TW201818624A - Laser pump chamber device - Google Patents

Abstract

Provided is a laser pump chamber that extracts high-output, high-quality laser light. A laser pump chamber device 1 provided with: a laser medium 10; excitation light source elements 2 that are placed at equal intervals around a central axis 10P of the laser medium 10, and have a light axis that intersects the central axis 10P; irradiation optical systems 3 placed on the light axis, that condense the excitation light emitted from the excitation light source elements 2 and irradiate the result on a laser medium; and a frame body 4 that supports the end part of the laser medium 10, and also supports the irradiation optical systems 3 and the excitation light source elements 2. The frame body 4 is configured using a thermally conductive member, and a temperature adjusting member 5 is placed on the outer surface of the frame body 4.

Description

Laser pump chamber device and laser oscillation device

The invention relates to a laser pump chamber device.

In order to ensure the oscillation stability, the cooling of the laser medium in a high-output solid-state laser oscillation device (for example, a YAG laser oscillation device) is indispensable. Previously, high-output solid-state laser oscillators used a YAG rod as a laser medium and a water-cooled jacketed laser pump chamber sealed by a flash lamp as an excitation light source. The laser pump chamber was maintained by circulating cooling water for cooling Thermal stability. In contrast, in places where water use or water generation is prohibited (water forbidden), high-output solid-state laser oscillation devices are required. Instead of the aforementioned water-cooled type, air-cooled lasers are being developed to deal with high-output lasers. Pump chamber. The previous examples of this type of laser pump chamber are known as follows, including: a YAG rod; a flash lamp; a circular reflection optical system for condensing and emitting light emitted from the flash lamp on the YAG rod; and water It is provided to surround these, and includes: a temperature adjustment mechanism that adjusts the temperature of the air in the frame in which the laser oscillation device of the laser pump chamber is arranged to be constant; and a blower mechanism that sends the air in the frame into the lightning Inside the pump pump chamber (see Patent Document 1 below). [Advanced Technical Documents] [Patent Documents] Patent Document 1: Japanese Patent Publication No. 2012-156435

[Problems to be Solved by the Invention] Although the foregoing previous example can obtain an air-cooled laser pump chamber that can be used in a water-restricted place, it is difficult to perform cooling at the same level as the water-cooled type, and it cannot obtain a high output of the water-cooled type. . In addition, on the other hand, a laser pump chamber capable of extracting high-quality laser light having a high output and exhibiting an axis-symmetrical output distribution is required, but there is a problem that the aforementioned prior art cannot meet such a requirement. The present invention has been made in order to cope with such problems. That is, the subject of this invention is providing the laser pump chamber etc. which can extract high-quality and high-quality laser light. [Technical Solution to Problem] In order to solve such a problem, the laser pump chamber of the present invention includes the following components. A laser pump chamber device, comprising: a laser medium; an excitation light source element arranged at equal intervals around a central axis of the laser medium and having an optical axis crossing the central axis; an irradiation optical system, It is arranged on the optical axis, collects the excitation light emitted from the excitation light source element, and irradiates the laser medium; and a frame body supports the end portion of the laser medium, and supports the irradiation optical system and the excitation. In the light source element, the frame is made of a thermally conductive member, and a temperature adjustment member is disposed on an outer surface of the frame.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same symbols in different drawings represent the parts with the same function, and repeated descriptions in the drawings are appropriately omitted. As shown in FIGS. 1 and 2, the laser pump chamber device 1 includes a laser medium 10, an excitation light source element 2, an irradiation optical system 3, and a housing 4. The laser medium 10 is, for example, a YAG rod or a cylindrical laser rod having a central axis 10P, and is supported on the frame 4 in a state where the end surfaces 10A and 10B orthogonal to the central axis 10P are open. The excitation light source element 2 is, for example, a laser diode, and has an optical axis crossing the central axis 10P of the laser medium 10. A plurality of excitation light source elements 2 are arranged at equal intervals around the central axis 10P. In the example shown in the figure, three excitation light source elements 2 are arranged around the central axis 10P at 120 ° intervals, and are arranged so that the optical axis of each excitation light source element 2 is orthogonal to the central axis 10P. The irradiation optical system 3 is arranged on the optical axis of the excitation light source element 2, collects light emitted from the excitation light source element 2, and irradiates the laser medium 10. In the example shown in the figure, a cylindrical lens is used as the irradiation optical system 3, and light having a divergence angle (laser light) emitted from the excitation light source element 2 is set as parallel light and irradiates the laser medium 10. In order to irradiate the excitation light to the laser medium 10 with high efficiency, an irradiation optical system 3 including a cylindrical lens is used, which condenses the light emitted from the excitation light source element 2 into parallel with the same diameter as the rod diameter of the laser medium 10 Light is irradiated onto the laser medium 10. The frame 4 supports the end portion of the laser medium 10 and supports the irradiation optical system 3 and the excitation light source element 2. In the example shown in the figure, the frame 4 is composed of a plurality of blocks. Specifically, the frame 4 includes end support blocks 40 and 41, inner blocks 42, 43, 44 and an outer peripheral block 45, and includes end blocks 51 and 52. The end support blocks 40 and 41 individually support the longitudinal ends of the laser medium 10 and have openings 40A and 41A through which the ends of the laser medium 10 can be inserted. In the example shown, O-rings 53 are arranged in the openings 40A and 41A, and the ends of the laser medium 10 inserted into the openings 40A and 41A are supported by the end support blocks 40 and 41 via the O-rings 53. . In the example shown, the end support blocks 40 and 41 are connected to the end blocks 51 and 52, and the openings 51A and 52A of the end blocks 51 and 52 and the openings 40A and 41A of the end support blocks 40 and 41 are arranged. On the coaxial. Thereby, the end surface 10A of the laser medium 10 is opened through the opening 51A, and the end surface 10B is opened through the opening 52A. In the illustrated example, the end support blocks 40 and 41 and the end blocks 51 and 52 are different blocks, but these may be integrated blocks. The inner blocks 42, 43, and 44 form a surrounding space 4A of the laser medium 10 and a supporting space 4B of the irradiation optical system 3 and the excitation light source element 2 by these. The surrounding space 4A has a cylindrical shape coaxial with the central axis 10P of the laser medium 10, and its inner surface becomes a cylindrical reflecting surface 4C coaxial with the central axis 10P. Specifically, a cylindrical reflecting surface 4C is formed by applying a reflective coating such as gold plating to the inner surfaces of the inner blocks 42, 43, and 44. The outer peripheral block 45 is arranged so as to surround the periphery of the inner blocks 42, 43, and 44, and a part of the outer peripheral block 45 supports the excitation light source element 2. The peripheral block 45 may be divided into a plurality of blocks, or may be integrated blocks. The blocks (end support blocks 40, 41, inner blocks 42, 43, 44, and outer blocks 45) constituting the frame 4 are all composed of thermally conductive members (highly thermally conductive members such as copper), and are closely connected to each other and connected. . It is preferable to use an adhesive material (metal paste) having high thermal conductivity for bonding between the adhesion surfaces of the blocks. A temperature adjustment member 5 such as a Peltier element is disposed on the outer surface of the housing 4, specifically, a part of the outer surface of the outer peripheral block 45. The laser pump chamber device 1 of this kind can adjust the temperature of the temperature adjusting member 5 to make the frame 4 supporting the excitation light source element 2 a uniform temperature, thereby keeping the emission wavelengths of all the excitation light source elements 2 constant. Since the blocks (end support blocks 40, 41, inner blocks 42, 43, 44 and outer peripheral blocks 45) constituting the frame 4 are all made of thermally conductive members, the temperature adjustment is arranged by placing a part of the outer surface of the frame 4 The member 5 can make the whole frame 4 uniform temperature. When a laser diode is used as the excitation light source element 2, the emission wavelength changes according to the temperature of the laser diode, but in order to perform efficient excitation, it is required that the wavelength of the excitation light irradiated to the laser medium 10 be maintained at A certain wavelength that is easily absorbed by the laser medium 10. For example, when a neodymium YAG rod is used as the laser medium 10, efficient excitation can be performed by maintaining the wavelength of the excitation light at 798 nm to 808 nm. The laser pump chamber device 1 can maintain the temperature of the laser diode as the excitation light source element 2 by the temperature adjustment member 5 at a temperature (for example, 25 ° C.) that emits light at 798 nm to 808 nm. Therefore, when using a neodymium YAG rod, In the case of the laser medium 10, efficient excitation can be performed. The support space 4B of the irradiation optical system 3 and the excitation light source element 2 composed of the blocks of the housing 4 is arranged at equal intervals around the central axis 10P of the laser medium 10. In the example shown in the figure, the support spaces 4B are arranged at three positions around the central axis 10P at 120 ° intervals. A substrate 2A of the excitation light source element 2 is fixed to a part of the support space 4B on the outer peripheral block 45, and the excitation light source element 2 is supported so that its optical axis is orthogonal to the central axis 10P of the laser medium 10. A cylindrical lens and a lens support member 3A as the irradiation optical system 3 are arranged in a part of the support space 4B, and the irradiation optical system 3 is arranged on the optical axis of the excitation light source element 2. The peripheral space 4A of the laser medium 10 composed of the blocks of the frame 4 is in communication with the support space 4B, and the center thereof is coaxial with the central axis 10P. The plurality of excitation light source elements 2 supported by the support space 4B radiate excitation light from the three directions (other directions) of axisymmetricity to the sides of the laser medium (YAG rod) 10. In addition, in the irradiation optical system 3, the excitation light that is condensed to have a diameter almost the same as the rod diameter of the laser medium 10 is efficiently irradiated to the laser medium 10, and the light reflected on the surface of the laser medium 10 is The cylindrical reflecting surface 4C formed on the inner surface of the surrounding space 4A reflects and is irradiated to the side surface of the laser medium 10 again, so the excitation light is more efficiently radiated to the laser medium 10. Thereby, high-quality light emission having an axis-symmetric output distribution can be obtained from the laser medium 10, and high-output light emission can be obtained by irradiation of efficient excitation light. The housing 4 is provided with a refrigerant inflow path 4D and a refrigerant outflow path 4F, whereby the laser pump chamber device 1 can effectively cool the laser medium 10. In the example shown in the figure, the refrigerant inflow path 4D is a linear flow path extended along the direction intersecting the central axis 10P of the laser medium 10, and three (plurality) are evenly arranged around the central axis 10P. Formed in the end support block 40. The refrigerant outflow path 4F is a linear flow path along the central axis 10P, and is formed in the end support block 41 and the end block 52. In the air-cooled laser pump chamber device 1, a connection portion 4E communicating with the refrigerant inflow path 4D is provided at one of the end blocks 51 in the housing 4, and an air supply pipe for conveying compressed air is connected to the connection portion 4E. 50. Then, the compressed air that has come into contact with the laser medium 10 is exhausted through the refrigerant outflow path 4F formed in the end block 52 and the end support block 41. In this way, the laser pump chamber device 1 is provided with a refrigerant inflow path 4D for allowing compressed air to come in contact with the air from multiple directions on the side of the laser medium 10, and along the central axis 10P is provided with compressed air that has come into contact with the laser medium 10. Since the exhaust gas has a refrigerant outflow path 4F, the laser medium 10 can be efficiently cooled. Thereby, even if it is an air-cooled type, high-output light emission can be obtained. Furthermore, in the laser pump chamber device 1 having such a structure, a circulating water flow path connecting the refrigerant inflow path 4D and the refrigerant outflow path 4F is formed to ensure the tightness in the surrounding space 4A, thereby enabling conversion to water cooling. formula. FIG. 3 shows a laser oscillation device 20 including a laser pump chamber device 1. The laser oscillating device 20 can be arranged within the frame 20A so as to face the central axis 10P of the laser pump chamber device 1, and the resonant mirror including the output mirror 21 and the reflecting mirror 22 is included, and will include 1/4 if necessary The Q switch 23 such as a wavelength plate 23A, a Bockels cell 23B, a polarizer 23C, and the like is arranged in a resonant mirror. This type of laser oscillation device 20 can emit light with an axially symmetrical output distribution from the laser medium 10 by the air-cooled laser pump chamber device 1, and can effectively cool the laser medium 10. It is cold type and can take out high output and high quality laser light. In addition, by ensuring the tightness of the surrounding space 4A in the casing 4 of the laser pump chamber device 1, it can also be converted to a water-cooled laser pump chamber device 1. It is possible to obtain a higher output by setting the water cooling type. The embodiments of the present invention have been described in detail with reference to the drawings, but the specific configuration is not limited to these embodiments, and design changes and the like without departing from the scope of the present invention are also included in the present invention. In addition, as long as there is no particular contradiction or problem in the purpose and configuration of the above-mentioned embodiments, the technologies of each other can be used and combined.

1‧‧‧Laser pump chamber device

2‧‧‧ Excitation light source element (laser diode)

2A‧‧‧ substrate

3‧‧‧illumination optical system (cylindrical lens)

3A‧‧‧lens support member

4‧‧‧frame

4A‧‧‧surrounding space

4B‧‧‧Support Space

4C‧‧‧Cylinder reflective surface

4D‧‧‧Refrigerant inflow

4E‧‧‧Connecting Department

4F‧‧‧Exhaust Outflow

5‧‧‧Temperature adjustment member (Peltier element)

10‧‧‧laser medium (YAG rod)

10P‧‧‧Center axis

10A, 10B‧‧‧face

20‧‧‧laser oscillator

20A‧‧‧Frame

21‧‧‧ output mirror

22‧‧‧Mirror

23‧‧‧Q switch

23A‧‧‧1 / 4 wave plate

23B‧‧‧Bockels Box

23C‧‧‧Polarizer

40, 41‧‧‧ end support blocks

40A, 41A‧‧‧Open

42, 43, 44 ‧ ‧ ‧ Internal blocks

45‧‧‧Peripheral block

50‧‧‧Air pipe

51, 52‧‧‧ end blocks

51A, 52A‧‧‧Open

53‧‧‧O-ring

Fig. 1 is a sectional view (a sectional view taken along the line B-B in Fig. 2) showing a laser pump chamber device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view (a cross-sectional view taken along A-A in Fig. 1) of a laser pump chamber device according to an embodiment of the present invention. FIG. 3 is an explanatory diagram showing a laser oscillation device including a laser pump chamber device.

Claims (9)

A laser pump chamber device, comprising: a laser medium; an excitation light source element arranged at equal intervals around a central axis of the laser medium and having an optical axis crossing the central axis; an irradiation optical system It is arranged on the optical axis and focuses the excitation light emitted from the excitation light source element to irradiate the laser medium; and the frame body supports the end portion of the laser medium, and supports the irradiation optical system and the above. The excitation light source element; and the frame is made of a thermally conductive member, and a temperature adjustment member is disposed on an outer surface of the frame. For example, the laser pump chamber device of claim 1, wherein the frame body includes a refrigerant inflow path and a refrigerant outflow path, and the refrigerant inflow path extends along a direction intersecting the central axis of the laser medium, and the refrigerant outflow path On the above central axis. For example, the laser pump chamber device of claim 1 or 2, wherein the frame system is tightly connected by the end support block, the inner block and the outer block, and the end support block supports the end of the laser medium, and the inner block A peripheral space of the laser medium and a supporting space of the irradiation optical system and the excitation light source element are formed, and the outer peripheral block supports the excitation light source element and surrounds an outer periphery of the inner block. The laser pump chamber device of claim 3, wherein the inner surface of the surrounding space is a cylindrical reflecting surface coaxial with the central axis. The laser pump chamber device according to claim 1 or 2, wherein the above-mentioned illumination optical system is a cylindrical lens that makes the light emitted from the excitation light source element a parallel light having the same diameter as the rod diameter of the laser medium. The laser pump chamber device according to claim 1 or 2, wherein the temperature adjustment member is a Peltier element. The laser pump chamber device of claim 1 or 2, wherein the excitation light source element is a laser diode. The laser pump chamber device of claim 1 or 2, wherein the above-mentioned laser medium is a YAG rod. A laser oscillation device includes the laser pump chamber device of claim 1 or 2, and a resonator mirror is disposed so as to face the central axis.