bottom surface of the right trapezoid prism B and points from the bottom surface with a larger area to the bottom surface with a smaller area is set as an X direction, and when laser light propagates in the phase retarder along the X direction, the phase difference between the o light and the e light in the laser light is equal to pi or odd times of pi; the optical axis of the phase retarder and the S polarization direction of the light ray propagating in the phase retarder along the X direction form an included angle of 45 degrees, and the plane formed by the optical axis of the phase retarder and the S polarization direction is perpendicular to the light ray propagating in the phase retarder along the X direction.

Further, in the phase retardation plate, the surface facing the inclined surface of the prism A is SA1, and the surface opposite to SA1 is SA2; the surface with an included angle of 135 degrees with SA1 is SA3, and the surface with an included angle of 45 degrees with SA1 is SA4; in the parallelogram prism, a surface facing to the inclined plane of the prism A is SB3, a surface parallel to SB3 is SB2, a surface with an included angle of 135 degrees with SB3 is SB1, and a surface with an included angle of 45 degrees with SB3 is SB4; in the prism A, a first right-angle surface is a cutting surface or a frosted surface or a polished surface, and a second right-angle surface is plated with an antireflection film matched with the laser wavelength; the phase retardation plate is characterized in that SA1 and SA2 of the phase retardation plate are plated with antireflection films matched with laser wavelengths, and SA3 and SA4 of the phase retardation plate are cut surfaces or frosted surfaces or polished surfaces; the parallelogram prism has SB1 and SB4 coated with antireflection film matching the laser wavelength, and SB2 polished film or high reflection film matching the laser wavelength.

Furthermore, the inclined plane of the prism A is plated with an antireflection film matched with the laser wavelength; the SB3 face of the parallelogram prism is plated with a PBS film matched with the laser wavelength.

Furthermore, the inclined plane of the prism A is plated with a PBS film matched with the laser wavelength; SB3 of the parallelogram prism is coated with an antireflection film matched with the laser wavelength.

Further, the prism a, the parallelogram prism and the phase retarder are sequentially bonded.

Further, in the phase retardation plate, the surface facing the inclined surface of the prism A is SA1, and the surface opposite to SA1 is SA2; the surface with an included angle of 135 degrees with SA1 is SA3, and the surface with an included angle of 45 degrees with SA1 is SA4; in the parallelogram prism, a surface facing to the inclined plane of the prism A is SB3, a surface parallel to SB3 is SB2, a surface forming an included angle of 135 degrees with SB3 is SB1, and a surface forming an included angle of 45 degrees with SB3 is SB4; in the prism A, a first right-angle surface is a cutting surface or a frosted surface or a polished surface, and an anti-reflection film matched with the laser wavelength is plated on an inclined surface and a second right-angle surface of the prism A; the phase retardation plate is characterized in that SA1 of the phase retardation plate is plated with an antireflection film matched with the laser wavelength, SA2 of the phase retardation plate is plated with a high-reflection film matched with the laser wavelength, and SA3 and SA4 of the phase retardation plate are cutting surfaces or frosted surfaces or polished surfaces; and the parallelogram prism has SB1, SB2 and SB4 coated with antireflection film matching the laser wavelength and SB3 coated with PBS film matching the laser wavelength.

The utility model has the advantages and positive effects be: adopt the utility model discloses an improve device of semiconductor laser slow axis light beam quality folds the compression to the collimation facula size of semiconductor laser's slow axis direction, and its fast axis direction facula size remains unchanged. The BPP of the folded and compressed laser in the slow axis direction is reduced, and the beam quality is improved.

Drawings

Fig. 1 is a schematic view of an implementation structure and a light transmission diagram of embodiment 1 of the present invention.

Fig. 2 is an implementation structure schematic diagram and a light transmission diagram of embodiment 2 of the present invention.

Fig. 3 is a schematic view of an implementation structure and a light transmission diagram of embodiment 3 of the present invention.

Fig. 4 is a schematic structural diagram of the phase retarder of the present invention.

Fig. 5 is a schematic structural view of the parallelogram prism of the present invention.

Fig. 6 is a schematic structural diagram of the right trapezoid prism a of the present invention.

In the figure: 1. a parallelogram prism; 2. a right-angle trapezoidal prism A; 3. a phase retarder.

Detailed Description

For further understanding of the contents, features and effects of the present invention, the following embodiments will be described in detail in conjunction with the accompanying drawings:

referring to fig. 1 to 6, a device for improving the slow axis beam quality of a semiconductor laser includes a phase retarder 3, a parallelogram prism 1, and a prism a with a right triangle or right trapezoid cross section; the prism A, the phase delay sheet 3 and the parallelogram prism 1 are jointed to form a right-angle trapezoidal prism B; the prism A comprises a first right-angle surface, a second right-angle surface and an inclined surface which are sequentially intersected, the included angle between the inclined surface and the second right-angle surface is 45 degrees, and the inclined surface is attached to the phase delay sheet 3 or the parallelogram prism 1.

The prism a may be an isosceles right-angle prism or a right-angle trapezoidal prism.

The isosceles right-angle prism comprises a first right-angle surface, a second right-angle surface and an inclined surface which are sequentially intersected, and the second right-angle surface is also called as a bottom surface.

The right-angle trapezoidal prism comprises a first right-angle surface, a second right-angle surface, an inclined surface and a fourth right-angle surface which are sequentially intersected, wherein the first right-angle surface is opposite to the inclined surface, and the first right-angle surface and the inclined surface are also called waist surfaces; the second right-angle surface is opposite to the fourth right-angle surface, and the second right-angle surface and the fourth right-angle surface are also called as bottom surfaces. The area of the second right-angle surface is larger than that of the fourth right-angle surface.

The cross section of the right trapezoid prism B is a right trapezoid, and the bottom surface of the right trapezoid prism B with a larger area is arranged at the same side of the second right-angle surface.

Preferably, the parallelogram prism 1, the phase retarder 3 and the prism a can be attached by optical cement or gluing.

Preferably, the prism a, the phase retarder 3, and the parallelogram prism 1 may be attached in sequence.

Preferably, a direction perpendicular to the bottom surface of the right trapezoid prism B and directed from the larger-area bottom surface to the smaller-area bottom surface may be set to be an X direction, and when the laser light propagates in the phase retarder 3 in the X direction, a phase difference between o light and e light in the laser light may be equal to pi or an odd multiple of pi; the optical axis of the phase retarder 3 may form an angle of 45 degrees with the S-polarization direction of the light propagating in the phase retarder 3 along the X-direction, and a plane formed by the optical axis of the phase retarder 3 and the S-polarization direction may be perpendicular to the light propagating in the phase retarder 3 along the X-direction.

Preferably, in the retardation plate 3, a surface facing the inclined surface of the prism a is SA1, and a surface opposite to SA1 is SA2; a surface with an included angle of 135 degrees with SA1 is SA3, and a surface with an included angle of 45 degrees with SA1 is SA4; in the parallelogram prism 1, a surface facing to the inclined plane of the prism A is SB3, a surface parallel to SB3 is SB2, a surface with an included angle of 135 degrees with SB3 is SB1, and a surface with an included angle of 45 degrees with SB3 is SB4; in the prism A, a first right-angle surface can be a cutting surface, a frosted surface or a polished surface, and a second right-angle surface can be plated with an antireflection film matched with the laser wavelength; the phase retardation plate 3 can be coated with antireflection films matched with the laser wavelength at SA1 and SA2, and the cut surface or the frosted surface or the polished surface at SA3 and SA4; the parallelogram prism 1, SB1 and SB4 can be coated with anti-reflection film matching with laser wavelength, and SB2 can be polished without coating film or coated with high reflection film matching with laser wavelength.

Preferably, the inclined plane of the prism A can be plated with an antireflection film matched with the laser wavelength; the SB3 face of the parallelogram prism 1 may be coated with a PBS film matching the laser wavelength.

Preferably, the inclined plane of the prism A can be plated with a PBS film matched with the laser wavelength; SB3 of the parallelogram prism 1 may be coated with an antireflection film matching the laser wavelength.

Preferably, the prism a, the parallelogram prism 1 and the phase retarder 3 may be attached in sequence. The direction parallel to the bottom surface of the right trapezoid prism B and from the inclined surface of the right trapezoid prism B to the opposite right-angle surface can be set as Y direction, when the laser propagates in the phase retarder along the Y direction, the phase difference between the o light and the e light in the laser is equal to pi or odd times of pi; the optical axis of the phase retarder and the P polarization direction of the light ray propagating in the phase retarder along the Y direction form an included angle of 45 degrees, and the plane formed by the optical axis of the phase retarder and the P polarization direction is perpendicular to the light ray propagating in the phase retarder along the Y direction.

Preferably, in the retardation plate 3, a surface facing the inclined surface of the prism a is SA1, and a surface opposite to SA1 is SA2; a surface with an included angle of 135 degrees with SA1 is SA3, and a surface with an included angle of 45 degrees with SA1 is SA4; in the parallelogram prism 1, a surface facing the inclined plane of the prism A is SB3, a surface parallel to SB3 is SB2, a surface with an included angle of 135 degrees with SB3 is SB1, and a surface with an included angle of 45 degrees with SB3 is SB4; in the prism A, a first right-angle surface can be a cutting surface, a frosted surface or a polished surface, and an anti-reflection film matched with the laser wavelength can be plated on an inclined surface and a second right-angle surface; the phase retarder 3 can be coated with an antireflection film matched with the laser wavelength at SA1, coated with a high-reflection film matched with the laser wavelength at SA2, and cut surfaces, frosted surfaces or polished surfaces at SA3 and SA4; the parallelogram prism 1 may be coated with an antireflection film matching the wavelength of the laser light at SB1, SB2, and SB4, and with a PBS film matching the wavelength of the laser light at SB 3.

The utility model also provides a method for improving the quality of the slow axis light beam of the semiconductor laser, which utilizes the device for improving the quality of the slow axis light beam of the semiconductor laser; the S-polarized laser beam or the P-polarized laser beam output by the semiconductor laser and collimated by the fast and slow axes enters from the bottom surface side with larger area of the right trapezoid prism B, the incident direction is vertical to the bottom surface of the right trapezoid prism B, and the projection profile of the S-polarized laser beam or the P-polarized laser beam along the incident direction is correspondingly positioned in the projection range of the parallelogram prism 1.

The structure and the working principle of the present invention will be further described with several preferred embodiments of the present invention as follows:

example 1:

as shown in fig. 1, a schematic structural diagram of a device for improving the quality of a semiconductor laser beam according to embodiment 1 of the present invention is shown, wherein the device includes: parallelogram prism 1, right trapezoid prism A2, phase delay piece 3. The parallelogram prism, the phase delay plate and the right trapezoid prism A2 are sequentially glued or glued into a whole from bottom to top to form a right trapezoid prism B.

As shown in fig. 4, 5 and 6, in the retardation plate, a surface facing the inclined surface of the right-angled trapezoidal prism A2 is SA1, and a surface opposite to SA1 is SA2; the surface at 135 degrees to SA1 is SA3, and the surface at 45 degrees to SA1 is SA4. In the parallelogram prism, the surface facing the inclined plane of the right trapezoid prism is SB3, and the surface parallel to SB3 is SB2; the surface which forms an included angle of 135 degrees with SB3 is SB1; the surface forming an angle of 45 degrees with SB3 is SB4. In the rectangular prism a, the bottom surface having a large area is SC1, the inclined surface thereof is SC2, the surface thereof opposite to the inclined surface is SC3, and the bottom surface having a small area is SC4.

The SA1 surface of the phase retarder 3 and the inclined surface of the right trapezoid prism A2 are glued or glued into a whole, and the SA2 surface of the phase retarder 3 and the SA3 surface of the parallelogram prism 1 are glued or glued into a whole.

The included angle between the surfaces SB1 and SB2 of the parallelogram prism 1 is 45 degrees, and the included angle between the surfaces SB3 and SB4 is 45 degrees. The SB1 and SB4 surfaces of the parallelogram prism 1 are plated with antireflection films matched with laser wavelength, the SB2 surface of the parallelogram prism 1 is plated with a high-reflection film matched with laser wavelength or is not plated with a polished film, the SB3 surface of the parallelogram prism 1 is plated with a PBS film matched with laser wavelength, and the PBS film is high in reflection to S polarized light and high in transmission to P polarized light.

Wherein, SA1 and SA2 surfaces of the phase retardation plate 3 are plated with antireflection films matched with laser wavelengths, and SA3 and SA4 surfaces of the phase retardation plate 3 are cut surfaces, frosted surfaces or polished surfaces.

The included angle between the SC1 and SC2 surfaces of the right-angle trapezoidal prism A2 is 45 degrees. SC1 and SC2 surfaces of the right-angle trapezoidal prism A2 are plated with antireflection films matched with laser wavelength, and SC3 and SC4 surfaces of the right-angle trapezoidal prism A2 are cutting surfaces or frosted surfaces or polished surfaces. The right-angle trapezoidal prism A2 can also be an isosceles right-angle prism.

The dimensions of the SB2 and SB3 surfaces of the parallelogram prism 1, the SA1 and SA2 surfaces of the phase retarder 3, and the SC2 surface of the rectangular prism A2 are the same. The dimensions of the SB1 surface of the parallelogram prism 1 and the SC3 surface of the right-angle trapezoidal prism A2 are the same.

Wherein the phase difference between the o light and the e light of the phase retarder 3 for the laser light transmitted in the direction perpendicular to the SA3 plane thereof (the arrow a direction shown in fig. 4) is equal to pi or an odd multiple of pi. The optical axis of the phase retarder 3 and the S-polarization direction form an angle of 45 degrees, and the plane formed by the two is perpendicular to the incident light.

The size of the vertical direction of the beam projection of the S-polarized laser beam output by the semiconductor laser and collimated by the fast axis and the slow axis is twice of the size of SB1 of the parallelogram prism 1, and the light ray 1 and the light ray 6 are marginal light rays of the slow axis direction of the beam. The light rays 1 and 3 are edge rays that can be transmitted through the SB1 plane of the parallelogram prism 1, and the light ray 2 is a typical light ray that can be transmitted through the SB1 plane of the parallelogram prism 1. The light rays 4 and 6 are marginal light rays that can transmit the SB4 plane of the right trapezoid prism A2, the phase retardation plate 3, and the parallelogram prism 1, and the light ray 5 is a typical light ray that can transmit the SB4 plane of the right trapezoid prism A2, the phase retardation plate 3, and the parallelogram prism 1. The light between the rays 3 and 4 is scattered by the SA3 surface of the phase retarder.

Taking a typical S-polarized light ray 2 as an example, the light ray enters the parallelogram prism 1 from left to right, passes through the SB1 surface of the parallelogram prism 1, is reflected by the SB2 surface of the parallelogram prism 1, is transmitted upward, enters the PBS film on the SB3 surface of the parallelogram prism 1, is reflected, passes through the SB4 surface of the parallelogram prism 1 from left to right, and is output as the S-polarized light ray 2.

Taking a typical S-polarized light ray 5 as an example, the light enters the right trapezoid prism A2 from left to right, then enters the phase retarder 3 after passing through the S1 and S2 surfaces of the right trapezoid prism A2, respectively, and then the polarization direction of the light is rotated by 90 degrees after passing through the phase retarder 3 from left to right, and then the light becomes P-polarized light, which enters the PBS film on the S3 surface of the parallelogram prism 1 and then is transmitted, and then passes through the SB4 surface of the parallelogram prism 1 from left to right and then is output as the P-polarized light ray 5.

The light beam composed of the S polarized light 1, the S polarized light 2 and the S polarized light 3 is still output as the S polarized light beam composed of the S polarized light 1, the S polarized light 2 and the S polarized light 3 after passing through the device; the light beam composed of the S-polarized light 4, the S-polarized light 5, and the S-polarized light 6 passes through the device and is converted into a P-polarized light beam composed of the P-polarized light 4, the P-polarized light 5, and the P-polarized light 6, and is output. The S polarized light beam and the P polarized light beam are overlapped together in space to form a light beam which is output.

Example 2:

as shown in fig. 2, the schematic structural diagram of the device for improving the beam quality of a semiconductor laser according to embodiment 2 of the present invention is that: parallelogram prism 1, right trapezoid prism A2, phase delay piece 3.

As shown in fig. 4, 5 and 6, in the retardation plate, a surface facing the inclined surface of the right-angled trapezoidal prism A2 is SA1, and a surface opposite to SA1 is SA2; the surface at 135 degrees from SA1 is SA3, and the surface at 45 degrees from SA1 is SA4. In the parallelogram prism, the surface facing the inclined plane of the right trapezoid prism is SB3, and the surface parallel to SB3 is SB2; the surface which forms an included angle of 135 degrees with SB3 is SB1; the surface forming an angle of 45 degrees with SB3 is SB4. In the right trapezoid prism a, the bottom surface with a large area is SC1, the inclined surface thereof is SC2, the surface thereof opposite to the inclined surface is SC3, and the bottom surface with a small area is SC4.

The SB1, SB3 and SB4 surfaces of the parallelogram prism 1 are plated with antireflection films matched with laser wavelength, and the SB2 surface of the parallelogram prism 1 is plated with a high-reflection film or polished without film matched with laser wavelength.

The SA1 and SA2 surfaces of the phase retardation plate 3 are plated with antireflection films matched with laser wavelengths, and the SA3 and SA4 surfaces of the phase retardation plate 3 are cut surfaces, frosted surfaces or polished surfaces.

The included angle between the SC1 and SC2 surfaces of the right-angle trapezoidal prism A2 is 45 degrees. The SC1 surface of the right trapezoid prism A2 is plated with an antireflection film matched with the laser wavelength, the SC2 surface of the right trapezoid prism A2 is plated with a PBS film matched with the laser wavelength, the PBS film is highly reflective to S polarized light and highly transparent to P polarized light, and the SC3 surface and the SC4 surface of the right trapezoid prism A2 are cut surfaces or frosted surfaces or polished surfaces.

The dimensions of the SB2 and SB3 surfaces of the parallelogram prism 1, the SA1 and SA2 surfaces of the phase retarder 3, and the SC2 surface of the rectangular trapezoid prism A2 are the same. The dimensions of the SB1 surface of the parallelogram prism 1 and the SC3 surface of the right-angle trapezoidal prism A2 are the same.

The phase retarder 3 has a phase difference equal to pi or an odd multiple of pi between o-light and e-light of laser light propagating in a direction parallel to the SA3 plane (the direction of arrow b shown in fig. 4). The optical axis of the phase retarder 3 and the p-polarization direction of the light rays propagating up and down form an included angle of 45 degrees, and the plane formed by the optical axis and the p-polarization direction is perpendicular to the light rays propagating up and down.

The SA1 surface of the phase retarder 3 and the SC2 surface of the right trapezoid prism A2 are optically glued or glued into a whole, the SA2 surface of the phase retarder 3 and the SB3 surface of the parallelogram prism 1 are optically glued or glued into a whole, and the parallelogram prism 1, the phase retarder 3 and the right trapezoid prism A2 are optically glued or glued into a whole in sequence from bottom to top to form a right trapezoid prism B.

The size of the slow axis direction of the P-polarized laser beam output by the semiconductor laser and collimated by the fast axis and the slow axis is twice of the size of SB1 of the parallelogram prism 1, and the light ray 1 and the light ray 6 are marginal light rays of the slow axis direction of the light beam. The light rays 1 and 3 are marginal light rays that can transmit the SB1 plane of the parallelogram prism 1, and the light ray 2 is a typical light ray that can transmit the SB1 plane of the parallelogram prism 1. The light rays 4 and 6 are edge light rays that can be transmitted through the surfaces SB4 of the right trapezoid prism A2, the phase retardation plate 3, and the parallelogram prism 1, and the light ray 5 is a typical light ray that can be transmitted through the surfaces SB4 of the right trapezoid prism A2, the phase retardation plate 3, and the parallelogram prism 1. The light between the light rays 3 and 4 is scattered by the SA3 surface of the phase retarder.

Taking a typical P-polarized light ray 2 as an example, the light ray enters the parallelogram prism 1 from left to right, passes through the SB1 surface of the parallelogram prism 1, is reflected by the SB2 surface of the parallelogram prism 1, is transmitted upward, passes through the SB3 surface of the parallelogram prism 1, enters the phase retarder 3, passes through the phase retarder 3, becomes S-polarized light, enters the PBS film on the SC2 surface of the right trapezoid prism A2, is reflected, passes through the phase retarder 3 again, remains as S-polarized light, passes through the SB4 surface of the parallelogram prism 1, and is output as S-polarized light ray 2.

Taking a typical P-polarized light ray 5 as an example, the light enters the right trapezoid prism A2 from left to right, passes through the SC1 surface of the right trapezoid prism A2, enters the PBS film on the SC2 surface of the right trapezoid prism A2, is transmitted by the PBS film, enters the phase retarder 3, passes through the phase retarder 3 from left to right, remains as P-polarized light, and passes through the SB4 surface of the parallelogram prism 1 to be output as the P-polarized light ray 5.

The light beam composed of the P polarized light 1, the P polarized light 2 and the P polarized light 3 is changed into an S polarized light beam composed of the S polarized light 1, the S polarized light 2 and the S polarized light 3 to be output after passing through the structure; the light beam composed of the P-polarized light 4, the P-polarized light 5 and the P-polarized light 6 is still output as the P-polarized light beam composed of the P-polarized light 4, the P-polarized light 5 and the P-polarized light 6 after passing through the structure. The S polarized light beam and the P polarized light beam are overlapped together in space to form a light beam which is output.

Example 3:

as shown in fig. 3, the schematic structural diagram of a device for improving the beam quality of a semiconductor laser according to embodiment 3 of the present invention is shown, wherein the device includes: parallelogram prism 1, right trapezoid prism A2, phase delay piece 3. The SC2 surface of the right trapezoid prism A2 and the SB3 surface of the parallelogram prism 1 are optically glued or glued into a whole, the SA1 surface of the phase retarder 3 and the SB2 surface of the parallelogram prism 1 are optically glued or glued into a whole, and the phase retarder 3, the parallelogram prism 1 and the right trapezoid prism A2 are optically glued or glued into a whole according to the sequence from bottom to top to form a right trapezoid prism B.

As shown in fig. 4, 5 and 6, in the retardation plate, the surface facing the inclined surface of the right-angled trapezoidal prism A2 is designated as SA1, and the surface facing SA1 is designated as SA2; the surface at 135 degrees to SA1 is SA3, and the surface at 45 degrees to SA1 is SA4. In the parallelogram prism, a surface facing to the inclined plane of the right trapezoid prism is SB3, and a surface parallel to SB3 is SB2; the surface which forms an included angle of 135 degrees with SB3 is SB1; the surface forming an angle of 45 degrees with SB3 is SB4. In the right trapezoid prism a, the bottom surface with a large area is SC1, the inclined surface thereof is SC2, the surface thereof opposite to the inclined surface is SC3, and the bottom surface with a small area is SC4.

The included angle between the surfaces SB1 and SB2 of the parallelogram prism 1 is 45 degrees, and the included angle between the surfaces SB3 and SB4 is 45 degrees. The SB1, SB2 and SB4 surfaces of the parallelogram prism 1 are plated with antireflection films matched with laser wavelength, the SB3 surface of the parallelogram prism 1 is plated with PBS films matched with laser wavelength, and the PBS films are highly reflective to S polarized light and highly transparent to P polarized light.

Wherein, the SA1 surface of the phase retardation plate 3 is plated with an antireflection film matched with the laser wavelength, the SA2 surface of the phase retardation plate 3 is plated with a high reflection film matched with the laser wavelength, and the SA3 and SA4 surfaces of the phase retardation plate 3 are cutting surfaces, frosting surfaces or polishing surfaces.

The included angle between the SC1 and SC2 surfaces of the right-angle trapezoidal prism A2 is 45 degrees. SC1 and SC2 surfaces of the right-angle trapezoidal prism A2 are plated with antireflection films matched with laser wavelength, and SC3 and SC4 surfaces of the right-angle trapezoidal prism A2 are cutting surfaces or frosted surfaces or polished surfaces. The right-angle trapezoidal prism A2 can also be replaced by an isosceles right-angle prism.

The dimensions of the SB2 and SB3 surfaces of the parallelogram prism 1, the SA1 and SA2 surfaces of the phase retarder 3, and the SC2 surface of the rectangular trapezoid prism A2 are the same. The dimensions of the SB1 surface of the parallelogram prism 1 and the SC3 surface of the right-angle trapezoidal prism A2 are the same.

Wherein the phase difference between the o light and the e light of the phase retarder 3 for the laser light transmitted in the direction parallel to the surface of the SA3 (the direction of arrow b shown in fig. 4) is equal to pi or an odd multiple of pi. The optical axis of the phase retarder 3 and the p-polarization direction of the light rays propagating up and down form an included angle of 45 degrees, and the plane formed by the optical axis and the p-polarization direction is perpendicular to the light rays propagating up and down.

The size of the slow axis direction of the P-polarized laser beam output by the semiconductor laser and collimated by the fast axis and the slow axis is twice as large as the size of SB1 of the parallelogram prism 1, and the light ray 1 and the light ray 6 are marginal light rays of the slow axis direction of the light beam. The light rays 1 and 3 are edge rays that can pass through the SB1 plane of the parallelogram prism 1 and the phase retarder 3, and the light ray 2 is a typical light ray that can pass through the SB1 plane of the parallelogram prism 1 and the phase retarder 3. The light rays 4 and 6 are edge light rays that can transmit the SB4 plane of the right trapezoid prism A2 and the parallelogram prism 1, and the light ray 5 is a typical light ray that can transmit the SB4 plane of the right trapezoid prism A2 and the parallelogram prism 1. The light between the light rays 3 and 4 is scattered by the SA4 surface of the phase retarder 3.

Taking a typical P-polarized light ray 2 as an example, the P-polarized light ray enters the parallelogram prism 1 from left to right, passes through the SB1 surface of the parallelogram prism 1, is transmitted by the SB2 surface of the parallelogram prism 1, enters the phase retarder 3,P, is transmitted to the SA2 surface of the phase retarder 3 with the polarization direction of the polarized light unchanged, is reflected by the SA2 surface of the phase retarder 3, passes through the phase retarder 3 again, passes through the phase retarder 3, becomes S-polarized light after passing through the phase retarder 3, enters the PBS film on the SB3 surface of the parallelogram prism 1, is reflected by the SB3 surface of the parallelogram prism 1, passes through the SB4 surface of the parallelogram prism 1 from left to right, and is output as S-polarized light ray 2.

Taking a typical P-polarized light ray 5 as an example, the light enters the right trapezoid prism A2 from left to right, passes through the SC1 and SC2 surfaces of the right trapezoid prism A2, enters the PBS film on the SB3 surface of the parallelogram prism 1, is transmitted by the PBS film on the SB3 surface of the parallelogram prism 1, remains as P-polarized light, and passes through the SB4 surface of the parallelogram prism 1 from left to right, and is output as the P-polarized light ray 5.

The light beam composed of the P polarized light 1, the P polarized light 2 and the P polarized light 3 is changed into an S polarized light beam composed of the S polarized light 1, the S polarized light 2 and the S polarized light 3 to be output after passing through the structure; the light beam composed of the P-polarized light 4, the P-polarized light 5 and the P-polarized light 6 is still output as the P-polarized light beam composed of the P-polarized light 4, the P-polarized light 5 and the P-polarized light 6 after passing through the structure. The S polarized light beam and the P polarized light beam are overlapped together in space to form a light beam which is output.

The above embodiments are only used to illustrate the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention accordingly, and the scope of the present invention should not be limited by the embodiments, i.e. all equivalent changes or modifications made by the spirit of the present invention are still within the scope of the present invention.

Claims (9)

1. A device for improving the slow axis beam quality of a semiconductor laser is characterized by comprising a phase delay plate, a parallelogram prism and a prism A with a right-angled triangle or right-angled trapezoid cross section; the prism A, the phase delay sheet and the parallelogram prism are jointed to form a right-angle trapezoidal prism B; the prism A comprises a first right-angle surface, a second right-angle surface and an inclined surface which are sequentially intersected, the included angle between the inclined surface and the second right-angle surface is 45 degrees, and the inclined surface is attached to the phase retarder or the parallelogram prism.

2. The apparatus as claimed in claim 1 wherein the parallelogram prisms, phase retarders and prisms A are bonded by optical glue or gluing.

3. The apparatus as claimed in claim 1 wherein the prism a, the retardation plate and the parallelogram prism are sequentially bonded.

4. An apparatus as claimed in claim 3, wherein the direction perpendicular to the bottom surface of the right trapezoid prism B and from the larger area bottom surface to the smaller area bottom surface is set as X direction, and when the laser propagates in the phase retardation plate along the X direction, the phase difference between the o light and the e light in the laser is equal to pi or odd multiple of pi; the optical axis of the phase retarder and the S polarization direction of the light propagating in the phase retarder along the X direction form an included angle of 45 degrees, and the plane formed by the optical axis of the phase retarder and the S polarization direction is perpendicular to the light propagating in the phase retarder along the X direction.

5. The device for improving the slow-axis beam quality of a semiconductor laser as claimed in claim 3, wherein in the phase retardation plate, the surface facing the inclined plane of the prism A is SA1, and the surface opposite to SA1 is SA2; the surface with an included angle of 135 degrees with SA1 is SA3, and the surface with an included angle of 45 degrees with SA1 is SA4; in the parallelogram prism, a surface facing to the inclined plane of the prism A is SB3, a surface parallel to SB3 is SB2, a surface with an included angle of 135 degrees with SB3 is SB1, and a surface with an included angle of 45 degrees with SB3 is SB4; in the prism A, a first right-angle surface is a cutting surface, a frosted surface or a polished surface, and a second right-angle surface is plated with an antireflection film matched with the laser wavelength; the phase retardation plate is characterized in that SA1 and SA2 of the phase retardation plate are plated with antireflection films matched with laser wavelengths, and SA3 and SA4 of the phase retardation plate are cut surfaces or frosted surfaces or polished surfaces; the parallelogram prism has SB1 and SB4 coated with antireflection film matching the laser wavelength, and SB2 polished film or high reflection film matching the laser wavelength.

6. The device for improving the slow-axis beam quality of a semiconductor laser as claimed in claim 5, wherein the inclined surface of the prism A is plated with an antireflection film matched with the laser wavelength; the SB3 face of the parallelogram prism is plated with a PBS film matched with the laser wavelength.

7. An apparatus as claimed in claim 5 wherein the bevel of the prism a is coated with PBS film matching the laser wavelength; SB3 of the parallelogram prism is coated with an antireflection film matched with the laser wavelength.

8. The apparatus as claimed in claim 1 wherein the prism a, the parallelogram prism and the phase retarder are sequentially bonded.

9. The apparatus as claimed in claim 8, wherein the surface of the retardation plate facing the inclined plane of the prism a is SA1, and the surface opposite to SA1 is SA2; the surface with an included angle of 135 degrees with SA1 is SA3, and the surface with an included angle of 45 degrees with SA1 is SA4; in the parallelogram prism, a surface facing to the inclined plane of the prism A is SB3, a surface parallel to SB3 is SB2, a surface with an included angle of 135 degrees with SB3 is SB1, and a surface with an included angle of 45 degrees with SB3 is SB4; in the prism A, a first right-angle surface is a cutting surface or a frosted surface or a polished surface, and an inclined surface and a second right-angle surface are plated with antireflection films matched with laser wavelength; the phase retardation plate is characterized in that SA1 of the phase retardation plate is plated with an antireflection film matched with the laser wavelength, SA2 of the phase retardation plate is plated with a high-reflection film matched with the laser wavelength, and SA3 and SA4 of the phase retardation plate are cutting surfaces or frosted surfaces or polished surfaces; and the parallelogram prism has SB1, SB2 and SB4 coated with antireflection film matching the laser wavelength and SB3 coated with PBS film matching the laser wavelength.

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