Side pump solid laser with radially added circular array thin rods

Abstract

The invention discloses a side pump solid-state laser with radially added circular array thin rods. The side pump solid-state laser comprises an optical resonant cavity, a pumping source, gain medium thin rods and a pumping cavity, the pumping cavity is arranged in the optical resonant cavity, the plurality of gain medium thin rods are arranged in the pumping cavity, and the pumping source is arranged outside the pumping cavity. According to the invention, a laser diode side pumping mode is adopted, pumping light emitted by each column of laser diodes firstly irradiates the gain medium rods on the inner circumference of the corresponding cylindrical pumping cavity, and the unabsorbed part of the pumping light penetrates through the gain medium rods on the circumference and then enters the gain medium rods on the central axis; bursting of the gain medium rod on the central axis due to excessive heat accumulation can be avoided under large pumping energy.

Description

Technical Field

[0001] The invention belongs to the technical field of solid lasers and relates to a side-pumped solid laser with radially increased circular array thin rods. Background Art

[0002] Over the years, with the continuous development of laser technology, all-solid-state lasers have achieved rapid development, laser output power has been continuously improved, and the average output power has exceeded 10,000 watts, and is widely used in industrial and military fields. However, in the operation of solid-state lasers, when the pump source provides the energy required for the gain medium to generate lasers, due to the "quantum defects" in the gain medium, the pump energy cannot be completely converted into laser energy, which greatly reduces the utilization rate of the pump energy, and the unused energy is released in the form of heat. These useless heats can cause thermal lensing, stress, depolarization, birefringence and other effects in the gain medium, affecting the operation of the laser, reducing the beam quality of the laser output laser, limiting the output power, and in severe cases causing the gain medium to explode. These factors severely limit the maximum output power of solid-state lasers, making it unable to meet the growing laser power requirements in real applications.

[0003] As the most mature and widely used solid laser, the round rod-shaped gain medium solid laser has two main pumping modes: end pumping and side pumping. The end pumping mode is constrained by the volume of the fundamental mode of the resonant cavity, and requires the pump light to be incident from the end face with a smaller area. Although it can obtain good beam quality, it will limit the injected pump power, and will also produce a large temperature gradient and complex thermo-optical effect in the gain medium. Therefore, it is difficult to obtain a high average power output of kilowatts by end pumping. Side pumping can easily obtain high power output, but because the center temperature of the gain medium is higher than the surface temperature, serious thermal lens effect and thermal depolarization effect will occur in the crystal, reducing the quality of the laser beam. Generally, the light-to-light conversion efficiency of the side pump is about 40%. Although side pumping can obtain high power output, the gain medium has a pump energy damage threshold, which makes the output laser power of the side pump solid laser have an upper limit. However, methods such as changing the doping concentration of the activation ion or increasing the diameter size of the gain medium rod cannot solve the above problems well. Summary of the invention

[0004] (I) Purpose of the invention

[0005] The purpose of the present invention is to design an all-solid-state laser diode side-pump solid laser with multiple thin-diameter gain medium rods placed in a resonant cavity to improve the output power of the side-pump solid laser.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a side-pumped solid-state laser with radially increased circular array thin rods, which includes: an optical resonant cavity, a pump source, a gain medium thin rod 1, and a pump cavity 2; the pump cavity 2 is arranged in the optical resonant cavity, a plurality of gain medium thin rods 1 are arranged in the pump cavity 2, and the pump source is arranged outside the pump cavity 2.

[0008] A cooling system is arranged on the inner wall of the pump cavity 2, and a water inlet and a water outlet are arranged at both ends, and are connected to a water cooler.

[0009] A mechanical mechanism is arranged in the pump cavity 2 to play a solid clamping role on the gain medium thin rod 1 .

[0010] There are an even number of gain medium thin rods 1 , one of which is arranged at the center of the pump cavity 2 , and the others are evenly distributed at a set distance around the periphery of the central gain medium thin rod 1 .

[0011] The pump source includes a plurality of laser diode arrays, which are arranged one by one outside the peripheral gain medium thin rod 1.

[0012] There are six gain medium thin rods 1 and five laser diode arrays, and the five laser diode arrays are placed in parallel.

[0013] The laser diode array is composed of multiple point light sources combined in a line array.

[0014] The gain medium thin rod 1 is a long cylinder with a set diameter.

[0015] The optical resonant cavity includes a front cavity mirror group 8 and a rear cavity mirror group 9, which are respectively arranged at two ends of the pump cavity 2.

[0016] (III) Beneficial effects

[0017] The side-pumped solid-state laser with radially increased circular array thin rods provided by the above technical solution has the following beneficial effects:

[0018] 1. The present invention adopts a combination of multiple thin-diameter gain medium rods, which not only avoids the problem of limited laser gain medium size, but also effectively reduces the thermal effect problem in large-sized laser rods. In addition, the number of rods can be determined according to the required power.

[0019] 2. The present invention adopts a flowing liquid cooling solution, which has a good cooling effect and avoids a large amount of heat accumulation in the gain medium rod.

[0020] 3. The present invention adopts a parallel arrangement of gain medium rods, which can greatly increase the output laser power without increasing the cavity length.

[0021] 4. The present invention adopts the laser diode side pumping method, and the pump light emitted by each column of laser diodes is first irradiated to the gain medium rod on the circumference of the corresponding cylindrical pump cavity. The unabsorbed part of the pump light penetrates the gain medium rod on the circumference and then enters the gain medium rod on the central axis. Under large pumping energy, the gain medium rod on the central axis can be prevented from bursting due to excessive heat accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a spatial schematic diagram of radially increasing circular array thin rods.

[0023] Figure 2 It is a schematic diagram of the pump structure with radially added circular array thin rods.

[0024] Figure 3 It is a schematic diagram of the end face of radially increasing circular array thin-rod laser diode side pumping.

[0025] Figure 4 is a schematic diagram of a laser diode.

[0026] Figure 5 is a schematic diagram of the gain medium rod.

[0027] Figure 6 It is a schematic diagram of the structure of a radially increased circular array thin rod side-pumped solid-state laser. DETAILED DESCRIPTION

[0028] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0029] It should be pointed out that the specific embodiments described here are only used to explain the present invention, and are applicable to but not limited to narrow-diameter solid-state lasers; and applicable to but not limited to laser diode pumping methods.

[0030] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "left side" and "right side" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction.

[0031] In order to further improve the output power of the side-pumped solid-state laser, the present invention proposes to add a group of circumferential array gain medium thin rods in the radial direction around the gain medium thin rod on the basis of the traditional side-pumped single-rod solid-state laser. Without increasing the cavity length, by increasing the number of gain media, a high-power laser far higher than the current side-pumped solid-state laser can be obtained.

[0032] See first Figure 1 , Figure 1Schematic diagram of the space of the invention with radially increasing circular array thin rods. Figure 1 It can be seen that the layout of multiple gain medium thin rods 1 in the pump cavity 2 is: place a gain medium thin rod 1 on the central axis, and then place an odd number of gain medium thin rods 1 at equal intervals on the circumference of a set distance from the central axis. The number of gain medium thin rods on the circumference is not fixed, and the specific number is determined by the desired laser power, but an odd number must be maintained. The odd number of gain medium thin rods will not have the center line of two rods passing through the central axis in the arrangement, so as to avoid the situation where two laser diode arrays are irradiated against each other when pumping the gain medium thin rods, and prevent damage to the laser diode array. In addition, the gain medium thin rods 1 used are exactly the same and are all placed in the cylindrical cavity structure 2.

[0033] See also Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the pump structure with radially increasing circular array thin rods. Figure 3 This is a schematic diagram of the end face of radially increasing circular array thin rod laser diode side pumping. Figure 2 visible, Figure 2 The laser diode arrays 3, 4, 5, 6, and 7 are placed on the circumference of the pump cavity 2, one by one, outside the gain medium thin rod 1. Figure 3 It can be seen that the pump light emitted by the laser diode array is first absorbed by the gain medium rod 1 in front, and the remaining part can irradiate the gain medium rod 1 on the central axis. Although the pump intensity of the peripheral gain medium rods on a pumping path is high and the pump intensity of the central gain medium rod is low, when multiple laser diode arrays are pumped with the same power, it can ensure that the pump power finally absorbed by the gain medium rod on the central axis is equivalent to the pump power absorbed by the gain medium rod on the circumference, so that all the gain medium rods produce the same or similar stimulated radiation, so that the final emitted laser has a higher output power.

[0034] Figure 4 It is a schematic diagram of a laser diode array. It can be seen from the figure that the laser diode array is composed of multiple point light sources combined in a line array.

[0035] Figure 5 is a schematic diagram of a gain medium rod, which is a long cylinder of a set diameter.

[0036] Last read Figure 6 , Figure 6 The figure is a schematic diagram of the structure of a radially increased circular array thin rod side-pumped solid-state laser. Figure 6 It can be seen that the laser includes an optical resonant cavity, a pump source, a gain medium rod 1, and a pump cavity 2; the pump cavity 2 is arranged in the optical resonant cavity, a plurality of gain medium rods 1 are arranged in the pump cavity 2, and the pump source is arranged outside the pump cavity 2.

[0037] A cooling system is arranged on the inner wall of the pump cavity 2, and a water inlet and a water outlet are arranged at both ends respectively, and are connected to a water cooler.

[0038] A mechanical mechanism is arranged in the pump cavity 2 to play a solid clamping role on the gain medium thin rod 1.

[0039] There are an even number of gain medium thin rods 1 , one of which is arranged at the center of the pump cavity 2 , and the others are evenly distributed at a set distance around the periphery of the central gain medium thin rod 1 .

[0040] The pump source includes a plurality of laser diode arrays, which are arranged one by one outside the peripheral gain medium thin rod 1.

[0041] In this embodiment, there are six gain medium thin rods 1 and five laser diode arrays, and the five laser diode arrays 3, 4, 5, 6, and 7 are placed in parallel.

[0042] The optical resonant cavity comprises a front cavity mirror group 8 and a rear cavity mirror group 9 which are arranged at two ends of the pump cavity 2 respectively.

[0043] The invention is applicable to high-power medium-wave infrared solid lasers and can change the number of gain medium thin rods according to required laser energy, thereby adjusting the laser output energy.

[0044] It can be seen from the above technical scheme that the key to the laser system of the present invention lies in the number of gain medium rods in the resonant cavity, the placement method and the pumping position of the laser diode. In the cylindrical cavity, a gain medium rod is placed on the central axis, and an odd number of gain medium rods are placed on the concentric circles around the central axis. The number of rods is determined according to the laser power to be output. The laser diode is placed outside the cylindrical cavity, corresponding to the position of the gain medium rods arranged in a ring shape in the cavity. The distance between each rod is equal, and the distance between each rod and the laser diode is consistent. Try to ensure that each gain medium rod has the same activation condition, and the gain medium rods are cooled by liquid. The laser has the advantages of compact structure and high laser output power.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A side-pumped solid-state laser with radially increased circular array thin rods, characterized in that: include: An optical resonant cavity, a pump source, a gain medium thin rod (1), and a pump cavity (2); the pump cavity (2) is arranged in the optical resonant cavity, a plurality of gain medium thin rods (1) are arranged in the pump cavity (2), and the pump source is arranged outside the pump cavity (2).

2. The side-pumped solid-state laser with radially increased circular array thin rods as claimed in claim 1, characterized in that: A cooling system is arranged on the inner wall of the pump cavity (2), with a water inlet and a water outlet respectively arranged at both ends, and connected to a water cooler.

3. The side-pumped solid-state laser with radially increased circular array thin rods as claimed in claim 1, characterized in that: A mechanical mechanism is arranged in the pump cavity (2) to play a solid clamping role on the gain medium thin rod (1).

4. The side-pumped solid-state laser with radially increased circular array thin rods as claimed in claim 1, characterized in that: There are an even number of gain medium thin rods (1), one of which is arranged at the center of the pump cavity (2), and the others are evenly distributed at a set distance around the periphery of the central gain medium thin rod (1).

5. The side-pumped solid-state laser with radially increased circular array thin rods as claimed in claim 4, characterized in that: The pump source comprises a plurality of laser diode arrays which are arranged one by one outside the peripheral gain medium thin rod (1).

6. The side-pumped solid-state laser with radially increased circular array thin rods as claimed in claim 5, characterized in that: There are six gain medium thin rods (1) and five laser diode arrays, and the five laser diode arrays are placed in parallel.

7. The side-pumped solid-state laser with radially increased circular array thin rods as claimed in claim 6, characterized in that: The laser diode array is composed of multiple point light sources combined in a linear array.

8. The side-pumped solid-state laser with radially increased circular array thin rods as claimed in claim 7, characterized in that: The gain medium thin rod (1) is a long cylinder with a set diameter.

9. The side-pumped solid-state laser with radially increased circular array thin rods as claimed in claim 1, characterized in that: The optical resonant cavity comprises a front cavity mirror group (8) and a rear cavity mirror group (9), which are respectively arranged at two ends of the pump cavity (2).

10. An optical system, characterized in that: A side-pumped solid-state laser comprising radially increased circular array thin rods as claimed in any one of claims 1 to 9.

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