JP2004172534A - Solid-state laser apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state laser apparatus wherefrom a high-power laser beam can be obtained in spite of its small size. <P>SOLUTION: The solid-state laser apparatus 1 has five laser modules 2 and a pair of front and rear mirrors 3, 4. The solid-state laser apparatus 1 has a rectangular-box-form attaching base 6, and the respective laser modules 2 are so disposed in the positions of the respective vertical surfaces of the attaching base 6 as to orient them respectively toward the inside of the attaching base 6. Laser beams L oscillated from laser media 5 of the respective laser modules 2 are so reflected many times and so amplified that their optical paths intersect in the space portion surrounded by the respective laser media 5. Thereby, there can be provided the small-sized solid-state laser apparatus wherefrom a high-power laser beam L is obtained. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solid-state laser device, and more particularly, to a solid-state laser device in which laser light is amplified by a plurality of thin-plate-shaped laser media.
[0002]
[Prior art]
Conventionally, a solid-state laser device having the following configuration is known. That is, a pair of front mirrors and rear mirrors, a plurality of laser media having a reflection surface that oscillates laser light when irradiated with the excitation light and reflects the laser light, and the excitation light from the back surface of each laser medium. There is known a solid-state laser device provided with an excitation light irradiating unit for irradiating light.
In the above-described conventional apparatus, by forming the laser medium in a thin plate shape, it is possible to suppress thermal distortion generated in the laser medium and prevent the quality of laser light from deteriorating. In addition, the laser gain is increased by increasing the number of laser media, so that high-power laser light can be oscillated.
[Patent Document 1]
JP-A-4-30484 [Patent Document 2]
JP-A-2002-76480
[Problems to be solved by the invention]
However, the above-described conventional apparatus has a drawback that when the number of laser media is increased to increase the output of laser light, the entire laser apparatus becomes large. Moreover, in the above-described conventional apparatus, since the laser light is sequentially reflected in a zigzag manner and amplified, it is necessary to arrange a plurality of laser media along a direction in which the laser light extends in a zigzag manner. From this point, it has been pointed out that the above-mentioned conventional solid-state laser device is disadvantageous in that it is enlarged.
Therefore, an object of the present invention is to provide a solid-state laser device which can obtain high-power laser light while being small.
[0004]
[Means for Solving the Problems]
That is, the present invention provides a pair of front mirror and rear mirror, a plurality of laser media having a reflection surface on the back side that oscillates laser light when irradiated with excitation light and reflects the laser light, and each laser medium. A solid-state laser device comprising excitation light irradiating means for irradiating excitation light from the back surface thereof.
Each of the laser media is formed in a thin plate shape, and each of the laser media is arranged so that the reflection surface is located on a straight line forming a polygon. In an area inside the polygon, an optical path is formed. The laser light is repeatedly reflected so as to intersect and is amplified.
According to such a configuration, a plurality of laser media can be concentrated and arranged at the positions of the polygon, and the laser light can be repeatedly reflected and amplified on the inner side of the polygon.
Therefore, it is possible to provide a solid-state laser device which is smaller and has higher output than the above-described conventional device.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2, a solid-state laser device 1 includes five laser modules 2 having the same configuration, and a pair of front mirrors arranged at predetermined positions to form a resonator. 3 and a rear mirror 4.
In this embodiment, the laser modules 2 are arranged as follows. That is, the laser modules 2 are arranged so that the optical path of the laser light L between the front mirror 3 and the rear mirror 4 passes through the laser medium 5 provided in each laser module 2 and is reflected by the reflection surface 5A. ing. Then, the laser light L is oscillated and amplified from the laser medium 5 included in each laser module 2, and the laser light L amplified to a predetermined output or more is transmitted through the front mirror 3 and output in the arrow direction. Has become.
[0006]
This solid-state laser device 1 includes a rectangular box-shaped mounting base 6. Each of the laser modules 2 has a reflecting surface 5 </ b> A of each laser medium corresponding to each surface 6 </ b> A to 6 </ b> D of the mounting base 6. Are linked.
Each laser module 2 includes a rectangular prism holder 7 connected to the mounting base 6, the laser medium 5 mounted on the front surface of the holder 7, the cylindrical lens 8 mounted on the back surface of the holder 7, and the holder 7. And a conventionally known semiconductor laser 11 arranged on the back side of the lens and spaced apart from the cylindrical lens 8.
The holder 7 is provided with a horizontal through hole 7A penetrating from the back side to the front side. The opening on the front side of the through hole 7A is closed while maintaining liquid tightness by the laser medium 5 formed in a thin plate shape, while the opening on the back side of the through hole 7A is closed by the cylindrical lens 8. Keep tight and closed. The laser medium 5 and the cylindrical lens 8 are arranged such that their centers coincide at the same height. Cooling water is stored in the through hole 7A, and the cooling water in the through hole 7A is circulated through a passage and a pump (not shown) formed in the holder 7. That is, the holder 7 of the present embodiment also serves as a cooling means, and cools the laser medium 5 and the cylindrical lens 8 with the cooling water in the through hole 7A.
[0007]
The semiconductor laser 11 is horizontally fixed on a bracket 12 attached to the back of the holder 7. The semiconductor laser 11 is disposed at a position where its optical axis is on the same straight line as the center of the cylindrical lens 8 and the center of the laser medium 5. When the semiconductor laser 11 is operated, the semiconductor laser light L1 as excitation light is oscillated toward the cylindrical lens 8. Then, the semiconductor laser light L1 passes through the cylindrical lens 8 and then passes through the cooling water in the through-hole 7A, so that the laser medium 5 is irradiated from the back side. The sectional shape of the semiconductor laser light L1 oscillated from the semiconductor laser 11 is condensed in the width direction by transmitting through the cylindrical lens 8. Therefore, a region shown by a horizontally long ellipse in FIG. 3 is a region where the laser medium 5 is irradiated with the semiconductor laser light L1 and almost coincides with a region where the laser light L to be amplified passes. In the irradiation area of the semiconductor laser L1, the laser medium 5 is excited and the laser light L is oscillated efficiently.
The semiconductor laser 11 is provided with a conventionally known cooling means, and is cooled by this cooling means. Further, the detailed configuration of the semiconductor laser 11 is already known, and the detailed description is omitted.
A thin YAG crystal is used as the laser medium 5, the front surface and the back surface of which are parallel to each other, and the back surface is used as a reflection surface 5 </ b> A for reflecting the laser light L generated inside the laser medium 5. I have.
The five laser modules 2 included in the solid-state laser device 1 have the same configuration.
[0008]
In this embodiment, the arrangement of the five laser modules 2 and the mirrors 3 and 4 is devised so that a small, high-output laser beam L can be obtained.
That is, two laser modules 2 and 2 are connected in parallel such that the optical axis of the semiconductor laser beam L1 is orthogonal to one surface 6A of the mounting base 6 having a rectangular box shape. Similarly, the remaining three laser modules 2 are connected to the other three surfaces 6B, 6C, 6D of the mounting base 6 one by one. Here, the reflecting surfaces 5A of the respective laser media 5 are positioned so that the laser modules 2 are at the same height and are positioned on each side of a rectangle (on a straight line forming a polygon) which is a contour of the mounting base 6. Are arranged so as to be located.
The front mirror 3 is provided at a position outside the space surrounded by the five laser media 5 and at an intermediate position between the laser modules 2 and 2 provided at the positions of the adjacent surfaces 6B and 6C. ing. Further, the rear mirror 4 is provided at a position outside the space surrounded by the five laser media 5 and at an intermediate position between the laser modules 2 and 2 provided at the positions of the adjacent surfaces 6C and 6D. I have. The front mirror 3 is arranged such that its axis is at an angle of 45 degrees with respect to the left laser medium 5 at the position of the surface 6A. The rear mirror 4 is arranged so that its axis is at an angle of 45 degrees with respect to the laser medium 5 located to the right of the surface 6A.
The height of each module 2 and both mirrors 3 and 4 is adjusted so that the reflection surface 5A of the laser medium 5 of each laser module 2 and the axis of both mirrors 3 and 4 are located on the same horizontal plane. Have been.
[0009]
As described above, since each laser module 2 and both mirrors 3 and 4 are arranged, the laser light L oscillated from each laser medium 5 has an angle of 45 degrees toward the reflection surface of the laser medium 5 at the adjacent position. , Is reflected at an angle of 45 degrees, and further enters both mirrors 3 and 4. The laser light L incident on both mirrors 3 and 4 returns in the optical path up to that point in the opposite direction.
The laser light L oscillated synchronously by each laser medium 5 is reflected by the mirrors 3 and 4 and the reflection surface 5A of each laser medium 5 so that the optical paths intersect in the space surrounded by each laser medium 5. It is reflected many times and amplified. When the laser light L is amplified beyond a predetermined output, the laser light L is transmitted through the front mirror 3 and output in the direction of the arrow.
In the present embodiment, each laser module 2 is arranged so that each laser medium 5 is located at the position of each surface 6A to 6D of the mounting base 6 having a polygonal rectangular outline. The two mirrors 3 and 4 are disposed outside the space surrounded by the medium 5.
Therefore, the laser light L can be reflected many times in the space on the inner side surrounded by each laser medium 5. In particular, in the inner space surrounded by each laser medium 5, the laser light L is repeatedly reflected so that the optical paths of the laser light L intersect with each other, so that the optical path of the laser light L passes through many laser media. The laser beam L can pass through, and the installation space of the solid-state laser device 1 can be suppressed small, and high-power laser light L can be obtained.
Further, since the holder 7 as cooling means is disposed on the back side of the laser medium 5, the thin plate-shaped laser medium 5 and the cylindrical lens 8 can be efficiently cooled, and the laser medium 5 due to thermal distortion can be cooled. The occurrence of a refractive index distribution can be reduced.
[0010]
Next, FIG. 4 shows a second embodiment of the present invention. In the second embodiment, a mounting base 13 that is horizontally long and hexagonal when viewed from above is used, and two laser modules 2 and 2 are provided on both sides of the mounting base 13 at opposing positions 13A and 13D. Are installed in parallel. Also, one laser module 2 is attached to each of the other three surfaces 13B, 13C, and 13F. Further, the front mirror 4 and the rear mirror 5 are arranged at positions on the outer side with respect to the remaining surface 13E where the laser module 2 is not provided. In the second embodiment, the incident angle (reflection angle) of the laser light L with respect to each laser medium 5 is 60 degrees. The other configuration is the same as that of the first embodiment.
In the configuration of the second embodiment as well, a large number of laser media can be provided in the optical path of the laser light L by reflecting the laser light L many times in the space surrounded by each laser medium 5. .
Therefore, in the second embodiment, the same operation and effect as those of the above embodiments can be obtained.
[0011]
Next, FIGS. 5 to 7 show a third embodiment of the present invention. In the third embodiment, the members corresponding to those in the first embodiment are indicated by the member numbers obtained by adding 100.
In the third embodiment, the holder 7 in the first embodiment is omitted, and a mounting base 106 having a square cross section is used instead. A horizontal through-hole 106H is formed in each of the surfaces 106A to 106D of the mounting base 106. Then, the laser medium 105 is mounted on four inner surfaces of the mounting base 106, which are inner ends of the through holes 106H. Further, a cylindrical lens 108 is attached to each of the surfaces 106A to 106D which are outer ends of the through holes 106H. Cooling water is circulated through each through hole 106H as in the first embodiment, so that each laser medium 105 and the cylindrical lens 108 can be cooled.
In the third embodiment, two semiconductor lasers 111 and two laser beams are respectively applied to the laser medium 105 and the cylindrical lens 108 provided on each of the surfaces 106A to 106D of the mounting base 106 so as to irradiate the excitation light L1 from a substantially orthogonal direction. 111 are arranged. When the two semiconductor lasers 111 directed toward each laser medium 105 irradiate the laser medium 105 with the excitation light L1 in synchronization with the laser medium 105 from the back side, as shown in FIG. In the shape of an elongated ellipse.
As shown in FIG. 7, in the third embodiment, the laser light L is sequentially reflected at seven positions in the horizontal direction of the reflection surface 105A in each of the horizontally long laser media 105. In the third embodiment, the incident angle and the reflection angle of the laser light L with respect to each laser medium 105 are 45 degrees. Other configurations are the same as those in the first embodiment.
In the configuration of the third embodiment as well, a large number of laser media can be provided in the optical path of the laser light L by reflecting the laser light L many times in the space surrounded by each laser medium 105. . Therefore, in the third embodiment, the same operation and effect as those of the first embodiment can be obtained.
In each of the above embodiments, if a plurality of laser media are provided on the mounting base and a plurality of units forming a space surrounded by the laser media are arranged between the front mirror and the rear mirror, the high output of the solid-state laser device can be further improved. Is possible.
In addition, instead of the cylindrical lens in each of the above embodiments, a window using flat and transparent glass may be used.
[0012]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an effect that a solid-state laser device that is small and can obtain high output can be provided.
[Brief description of the drawings]
FIG. 1 is a plan view showing a first embodiment of the present invention.
FIG. 2 is a sectional view taken along the line II-II in FIG.
FIG. 3 is a front view of the laser medium 5 of FIG. 1 as viewed from the front side.
FIG. 4 is a plan view showing a second embodiment of the present invention.
FIG. 5 is a plan view showing a third embodiment of the present invention.
FIG. 6 is a sectional view of a main part taken along line VI-VI in FIG. 5;
7 is a front view of the laser medium 105 of FIG. 6 as viewed from the front side.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Solid-state laser device 2, 102 ... Laser module 3, 103 ... Front mirror 4, 104 ... Rear mirror 5, 105 ... Laser medium 5A, 105A ... Reflection surface 11, 111 ... Semiconductor laser L ... Laser light L1 ... Excitation light

Claims (3)

A pair of front mirrors and rear mirrors, a plurality of laser media having a reflection surface on the back side that oscillates laser light when irradiated with excitation light and reflects the laser light, and pumps each laser medium from the back surface. In a solid-state laser device having excitation light irradiation means for irradiating light,
Each of the laser media is formed in a thin plate shape, and each of the laser media is arranged such that the reflection surface is located on a straight line forming a polygon. In a region on the inner side of the polygon, an optical path is formed. A solid-state laser device wherein laser light is repeatedly reflected and amplified so as to cross each other. Cooling means is provided on the back surface of the laser medium, and the cooling means includes a through-hole for transmitting the excitation light, and is configured to cool the laser medium by circulating cooling water in the through-hole. The solid-state laser device according to claim 1, wherein: The solid-state laser device according to claim 1, wherein the polygon is a quadrangle or a hexagon.

Images