Chromium-doped gain medium solid laser based on thulium solid laser pumping

Abstract

The utility model provides a chromium-doped gain medium solid laser based on thulium solid laser pumping. Comprising a pumping source, a pumping light coupling device, a first laser lens, a thulium-doped laser gain medium, a first laser coupling output lens, a light coupling device, a second laser lens, a chromium-doped laser gain medium and a second laser coupling output lens which are arranged in sequence, the thulium-doped laser gain medium is a thulium-doped solid gain medium; the chromium-doped laser gain medium is a chromium-doped solid gain medium; a first oscillation cavity of laser is constructed between the first laser lens and the first laser coupling output lens; and a second oscillation cavity of the laser is constructed between the second laser lens and the second laser coupling output lens, and is used for wavelength selection to realize the output of the laser at the wave band of 1.9-3 microns. According to the utility model, the thulium-doped solid laser is used as a pumping source for pumping the chromium-doped crystal, so that the problem that the chromium-doped crystal is low in pumping efficiency and output power under other pumping sources such as an optical fiber laser is solved.

Description

Technical Field

[0001] This invention belongs to the field of solid-state laser technology, and particularly relates to a chromium-doped gain medium solid-state laser pumped by a thulium solid-state laser. Background Technology

[0002] Cr²⁺:ZnSe lasers are ideal light sources for gas detection, remote sensing, and optical communication. Because Cr²⁺ ions have a broad absorption spectrum (1.5–2.1 μm), there are various pump sources to choose from, with the pump wavelength typically around 2 μm for Cr²⁺:ZnSe. The absorption peak of Cr²⁺ ions is near 1.75 μm, but currently, very few lasers can provide effective pumping in this band. Therefore, the selection of the pump source is crucial for obtaining high-power laser output in Cr²⁺:ZnSe and Cr²⁺:ZnS lasers.

[0003] Currently, there are three main types of pump sources for Cr2+:ZnSe: diode lasers (LDs), thulium-doped fiber lasers, and holmium-doped or thulium-doped all-solid-state lasers. Diode lasers, using InGaAsP or similar gain media, are located in the 1.6–1.9 μm range, which can improve electro-optical conversion efficiency and effectively reduce costs. However, the output brightness of these semiconductor lasers is relatively poor, and chromium-doped lasers directly pumped by LDs generally have low output power. Thulium-doped fiber lasers, by adding a wavelength selector, can control the output wavelength of the laser to a wavelength near the Cr2+ ion absorption peak, such as 1.83 μm, which can greatly improve the optical-optical conversion efficiency. However, wavelength selectors for thulium-doped fiber lasers are relatively expensive, making them difficult to popularize in industry. In addition, there are some less commonly used pumping options, such as 1.75–2.1 μm tunable Co2+:MgF2 lasers and 1.5–2 μm optical parametric lasers. However, these lasers are expensive and easily damaged when used as pumps. The selection of the pump source must fully consider factors such as quantum defect and absorption coefficient. If the quantum defect is large, heat will accumulate inside the Cr2+:ZnSe crystal, and the enhanced thermal effect will reduce the laser operating efficiency. Utility Model Content

[0004] The technical objective of this invention is to provide a chromium-doped gain medium solid-state laser based on a thulium solid-state laser pump. By using a thulium-doped solid-state laser as a pump source to pump a chromium-doped crystal, high power output of the chromium-doped laser can be achieved by improving the optical-to-optical conversion efficiency.

[0005] To solve the above-mentioned technical problems, this utility model is implemented as follows: a chromium-doped gain medium solid-state laser based on a thulium solid-state laser pump, comprising, in sequence, a pump source, a pump optical coupling device, a first laser mirror, a thulium-doped laser gain medium, a first laser coupling output mirror, an optical coupling device, a second laser mirror, a chromium-doped laser gain medium, and a second laser coupling output mirror; wherein, the thulium-doped laser gain medium is a thulium-doped solid-state gain medium; the chromium-doped laser gain medium is a chromium-doped solid-state gain medium with laser gain characteristics; a first laser oscillation cavity is constructed between the first laser mirror and the first laser coupling output mirror; a second laser oscillation cavity is constructed between the second laser mirror and the second laser coupling output mirror, used to perform wavelength selection on the laser generated by the chromium-doped laser gain medium, outputting a 2.4-micron wavelength laser.

[0006] Furthermore, the thulium-doped laser gain medium is any one of thulium-doped glass, thulium-doped crystal, or thulium-doped laser ceramic.

[0007] Furthermore, the first laser lens and the first laser coupling output lens constitute a stable cavity, the cavity type of which is any one of flat-flat, flat-concave, or concave-flat cavity.

[0008] Furthermore, the second oscillation cavity is any one of an FP cavity, a folded cavity, or a ring cavity.

[0009] Furthermore, the first laser lens is used to reflect laser light provided by the pump source and laser light emitted by the thulium-doped laser gain medium with a reflectivity greater than 99.5%.

[0010] The first laser coupling output lens is used to transmit the laser emitted by the thulium-doped laser gain medium, and its transmittance in the wavelength band above 1900nm is greater than 90%.

[0011] Furthermore, the second laser lens is used for reflecting laser light emitted through the thulium-doped laser gain medium, and the reflectivity of the laser light emitted by the chromium-doped laser gain medium is greater than 99.5%.

[0012] Furthermore, the second laser coupling output lens, used to transmit the laser emitted through the chromium-doped laser gain medium, has a transmittance of no more than 50%.

[0013] Furthermore, it is used to achieve laser output in the 1.9–3 μm band.

[0014] Furthermore, it also includes a first reflecting mirror and a second reflecting mirror located between the optical path of the chromium-doped laser gain medium and the second laser coupling output mirror. The first reflecting mirror is used to reflect the laser output by the chromium-doped laser gain medium, and the second reflecting mirror is used to receive the laser reflected by the first reflecting mirror and reflect it to the second laser coupling output mirror. The reflectivity of the first reflecting mirror and the second reflecting mirror to the laser emitted by the chromium-doped laser gain medium is greater than 99.5%.

[0015] Furthermore, it also includes a first reflecting mirror and a second reflecting mirror located between the optical path of the chromium-doped laser gain medium and the second laser coupling output mirror. The first reflecting mirror is used to reflect the laser output by the chromium-doped laser gain medium, and the second reflecting mirror is used to receive the laser reflected by the first reflecting mirror and reflect it to the second laser coupling output mirror. The second laser mirror is used to reflect the laser emitted by the chromium-doped laser gain medium to the second laser coupling output mirror. The reflectivity of the first reflecting mirror and the second reflecting mirror to the laser emitted by the chromium-doped laser gain medium is greater than 99.5%.

[0016] Compared with existing technologies, the chromium-doped gain medium solid-state laser based on thulium solid-state laser pumping in this invention has the following advantages:

[0017] A pump source is used to provide laser light of a wavelength that can be absorbed by the thulium-doped laser gain medium. A pump optical coupling device is used to focus the laser light provided by the pump source into the thulium-doped laser gain medium, and to couple and focus the laser light emitted from the thulium-doped laser gain medium into the chromium-doped laser gain medium. The thulium-doped laser gain medium is a thulium-doped solid-state gain medium; the chromium-doped laser gain medium is a chromium-doped solid-state gain medium with laser gain characteristics. A first oscillation cavity for the laser is constructed between a first laser mirror and a first laser coupling output mirror. A second oscillation cavity for the laser is constructed between a second laser mirror and a second laser coupling output mirror, used to perform wavelength selection on the laser light generated by the chromium-doped laser gain medium, outputting a 2.4-micron wavelength laser. This invention, by using a thulium-doped solid-state laser as a pump source to pump a chromium-doped crystal, achieves a pump absorption efficiency of 80% and an output power of 1W, solving the problem of low pump efficiency and output power of chromium-doped crystals under other pump sources such as fiber lasers. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the first structural layout of a chromium-doped gain medium solid-state laser pumped by a thulium solid-state laser in this embodiment of the present invention.

[0019] Figure 2This is a schematic diagram of the second structural layout of a chromium-doped gain medium solid-state laser pumped by a thulium solid-state laser in this embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the third structural layout of a chromium-doped gain medium solid-state laser pumped by a thulium solid-state laser in this embodiment of the present invention. Detailed Implementation

[0021] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0022] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "circumferential", "radial", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this utility model.

[0023] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] Combination Figure 1This invention provides a chromium-doped gain medium solid-state laser pumped by a thulium solid-state laser, comprising, in sequence, a pump source 1, a pump optical coupling device 2, a first laser mirror 3, a thulium-doped laser gain medium 4, a first laser coupling output mirror 5, an optical coupling device 6, a second laser mirror 7, a chromium-doped laser gain medium 8, and a second laser coupling output mirror 9; wherein, the thulium-doped laser gain medium 4 is a thulium-doped solid-state gain medium; the chromium-doped laser gain medium 8 is a chromium-doped solid-state gain medium with laser gain characteristics; a first oscillation cavity for the laser is constructed between the first laser mirror 3 and the first laser coupling output mirror 5; a second oscillation cavity for the laser is constructed between the second laser mirror 7 and the second laser coupling output mirror 9, used to perform wavelength selection on the laser generated by the chromium-doped laser gain medium 8 to achieve laser output in the 1.9–3 μm band, such as outputting a 2.4 μm wavelength laser.

[0025] In this scheme, pump source 1 is used to provide laser light of a wavelength that can be absorbed by thulium-doped laser gain medium 4; pump optical coupling device 2 is used to focus the laser light provided by pump source 1 into thulium-doped laser gain medium 4; optical coupling device 6 is used to couple and focus the laser light emitted from thulium-doped laser gain medium 4 into chromium-doped laser gain medium 8. Thulium-doped laser gain medium 4 is a thulium-doped solid gain medium; chromium-doped laser gain medium 8 is a chromium-doped solid gain medium with laser gain characteristics; a first laser oscillation cavity is constructed between the first laser lens 3 and the first laser coupling output lens 5; a second laser oscillation cavity is constructed between the second laser lens 7 and the second laser coupling output lens 9, used to perform wavelength selection on the laser light generated by chromium-doped laser gain medium 8, outputting a 2.4-micron wavelength laser light. This invention uses a thulium-doped solid-state laser as the pump source 1 to pump a chromium-doped crystal, achieving a pump efficiency of up to 80% absorption efficiency and an output power of up to 1W. This solves the problem of low pump efficiency and output power of chromium-doped crystals in other pump sources such as fiber lasers.

[0026] Furthermore, the thulium-doped laser gain medium 4 can be any one of thulium-doped glass, thulium-doped crystal, or thulium-doped laser ceramic.

[0027] Furthermore, the first laser lens 3 and the first laser coupling output lens 5 form a stable cavity, with the cavity shape being any one of the following: flat-flat, flat-concave, or concave-flat. Specifically, the first laser lens 3 is used to transmit the laser provided by the pump source 1 with high transmittance and to reflect the laser emitted by the thulium-doped laser gain medium 4 with high reflectivity; its transmittance for the laser provided by the pump source is greater than 90%, and its reflectivity for the laser emitted by the thulium-doped laser gain medium 4 is greater than 99.5%. The first laser coupling output lens 5 is used to transmit the laser emitted by the thulium-doped laser gain medium 4 with high transmittance; its transmittance for wavelengths above 1900nm is greater than 90%. The first laser lens 3 and the first laser coupling output lens 5 form a first oscillation cavity, which can provide positive feedback for laser oscillation, allowing for wavelength selection of the generated laser and outputting a mid-infrared laser.

[0028] Furthermore, the second oscillation cavity can be any one of an FP cavity, a folded cavity, or a ring cavity.

[0029] Furthermore, the second laser lens 7 is used to transmit laser light emitted through the thulium-doped laser gain medium 4 and reflect laser light emitted through the chromium-doped laser gain medium 8 with a reflectivity greater than 99.5%; the second laser coupling output lens 9 is used to transmit laser light emitted through the chromium-doped laser gain medium 8 with a transmittance of no more than 50%. The chromium-doped laser gain medium 8 is a chromium-doped solid gain medium with laser gain characteristics. The second laser lens 7 and the second laser coupling output lens 9 form a second oscillation cavity, which is used to select the wavelength of the laser light generated by the chromium-doped laser gain medium 8 and output laser light with a wavelength of 2.4 micrometers.

[0030] Combination Figure 2 In one embodiment, the second oscillation cavity is a folded cavity. The chromium-doped gain medium solid-state laser pumped by the thulium solid-state laser also includes a first reflecting mirror 10 and a second reflecting mirror 11 located between the optical paths of the chromium-doped laser gain medium 8 and the second laser coupling output lens 9. The first reflecting mirror 10 is used to reflect the laser output from the chromium-doped laser gain medium 8, and the second reflecting mirror 11 is used to receive the laser reflected by the first reflecting mirror 10 and reflect it to the second laser coupling output lens 9. The reflectivity of the first reflecting mirror 10 and the second reflecting mirror 11 to the laser emitted by the chromium-doped laser gain medium 8 is greater than 99.5%. Specifically, in this embodiment, the pump source 1, pump optical coupling device 2, first laser lens 3, thulium-doped laser gain medium 4, first laser coupling output lens 5, optical coupling device 6, second laser lens 7, chromium-doped laser gain medium 8, and first reflector 10 are arranged in a straight line. The angle between the first reflector 10 and the straight line is 30 to 75°, preferably 45°. The second reflector 11 and the second laser coupling output lens 9 are arranged in a straight line and parallel to the arrangement direction from the pump source 1 to the first reflector 10.

[0031] In this folded resonant cavity, the second laser lens 7, the first reflector 10, the second reflector 11, and the second laser coupling output lens 9 together form the lens group. The pump light emitted from the pump source 1 passes through the pump coupling device, is collimated and focused by the pump coupling device, and then acts on the thulium-doped solid laser gain medium through the first laser lens 3. Under the action of the focused pump light, the thulium-doped solid laser gain medium undergoes population inversion, thereby generating laser light. The generated laser light is oscillated and reflected by the first laser lens 3 and the first laser coupling output lens 5, and then output by the first laser coupling output lens 5 as pump light. It is coupled and focused by the optical coupling device 6 and acts on the chromium-doped solid gain medium through the second laser lens 7. In this folded cavity, the second laser lens 7, the second laser coupling output lens 9, and the second reflector 11 can allow the high transmittance of the laser light provided by the thulium-doped laser gain medium 4 to pass through, and can reflect the high reflectance of the laser light emitted by the chromium-doped laser gain medium 8. The second laser coupling output lens 9 has a certain transmittance for the laser light emitted by the chromium-doped laser gain medium 8. The folded cavity can introduce a grating element to replace lens 10 or lens 11, serving as a wavelength tuning element.

[0032] Combination Figure 3 In one embodiment, the second oscillation cavity is a ring cavity. The chromium-doped gain medium solid-state laser pumped by the thulium solid-state laser further includes a first reflecting mirror 10 and a second reflecting mirror 11 located between the optical paths of the chromium-doped laser gain medium 8 and the second laser coupling output mirror 9. The first reflecting mirror 10 is used to reflect the laser output from the chromium-doped laser gain medium 8, and the second reflecting mirror 11 is used to receive the laser reflected by the first reflecting mirror 10 and reflect it to the second laser coupling output mirror 9. The second laser mirror 7 is used to reflect the laser emitted by the chromium-doped laser gain medium 8 to the second laser coupling output mirror 9. The reflectivity of the first reflecting mirror 10 and the second reflecting mirror 11 to the laser emitted by the chromium-doped laser gain medium 8 is greater than 99.5%. Specifically, in this embodiment, the pump source 1, pump optical coupling device 2, first laser lens 3, thulium-doped laser gain medium 4, first laser coupling output lens 5, optical coupling device 6, second laser lens 7, chromium-doped laser gain medium 8, and first reflector 10 are arranged in a straight line. The angle between the second laser lens 7 and the straight line is 30-75°, preferably 45°. The angle between the first reflector 10 and the straight line is 30-75°, preferably 45°. The second reflector 11 and the second laser coupling output lens 9 are arranged along a straight line and parallel to the arrangement direction from the pump source 1 to the first reflector 10. The second laser coupling output lens 9 is tilted so that it can receive the light reflected by the second laser lens 7.

[0033] The second laser lens 7, the first reflector 10, the second reflector 11, and the second laser coupling output lens 9 together constitute the lens group of the ring resonant cavity. The pump light emitted from the pump source 1 passes through the pump coupling device, is collimated and focused by the pump coupling device, and then acts on the thulium-doped solid laser gain medium through the first laser lens 3. Under the action of the focused pump light, the thulium-doped solid laser gain medium undergoes population inversion, thereby generating laser light. The generated laser light is oscillated and reflected by the first laser lens 3 and the first laser coupling output lens 5, and then output by the first laser coupling output lens 5 as pump light. It is coupled and focused by the optical coupling device 6 and acts on the chromium-doped solid gain medium through the second laser lens 7. In this folded cavity, the second laser lens 7, the second laser coupling output lens 9, and the second reflector 11 can allow the high transmittance of the laser light provided by the thulium-doped laser gain medium 4 to pass through, and can reflect the high reflectance of the laser light emitted by the chromium-doped laser gain medium 8. The second laser coupling output lens 9 has a certain transmittance for the laser light emitted by the chromium-doped laser gain medium 8. Such folded cavities can generate traveling wave oscillations of laser light, enabling narrow linewidth laser output.

[0034] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A chromium-doped gain-medium solid-state laser pumped by a thulium solid-state laser, characterized in that, The system includes, in sequence, a pump source, a pump optical coupling device, a first laser mirror, a thulium-doped laser gain medium, a first laser coupling output mirror, an optical coupling device, a second laser mirror, a chromium-doped laser gain medium, and a second laser coupling output mirror; wherein, the thulium-doped laser gain medium is a thulium-doped solid-state gain medium; the chromium-doped laser gain medium is a chromium-doped solid-state gain medium with laser gain characteristics; a first laser oscillation cavity is constructed between the first laser mirror and the first laser coupling output mirror; a second laser oscillation cavity is constructed between the second laser mirror and the second laser coupling output mirror, used to perform wavelength selection on the laser generated by the chromium-doped laser gain medium, outputting a 2.4-micron wavelength laser.

2. The chromium-doped gain dielectric solid-state laser based on thulium solid-state laser pumping according to claim 1, characterized in that, The first laser lens and the first laser coupling output lens form a stable cavity, and the cavity shape is any one of the following: flat-flat, flat-concave, or concave-flat cavity.

3. The chromium-doped gain dielectric solid-state laser based on thulium solid-state laser pumping according to claim 1, characterized in that, The second oscillation cavity is any one of an FP cavity, a folded cavity, or a ring cavity.

4. The chromium-doped gain-medium solid-state laser based on thulium solid-state laser pumping according to claim 1, characterized in that, The first laser lens is used to reflect the laser provided by the pump source and the laser emitted by the thulium-doped laser gain medium, wherein the reflectivity of the first laser lens for the laser emitted by the thulium-doped laser gain medium is greater than 99.5%. The first laser coupling output lens is used to transmit the laser emitted by the thulium-doped laser gain medium, and its transmittance in the wavelength band above 1900nm is greater than 90%.

5. The chromium-doped gain dielectric solid-state laser based on thulium solid-state laser pumping according to claim 1, characterized in that, The second laser lens is used to transmit laser light emitted through the thulium-doped laser gain medium and to reflect laser light emitted through the chromium-doped laser gain medium, and has a reflectivity greater than 99.5%.

6. The chromium-doped gain-medium solid-state laser based on thulium solid-state laser pumping according to claim 1, characterized in that, The second laser coupling output lens is used to transmit the laser emitted through the chromium-doped laser gain medium, and its transmittance is not greater than 50%.

7. The chromium-doped gain dielectric solid-state laser based on thulium solid-state laser pumping according to claim 1, characterized in that, Used to achieve laser output in the 1.9~3μm band.

8. The chromium-doped gain dielectric solid-state laser based on a thulium solid-state laser pump according to any one of claims 1-7, characterized in that, It also includes a first reflecting mirror and a second reflecting mirror located between the optical path of the chromium-doped laser gain medium and the second laser coupling output mirror. The first reflecting mirror is used to reflect the laser output by the chromium-doped laser gain medium, and the second reflecting mirror is used to receive the laser reflected by the first reflecting mirror and reflect it to the second laser coupling output mirror. The reflectivity of the first reflecting mirror and the second reflecting mirror to the laser emitted by the chromium-doped laser gain medium is greater than 99.5%.

9. The chromium-doped gain dielectric solid-state laser based on a thulium solid-state laser pump according to any one of claims 1-7, characterized in that, It also includes a first reflecting mirror and a second reflecting mirror located between the optical path of the chromium-doped laser gain medium and the second laser coupling output mirror. The first reflecting mirror is used to reflect the laser output by the chromium-doped laser gain medium, and the second reflecting mirror is used to receive the laser reflected by the first reflecting mirror and reflect it to the second laser coupling output mirror. The second laser mirror is used to reflect the laser emitted by the chromium-doped laser gain medium to the second laser coupling output mirror. The reflectivity of the first reflecting mirror and the second reflecting mirror to the laser emitted by the chromium-doped laser gain medium is greater than 99.5%.

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