Solid state laser concave slab pumping structure

Abstract

The application discloses a concave slab-pumped structure of a solid laser, and belongs to the technical field of solid lasers.A slab-shaped gain medium is provided with an inner concave shape and two sides provided with light splitting prisms, the inner concave surface is used as a pumping surface, light emitted by a pumping source is reflected by the light splitting prisms, enters the inside of the gain medium from the pumping surface and is reflected for multiple times, a long light absorption path is achieved, pumping light is fully absorbed, and pumping efficiency and laser output power are improved.The pumping surface is a plane or a cylindrical surface, the pumping source is a single laser diode or a laser diode array, and an anti-reflection film with high transmittance for the pumping wavelength is coated on the pumping surface to reduce reflection loss.The light splitting prisms are coated with an anti-reflection film with high reflectivity for the pumping light to ensure that as much pumping light as possible enters the gain medium.The gain medium is closely combined with a heat sink to effectively dissipate heat.The application has the advantages of improved pumping efficiency and compact structure by optimizing the slab shape and cooperating with the light splitting prisms.

Description

Technical Field

[0001] This invention belongs to the field of solid-state laser technology, and specifically relates to a concave strip pumping structure for a solid-state laser. Background Technology

[0002] Solid-state lasers are widely used in industry, medicine, and scientific research due to their high power, high efficiency, and high stability. Traditional slab-type solid-state lasers typically employ planar or convex gain media, and currently, the main pumping methods are: surface pumping, side pumping, and end pumping. Surface pumping and side pumping laser structures suffer from problems such as short pump light absorption path length and low pumping efficiency. End pumping improves upon the low pumping efficiency issue, but its coupling structure is complex and requires sophisticated coating.

[0003] like Figure 1 As shown, the chamfered pumped slab laser consists of pump light G9, pump light H10, pump light I11, pump light J12, and laser gain medium 109. Pump light G9, pump light H10, pump light I11, and pump light J12 are incident on the gain medium through the pump surface formed by the chamfered edges, which improves the pumping efficiency. However, its pumping structure is more complex and does not take advantage of laser miniaturization design.

[0004] In traditional pumping methods, during the coupling of pump light into the laser gain medium, as is known in laser theory, some pump light that is not converted into laser light is converted into heat. This heat affects the laser's operation and limits further performance improvements. When the laser generates heat, thermal stress is generated in the gain medium. If the thermal stress is too high, it can damage the gain medium, preventing the laser from functioning properly and thus limiting its power level. Improved edge-beveled pumping methods increase pump efficiency and reduce the impact of thermal stress, but the structure is more complex. To improve pump efficiency and laser output stability, and to improve the pump structure for more compact laser design, a novel gain medium structure design is needed. Summary of the Invention

[0005] The present invention aims to solve the problems of thermal stress and beam quality degradation caused by slab lasers at high power output in the prior art, and can achieve normal incident pump light, with simple pumping method, compact laser structure, and easy miniaturization, thereby providing a concave slab pumping structure for solid-state lasers.

[0006] The technical solution adopted in this invention is:

[0007] The solid laser concave slab pumping structure comprises a slab gain medium, at least one side of the slab gain medium is in a concave shape, and the concave surface is used as a pumping surface, so that the light emitted by the pumping source can enter the interior of the slab gain medium and be fully absorbed after multiple reflections.

[0008] The solid laser system comprises a beam splitter prism A, a beam splitter prism B, a pumping light A, a pumping light B, a cavity mirror A, a cavity mirror B and the solid laser concave slab pumping structure.

[0009] The beam splitter prism A and the beam splitter prism B are respectively arranged at the pumping surface of the slab gain medium, the pumping light A and the pumping light B are respectively reflected by the beam splitter prism A and the beam splitter prism B and are incident from the pumping surface of the slab gain medium, and the cavity mirror A and the cavity mirror B are arranged at two ends of the slab gain medium and are used for forming a resonant cavity.

[0010] Compared with the prior art, the present application has the following beneficial effects:

[0011] The slab gain medium of the present application is designed to have a concave shape and is provided with the beam splitter prisms on two sides, the concave surface is used as a pumping surface, the light emitted by the pumping source is reflected by the beam splitter prisms and enters the interior of the gain medium from the pumping surface and is reflected multiple times, has a long light absorption path, the pumping light is fully absorbed, the pumping efficiency and the laser output power are improved.

[0012] The pumping surface of the gain medium can be a flat surface or a cylindrical surface, the pumping source can be a single laser diode or a laser diode array, the antireflection film with high transmittance to the pumping wavelength is coated on the pumping surface to reduce the reflection loss, the antireflection film with high reflectivity to the pumping light is coated on the surface of the beam splitter prism to ensure that as much pumping light as possible enters the gain medium, and the gain medium is closely combined with the heat sink to effectively dissipate heat.

[0013] The laser pumping surface in the present application is large, has good power scalability, the pumping surface and the cooling surface are separated, the system structure is simplified, the pumping light can be normally incident to the pumping surface, the pumping method is simple, the laser structure is compact, and the laser is small in size and can be used for satellites or spaceships and other vehicles with high load and space restrictions. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of a slab laser in an existing edge chamfer pumping form;

[0015] Figure 2 is a schematic diagram of a solid laser system structure of the present application;

[0016] Figure 3is a cross-sectional view of the slab gain medium of the present application;

[0017] Figure 4 is a schematic diagram of the concave pumping surface of the present application in various different shapes;

[0018] Figure 5 is a schematic diagram of the slab structure of the present application with a single-sided concave structure;

[0019] Figure 6 is a schematic diagram of the same-side two pumping surfaces of the present application with different included angles and areas;

[0020] Figure 7 is a structure diagram of the light splitting prism of the present application;

[0021] wherein: 1, slab gain medium; 2, light splitting prism A; 3, light splitting prism B; 4, pumping light A; 5, pumping light B; 7, cavity mirror A; 8, cavity mirror B; 9, pumping light G; 10, pumping light H; 11, pumping light I; 12, pumping light J; 15, emitted pumping light C; 16, collimator A; 17, laser diode A; 18, pumping light D; 20, pumping light E; 21, laser diode B; 22, collimator B; 23, pumping light F; 109, laser gain medium. DETAILED DESCRIPTION

[0022] In order to better understand the purpose, structure and function of the present application, the present application will be further described in detail below in conjunction with the drawings.

[0023] As shown in Figure 2 , Figure 3 , the present application provides a solid laser concave slab pumping structure, which comprises a slab gain medium 1, at least one side of the slab gain medium 1 is concave, and the concave surface serves as a pumping surface, so that the light emitted by the pumping source can enter the interior of the slab gain medium 1 and be fully absorbed after multiple reflections inside.

[0024] As shown in Figure 4 , the pumping surface is planar or cylindrical in shape to adapt to different pumping requirements and optical design. Figure 4 a is a planar, Figure 4 b is a cylindrical.

[0025] As shown in Figure 3 , the slab gain medium 1 is of a two-sided concave structure.

[0026] As shown in Figure 5 , the slab gain medium 1 is of a single-sided concave structure.

[0027] The pumping surface is coated with an anti-reflection film with high transmittance for the pumping wavelength to reduce the reflection loss of the pumping light and improve the pumping efficiency.

[0028] The slab gain medium 1 is a laser crystal medium to adapt to different laser output wavelengths and power requirements.

[0029] As shown in Figure 2 The solid laser system provided by the present application comprises a beam splitter prism A2, a beam splitter prism B3, a pump light A4, a pump light B5, a cavity mirror A7, a cavity mirror B8 and the solid laser concave slab pumping structure according to any one of claims 1-4.

[0030] The beam splitter prism A2 and the beam splitter prism B3 are respectively arranged at the pumping surface of the slab gain medium 1, the pump light A4 and the pump light B5 are respectively reflected by the beam splitter prism A2 and the beam splitter prism B3 and are incident from the pumping surface of the slab gain medium 1. Since the incident angle and the surface of the slab gain medium 1 are both at an angle, the pump light can be reflected multiple times inside the slab gain medium 1, so that the pump light is fully absorbed by the slab gain medium 1. This multiple absorption mechanism not only significantly improves the pumping efficiency, but also ensures the uniform distribution of the pump light inside the gain medium.

[0031] The slab gain medium 1 is provided with the cavity mirror A7 and the cavity mirror B8 at both ends to form a resonant cavity.

[0032] The laser oscillates in the resonant cavity defined by the cavity mirror A7 and the cavity mirror B8, and is amplified by the slab gain medium 1 in the process. Finally, the laser energy is output through the cavity mirror B8 coated with a partial reflection film. Specifically, the surface of the cavity mirror A7 is coated with a full reflection film to ensure full internal reflection of the laser wavelength, while the cavity mirror B8 is designed with a partial reflection film to allow part of the laser energy to pass through and be output.

[0033] The laser resonant cavity can be selected as a stable cavity or a non-stable cavity structure according to actual requirements to meet the requirements of different application scenarios.

[0034] The slab gain medium 1 can also be in contact with a heat sink. Through the integrated cooling system, the system can effectively manage and dissipate the generated heat, so as to ensure that the laser can output higher power and better beam quality.

[0035] The pump source of the pump light A4 and the pump light B5 can be a single laser diode to incident the pump light into the slab gain medium 1, or a coupling array structure composed of multiple laser diodes to incident the pump light into the slab gain medium 1.

[0036] The main optical axis of the pump source is perpendicular to the pumping surface of the slab gain medium 1 to ensure that as many pump light rays as possible can be incident into the slab gain medium 1.

[0037] The surface of the light splitting prism A2 and the light splitting prism B3 is coated with a high reflectivity film for pump light, which ensures that as much pump light as possible enters the slab gain medium 1.

[0038] The slab gain medium 1 is tightly combined with a heat sink to effectively dissipate heat, reduce thermal effects, and improve the stability and service life of the laser.

[0039] The mounting precision of the cavity mirrors A7 and B8 directly affects the quality of the laser output, ensuring accurate alignment between the cavity mirrors A7 and B8 and the slab gain medium 1.

[0040] The slab gain medium 1 has a cross-sectional structure as shown in Figure 3 Specifically, the slab gain medium 1 is characterized in that its concave surface is used as a pump surface to receive pump light C15, D18, E20, and F23 emitted by the laser diodes A17 and B21. Pump light C15 and D18 pass through collimation by collimator A16 and reflection by light splitting prism B3, while pump light E20 and F23 pass through collimation by collimator B22 and reflection by light splitting prism A2. Pump light C15, D18, E20, and F23 are incident into the slab gain medium 1 through the pump surface and undergo multiple total reflections on the medium surface, thereby being effectively confined within the slab gain medium 1 and achieving multiple absorption processes.

[0041] The pump surface of the laser in the present application can be designed as a plane or a cylindrical surface, as shown in Figure 4 Figure 4 (a) shows a design in which the pump surface is a plane, and pump light C15 and D18 emitted by laser diode A17 pass through collimation by collimator A16 and reflection by light splitting prism B3, and enter the slab gain medium 1 through the planar pump surface.

[0042] Figure 4 (b) shows a design in which the pump surface is a cylindrical surface, and pump light C15 and D18 emitted by laser diode A17 pass through collimation by collimator A16 and reflection by light splitting prism B3, and enter the slab gain medium 1 through the pump surface.

[0043] To meet different application requirements, the side surface of the slab gain medium 1 in the present laser is designed to be recessed on one side, as shown in Figure 5 The side surface can be designed to be recessed on the left side or the right side, and whether to recess on one side and the direction of recessing can be determined according to actual needs.

[0044] The edge of the slab gain medium 1 in the present application can be designed to have a side surface recessing angle according to actual needs.​Figure 6 The image shows several examples of slats with different side angles. It is worth noting that the angle of the side concavity is not limited to... Figure 6 As shown, it can be flexibly adjusted according to actual needs.

[0045] The beam-splitting prism in this invention exhibits diverse forms, such as... Figure 7 As shown, a beam splitter structure is used to match different tilt angles of the pump surface, so that the laser entering the pump surface is perpendicularly incident, thereby achieving high transmittance.

[0046] To further promote the high-power application of concave slab solid-state lasers, this invention utilizes a light guide mirror and a laser diode array to enable pump light to be efficiently incident into the interior of the slab-shaped gain medium, thereby significantly improving pump power.

[0047] In summary, the concave slab pumping structure for solid-state lasers designed in this invention not only optimizes the absorption efficiency of pump light, but also simplifies the pumping method and makes the laser structure compact through flexible pump surface morphology design and power expansion strategy, providing a solid foundation for the high-power and miniaturized application of concave slab structure solid-state lasers.

[0048] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A solid state laser concave slab pump structure, characterized by: The application relates to a solid laser concave slab pumping structure, which comprises a slab gain medium (1), at least one side of the slab gain medium (1) is concave, the concave surface is used as a pumping surface, so that light emitted by a pumping source can enter the interior of the slab gain medium (1) and be fully absorbed after multiple reflections, a beam splitter A (2) and a beam splitter B (3) are arranged at the pumping surface of the slab gain medium (1) respectively, pumping light A (4) and pumping light B (5) are reflected by the beam splitter A (2) and the beam splitter B (3) respectively and are incident from the pumping surface of the slab gain medium (1), The pumping surface is a plane or a cylindrical surface, An anti-reflection film with high transmissivity for the pumping wavelength is coated on the pumping surface.

2. A solid state laser concave slab pump structure according to claim 1, wherein: The slab gain medium (1) is a laser crystal medium, so as to adapt to different laser output wavelengths and power requirements.

3. A solid state laser system, characterized by: The application further discloses a solid laser concave slab pumping structure comprising the beam splitter A (2), the beam splitter B (3), the pumping light A (4), the pumping light B (5), cavity mirrors A (7) and B (8), a collimator and the solid laser concave slab pumping structure according to any one of claims 1-2. The beam splitter A (2) and the beam splitter B (3) are arranged at the pumping surface of the slab gain medium (1) respectively, the pumping light A (4) and the pumping light B (5) are collimated by the collimator and reflected by the beam splitter A (2) and the beam splitter B (3) respectively and are incident from the pumping surface of the slab gain medium (1), cavity mirrors A (7) and B (8) are arranged at two ends of the slab gain medium (1) and are used for forming a resonant cavity, the main optical axis of the pumping source is perpendicular to the pumping surface of the slab gain medium (1), an anti-reflection film with high reflectivity for the pumping light is coated on the surface of the beam splitter A (2) and the beam splitter B (3), and the beam splitter cooperates with the pumping surface, so that the laser entering the pumping surface is perpendicular incident.

4. A solid state laser system as claimed in claim 3, characterized in that: The pumping source of the pumping light A (4) and the pumping light B (5) is a single laser diode, or a coupling array structure composed of multiple laser diodes.

5. A solid state laser system as claimed in claim 3, characterized in that: The slab gain medium (1) is closely combined with a heat sink.

6. A solid state laser system as claimed in claim 3, characterized in that: The cavity mirrors A (7) and B (8) are accurately aligned with the slab gain medium (1). The cavity mirrors A (7) and B (8) are accurately aligned with the slab gain medium (1).

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