A high-efficiency laser

Abstract

This invention relates to a high-efficiency laser, belonging to the field of laser technology. The high-efficiency laser includes a laser source, a first half-wave plate, a polarization beam splitter, a frequency conversion element, a first transmission mirror, and a second transmission mirror. The laser source emits a laser beam, which sequentially passes through the first half-wave plate, the polarization beam splitter, and the frequency conversion element. The laser beam converted by the frequency conversion element is transmitted through the first transmission mirror to form a first sub-beam, and the unconverted laser beam is reflected to form a second sub-beam. Within the second sub-beam, the laser beam converted by the frequency conversion element passes through the second transmission mirror to form a third sub-beam, and the unconverted laser beam is reflected to form a fourth sub-beam. The reflected fourth sub-beam, after passing through the polarization beam splitter, is again converted by the frequency conversion element and emitted towards the first and second transmission mirrors. This high-efficiency laser combines the frequency-converted laser beams multiple times for output, improving the energy utilization rate of the laser.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, and specifically relates to a high-efficiency laser. Background Technology

[0002] To achieve high output power and excellent beam quality, existing green frequency-doubled lasers generally use high-power, narrow-linewidth fiber lasers as the fundamental frequency source, combined with a nonlinear crystal for single-pass frequency doubling. However, current structures are limited by the weak absorption effect of the crystal, with conversion efficiencies typically between 40-50%. A large amount of unconverted infrared laser light remains after each conversion, and this portion is usually treated as non-target light and directly processed by structures such as absorption cells, resulting in generally low conversion efficiency. Summary of the Invention

[0003] This invention provides a high-efficiency laser to solve the technical problem of low conversion efficiency of current infrared lasers.

[0004] This invention is achieved through the following technical solution: a high-efficiency laser, comprising a laser source, a first half-wave plate, a polarization beam splitter, a frequency conversion element, a first transmission mirror, and a second transmission mirror; the laser source is used to emit a laser beam, the laser beam sequentially passes through the first half-wave plate, the polarization beam splitter, and the frequency conversion element; the laser beam converted by the frequency conversion element is transmitted through the first transmission mirror to form a first sub-beam, and the unconverted laser beam is reflected to form a second sub-beam; in the second sub-beam, the laser beam converted by the frequency conversion element passes through the second transmission mirror to form a third sub-beam, and the unconverted laser beam is reflected to form a fourth sub-beam; the laser beams transmitted by the first and second transmission mirrors are combined and output; the reflected fourth sub-beam, after passing through the polarization beam splitter, is converted again by the frequency conversion element and emitted towards the first and second transmission mirrors.

[0005] Optionally, the frequency conversion element includes a first LBO crystal, which is disposed between the polarization beam splitter and the first mirror.

[0006] Optionally, the frequency conversion element further includes a second LBO crystal, which is disposed between the first and second mirrors. After the second sub-beam is transmitted through the second LBO crystal and the second mirror to form the third sub-beam and reflected to form the fourth sub-beam, the fourth sub-beam is emitted towards the polarization beam splitter.

[0007] Optionally, it further includes a second half-wave plate, which is disposed between the second LBO crystal and the polarization beam splitter, so that the laser light passing through the second half-wave plate is reflected or transmitted by the polarization beam splitter.

[0008] Optionally, it also includes a light-collecting tube, wherein the fourth sub-beam is transmitted through the first mirror to produce a sixth sub-beam and reflected to produce a fifth sub-beam, and the fifth sub-beam is sequentially transmitted through the second LBO crystal, the second half-wave plate, and the polarization beam splitter. The light-collecting tube is installed on the optical path of the fifth sub-beam transmitted through the polarization beam splitter, and the light-collecting tube is used to collect the sixth sub-beam transmitted through the polarization beam splitter.

[0009] Optionally, a third half-wave plate is also included, which is disposed between the polarization beam splitter and the frequency conversion element, so that the laser emitted to the frequency conversion element is converted into polarized light that satisfies the second type of phase matching of the frequency conversion element.

[0010] Optionally, it also includes two focusing lenses, which are respectively mounted on the light-incident side of the first LBO crystal and the light-incident side of the second LBO crystal.

[0011] Optionally, it also includes two collimating lenses, which are respectively mounted on the light-emitting side of the first LBO crystal and the light-emitting side of the second LBO crystal.

[0012] Optionally, it also includes a beam combiner and an output optical fiber, wherein the frequency-converted light transmitted through the first and second mirrors is combined by the beam combiner; the output optical fiber is connected to the beam combiner for outputting the combined laser.

[0013] Optionally, the laser source includes a narrow linewidth polarization-maintaining laser and a spatial frequency doubling component. The narrow linewidth polarization-maintaining laser is used to output a fundamental frequency light source, providing linearly polarized infrared fundamental frequency light with narrow linewidth and high beam quality for the subsequent spatial green light frequency doubling. The spatial frequency doubling component is used to double the output frequency of the light source.

[0014] Compared with the prior art, the present invention has the following advantages: The present invention provides a high-efficiency laser comprising a laser source, a first half-wave plate, a polarization beam splitter, a frequency conversion element, a first transmission mirror, and a second transmission mirror. The laser source emits a laser beam, which passes sequentially through the first half-wave plate, the polarization beam splitter, and the frequency conversion element. The laser beam converted by the frequency conversion element is transmitted through the first transmission mirror to form a first sub-beam, and the unconverted laser beam is reflected to form a second sub-beam. In the second sub-beam, the laser beam converted by the frequency conversion element passes through the second transmission mirror to form a third sub-beam, and the unconverted laser beam is reflected to form a fourth sub-beam. The laser beams transmitted by the first and second transmission mirrors are combined and output. The reflected fourth sub-beam passes through the polarization beam splitter and is converted again by the frequency conversion element before being emitted towards the first and second transmission mirrors.

[0015] Through the above steps, the high-efficiency laser provided by this invention, in use, emits laser light from a laser source. The laser beam passes through a first half-wave plate, converting it into a first polarization state laser beam that can pass through a polarization beam splitter. Then, the laser beam is converted by a frequency conversion element and emitted towards a first transflector. The first transflector transmits the laser beam converted by the frequency conversion element to form a first sub-beam, and reflects the unconverted laser beam to form a second sub-beam. The laser beam converted by the frequency conversion element in the second sub-beam passes through a second transflector to form a third sub-beam, and the unconverted laser beam is reflected to form the fourth sub-beam. The reflected fourth sub-beam, after passing through a polarization beam splitter, is converted again by a frequency conversion element and emitted towards the first and second transflectors. It then passes through the first and second transflectors again for transmission and reflection, and is transmitted again by the second transflector. The frequency-converted laser beams transmitted twice by the first and second transflectors are combined and output. Therefore, this high-efficiency laser improves the energy utilization rate of the laser by combining the frequency-converted laser beams multiple times. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a high-efficiency laser provided by the present invention.

[0018] In the picture: 1-Laser source, 2-First half-wave plate, 3-Polarization beam splitter, 4-First LBO crystal, 5-First transflector, 6-Second half-wave plate, 7-Third half-wave plate, 8-Second LBO crystal, 9-Second transflector, 10-Focusing lens, 11-Collimating lens, 12-Band combiner, 13-Output fiber, 14-Light receiver. Detailed Implementation

[0019] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] This invention provides a high-efficiency laser, solving the current technical problems. The high-efficiency laser includes a laser source 1, a first half-wave plate 2, a polarization beam splitter 3, a frequency conversion element, a first transmission mirror 5, and a second transmission mirror 9. Laser source 1 emits laser light. The laser beam passes through the first half-wave plate 2, converting it into a first polarization state laser beam that can pass through the polarization beam splitter 3. The first polarization state laser beam can be either a polarization state that can be transmitted through the polarization beam splitter 3 or a polarization state that can be reflected by the polarization beam splitter 3. The laser beam passing through the deflection conversion element exits into the frequency conversion element. After passing through the frequency conversion element, the laser beam exits into the first transmission mirror 5. The laser beam passing through the frequency conversion element includes frequency-converted light and fundamental frequency light that has not undergone frequency conversion. The frequency-converted laser beam is transmitted through the first transmission mirror 5 to form a first sub-beam, and the unconverted laser beam is reflected to form a second sub-beam. The laser beam converted by the frequency conversion element in the second sub-beam exits into the second transmission mirror 9. The laser beam converted by the frequency conversion element is transmitted through the second transmission mirror 9 to form a third sub-beam, and the unconverted laser beam is reflected to form a third sub-beam. The fourth sub-beam, specifically, can be reflected by multiple mirrors and then emitted into the polarization beam splitter 3. After passing through the polarization beam splitter 3, the reflected fourth sub-beam is converted again by the frequency conversion element and emitted into the directions of the first transmission mirror 5 and the second transmission mirror 9. It is then transmitted and reflected again by the first transmission mirror 5 and transmitted through the second transmission mirror 9. Specifically, the laser beam converted by the frequency conversion element for the second time still includes the frequency-converted light and the fundamental frequency light that has not undergone frequency conversion. Similarly, the frequency-converted laser beam is transmitted through the first transmission mirror 5, the unconverted laser beam is reflected, and the laser beam that is reflected twice by the first transmission mirror 5 passes through the second transmission mirror 9. The frequency-converted laser beam passes through the second transmission mirror 9, and the frequency-converted laser beam transmitted through the first transmission mirror 5 and the second transmission mirror 9 is combined and output. Thus, the unconverted laser beam is converted and combined multiple times, thereby improving the energy utilization rate of the laser.

[0024] An optional implementation of this embodiment is as follows: The frequency conversion element includes a first LBO crystal 4, which is disposed between the polarization beam splitter 3 and the first transflector 5. The first LBO crystal 4 is used to convert 1064nm infrared light emitted by the laser source 1 into 532nm green light.

[0025] An optional implementation of this embodiment is as follows: The frequency conversion element further includes a second LBO crystal 8. The second LBO crystal 8 and the first LBO crystal 4 are the same structural components, that is, the second LBO crystal 8 is also used to convert 1064nm infrared light into 532nm green light, so as to obtain the same color light as the first beam. The second LBO crystal 8 is disposed between the first transflector 5 and the second transflector 9. The second sub-beam reflected by the first transflector 5 first undergoes frequency conversion by the second LBO crystal 8, and then passes through the second transflector to form a third sub-beam, which is then combined with the first sub-beam for output. By performing frequency conversion on the laser twice and combining the laser after frequency conversion with the laser after the first frequency conversion, the utilization rate of the laser is improved, and the efficiency of the emitted target color light is improved. The part of the second sub-beam that has not undergone frequency conversion is transmitted through the second transflector 9 to form a third sub-beam, and the fourth sub-beam is emitted to the polarization beam splitter 3.

[0026] An optional implementation of this embodiment is as follows: it further includes a second half-wave plate 6, which is disposed between the second LBO crystal 8 and the polarization beam splitter 3. The second half-wave plate 6 is used to convert the first polarized laser beam passing through the first half-wave plate 2 into a second polarized laser beam. After changing the polarization state of the laser beam, the laser beam passing through the second half-wave plate 6 is reflected or transmitted through the polarization beam splitter 3. Specifically, in one embodiment provided by this embodiment, the laser beam passing through the first half-wave plate 2 is transmitted through the polarization beam splitter 3, and the laser beam passing through the second half-wave plate 6 is transmitted through the polarization beam splitter 3. This allows the fourth sub-beam and the laser beam emitted from the laser source 1 to be emitted from two directions through the polarization beam splitter towards the first LBO crystal 4, reducing the obstruction of the initial beam emitted from the laser source 1 by other components when the fourth sub-beam is emitted towards the first LBO crystal 4.

[0027] An optional implementation of this embodiment is as follows: It also includes a light-collecting tube 14. The fourth sub-beam is transmitted through the first reflector 5 to produce the sixth sub-beam and reflected to produce the fifth sub-beam. The fifth sub-beam passes sequentially through the second LBO crystal 8, the second half-wave plate 6, and the second reflector 9, and is transmitted through the polarization beam splitter 3. The frequency-converted light of the first sub-beam, the third sub-beam, the sixth sub-beam, and the fifth sub-beam transmitted through the second reflector 9 for the second time is combined and output. By converting multiple times, the unconverted fundamental frequency light in the laser beam is utilized, thereby improving the utilization rate of the laser. The light-collecting tube 14 is installed on the optical path of the fifth sub-beam transmitted through the polarization beam splitter 3. The light-collecting tube 14 is used to collect the portion of the sixth sub-beam transmitted through the polarization beam splitter 3. The amount of this residual laser beam is too small. Collecting it through the light-collecting tube 14 can reduce the internal space and component cost occupied by the re-conversion and reuse. At the same time, it can also reduce the impact on other components caused by the laser beam not being collected.

[0028] An optional implementation of this embodiment is as follows: it further includes a third half-wave plate 7, which is disposed between the polarization beam splitter 3 and the frequency conversion element, so that the laser emitted to the frequency conversion element is converted into polarized light that satisfies the second type of phase matching of the frequency conversion element. The frequency conversion element includes a first LBO crystal 4 and a second LBO crystal 8. The first LBO crystal 4 and the second LBO crystal 8 are the same nonlinear crystal, that is, the polarized light converted by the third half-wave plate 7 can simultaneously satisfy the first LBO crystal 4 and the second LBO crystal 8.

[0029] An optional implementation of this embodiment is as follows: it also includes a focusing lens 10. There are two focusing lenses 10. The two focusing lenses 10 are respectively installed on the light-incident side of the first LBO crystal 4 and the light-incident side of the second LBO crystal 8. The focusing lens 10 is used to focus the laser beam so that the laser beam can pass through the target area of ​​the first LBO crystal 4 and the second LBO crystal 8, thereby improving the conversion efficiency of the laser.

[0030] An optional implementation of this embodiment is as follows: it also includes collimating lenses 11. There are two collimating lenses 11. The two collimating lenses 11 are respectively installed on the light-emitting side of the first LBO crystal 4 and the light-emitting side of the second LBO crystal 8. The collimating lenses 11 are used to re-collimate the laser beams passing through the first LBO crystal 4 and the second LBO crystal 8, so that the laser beams are converted back into parallel beams for subsequent transmission.

[0031] An optional implementation of this embodiment is as follows: it further includes a beam combiner 12 and an output optical fiber 13. The frequency-converted light transmitted through the first reflective mirror 5 and the second reflective mirror 9 is combined by the beam combiner 12, so as to combine multiple laser beams for output. The output optical fiber 13 is connected to the beam combiner 12 to output the combined laser beam.

[0032] An optional implementation of this embodiment is as follows: The laser source 1 includes a narrow linewidth polarization-maintaining laser and a spatial frequency doubling component. The narrow linewidth polarization-maintaining laser is used to output a fundamental frequency light source, providing linearly polarized infrared fundamental frequency light with narrow linewidth and high beam quality for the subsequent spatial green light frequency doubling. The spatial frequency doubling component is used to double the output of the light source.

[0033] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope described in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high efficiency laser characterized by, include: Laser source, first half-wave plate, polarization beam splitter, frequency conversion element, first transflector, second transflector; The laser source is used to emit a laser beam. The laser beam passes sequentially through the first half-wave plate, the polarization beam splitter, and the frequency conversion element. The laser beam converted by the frequency conversion element is transmitted through the first transflector to form a first sub-beam, and the unconverted laser beam is reflected to form a second sub-beam. In the second sub-beam, the laser beam converted by the frequency conversion element passes through the second transflector to form a third sub-beam, and the unconverted laser beam is reflected to form a fourth sub-beam. The laser beams transmitted by the first and second transflectors are combined and output. The reflected fourth sub-beam passes through the polarization beam splitter and is converted again by the frequency conversion element before being emitted in the direction of the first and second transflectors.

2. A high efficiency laser as claimed in claim 1, wherein, The frequency conversion element includes: A first LBO crystal is disposed between the polarization beam splitter and the first transflector.

3. A high efficiency laser as claimed in claim 2, wherein, The frequency conversion element further includes: The second LBO crystal is disposed between the first and second transflectors. The second sub-beam is transmitted through the second LBO crystal and the second transflector to form the third sub-beam, and then reflected to form the fourth sub-beam. The fourth sub-beam is then emitted toward the polarization beam splitter.

4. A high efficiency laser as claimed in claim 3, wherein, Also includes: The second half-wave plate is disposed between the second LBO crystal and the polarization beam splitter so that the laser light passing through the second half-wave plate is reflected or transmitted by the polarization beam splitter.

5. A high efficiency laser as claimed in claim 4, wherein, Also includes: The light-collecting tube is used to collect the sixth sub-beam transmitted through the first mirror and reflected by the first mirror. The fifth sub-beam passes through the second LBO crystal, the second half-wave plate, and the polarizing beam splitter in sequence. The light-collecting tube is installed on the optical path of the fifth sub-beam transmitted through the polarizing beam splitter.

6. The high efficiency laser of claim 1 wherein, Also includes: A third half-wave plate is disposed between the polarization beam splitter and the frequency conversion element to convert the laser emitted towards the frequency conversion element into polarized light that satisfies the second type of phase matching of the frequency conversion element.

7. The high efficiency laser of claim 3 wherein, Also includes: Two focusing lenses are respectively mounted on the light-incident side of the first LBO crystal and the light-incident side of the second LBO crystal.

8. The high efficiency laser of claim 3, wherein, Also includes: Two collimating lenses are respectively installed on the light-emitting side of the first LBO crystal and the light-emitting side of the second LBO crystal.

9. The high efficiency laser of claim 1 wherein, Also includes: The beam combiner combines the frequency-converted light transmitted through the first and second mirrors. An output optical fiber is connected to the combiner to output the combined laser beam.

10. The high efficiency laser of claim 1 wherein, The laser source includes: The narrow-linewidth polarization-maintaining laser and the spatial frequency doubling component are used to output a fundamental frequency light source, providing linearly polarized infrared fundamental frequency light with narrow linewidth and high beam quality for the subsequent spatial green light frequency doubling. The spatial frequency doubling component is used to double the output frequency of the light source.

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