Laser with adjustable polarization direction

Abstract

The invention relates to a laser with an adjustable polarization direction. The laser with the adjustable polarization direction comprises a light-emitting assembly, a front light path assembly and a rear light path assembly, the light-emitting assembly is fixedly connected to one end of the front light path assembly, and the rear light path assembly is connected to the other end of the front light path assembly; the rear light path assembly comprises quartz plates which are installed at Brewster angles. According to the laser provided by the invention, the quartz plate arranged at the Brewster angle is arranged in the laser, so that a light beam is subjected to polarization refraction in an oscillation process in the laser, and linearly polarized light with a high polarization ratio is obtained. In addition, the polarization direction of the emergent laser can be directly changed by rotating the quartz plate in the axis direction. Compared with the prior art, the laser is simple in structure and high in integration level, the overall size of the device can be effectively reduced, and extra loss cannot be caused due to integration in the device.

Description

Technical Field

[0001] The invention relates to the field of laser technology, in particular to a laser with adjustable polarization direction. Background Art

[0002] There are several main methods for adjusting the vibration direction of non-polarized lasers in the prior art. One is to use a half wave plate, which can change the polarization angle of the incident linearly polarized laser so that the polarization angle of the outgoing light becomes twice the angle between the polarization direction of the incident light and the optical axis of the wave plate; the second is to use a quartz plate, after the non-polarized laser passes through the quartz plate, it can obtain linearly polarized light consistent with the direction of the quartz plate; the third is to use a birefringent crystal, insert a birefringent crystal into the laser to decompose the laser into two beams of linearly polarized light with perpendicular polarization directions, and then combine it with PBS or a quartz plate to obtain a single beam of linearly polarized light.

[0003] However, all of the above methods have certain problems. The half-wave plate requires that the incident laser must be linearly polarized light, and the wave plate can only be set outside the laser, with low integration. The quartz plate only allows light with the same polarization direction to pass through, resulting in large losses. The two beams of linearly polarized light decomposed by the birefringent crystal are close to each other and are easily mixed, and the separation effect is affected by factors such as the crystal material, thickness, incident light angle and intensity. Summary of the invention

[0004] Based on this, an object of the present invention is to provide a laser with adjustable polarization direction.

[0005] A laser with adjustable polarization direction comprises a light emitting component, a front optical path component and a rear optical path component, wherein the light emitting component is fixedly connected to one end of the front optical path component, and the rear optical path component is connected to the other end of the front optical path component; the front optical path component comprises a fundamental frequency light channel, a pump light channel and a semi-reflecting mirror, wherein the fundamental frequency light channel runs through both ends of the front optical path component and connects the light emitting component and the rear optical path component, the pump light channel runs through the side wall of the front optical path component and connects the side of the front optical path component and the fundamental frequency light channel, and the semi-reflecting mirror is installed in the fundamental frequency light channel and is located at the light outlet of the pump light channel; the rear optical path component comprises a polarized light channel, a quartz plate and an output mirror, wherein the polarized light channel runs through both ends of the rear optical path component, the quartz plate is installed in the polarized light channel at a Brewster angle, and the output mirror is installed at one end of the polarized light channel away from the front optical path component.

[0006] The polarization-adjustable laser described in the present invention obtains partially polarized refracted light by placing a quartz plate at the Brewster angle inside the laser using Brewster's law. And because the quartz plate is placed inside the laser, the refracted light passes through the quartz plate multiple times when oscillating in the laser, and each time it passes through the quartz plate, it undergoes polarization refraction, so that the refracted light continuously improves the polarization ratio during the oscillation process, and finally obtains linear polarized light with a high polarization ratio. In addition, by rotating the quartz plate along the axial direction, the polarization direction of the emitted laser can be changed. The quartz plate of the present invention is integrated inside the laser. Compared with the prior art that relies on external components to adjust the polarization, the present invention can effectively reduce the volume of the device and reduce laser loss.

[0007] Furthermore, the rear optical path component is rotatably connected to the front optical path component.

[0008] Furthermore, it also includes a rotating mechanism, which is arranged at the connection between the rear optical path component and the front optical path component and is used to drive the rear optical path component to rotate.

[0009] Furthermore, the rotating mechanism is a fine thread tooth, and the fine thread tooth is arranged on the outer side of the end where the rear optical path component is connected to the front optical path component, and correspondingly, a fine thread groove is also arranged on the inner side of the end where the front optical path component is connected to the rear optical path component.

[0010] Furthermore, the rotating mechanism also includes a driving member, which is drivingly connected to the rear optical path component and is used to drive the rear optical path component to rotate.

[0011] Furthermore, the angle between the reflective surface of the semi-reflective mirror and the axis of the pump light channel is 45°.

[0012] Furthermore, one side of the semi-reflective mirror facing the light-emitting component is coated with a film layer with high reflectivity to the pump light and high transmittance to the fundamental frequency light, and the other side is coated with a film layer with high transmittance to the fundamental frequency light.

[0013] Furthermore, both sides of the quartz plate are coated with a film layer with high transmittance to fundamental frequency light.

[0014] Furthermore, the light-emitting component includes a metal heat sink and a semiconductor light-emitting chip, the semiconductor light-emitting chip is fixed to the metal heat sink, the metal heat sink is fixed to one end of the front light path component, and the semiconductor light-emitting chip is located in the baseband light channel.

[0015] Furthermore, the central axis of the output mirror and the central axis of the quartz plate are located on different straight lines, so that the light refracted by the quartz plate is irradiated to the center of the output mirror.

[0016] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is an overall schematic diagram of the laser of the present invention; Figure 2 is a cross-sectional view of the laser of the present invention; Figure 3 This is a schematic diagram of the front light path component of the present invention; Figure 4 This is a schematic diagram of the rear optical path component of the present invention. DETAILED DESCRIPTION

[0018] See also Figure 1 A polarization-adjustable laser includes a light-emitting component 10, a front optical path component 20, and a rear optical path component 30. The light-emitting component 10 is mounted at one end of the front optical path component 20, and the rear optical path component 30 is mounted at the other end of the front optical path component 20. A pump light source is irradiated onto the light-emitting component 10 through the front optical path component 20 to excite it to generate laser light. The laser light is irradiated onto an optical element placed at a Brewster angle in the rear optical path component 30 to obtain an output laser light with a changed polarization angle, thereby realizing the adjustment of the polarization direction of the laser light.

[0019] See also Figure 2 The light emitting component 10 includes a metal heat sink 11 and a semiconductor light emitting chip 12. The metal heat sink 11 is made of a mixture of copper and diamond, and the semiconductor light emitting chip 12 is fixed to the metal heat sink 11 by welding or the like. The metal heat sink 11 is fixed to one end of the front light path component 20 by screws or the like, and one side of the semiconductor light emitting chip 12 faces the front light path component 20.

[0020] The front optical path component 20 includes a fundamental frequency optical channel 21, a pump optical channel 22 and a half-reflecting mirror 23. The fundamental frequency optical channel 21 runs through both ends of the front optical path component 20, connecting the light-emitting component 10 and the rear optical path component 30. The aperture of the fundamental frequency optical channel 21 is larger than the semiconductor light-emitting chip 12 but smaller than the metal heat sink 11, so that the semiconductor light-emitting chip 12 extends into the fundamental frequency optical channel 21, and the metal heat sink 11 is stuck outside the fundamental frequency optical channel 21, so that the laser emitted by the light-emitting component 10 can pass through the front optical path component 20 to reach the rear optical path component 30. The pump optical channel 22 runs through the side wall of the front optical path component 20, connecting the side end of the front optical path component 20 and the fundamental frequency optical channel 21, so that the pump light emitted by the pump source can be irradiated from the side of the front optical path component 20 into the fundamental frequency optical channel 21. Preferably, the pump optical channel 22 and the fundamental frequency optical channel 21 are perpendicular to each other. The semi-reflective mirror 23 is installed in the fundamental frequency light channel 21, located at the light outlet of the pump light channel 22, and is used to reflect the pump light entering from the pump light channel 22 to the light-emitting component 10. Preferably, the angle between the reflective surface of the semi-reflective mirror 23 and the axis of the pump light channel 22 is 45°, so that the pump light incident parallel to the pump light channel 22 is irradiated to the light-emitting component 10 in a direction parallel to the fundamental frequency light channel 21 after reflection, which is conducive to keeping the laser parallel to the fundamental frequency light channel 21. More preferably, the side of the semi-reflective mirror 23 facing the light-emitting component 10 is coated with a film layer with high reflectivity to the pump light and high transmittance to the fundamental frequency light, and the other side is coated with a film layer with high transmittance to the fundamental frequency light, thereby reflecting as much pump light as possible to the light-emitting component 10 to excite more fundamental frequency light, while reducing the reflection of the fundamental frequency light.

[0021] The rear optical path component 30 includes a polarized light channel 31, a quartz plate 32 and an output mirror 33. The polarized light channel 31 runs through both ends of the rear optical path component 30, connects the front optical path component 20 and the external space, so that the light emitted by the front optical path component 20 can pass through the rear optical path component 30 to the external space. The quartz plate 32 is installed in the polarized light channel 31 at the Brewster angle, so that the light incident from the front optical path component 20 is incident on the quartz plate 32 at the Brewster angle, and is refracted and emitted to the output mirror 33. Preferably, both sides of the quartz plate 32 are coated with a film layer with high transmittance to the fundamental frequency light. The output mirror 33 is installed at one end of the polarized light channel 31 connected to the external space, and is perpendicular to the polarized light channel 31, and is coated with a film layer with high reflectivity to the fundamental frequency light. Preferably, the central axis of the output mirror 33 and the central axis of the quartz plate 32 are located on different straight lines, thereby compensating for the change in light path caused by refraction of the semi-reflective mirror 23 and the quartz plate 32 and aligning the polarized light to the center of the output mirror 33 .

[0022] The output mirror 33 and the light emitting component 10 form a resonant cavity, so that when the fundamental frequency light reaches the output mirror 33, it is reflected by the output mirror 33 and returns to the light emitting component 10 along the original optical path, and the light emitting component 10 also reflects the fundamental frequency light so that it is irradiated to the output mirror 33 again, thereby causing the fundamental frequency light to oscillate between the output mirror 33 and the light emitting component 10, and is continuously amplified during the oscillation process, and is finally amplified to a certain power to penetrate the output mirror 33 to form a laser. During the oscillation process, when the fundamental frequency light is emitted from the light emitting component 10 to the output mirror 33, it will pass through the quartz plate 32 at the Brewster angle. According to Brewster's law, the refracted light formed by the fundamental frequency light passing through the quartz plate 32 is partially polarized light, so each time it passes through the quartz plate 32, a polarization refraction will be performed, thereby continuously improving the polarization ratio of the fundamental frequency light. When the fundamental frequency light oscillates and amplifies to a level sufficient to exit the output mirror 33, the fundamental frequency light has also undergone multiple polarization refractions, and a linearly polarized laser with a high polarization ratio can be obtained. Furthermore, according to Brewster's law, the polarization direction of most of the refracted light is parallel to the incident plane, and a small part of the light is perpendicular to the incident plane. Therefore, rotating the quartz plate 32 can change the direction of the incident plane and thus change the polarization direction of the refracted light.

[0023] See also Figure 3 and 4 As a preferred embodiment, the rear optical path component 30 further includes a rotating mechanism 34, through which the rear optical path component 30 is rotated, and then the quartz plate 32 is rotated along the axis, thereby changing the polarization angle of the refracted light. The rotating mechanism 34 is installed at one end of the rear optical path component 30 connected to the front optical path component 20, so that the rear optical path component 30 is rotatably connected to the front optical path component 20. The rotating mechanism 34 can be a gear rotation, a ball bearing, etc., and is a threaded structure in this embodiment. A fine thread is arranged on the outer side of one end of the rear optical path component 30 connected to the front optical path component 20, and a fine thread groove is arranged on the inner side of one end of the front optical path component 20 connected to the rear optical path component 30 to cooperate with it, thereby realizing the relative rotation between the rear optical path component 30 and the front optical path component 20. In addition, since the pitch of the fine thread is very small, the relative displacement between the rear optical path component and the front optical path component is also very small when rotating at a certain range of angles, and the influence on the optical path cavity length can be ignored.

[0024] More preferably, the rotating mechanism 34 further includes a driving member, which drives the rear optical path component 30 to rotate. The driving member may be an electric motor, a pneumatic spindle, etc., which is not limited in the present invention, as long as it can drive the rear optical path component 30 to rotate.

[0025] When in use, the pump light source is installed to align with the pump light channel 22 of the front optical path component 20, so that the pump light source enters the fundamental frequency light channel 21 through the pump light channel 22, and is reflected to the light emitting component 10 after being irradiated on the half-reflection mirror 23. The light emitting component 10 is excited by the pump light to generate fundamental frequency light, which is transmitted through the half-reflection mirror 23 and enters the rear optical path component 30, and is irradiated on the quartz plate 32 at the Brewster angle, and polarized light with a changed polarization angle is obtained, and finally output to the outside through the output mirror 33. At the same time, polarized light with different polarization angles can be obtained by rotating the rear optical path component 30.

[0026] The laser of the present invention provides a quartz plate placed at the Brewster angle inside the laser, so that the light beam undergoes polarization refraction during the oscillation process inside the laser, thereby obtaining linearly polarized light with a high polarization ratio. Moreover, by rotating the rear optical path component to drive the quartz plate to rotate, the polarization direction of the linearly polarized light can be conveniently adjusted. Compared with the prior art, the laser of the present invention has a simple structure and a high degree of integration, and can effectively reduce the overall volume of the device, and since it is integrated inside the device, no additional loss will be caused.

[0027] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present invention. The singular forms of "a", "said" and "the" used in the embodiments of the present invention and the claims are also intended to include plural forms unless the context clearly indicates other meanings. The term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items. When the above description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0028] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and the present invention is also intended to include these modifications and modifications.

Claims

1. A laser with adjustable polarization direction, characterized in that: The invention comprises a light-emitting component, a front optical path component and a rear optical path component, wherein the light-emitting component is fixedly connected to one end of the front optical path component, and the rear optical path component is connected to the other end of the front optical path component; the front optical path component comprises a fundamental frequency optical channel, a pumping optical channel and a semi-reflecting mirror, wherein the fundamental frequency optical channel runs through both ends of the front optical path component and connects the light-emitting component and the rear optical path component, the pumping optical channel runs through the side wall of the front optical path component and connects the side of the front optical path component and the fundamental frequency optical channel, and the semi-reflecting mirror is installed in the fundamental frequency optical channel and is located at the light outlet of the pumping optical channel; the rear optical path component comprises a polarized light channel, a quartz plate and an output mirror, wherein the polarized light channel runs through both ends of the rear optical path component, the quartz plate is installed in the polarized light channel at a Brewster angle, and the output mirror is installed at one end of the polarized light channel away from the front optical path component.

2. The laser according to claim 1, characterized in that: The rear optical path component is rotatably connected to the front optical path component.

3. The laser according to claim 2, characterized in that: It also includes a rotating mechanism, which is arranged at the connection between the rear optical path component and the front optical path component and is used to drive the rear optical path component to rotate.

4. The laser according to claim 3, characterized in that: The rotating mechanism is a fine thread tooth, which is arranged on the outer side of the end where the rear optical path component is connected to the front optical path component. In coordination with this, a fine thread groove is also arranged on the inner side of the end where the front optical path component is connected to the rear optical path component.

5. The laser according to any one of claims 3 or 4, characterized in that: The rotating mechanism further comprises a driving member, which is drivingly connected to the rear optical path component and is used to drive the rear optical path component to rotate.

6. The laser according to claim 1, characterized in that: The angle between the reflecting surface of the semi-reflecting mirror and the axis of the pump light channel is 45°.

7. The laser according to claim 1, characterized in that: The side of the semi-reflective mirror facing the light-emitting component is coated with a film layer with high reflectivity to pump light and high transmittance to fundamental frequency light, and the other side is coated with a film layer with high transmittance to fundamental frequency light.

8. The laser according to claim 1, characterized in that: Both sides of the quartz plate are coated with film layers with high transmittance to fundamental frequency light.

9. The laser according to claim 1, characterized in that: The light-emitting component comprises a metal heat sink and a semiconductor light-emitting chip. The semiconductor light-emitting chip is fixedly connected to the metal heat sink. The metal heat sink is fixedly connected to one end of the front optical path component. The semiconductor light-emitting chip is located in the fundamental frequency optical channel.

10. The laser according to claim 1, characterized in that: The central axis of the output mirror and the central axis of the quartz plate are located on different straight lines, so that the light refracted by the quartz plate is irradiated to the center of the output mirror.

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