Device for polarization separation and beam shaping of semiconductor laser stack array

Abstract

The invention provides a device for polarization separation and beam shaping of a semiconductor laser stack array. The device comprises a rotatable half-wave plate, a polarization splitting prism, a quarter-wave plate, a total reflection mirror and right-angle step prisms arranged at the upper end and the lower end of the polarization splitting prism, wherein the rotatable half-wave plate, the polarization splitting prism, the quarter-wave plate and the total reflection mirror are arranged in sequence. According to the embodiment, the adjustment of the P light and S light components in the light beam is realized by rotating the half-wave plate; the polarization splitting prism can totally reflect the S light and emit the S light through the right-angle step prism above the polarization splitting prism; p light passes through the polarization splitting prism, is changed into right-handed circularly polarized light through the quarter-wave plate, is changed into left-handed circularly polarized light through mirror reflection of the holophote, is changed into S light through the quarter-wave plate again, and is emitted after passing through the right-angle step prism below, so that polarization separation and beam shaping of the semiconductor laser stack array are realized.

Description

Technical Field

[0001] The invention relates to the field of semiconductor laser technology, and in particular to a device for polarization separation and beam shaping of semiconductor laser stacked arrays. Background Art

[0002] Semiconductor lasers have many advantages such as low cost, high efficiency, compact structure, wide wavelength range, and high reliability. However, disadvantages such as low output power, poor beam quality, and low power density limit the application of semiconductor lasers as direct light sources. Therefore, how to increase the output power of semiconductor lasers, improve the beam quality of the light beam, and increase the laser output brightness has become an important technical bottleneck in the development of semiconductor lasers.

[0003] Semiconductor lasers can be divided into three types according to the number of light-emitting units and the packaging method: single tube, bar and stacked array. Compared with single tube and bar, semiconductor laser stack is to stack semiconductor laser bars along the fast axis direction, so the output power of semiconductor laser stack is generally several to dozens of times that of semiconductor laser bars. At present, the maximum output power of commercial semiconductor laser stack devices can reach more than 10,000 watts.

[0004] However, due to the presence of dark areas between the light spots on the fast axis, superposition will deteriorate the beam quality of the fast axis. Therefore, how to maintain the power of the semiconductor laser stack while improving its output beam quality has become one of the key directions of researchers. In 2006, the Lincoln Laboratory in the United States first applied open-loop spectral beam combining to semiconductor laser stacks, with an output laser power of 89.5W, a spectral beam combining efficiency of 75%, and a spectral width of 14nm. In 2015, the China Academy of Engineering Physics used semiconductor laser stacks for spectral beam combining, achieving an output power of more than 120W, an electro-optical conversion efficiency of more than 48%, a fast-axis beam quality of 11.5, and a slow-axis beam quality of 10.2.

[0005] Currently, spectral beam combining for stacked semiconductor laser arrays is mainly carried out in the slow axis direction. Since stacked array spectral beam combining essentially cannot solve the problem of fast axis beam quality degradation when spatial spots are superimposed, the improvement in laser brightness is very limited. Summary of the invention

[0006] The content of the present invention is used to introduce the concepts in a brief form, which will be described in detail in the detailed implementation section below. The content of the present disclosure is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to limit the scope of the technical solution claimed for protection.

[0007] Some embodiments of the present invention provide devices for polarization separation and beam shaping of semiconductor laser stack arrays to solve the technical problems mentioned in the above background technology section.

[0008] Some embodiments of the present invention provide a device for polarization separation and beam shaping of a semiconductor laser stack, comprising a rotatable half-wave plate, a polarization beam splitter prism, a quarter-wave plate, a total reflection mirror, and right-angle step prisms arranged at the upper and lower ends of the polarization beam splitter prism, wherein:

[0009] The P and S components of the light beam are adjusted by rotating the half-wave plate.

[0010] The polarization beam splitter prism can make the S light totally reflected and emitted through the right-angle step prism above;

[0011] The P light passes through the polarization beam splitter prism, becomes right-handed circularly polarized light through a quarter-wave plate, becomes left-handed circularly polarized light through mirror reflection of a total reflection mirror, and becomes S light again through a quarter-wave plate, and then is emitted after passing through the right-angle step prism below.

[0012] Optionally, the rotatable half-wave plate is used to cause phase delay in light of two polarization states in the light beam, and the polarization state of the light beam is changed by changing the angle between the optical axis and the electric field direction of the output light beam.

[0013] Optionally, the optical adhesive surface of the polarization beam splitter prism is coated with a polarization beam splitter film, and all right-angle surfaces are coated with an anti-reflection film.

[0014] Optionally, the polarization beam splitting film is used to make the S light fully reflected and incident on the right-angle step prism.

[0015] Optionally, the polarization beam splitting film is used to allow P light to transmit through the polarization beam splitting prism.

[0016] Optionally, the polarization beam splitter prism is made of ultraviolet fused quartz.

[0017] Optionally, the vertical height of the stepped slope of the right-angle stepped prism should be no less than the width of the light emitted by a single bar along the fast axis direction.

[0018] Optionally, the quarter wave plate is used to convert left-handed circularly polarized light and right-handed circularly polarized light of the P light that transmits the polarization splitting film.

[0019] Optionally, the quarter wave plate is made of quartz crystal.

[0020] Optionally, the total reflection mirror is used to fold back the light path and realize the mirror image conversion of right-handed circularly polarized light and left-handed circularly polarized light.

[0021] The above embodiments of the present invention have the following beneficial effects:

[0022] The light beam emitted by the semiconductor laser stack is collimated by the fast and slow axis collimation array and then incident on the rotatable half-wave plate placed in front of the polarization beam splitter prism. The P and S light components in the light beam are adjusted by rotating the rotatable half-wave plate.

[0023] As the light beam enters the polarization splitter prism, the S light cannot pass through the polarization separation film, and is totally reflected here, and is incident upward onto the stepped slope of the right-angle step prism above, and then emitted to the right, achieving compression of the light beam in the fast axis direction.

[0024] For P light, it is directly transmitted through the polarization splitter prism and incident on the quarter-wave plate, and the P light is transformed into right-handed circularly polarized light through the quarter-wave plate. As the light path advances, the right-handed circularly polarized light is incident on the surface of the total reflection mirror.

[0025] Due to the mirror reflection of the total reflection mirror, the right circularly polarized light is converted into left circularly polarized light and propagates in the opposite direction along the original optical path. When the light beam passes through the quarter wave plate again, since the light beam at this time is left circularly polarized light, after passing through the quarter wave plate, the left circularly polarized light is converted into S light. As the optical path moves forward, the S light is totally reflected at the polarization beam splitter prism and incident on the stepped slope of the right-angle step prism below, and also emerges from the right.

[0026] At this point, polarization separation and beam shaping of the semiconductor laser stack array have been achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic structural diagram of an embodiment of a device for polarization separation and beam shaping of semiconductor laser stacked arrays of the present invention;

[0029] Figure 2 The schematic diagram of an embodiment of the device for polarization separation and beam shaping of semiconductor laser arrays of the present invention is shown in FIG.

[0030] Description of reference numerals:

[0031] 1. Rotatable half-wave plate; 2. Polarization splitter prism; 3. Right-angle step prism; 4. Quarter-wave plate; 5. Total reflection mirror. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. 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.

[0035] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0036] First see Figure 1 , Figure 1 FIG. 1 is a schematic diagram of a structure of an embodiment of a device for polarization separation and beam shaping of a semiconductor laser stack according to the present invention. Figure 1 As shown, the device for polarization separation and beam shaping of semiconductor laser stack includes a rotatable half-wave plate 1, a polarization beam splitter prism 2, a right-angle step prism 3, a quarter-wave plate 4 and a total reflection mirror 5.

[0037] The rotatable half-wave plate 1 is also called a phase retarder, which can cause a certain phase delay in the two polarization states of light in the light beam, and change the polarization state of the light beam by changing the angle between the optical axis and the electric field direction of the output light beam.

[0038] The polarization beam splitter prism 2 is arranged on the right side of the rotatable half-wave plate 1 ( Figure 1 It is made of UV fused quartz, with polarization splitter coating on the optical adhesive surface and anti-reflection coating on all right-angle surfaces.

[0039] The right-angle step prism 3 is arranged on the upper and lower end faces of the polarization beam splitter prism 2. The vertical height of the step slope of the right-angle step prism 3 should not be less than the width of the light emitted by a single bar along the fast axis direction.

[0040] The quarter wave plate 4 is made of quartz crystal and can realize the conversion of linear polarized light into left-handed circular polarized light and right-handed circular polarized light.

[0041] The total reflection mirror 5 can fold back the light path and realize the mirror image conversion between right-handed circularly polarized light and left-handed circularly polarized light.

[0042] See also Figure 2 , Figure 2 FIG. 1 is a schematic diagram of an embodiment of the device for polarization separation and beam shaping of semiconductor laser stack arrays of the present invention. Figure 2 As shown, the light beam emitted by the semiconductor laser stack is collimated by the fast and slow axis collimation array and then incident on the rotatable half-wave plate 1 placed in front of the polarization beam splitter prism 2. The P light and S light components in the light beam are adjusted by rotating the rotatable half-wave plate 1.

[0043] As the light beam enters the polarization beam splitter prism 2, since the bonding surface of the polarization beam splitter prism 2 is coated with a polarization separation film, the S light cannot pass through the polarization separation film, and is totally reflected here, and is incident upward to the stepped slope of the right-angle step prism 3 above, and then emitted to the right, realizing the compression of the light beam in the fast axis direction. For the P light, it is directly transmitted through the polarization separation film and incident on the quarter wave plate 4, and the conversion of the P light to right-handed circularly polarized light is realized through the quarter wave plate 4. As the light path advances, the right-handed circularly polarized light is incident on the surface of the total reflection mirror 5.

[0044] Due to the mirror reflection of the total reflection mirror 5, the right circularly polarized light is converted into left circularly polarized light and propagates in the opposite direction along the original optical path. When the light beam passes through the quarter wave plate 4 again, since the light beam at this time is left circularly polarized light, after passing through the quarter wave plate 4, the left circularly polarized light is converted into S light. As the optical path advances, the S light is totally reflected at the polarization separation film and is incident on the stepped inclined surface of the right-angle step prism 3 below, and is also emitted from the right.

[0045] At this point, polarization separation and beam shaping of the semiconductor laser stack array have been achieved.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for polarization separation and beam shaping of semiconductor laser arrays, characterized in that: The invention comprises a rotatable half-wave plate, a polarization beam splitter prism, a quarter-wave plate, a total reflection mirror and right-angle step prisms arranged at the upper and lower ends of the polarization beam splitter prism, wherein: The P and S components of the light beam are adjusted by rotating the half-wave plate. The polarization beam splitter prism can make the S light totally reflected and emitted through the right-angle step prism above; The P light passes through the polarization beam splitter prism, becomes right-handed circularly polarized light through a quarter-wave plate, becomes left-handed circularly polarized light through mirror reflection of a total reflection mirror, and becomes S light again through a quarter-wave plate, and then is emitted after passing through the right-angle step prism below.

2. The device for polarization separation and beam shaping of semiconductor laser arrays according to claim 1, characterized in that: The rotatable half-wave plate is used to cause phase delay of light in two polarization states in the light beam, and the polarization state of the light beam is changed by changing the angle between the optical axis and the electric field direction of the output light beam.

3. The device for polarization separation and beam shaping of semiconductor laser arrays according to claim 1, characterized in that: The optical adhesive surface of the polarization beam splitter prism is coated with a polarization beam splitter film, and all right-angle surfaces are coated with an anti-reflection film.

4. The device for polarization separation and beam shaping of semiconductor laser stack according to claim 3, characterized in that: The polarization beam splitting film is used to make the S light fully reflect and inject it into the right-angle step prism.

5. The device for polarization separation and beam shaping of semiconductor laser arrays according to claim 3, characterized in that: The polarization beam splitting film is used to allow the P light to transmit through the polarization beam splitting prism.

6. The device for polarization separation and beam shaping of semiconductor laser arrays according to claim 1, characterized in that: The polarization beam splitter prism is made of ultraviolet fused quartz.

7. The device for polarization separation and beam shaping of semiconductor laser arrays according to claim 1, characterized in that: The vertical height of the step slope of the right-angle step prism should not be less than the width of the light emitted by a single bar along the fast axis direction.

8. The device for polarization separation and beam shaping of semiconductor laser stack according to claim 5, characterized in that: The quarter wave plate is used to transform the left-handed circularly polarized light and the right-handed circularly polarized light of the P light that transmits the polarization splitting film.

9. The device for polarization separation and beam shaping of semiconductor laser stacked arrays according to claim 8, characterized in that: The quarter wave plate is made of quartz crystal.

10. The device for polarization separation and beam shaping of semiconductor laser arrays according to claim 1, characterized in that: The total reflection mirror is used to fold back the light path and realize the mirror image conversion of right-handed circularly polarized light and left-handed circularly polarized light.

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