Dual-wavelength laser with adjustable output ratio

Abstract

The utility model relates to the technical field of laser, and discloses a dual-wavelength laser with an adjustable output ratio, which comprises a pumping source, a pumping focusing mirror, a crescent mirror, a laser crystal, a polarizer, a first output mirror, a light polarization direction adjusting component, a second output mirror, a frequency doubling crystal and a total reflective mirror, wherein the first output mirror, the crescent mirror and the total reflective mirror form a resonant cavity; in the resonant cavity, a polarizer and a laser crystal are sequentially arranged between the first output port and the crescent mirror; a light polarization direction adjusting part, a second output mirror and a frequency doubling crystal are sequentially arranged between the crescent mirror and the total reflection mirror; the light polarization direction adjusting component is used for adjusting the polarization direction of the fundamental frequency light; and a pumping focus lens and a pumping source are sequentially arranged on the light incident side of the crescent mirror. Through ingenious structural arrangement, the light polarization direction adjusting component is arranged in the light path, and the output ratio of the fundamental frequency light to the frequency doubling light is controlled by changing the polarization angle of the fundamental frequency light.

Description

Technical Field

[0001] The present invention relates to the technical field of laser equipment, and in particular to a dual-wavelength laser with adjustable output ratio. Background Art

[0002] Existing dual-wavelength lasers typically use frequency doubling outside the resonant cavity. This determines whether to output frequency-doubled laser light by controlling whether the fundamental frequency light passes through the frequency-doubling crystal. This results in low frequency doubling efficiency, significantly reducing the output power of both the frequency-doubled and fundamental frequency light. Furthermore, the output ratio of traditional dual-wavelength lasers is fixed. Once the laser is finalized, the laser output power can only be adjusted by adjusting the power of the pump light source. This causes the output power of both the fundamental and frequency-doubled light to increase or decrease simultaneously. Summary of the Invention

[0003] The main purpose of the present invention is to provide a dual-wavelength laser with adjustable output ratio, aiming to solve the technical problem that the output ratio of the two wavelength lasers cannot be adjusted after the dual-wavelength laser is finalized.

[0004] To achieve the above object, the present invention provides a dual-wavelength laser with adjustable output ratio, characterized in that the dual-wavelength laser with adjustable output ratio comprises: a pump source, a pump focusing mirror, a crescent mirror, a laser crystal, a polarizer, a first output mirror, a light polarization direction adjustment component, a second output mirror, a frequency doubling crystal, and a total reflector;

[0005] The side of the crescent mirror close to the laser crystal is convex, the convex surface is coated with a high-reflection film for fundamental frequency light, and the convex surface reflects light with an incident angle greater than 0°; the first output mirror, the crescent mirror, and the total reflector form a resonant cavity;

[0006] In the resonant cavity, the polarizer and the laser crystal are sequentially arranged between the first output mirror and the crescent mirror, with the polarizer being located on a side close to the first output mirror; the light polarization direction adjustment component, the second output mirror, and the frequency doubling crystal are sequentially arranged between the crescent mirror and the total reflection mirror, with the light polarization direction adjustment component being located on a side close to the crescent mirror, and being used to adjust the polarization direction of the fundamental frequency light;

[0007] The pump focusing mirror and the pump source are sequentially arranged on the light incident side of the crescent mirror.

[0008] Optionally, in one embodiment, the light polarization direction adjusting component includes a half-wave plate and a rotating motor; the half-wave plate is arranged between the crescent mirror and the second output mirror; the moving end of the rotating motor is connected to the half-wave plate, and the rotating motor is used to rotate the half-wave plate to rotate the polarization direction of the fundamental frequency light.

[0009] Optionally, in one embodiment, the adjustable output ratio dual-wavelength laser further includes an acousto-optic Q-switch, and the acousto-optic Q-switch is disposed between the laser crystal and the polarizer to form a continuous laser or a pulsed laser.

[0010] Optionally, in one embodiment, the adjustable output ratio dual-wavelength laser further includes a folding mirror, which is arranged outside the resonant cavity and is used to adjust the direction of the frequency-doubled light reflected by the second output mirror so that the frequency-doubled light is output in a collimated manner.

[0011] Optionally, in one embodiment, the side of the crescent mirror close to the pump focusing mirror has a concave surface, and the curvature radius of the concave surface is 90 mm-110 mm.

[0012] Optionally, in one embodiment, the laser crystal is a Nd:YAG crystal, which is used to generate 1064nm fundamental frequency light;

[0013] And / or, the frequency-doubling crystal is an LBO crystal, which is used to generate 532nm frequency-doubled light.

[0014] Optionally, in one embodiment, the side of the first output mirror facing the crescent mirror is coated with a 1064nm high-reflection film with a reflectivity of 90%.

[0015] Optionally, in one embodiment, a side of the second output mirror close to the light polarization direction adjusting component is coated with a 1064nm anti-reflection film, and a side of the second output mirror close to the frequency doubling crystal is coated with a 532nm high-reflection film and a 1064nm anti-reflection film.

[0016] Optionally, in one embodiment, the crescent mirror is coated with an 808nm pump light anti-reflection film near the pump focusing mirror, and the fundamental frequency light high reflection film is a 1064nm high reflection film.

[0017] In the technical solution provided by the present invention, the polarizer imparts a polarization angle to the fundamental frequency light passing therethrough, causing the fundamental frequency light to become polarized light. Since the frequency doubling crystal has polarization requirements for the fundamental frequency light, the light polarization direction adjustment component provided in the resonant cavity of the present application can adjust the polarization angle of the polarized light, thereby changing the polarization angle of the fundamental frequency light incident on the frequency doubling crystal, thereby changing the proportion of the fundamental frequency light converted by the frequency doubling crystal, thereby achieving adjustment of the output ratio of the frequency doubling light. Through the ingenious arrangement of components, the present application enables, after the laser is formed, the ratio of the output power of the two wavelength lasers output by the laser to be adjusted by controlling the light polarization direction adjustment component, thereby solving the problem that the dual-wavelength output ratio of the dual-wavelength laser cannot be changed after formation, so that the formed dual-wavelength laser can meet the needs of dual wavelengths with a variety of different ratios, and has a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily illustrated by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0019] Figure 1 The figure is a schematic structural diagram of an embodiment of a dual-wavelength laser with adjustable output ratio according to the present invention.

[0020] Others: 1. Pump source; 2. Pump focusing mirror; 3. Crescent mirror; 4. Laser crystal; 5. Polarizer; 6. First output mirror; 7. Light polarization direction adjustment component; 8. Second output mirror; 9. Frequency doubling crystal; 10. Total reflection mirror; 11. Folding mirror; 12. Acousto-optic Q switch. DETAILED DESCRIPTION

[0021] To facilitate understanding of the present invention, the present invention is described in more detail below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly attached to the other element, or one or more elements can be interposed therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element, or one or more elements can be interposed therebetween. The terms "vertical," "horizontal," "left," "right," "inner," "outer," and similar expressions used in this specification are for illustrative purposes only. In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating relative importance or implicitly specifying the number of technical features indicated. Therefore, unless otherwise specified, features specified as "first" or "second" may explicitly or implicitly include one or more of such features; "plurality" means two or more. The term "comprising" and any variations thereof are intended to be non-exclusive, and one or more other features, integers, steps, operations, units, components, and / or combinations thereof may be present or added.

[0022] In addition, unless otherwise expressly specified and limited, 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, an indirect connection through an intermediate medium, or internal communication between two components. All technical and scientific terms used in this specification have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0023] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] In the embodiment of the present application, the wavelengths of the laser output by the adjustable output ratio dual-wavelength laser are 1064 nm and 532 nm respectively, but the invention is not limited to lasers of these two wavelengths.

[0025] Please refer to Figure 1 The present application discloses a dual-wavelength laser with adjustable output ratio, which includes: a pump source 1, a pump focusing mirror 2, a crescent mirror 3, a laser crystal 4, a polarizer 5, a first output mirror 6, a light polarization direction adjustment component 7, a second output mirror 8, a frequency doubling crystal 9 and a total reflector 10.

[0026] The side of the crescent mirror 3 close to the laser crystal 4 is convex, and the convex surface is coated with a high-reflection film for fundamental frequency light. The convex surface reflects light with an incident angle greater than 0°; the first output mirror, the crescent mirror, and the total reflector form a resonant cavity.

[0027] Inside the resonant cavity, a polarizer 5 and a laser crystal 4 are sequentially arranged between the first output mirror 6 and the crescent mirror 3, with the polarizer 5 located on the side closest to the first output mirror 6. A polarization adjustment component 7, a second output mirror 8, and a frequency-doubling crystal 9 are sequentially arranged between the crescent mirror 3 and the total reflection mirror 10, with the polarization adjustment component 7 located on the side closest to the crescent mirror 3 and used to adjust the polarization direction of the fundamental frequency light. A pump focusing mirror 2 and a pump source 1 are sequentially arranged on the light-entering side of the crescent mirror 3.

[0028] The pump light emitted by the pump source 1 is focused by the pump focusing mirror 2 to form a light spot of appropriate size. After the light spot passes through the crescent mirror 3, it is converted by the laser crystal 4 to generate fundamental frequency light. After passing through the polarizer 5, the fundamental frequency light is emitted to the first output mirror 6 in the form of polarized light. After being reflected by the first output mirror 6 and the crescent mirror 3, the fundamental frequency light enters the light polarization direction adjustment component 7, passes through the second output mirror 8 and the frequency doubling crystal 9, and then is emitted to the total reflection mirror 10. After being reflected by the total reflection mirror 10, the fundamental frequency light enters the frequency doubling crystal 9 again. The frequency doubling crystal 9 converts the specific angle polarized light emitted therein into frequency doubling light. The converted frequency doubling light and the unconverted fundamental frequency light are emitted to the second output mirror 8; the fundamental frequency light passes through the second output mirror 8 and is emitted to the crescent mirror 3 and is reflected by the crescent mirror 3 and then emitted to the first output mirror 6 again, while the frequency doubling light is emitted out of the resonant cavity under the reflection of the second output mirror 8.

[0029] In this embodiment, the laser with adjustable output ratio and dual-wavelength output has wavelengths of 1064 nm for the fundamental frequency and 532 nm for the frequency-doubled frequency. Pump source 1 is an LD pump source 1, which outputs 808 nm pump light. Laser crystal 4 is an Nd:YAG crystal, which converts the pump light into 1064 nm fundamental frequency light after injection. Frequency-doubled frequency crystal 9 is an LBO crystal, which converts the 1064 nm fundamental frequency light into 532 nm frequency-doubled frequency light.

[0030] In this embodiment, the side of the meniscus mirror 3 closest to the pump focusing lens 2 has a concave surface. The radius of curvature of this concave surface is set to 90mm-110mm to compensate for the thermal lensing effect caused by the light spot passing through the meniscus mirror 3, thereby enhancing the stability of the laser processing. In this embodiment, the radius of curvature of the concave surface is preferably 100mm, which can better compensate for the thermal lensing effect caused by the light spot passing through the meniscus mirror 3 and enhance the stability of the laser processing. To ensure that the focused light spot can pass through the meniscus mirror 3 smoothly, the concave surface of the meniscus mirror 3 closest to the pump focusing lens 2 is coated with an 808nm anti-reflection coating, while the convex surface of the meniscus mirror 3 is coated with a 1064nm high-reflection coating. Similarly, in order to allow the 1064nm fundamental frequency light to smoothly pass through the second output mirror 8 and enter the LBO crystal, the second output mirror 8 is coated with a 1064nm anti-reflection film on the side close to the light polarization direction adjustment component 7; the second output mirror 8 is coated with a 532nm high-reflection film and a 1064nm anti-reflection film on the side close to the LOB crystal. The 532nm high-reflection film is used to reflect the 532nm laser reflected by the total reflection mirror 10 onto the second output mirror 8, thereby allowing the 532nm laser to be output outside the resonant cavity, and the 1064nm anti-reflection film on the same side allows the 1064nm laser reflected by the total reflection mirror 10 onto the second output mirror 8 to smoothly penetrate the second output mirror 8 and be emitted toward the crescent mirror 3.

[0031] In this embodiment, the 1064nm fundamental frequency light generated by the Nd:YAG crystal conversion pump light is reflected between the first output mirror 6, the crescent mirror 3, and the total reflection mirror. The 1064nm fundamental frequency light continuously oscillates back and forth. Because it continuously encounters excited particles during operation, stimulated radiation is generated. Photons traveling along the axis will continuously multiply, thereby oscillating and amplifying. The 1064nm fundamental frequency light generated by the Nd:YAG crystal conversion is unpolarized light, but the LBO crystal has polarization requirements for the fundamental frequency light. The polarizer 5 converts the 1064nm fundamental frequency light passing through it into polarized light with a polarization angle. That is, the polarizer 5 causes the oscillating light to be output as polarized light. This application provides a light polarization direction adjustment component 7 at the front end of the LBO crystal's optical path to adjust the polarization angle of the polarized light entering the LBO crystal, thereby changing the proportion of the fundamental frequency light available for conversion by the LBO crystal, and thus adjusting the output ratio of the doubled frequency light to the fundamental frequency light.

[0032] In one embodiment, the light polarization direction adjustment component 7 includes a half-wave plate and a rotating motor, wherein the half-wave plate is arranged between the crescent mirror 3 and the second output mirror 8; the moving end of the rotating motor is connected to the mechanical structure of the half-wave plate, and the rotating motor is controlled by a computer control system of a dual-wavelength laser with an adjustable output ratio. Under the control of the computer, the rotating motor can rotate the half-wave plate according to the control parameters of the control system, so that the proportion of the laser light suitable for the polarization requirements of the LOB crystal in the 1064nm laser light after exiting the half-wave plate changes, thereby achieving the effect of adjusting the ratio of the two laser lights of different wavelengths output by the laser.

[0033] In one embodiment, the adjustable output ratio dual-wavelength laser further includes an acousto-optic Q-switch 12, which is disposed between the laser crystal 4 and the polarizer 5. The acousto-optic Q-switch 12 serves as a controlled variable loss element. Through laser Q-switching, the acousto-optic Q-switch 12 can convert continuous laser power output into laser pulse output with high peak power, thereby enabling the adjustable output ratio dual-wavelength laser to selectively output continuous laser or pulsed laser.

[0034] In one embodiment, the adjustable output ratio dual-wavelength laser also includes a folding mirror 11, which is arranged outside the resonant cavity. The folding mirror 11 is located on the light reflection path of the second output mirror 8, and reflects the 532nm laser frequency-doubled light output by the second output mirror 8. The folding mirror 11 adjusts the direction of the frequency-doubled light reflected by the second output mirror 8 so that the frequency-doubled light is collimated and output outside the resonant cavity.

[0035] In this embodiment, the surface of the first output mirror 6 facing the crescent mirror 3 is coated with a 1064nm high-reflection coating with a 90% reflectivity. This 1064nm high-reflection coating allows the first output mirror 6 to both output 1064nm laser light with a consistent propagation direction, frequency, and phase, while also reflecting the 1064nm laser light to oscillate within the resonant cavity. In other embodiments, both sides of the first output mirror 6 may be coated with a 1064nm high-reflection coating with a 90% reflectivity.

[0036] In this embodiment, the second output mirror 8 is coated with a 1064nm anti-reflection film on one side close to the light polarization direction adjustment component 7, and the second output mirror 8 is coated with a 532nm high-reflection film and a 1064nm anti-reflection film on one side close to the frequency doubling crystal 9. The 1064nm anti-reflection films arranged on both sides allow the 1064nm laser to smoothly penetrate the second output mirror 8, and the 532nm high-reflection film on one side allows the generated 532nm laser to be smoothly emitted out of the resonant cavity.

[0037] refer to Figure 1Pump source 1 emits 808nm pump light. The 808nm pump light is focused by pump focusing mirror 2 to form a light spot of appropriate size. The light spot enters the Nd:YAG crystal, which absorbs the 808nm pump light, causing population inversion and stimulated emission, generating 1064nm fundamental frequency light. The generated 1064nm fundamental frequency light oscillates within the resonant cavity formed by the first output mirror 6, the crescent mirror 3, and the total reflection mirror. The 1064nm fundamental frequency light passes through the polarizer 5, which imparts a polarization angle to the 1064nm fundamental frequency light, making it polarized light. After reflection from the first output mirror 6, the polarized 1064nm fundamental frequency light is emitted toward the crescent mirror 3. It is then reflected by the crescent mirror 3 and emitted toward the 1064nm half-wave plate. It then passes through the second output mirror 8 and the LOB crystal, and then toward the total reflection mirror 10. After reflection from the total reflection mirror 10, it is emitted again into the LOB crystal. The LOB crystal absorbs the 1064nm fundamental frequency light that meets the deflection requirements and is injected into it again, causing a population inversion and stimulated emission, generating 532nm frequency-doubled light. The uninverted 1064nm fundamental frequency light and the generated 532nm frequency-doubled light continue along the optical path toward the second output mirror 8. The 532nm frequency-doubled light is emitted to the side of the second output mirror 8 coated with a 532nm high-reflection film. The incident angle between the output plane of the second output mirror 8 and the optical path is greater than 0°, and the 532nm frequency-doubled light is reflected out of the resonant cavity; and the 1064nm fundamental frequency light passes through the second output mirror 8 and the half-wave plate again, and is then reflected by the crescent mirror 3 toward the first output mirror 6. In this way, the 1064nm fundamental frequency light completes a complete oscillation in the resonant cavity.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions described in the above embodiments, or to make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-wavelength laser with adjustable output ratio, characterized in that: The adjustable output ratio dual-wavelength laser comprises: a pump source, a pump focusing mirror, a crescent mirror, a laser crystal, a polarizer, a first output mirror, a light polarization direction adjustment component, a second output mirror, a frequency doubling crystal and a total reflector; The side of the crescent mirror close to the laser crystal is convex, the convex surface is coated with a high-reflection film for fundamental frequency light, and the convex surface reflects light with an incident angle greater than 0°; the first output mirror, the crescent mirror, and the total reflector form a resonant cavity; In the resonant cavity, the polarizer and the laser crystal are sequentially arranged between the first output mirror and the crescent mirror, and the polarizer is located on a side close to the first output mirror; the light polarization direction adjustment component, the second output mirror, and the frequency doubling crystal are sequentially arranged between the crescent mirror and the total reflector, and the light polarization direction adjustment component is located on a side close to the crescent mirror, and is used to adjust the polarization direction of the fundamental frequency light; The pump focusing mirror and the pump source are sequentially arranged on the light incident side of the crescent mirror.

2. The dual-wavelength laser with adjustable output ratio according to claim 1, characterized in that: The light polarization direction adjustment component includes a half-wave plate and a rotating motor; the half-wave plate is arranged between the crescent mirror and the second output mirror; the moving end of the rotating motor is connected to the half-wave plate to rotate the half-wave plate to rotate the polarization direction of the fundamental frequency light.

3. The dual-wavelength laser with adjustable output ratio according to claim 1, characterized in that: The adjustable output ratio dual-wavelength laser further includes an acousto-optic Q-switch, which is arranged between the laser crystal and the polarizer to form a continuous laser or a pulsed laser.

4. The dual-wavelength laser with adjustable output ratio according to claim 1, characterized in that: The adjustable output ratio dual-wavelength laser further includes a folding mirror, which is arranged outside the resonant cavity and is used to adjust the direction of the frequency-doubled light reflected by the second output mirror so that the frequency-doubled light is output in a collimated manner.

5. The dual-wavelength laser with adjustable output ratio according to claim 1, characterized in that: The side of the crescent mirror close to the pump focusing mirror has a concave surface, and the curvature radius of the concave surface is 90mm-110mm.

6. The dual-wavelength laser with adjustable output ratio according to claim 1, characterized in that: The laser crystal is a Nd:YAG crystal, which is used to generate 1064nm fundamental frequency light; And / or, the frequency-doubling crystal is an LBO crystal, which is used to generate 532nm frequency-doubled light.

7. The dual-wavelength laser with adjustable output ratio according to claim 1, characterized in that: The side of the first output mirror facing the crescent mirror is coated with a 1064nm high reflection film with a reflectivity of 90%.

8. The dual-wavelength laser with adjustable output ratio according to claim 1, characterized in that: The side of the second output mirror close to the light polarization direction adjusting component is coated with a 1064nm anti-reflection film, and the side of the second output mirror close to the frequency doubling crystal is coated with a 532nm high-reflection film and a 1064nm anti-reflection film.

9. The dual-wavelength laser with adjustable output ratio according to claim 1, characterized in that: The crescent mirror is coated with an 808nm pump light anti-reflection film near the pump focusing mirror, and the fundamental frequency light high reflection film is a 1064nm high reflection film.

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