High-power slab laser amplifier

Abstract

The invention discloses a high-power slab laser amplifier which comprises a seed source, a slab crystal medium, two pumping sources and a cooling device, the slab crystal medium is assembled in the cooling device, the pumping sources are correspondingly placed on the front side surface and the rear side surface of the slab crystal medium, and the pumping sources are located on the outer side of the cooling device. Pumping light generated by the pumping source is irradiated to the lath crystal medium through the cooling device; the cooling device comprises a cooling box and a first flow guide seat and a second flow guide seat which are installed at the upper end and the lower end of the cooling box respectively, the two pumping sources are located on the front side and the rear side of the cooling box respectively, glass windows are embedded in the front end and the rear end of the cooling box, and a first heat dissipation plate and a second heat dissipation plate are arranged on the front side and the rear side in the cooling box respectively. Through the structural design of combining water cooling and air cooling, the temperature of a medium is reduced, thermal stress can be effectively dispersed and reduced, and material deformation and corresponding optical performance reduction caused by temperature change are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of slab lasers, in particular to a high-power slab laser amplifier. Background Art

[0002] In the field of laser technology, slab laser amplifiers are widely used in many fields such as laser industry, laser processing and military due to their excellent optical properties and high output power. Traditional slab laser amplifiers mainly use solid-state slab crystals as gain media. These slab crystals often need to operate under high-power working conditions to provide the required laser output. However, high-power operation is accompanied by significant heat generation. If this heat cannot be effectively managed and dissipated, it will directly affect the performance and stability of the laser.

[0003] In the prior art, many slab laser amplifiers use water cooling systems to reduce heat accumulation in the gain medium. Water cooling is a relatively mature cooling method that can effectively reduce the temperature of the crystal and prevent performance degradation caused by overheating. However, current water cooling designs usually have a series of problems, especially in terms of all-round cooling capacity.

[0004] First, the existing water cooling system can only achieve single-direction cooling of the crystal surface, which means that in practical applications, some parts of the crystal interior or the cooled area may be locally overheated due to uneven heat dissipation. This local overheating will not only lead to uneven laser gain, but also may cause thermal stress in the crystal, and in severe cases may even cause physical damage or failure.

[0005] The patent with the publication number CN112636147A discloses a double-sided water cooling device for a slab laser crystal, including a clamping frame, an upper water channel seat, and a lower water channel seat. The clamping frame is provided with a slab laser crystal, and the top of the slab laser crystal is connected to the upper water channel seat through a fixing strip, and the bottom is connected to the lower water channel seat through a fixing strip; protective window glasses are respectively provided on the front and rear sides of the clamping frame; a water channel 1 is formed between the lower water channel seat and the two sides of the fixing strip, and a water channel 2 is formed between the two protective window glasses and the sides of the slab laser crystal; however, in this scheme, the entire slab crystal is directly immersed in the coolant, which will cause material degradation or chemical reaction, thereby damaging the structure and optical properties of the gain medium, and the optical properties of the slab crystal (such as refractive index, absorption and emission properties) will change due to immersion in the coolant. The refractive index of the coolant is different from that of the slab crystal, which can cause unstable laser performance or reduced efficiency, affecting the normal operation of the slab crystal, and the coolant is also prone to leave sediments or impurities on the surface of the medium, thereby causing a decrease in optical performance. Summary of the invention

[0006] The object of the present invention is to provide a high-power slab laser amplifier to solve the problems mentioned in the above background technology.

[0007] To achieve the above-mentioned object, the present invention provides the following technical solutions: a high-power slab laser amplifier, comprising a seed source, a slab crystal medium, two pump sources and a cooling device, wherein the slab crystal medium is assembled in the cooling device, and pump sources are placed correspondingly on the front and rear surfaces of the slab crystal medium, and the pump sources are located outside the cooling device, and the pump light generated by the pump sources is irradiated to the slab crystal medium through the cooling device; The cooling device comprises a cooling box and a first guide seat and a second guide seat respectively installed at the upper and lower ends of the cooling box, two pump sources are respectively located at the front and rear sides of the cooling box, the front and rear ends of the cooling box are both embedded with glass windows, the front and rear sides of the cooling box are respectively provided with a first heat sink and a second heat sink, the slat crystal is clamped and arranged between the first heat sink and the second heat sink, a sealed cavity is formed between the first heat sink and the front glass window of the cooling box and between the second heat sink and the rear glass window, the cavities on both sides constitute a first water channel, cooling water flows into the first water channel to absorb the heat on the first heat sink and the second heat sink; One side end of the first guide seat and the second guide seat is connected to a water nozzle, and a second water channel and a third water channel are respectively opened inside the first guide seat and the second guide seat, and the second water channel and the third water channel are connected to the first water channel at one end away from the water nozzle, and heat conduction plates are arranged on one end surface of the second water channel and the third water channel close to the slat crystal medium, and the heat conduction plates on both sides are respectively abutted against the upper and lower surfaces of the slat crystal medium for cooling the upper and lower surfaces of the slat crystal medium, and the cooling water enters from the third water channel, passes through the first water channel, and leaves from the second water channel.

[0008] Furthermore, the width of the water channel section on the third water channel and the second water channel located on the side of the slat crystal medium is smaller than the width of the water channel section connected to the water nozzle, and the second water channel and the third water channel are both provided with openings at one end close to the slat crystal medium, and the edges of the heat conduction plates on both sides are connected to the inner wall of the opening on the corresponding side through elastic rings.

[0009] Furthermore, cooling chambers are provided on both sides of the cooling box, and the cooling chambers are independent and unconnected with the cavity. The left and right end surfaces of the slat crystal medium pass through the cooling box respectively and are located in the cooling chambers on both sides. A glass plate is embedded in the end surface of the cooling chamber away from the cooling box. The laser beam of the seed source is introduced from the left end of the slat crystal medium and exported from the right end. The first and second air outlets are provided on the front and back sides of the cooling chambers on both sides. A first air duct is connected between the two first air outlets on the left and right sides, and a second air duct is connected between the second air outlets on the left and right sides.

[0010] Furthermore, the first air duct passes through the cooling box and extends to the lower side of the first water channel, the second air duct passes through the cooling box and extends to the upper side of the first water channel, a circulating air pump is installed on the top of the cooling box, and the middle part of the second air duct passes through the first water channel and extends to be connected to the circulating air pump.

[0011] Furthermore, the surface of the glass plate is coated with a film with high transmittance to the laser beam, and the inner wall of the cooling chamber is coated with a film with high reflectivity to the laser beam.

[0012] Furthermore, both left and right end surfaces of the cooling box are provided with openings, and fixing strips are arranged on the openings. The left and right end surfaces of the slat crystal medium extend into the cooling chamber after passing through the openings on the corresponding side.

[0013] Furthermore, the width of the first water channel is smaller than the width of the second water channel or the third water channel, and the end surfaces of one side of the first heat sink and the second heat sink close to the glass window are evenly spaced with a plurality of through grooves arranged in the vertical direction.

[0014] Furthermore, overflow ports are provided on both the front and rear sides of the second water channel and the third water channel away from the water nozzle, and the upper and lower sides of the cavities on both sides extend through the first guide seat and the second guide seat respectively, and the extended parts are connected to the overflow ports on the corresponding side.

[0015] Furthermore, the surfaces of the glass windows on both sides are coated with a film with high transmittance to the pump laser; the end faces of the first heat sink and the second heat sink on one side close to the slat crystal are coated with a high reflection film, and the other end faces are coated with an anti-reflection film.

[0016] Furthermore, the first heat sink and the second heat sink are both made of materials with high thermal conductivity and high transmittance to the pump light emitted by the pump source, such as (quartz, silicon nitride, fluoride glass, etc.).

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a structural design that combines water cooling and air cooling, which can effectively remove the heat generated by the slab crystal medium during operation, reduce the temperature of the medium, effectively disperse and reduce thermal stress, avoid material deformation and corresponding optical performance degradation caused by temperature changes, and ensure that the laser operates within an ideal operating temperature range.

[0018] 2. The unique water channel connection structure design of the first water channel, the second water channel and the third water channel of the present invention ensures the uniformity of flow in each key area and avoids the problem of local overheating. By optimizing the water flow path, a more uniform cooling effect can be achieved. The uniform cooling effect can effectively reduce the temperature difference of the gain medium.

[0019] 3. The linkage design of the cooling chamber, the first air duct and the second air duct of the present invention adopts an optimized airflow path design, which effectively improves the air flow efficiency and ensures that the input and output end faces of the slat crystal medium can achieve rapid heat dissipation during operation, thereby achieving all-round heat dissipation of the slat crystal medium, and at the same time can effectively avoid the influence of cooling water on the laser beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of a high-power slab laser amplifier of the present invention; Figure 2 A schematic diagram of a cooling device for a high-power slab laser amplifier according to the present invention; Figure 3 It is a front view of the water flow of a cooling device of a high-power slab laser amplifier of the present invention; Figure 4 A top view of the water flow of a cooling device for a high-power slab laser amplifier of the present invention; Figure 5 A top view of the cooling device structure of a high-power slab laser amplifier of the present invention; Figure 6 It is a schematic diagram of the heat conduction plate structure of the cooling device of the present invention; Figure 7 It is a schematic diagram of the distribution of air ducts in the cooling device of the present invention.

[0021] In the figure, seed source 1, slat crystal medium 2, pump source 3, cooling device 4, cooling box 41, first guide seat 42, second guide seat 43, glass window 44, first heat sink 45, second heat sink 46, first water channel 47, second water channel 48, third water channel 49, heat conduction plate 50, elastic ring 51, cooling chamber 52, glass plate 53, first air outlet 54, second air outlet 55, first air duct 56, second air duct 57, circulating air pump 58, through groove 59, overflow port 60. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] like Figure 1As shown, a high-power slab laser amplifier comprises a seed source 1, a slab crystal medium 2, two pump sources 3 and a cooling device 4. The slab crystal medium 2 is assembled in the cooling device 4. The pump sources 3 are placed on the front and rear surfaces of the slab crystal medium 2 respectively. The pump sources 3 are located outside the cooling device 4. The pump light generated by the pump sources 3 is irradiated to the slab crystal medium 2 through the cooling device 4. See also Figure 2 , Figure 3 and Figure 5 As shown, the cooling device 4 includes a cooling box 41 and a first guide seat 42 and a second guide seat 43 respectively installed at the upper and lower ends of the cooling box 41, two pump sources 3 are respectively located at the front and rear sides of the cooling box 41, and glass windows 44 are embedded at the front and rear ends of the cooling box 41. The first heat sink 45 and the second heat sink 46 are respectively arranged at the front and rear sides of the cooling box 41, and the slat crystal is clamped and arranged between the first heat sink 45 and the second heat sink 46. A sealed cavity is formed between the first heat sink 45 and the front glass window 44 of the cooling box 41 and between the second heat sink 46 and the rear glass window 44. The cavities on both sides constitute a first water channel 47, and cooling water flows into the first water channel 47 to absorb the heat on the first heat sink 45 and the second heat sink 46; The first guide seat 42 and the second guide seat 43 are both connected to a water nozzle at one side end, and the first guide seat 42 and the second guide seat 43 are respectively provided with a second water channel 48 and a third water channel 49 inside, and the second water channel 48 and the third water channel 49 are both connected to the first water channel 47 at one end away from the water nozzle. Heat conducting plates 50 are provided on one end surface of the second water channel 48 and the third water channel 49 close to the slat crystal medium 2, and the heat conducting plates 50 on both sides are respectively in contact with the upper and lower surfaces of the slat crystal medium 2, so as to cool the upper and lower surfaces of the slat crystal medium 2, and the cooling water enters from the third water channel 49, passes through the first water channel 47, and then leaves from the second water channel 48; When the cooling water flows in from the third water channel 49, it will first cool and dissipate heat to the lower surface of the slat crystal medium 2, and then when it flows into the first water channel 47 from the overflow port 60, it will cool and dissipate heat to the front and rear surfaces of the slat crystal medium 2, and finally it will flow out from the second water channel 48 to cool and dissipate heat to the upper surface of the slat crystal medium 2. Through this water channel design, the four sides of the slat crystal medium 2 can be cooled, the slat crystal medium can be evenly cooled, the generation of thermal gradient in the longitudinal direction can be reduced, and the output of high-power and high-quality light beams can be achieved.

[0024] See also Figure 3 and Figure 6As shown, the width of the water channel section on the side of the slat crystal medium 2 on the third water channel 49 and the second water channel 48 is smaller than the width of the water channel section connected to the water nozzle, and the second water channel 48 and the third water channel 49 are both provided with openings at one end close to the slat crystal medium 2, and the edges of the heat conducting plates 50 on both sides are connected to the inner wall of the opening on the corresponding side through the elastic ring 51; this width structure design will increase the water pressure when the cooling water flows into the water channel section located on the side of the slat crystal medium 2, thereby pushing the heat conducting plate 50 to move, and the heat conducting plate 50 is pressed outward by the water pressure to make the heat conducting plate 50 fully fit and contact with the slat crystal medium 2 to improve the thermal conductivity effect; and the reason why the heat conducting plate 50 is not fixed to the slat crystal medium 2 by welding can avoid the welding stress concentration area, which may cause material fatigue and cracking, and further affect the optical properties and thermal conductivity of the laser crystal.

[0025] See also Figure 2 , Figure 3 and Figure 7 As shown, cooling chambers 52 are provided on both sides of the cooling box 41, and the cooling chambers 52 are independent and non-connected with the cavity. Openings are provided on the left and right end faces of the cooling box 41, and fixing strips are provided on the openings. The left and right end surfaces of the slab crystal medium 2 extend into the cooling chamber 52 after passing through the openings on the corresponding sides, and a glass plate 53 is embedded on the end face of the cooling chamber 52 away from the cooling box 41. The laser beam of the seed source 1 is introduced from the left end of the slab crystal medium 2 and is led out from the right end. The cooling chambers 52 on both sides are provided with first air vents 54 and second air vents 55 on both sides, a first air duct 56 is connected between the two first air vents 54 on the left and right sides, a second air duct 57 is connected between the second air vents 55 on the left and right sides, the first air duct 56 penetrates the cooling box 41 and extends to the lower side of the first water channel 47, the second air duct 57 penetrates the cooling box 41 and extends to the upper side of the first water channel 47, a circulating air pump 58 is installed on the top of the cooling box 41, and the middle part of the second air duct 57 penetrates the first water channel 47 and extends to be connected to the circulating air pump 58; When the laser beam of the seed source 1 is irradiated onto the end face of the slab crystal medium 2, the temperature of the end face of the slab crystal medium 2 will rise. The gas in the cooling chamber 52 has a large contact area with the surface of the slab crystal medium 2, and can effectively absorb the heat of the left and right end faces of the slab crystal medium 2. The cooling chamber 52 uses gas cooling instead of cooling water to avoid changes in the laser beam (such as refractive index, absorption and emission characteristics) caused by the cooling water. The circulating air pump 58 drives the air flow so that the gas in the left cooling chamber 52 enters the right cooling chamber 52 along the first air duct 56, and then returns to the circulating air pump 58 from the second air duct 57. When the gas enters the first air duct 56 or the second air duct 57, the air duct will be cooled by the cooling water in the first water channel 47 on the outside, thereby absorbing the heat of the gas in the air duct.

[0026] See also Figure 5 As shown, the width of the first water channel 47 is smaller than the width of the second water channel 48 or the third water channel 49, and a plurality of through grooves 59 arranged in the vertical direction are evenly spaced apart on the end surfaces of one side of the first heat sink 45 and the second heat sink 46 close to the glass window 44; since the width of the first water channel 47 is smaller than that of the third water channel 49, the purpose of such arrangement is to accelerate the cooling water when it enters the first water channel 47 from the third water channel 49, so as to facilitate rapid cooling of the slab laser medium 2, and by providing through grooves 59 on the surfaces of the first heat sink 45 and the second heat sink 46, the contact area with the cooling water is increased, thereby promoting rapid heat conduction.

[0027] See also Figure 3 and Figure 4 As shown, overflow ports 60 are provided on both sides of the front and rear ends of the second water channel 48 and the third water channel 49 away from the water nozzle, and the upper and lower sides of the cavities on both sides extend through and extend into the first guide seat 42 and the second guide seat 43 respectively, and the extended parts are connected with the overflow ports 60 on the corresponding side. This structural design can make the cooling water flowing out of the overflow port 60 first fill the part of the rear cavity located in the second guide seat 43, and then flow up to the part in contact with the first heat sink 45 and the second heat sink 46 as the cooling water continues to flow in, and finally flow into the overflow port 60 of the second guide seat 43; this design ensures that the flow of cooling water remains stable and uniform in the first water channel 47, and avoids excessive pressure of the water flowing out of the overflow port 60, which will cause vibration of the first heat sink 45 or the second heat sink 46.

[0028] In this embodiment, the surface of the glass plate 53 is coated with a film with high transmittance to the laser beam, and the inner wall of the cooling chamber 52 is coated with a film with high reflectivity to the laser beam, so that the laser beam emitted by the seed source can enter the slab laser medium; The surfaces of the glass windows 44 on both sides are coated with a film with high transmittance to the pump laser; the end faces of the first heat sink 45 and the second heat sink 46 on one side close to the slab crystal are coated with a high-reflection film, and the end faces on the other side are coated with an anti-reflection film, which facilitates the pump light emitted by the pump source 3 to enter the slab laser medium.

[0029] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-power slab laser amplifier, comprising a seed source, a slab crystal medium, two pump sources and a cooling device, wherein the slab crystal medium is assembled in the cooling device, and pump sources are placed correspondingly on the front and rear surfaces of the slab crystal medium, and the pump sources are located outside the cooling device, and the pump light generated by the pump sources is irradiated to the slab crystal medium through the cooling device, characterized in that: The cooling device comprises a cooling box and a first guide seat and a second guide seat respectively installed at the upper and lower ends of the cooling box, two pump sources are respectively located at the front and rear sides of the cooling box, the front and rear ends of the cooling box are both embedded with glass windows, the front and rear sides of the cooling box are respectively provided with a first heat sink and a second heat sink, the slat crystal is clamped and arranged between the first heat sink and the second heat sink, a sealed cavity is formed between the first heat sink and the front glass window of the cooling box and between the second heat sink and the rear glass window, the cavities on both sides constitute a first water channel, cooling water flows into the first water channel to absorb the heat on the first heat sink and the second heat sink; One side end of the first guide seat and the second guide seat is connected to a water nozzle, and a second water channel and a third water channel are respectively opened inside the first guide seat and the second guide seat, and the second water channel and the third water channel are connected to the first water channel at one end away from the water nozzle, and heat conduction plates are arranged on one end surface of the second water channel and the third water channel close to the slat crystal medium, and the heat conduction plates on both sides are respectively abutted against the upper and lower surfaces of the slat crystal medium for cooling the upper and lower surfaces of the slat crystal medium, and the cooling water enters from the third water channel, passes through the first water channel, and leaves from the second water channel.

2. A high power slab laser amplifier according to claim 1, characterized in that: The width of the water channel section on the third water channel and the second water channel located on the side of the slat crystal medium is smaller than the width of the water channel section connected to the water nozzle. The second water channel and the third water channel are both provided with openings at one end close to the slat crystal medium, and the edges of the heat conducting plates on both sides are connected to the inner wall of the opening on the corresponding side through elastic rings.

3. A high power slab laser amplifier according to claim 1, characterized in that: Cooling chambers are provided on both sides of the cooling box, and the cooling chambers are independent and unconnected with the cavity. The left and right end surfaces of the slat crystal medium pass through the cooling box respectively and are located in the cooling chambers on both sides. A glass plate is embedded in the end surface of the cooling chamber away from the cooling box. The laser beam of the seed source is introduced from the left end of the slat crystal medium and exported from the right end. The first and second air outlets are provided on the front and back sides of the cooling chambers on both sides. A first air duct is connected between the two first air outlets on the left and right sides, and a second air duct is connected between the second air outlets on the left and right sides.

4. A high power slab laser amplifier according to claim 3, characterized in that: The first air duct passes through the cooling box and extends to the lower side of the first water channel, the second air duct passes through the cooling box and extends to the upper side of the first water channel, a circulating air pump is installed on the top of the cooling box, and the middle part of the second air duct passes through the first water channel and extends to connect with the circulating air pump.

5. A high power slab laser amplifier according to claim 3, characterized in that: The surface of the glass plate is coated with a film with high transmittance to the laser beam, and the inner wall of the cooling chamber is coated with a film with high reflectivity to the laser beam.

6. A high power slab laser amplifier according to claim 3, characterized in that: The left and right end surfaces of the cooling box are both provided with openings, and the openings are provided with fixing strips. The left and right end surfaces of the slat crystal medium respectively pass through the openings on the corresponding sides and extend into the cooling chamber.

7. A high power slab laser amplifier according to claim 1, characterized in that: The width of the first water channel is smaller than that of the second water channel or the third water channel. The first heat sink and the second heat sink are evenly spaced apart on one side of the end surface close to the glass window and are provided with a plurality of through grooves arranged in the vertical direction.

8. A high power slab laser amplifier according to claim 1, characterized in that: Overflow ports are provided on both the front and rear sides of the second and third water channels away from the water nozzles. The upper and lower sides of the cavities on both sides extend through the first guide seat and the second guide seat respectively, and the extended parts are connected to the overflow ports on the corresponding side.

9. A high power slab laser amplifier according to claim 1, characterized in that: The surfaces of the glass windows on both sides are coated with films with high transmittance to pump lasers; the end faces of the first heat sink and the second heat sink close to the slat crystal are coated with high reflection films, and the other end faces are coated with anti-reflection films.

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