Bulk laser crystal stimulated emission suppression device and laser gain module

Abstract

The utility model discloses a kind of blocky laser crystal stimulated emission suppression device and laser gain module, it includes: blocky laser crystal, the non-light passing surface of the blocky laser crystal is optical polishing surface;Wide-angle high-transmission film is plated on optical polishing surface surface, the wide-angle high-transmission film is set to the spontaneous emission fluorescence generated by the blocky laser crystal has high transmissivity;Absorption component for absorbing spontaneous emission fluorescence transmitted by wide-angle high-transmission film is set outside blocky laser crystal;The utility model is formed by wide-angle high-transmission film and absorption component "dredging-absorption" physical mechanism, actively provides low-loss escape channel for ASE, and eliminates from outside, inhibition effect is far superior to passive reflection, improve ASE inhibition effect.

Description

Technical Field

[0001] This utility model relates to the field of solid-state laser technology, specifically to a device for suppressing stimulated spontaneous emission of a bulk laser crystal and a laser gain module. Background Technology

[0002] In high-power or high-energy solid-state lasers, spontaneous emission is inevitably generated when the laser crystal is pumped to achieve population inversion energy storage. As this spontaneously emitted light propagates within the crystal, if its path satisfies the reflection condition, it will be continuously reflected between the crystal sidewalls and gain gain, forming a severe stimulated spontaneous emission (ASE) state. ASE severely depletes the number of particles in the upper energy level, reduces energy storage efficiency and energy extraction efficiency, leading to a decline in laser output performance and even damage to the crystal.

[0003] In the existing technology, common methods for suppressing ASE include addressing the ASE problem from different dimensions such as system optical path design, crystal structure, fiber material, and dynamic control.

[0004] For example, patent CN120320146A alters the geometry of the laser chip to disrupt the FP resonant cavity structure that forms the ASE (associated laser beam), but this method can only be applied to laser crystals with extremely low energy and cannot be used in the amplification of bulk laser crystals. Patent CN222814086U uses filters to separate and block spontaneous emission fluorescence in the spectrum; patent CN118311708A introduces a selective absorption layer (Sm³⁺) inside the fiber structure to absorb ASE along its propagation path; and patent CN118099907A collects ASE and converts it into continuous laser light, which is then used as a pump source. These methods can only be applied to fiber lasers and cannot be used in the amplification of bulk laser crystals.

[0005] Therefore, there is an urgent need for a new ASE suppression technology that is simple in structure, stable and efficient, suitable for high refractive index bulk laser crystals. Utility Model Content

[0006] Technical objective: To address the shortcomings of existing laser ASE suppression, this utility model discloses a device for suppressing stimulated spontaneous emission of bulk laser crystals and a laser gain module.

[0007] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution: A device for suppressing stimulated spontaneous emission of a bulk laser crystal includes: a bulk laser crystal, wherein the non-light-transmitting surface of the bulk laser crystal is an optically polished surface; a wide-angle high-transmittance film is deposited on the surface of the optically polished surface, wherein the wide-angle high-transmittance film is configured to have high transmittance to the spontaneous emission fluorescence generated by the bulk laser crystal; and an absorption component is disposed outside the bulk laser crystal for absorbing the spontaneous emission fluorescence transmitted by the wide-angle high-transmittance film.

[0008] Preferably, the absorption component of this invention is a fluorescent absorption solution, and the side of the bulk laser crystal is immersed in the fluorescent absorption solution.

[0009] Preferably, the fluorescent absorbing solution of this invention is deionized water, heavy water, or a chemical solution containing fluorescent absorbing components, and the refractive index of the fluorescent absorbing solution matches the refractive index of the wide-angle high-transmittance membrane.

[0010] Preferably, the device of this invention further includes a heat sink containing the fluorescent absorbing solution.

[0011] Preferably, the absorption component of this invention is a solid transparent absorber, and the solid transparent absorber and the wide-angle high-transmittance film of the optically polished surface of the bulk laser crystal are optically bonded together by an optical adhesive layer formed by optical adhesive or refractive index matching liquid.

[0012] Preferably, the solid transparent absorber of this invention is a glass or crystal doped with spontaneously emitting fluorescent absorbing ions.

[0013] Preferably, the outer surface of the wide-angle high-transparency membrane of this invention is also coated with an anti-corrosion film.

[0014] Preferably, the wide-angle high-transmittance film of this invention is configured to have high transmittance for spontaneous emission fluorescence in the incident angle range of 0° to 35°.

[0015] This utility model discloses a laser gain module having the above-described device.

[0016] Beneficial effects: The stimulated spontaneous emission suppression device for bulk laser crystals and the laser gain module disclosed in this utility model have the following beneficial effects: 1. This utility model actively provides a low-loss escape channel for ASE through the physical mechanism of "guidance-absorption" formed by the wide-angle high-transmittance membrane and the absorption component, and eliminates it from the outside, with a suppression effect far superior to passive reflection.

[0017] 2. This utility model ingeniously utilizes the interface of "high-transparency film-low refractive index absorbing medium" to replace the traditional "crystal-low refractive index cladding" interface, perfectly avoiding the problem of finding stable materials with ultra-low refractive index.

[0018] 3. This invention does not depend on a specific laser wavelength or working ion. As long as a high-transmittance film and selective absorber are designed for the target ASE wavelength, it can be applied to various laser systems such as Nd, Yb, Er, and Tm, and has strong adaptability.

[0019] 4. This invention transfers the energy absorption process of ASE from the inside of the crystal to the outside, and can cool and dissipate heat through an external heat sink, which helps to reduce the thermal load of the crystal and improve the thermal performance of the laser. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0021] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0023] Among them, 1. bulk laser crystal; 2. wide-angle high-transparency film; 3. fluorescence absorption solution; 4. heat sink; 5. solid transparent absorber; 6. optical adhesive layer. Detailed Implementation

[0024] Reference will now be made in detail to embodiments of the present disclosure, one or more of which are set forth herein. Each embodiment and example is provided by way of explanation of the apparatus, composition, and materials of the present disclosure, and not by way of limitation. Rather, the following description provides convenient illustrations for implementing exemplary embodiments of the present disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0025] A device for suppressing stimulated spontaneous emission of a bulk laser crystal includes: a bulk laser crystal 1, wherein the non-light-transmitting surface of the bulk laser crystal 1 is an optically polished surface; a wide-angle high-transmittance film 2 is deposited on the surface of the optically polished surface, wherein the wide-angle high-transmittance film 2 is configured to have high transmittance to the spontaneous emission fluorescence generated by the bulk laser crystal 1; and an absorption component is disposed outside the bulk laser crystal 1 for absorbing the spontaneous emission fluorescence transmitted by the wide-angle high-transmittance film 2.

[0026] The bulk laser crystal 1 can be an Nd:YAG, Yb:YAG, Nd:YVO4, or Er:YLF crystal. The wide-angle high-transmittance film 2 is matched with the crystal type to ensure high absorption rate for the corresponding spontaneous emission fluorescence. Preferably, it is a high-transmittance film with high transmittance in the incident angle range of 0 to 35° for spontaneous emission fluorescence wavelength, creating an efficient emission channel for ASE in a wide angle range, so that spontaneous emission fluorescence can be smoothly transmitted out of the crystal.

[0027] The absorbing component of this invention is used to absorb spontaneous emission fluorescence transmitted through a high-transmittance membrane. The absorbing component only needs to possess the ability to absorb spontaneous emission fluorescence; its dielectric form is not limited. Figure 1 and Figure 2 As shown, this utility model provides two embodiments of absorption components in the form of media. In embodiment 1, the absorption component is a fluorescent absorption solution 3, and the side of the bulk laser crystal 1 is immersed in the fluorescent absorption solution 3.

[0028] The fluorescent absorption solution 3 is a deionized water, heavy water, or chemical solution containing fluorescent absorption components, and the refractive index of the fluorescent absorption solution 3 matches the refractive index of the wide-angle high-transmittance membrane 2.

[0029] In Example 2, the absorbing component is a solid transparent absorber 5, which is glass or crystal doped with spontaneous emission fluorescent absorbing ions. The solid transparent absorber 5 and the wide-angle high-transmittance film of the optically polished surface of the bulk laser crystal 1 are optically bonded together by an optical adhesive layer 6 formed by optical adhesive or refractive index matching liquid. Example

[0030] like Figure 1 As shown, the apparatus in this embodiment is designed for a 60mm × 40mm × 10mm Nd:YAG bulk laser crystal 1. First, its sides are precision optically polished to a surface roughness Ra < 1nm, forming an optically polished surface for attaching a wide-angle high-transmittance film 2. Then, an ion beam sputtering technique is used to deposit a wide-angle high-transmittance film 2 for a wavelength of 1064nm on this polished surface. This film has an average transmittance of greater than 99.8% for spontaneous emission fluorescence at an incident angle of 0-35°.

[0031] To prevent the high-transmittance membrane from being corroded by the liquid absorption components, this invention further coats the wide-angle high-transmittance membrane 2 with a silicon dioxide anti-corrosion film. Finally, the processed bulk laser crystal 1 is placed in an embedded heat sink 4, and a fluorescence absorption solution 3 with high absorption of ASE fluorescence is injected into the heat sink 4, completely immersing the crystal sidewalls. The fluorescence absorption solution 3 has strong absorption of 1064nm light, and its refractive index matches the film layer well, enabling it to efficiently receive and absorb 1064nm ASE emitted from the crystal sidewalls, and dissipate heat through the heat sink 4. Example

[0032] like Figure 2 As shown, the difference between this embodiment and Embodiment 1 lies in the absorption component. After the bulk laser crystal 1 is coated with a wide-angle high-transmittance film 2, instead of using a fluorescence absorption solution, a Cr-doped YAG crystal is selected as a solid-state transparent absorber 5, which has strong absorption capability for a wavelength of 1064nm. A layer of refractive index-matching optical adhesive or refractive index-matching liquid is coated on the side surface and the wide-angle surface 2 of the bulk laser crystal 1 to form an optical adhesive layer 6, and then the solid absorber 5 is tightly bonded to it. This solution has a more compact structure, is liquid-free, and is suitable for applications with extremely high sealing requirements.

[0033] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A device for suppressing stimulated spontaneous emission of a bulk laser crystal, characterized in that, include: A bulk laser crystal (1) has an optically polished surface on its non-light-transmitting surface. A wide-angle high-transmittance film (2) is deposited on the surface of the optically polished surface. The wide-angle high-transmittance film (2) is configured to have high transmittance to the spontaneous emission fluorescence generated by the bulk laser crystal (1). An absorption component is provided on the outside of the bulk laser crystal (1) to absorb the spontaneous emission fluorescence transmitted by the wide-angle high-transmittance film (2).

2. The apparatus according to claim 1, characterized in that, The absorption component is a fluorescent absorption solution (3), and the side of the bulk laser crystal (1) is immersed in the fluorescent absorption solution (3).

3. The apparatus according to claim 2, characterized in that, The fluorescent absorption solution (3) is a deionized water, heavy water or chemical solution containing fluorescent absorption components, and the refractive index of the fluorescent absorption solution (3) matches the refractive index of the wide-angle high-transmittance film (2).

4. The apparatus according to claim 2 or 3, characterized in that, The device also includes a heat sink (4) containing the fluorescent absorption solution (3).

5. The apparatus according to claim 1, characterized in that, The absorption component is a solid transparent absorber (5). The solid transparent absorber (5) and the wide-angle high-transmittance film of the optically polished surface of the bulk laser crystal (1) are optically bonded together by an optical adhesive layer (6) formed by optical adhesive or refractive index matching liquid.

6. The apparatus according to claim 5, characterized in that, The solid transparent absorber (5) is a glass or crystal doped with spontaneously emitting fluorescent absorbing ions.

7. The apparatus according to any one of claims 1 to 6, characterized in that, The outer surface of the wide-angle high-transparency membrane (2) is also coated with an anti-corrosion membrane.

8. The apparatus according to claim 1, characterized in that, The wide-angle high-transmittance membrane (2) is configured to have high transmittance for spontaneous emission fluorescence in the incident angle range of 0° to 35°.

9. A laser gain module, characterized in that, The device having any one of claims 1-8.

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