JPH08316554A - Solid-state laser device - Google Patents

Abstract

PURPOSE: To provide a solid-state laser device where a semiconductor laser which is used for exciting a solid-state laser medium is easily replaced with a new one when it gets out of order. CONSTITUTION: A solid-state device is equipped with a semiconductor laser 28 which excites a solid-state laser medium 21 with laser rays, wherein a heat sink 23 provided with an inner surface which confronts the peripheral surface of the solid-state laser medium 21 and an outer surface, an optical waveguide 24 provided two ends, one is opened at the outer face of the heat sink 23 and the other is opened at the inner face of the heat sink 23, and a holding member 25 holding the semiconductor laser 28 and provided to the outer face of the heat sink 23 in a detachable manner so as to enable the semiconductor laser 28 to confront the opened end of the optical waveguide 24 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state laser device for optically exciting a solid-state laser medium with laser light output from a semiconductor laser.

[0002]

2. Description of the Related Art Generally, a solid-state laser device has a solid-state laser medium such as a YAG rod, and the solid-state laser medium is optically excited to generate laser light. A lamp such as a flash lamp or an arc lamp is used as a means for optically exciting the solid laser medium. In this case, the lamp is arranged at one focus inside the elliptical mirror, and the other focus is provided at the other focus. By arranging the solid-state laser medium, the excitation efficiency of the solid-state laser medium is increased.

However, in the structure in which the solid laser medium is lamp-excited, the light output from the lamp contains a large amount of light having a wavelength that is difficult to be absorbed by the solid laser medium, and therefore the excitation efficiency is high. It was very low.

Therefore, in order to improve the pumping efficiency, a solid-state laser apparatus has been developed which uses a semiconductor laser as a pumping light source, which outputs laser light having a wavelength absorbed by the solid-state laser medium. . FIG. 4 shows a conventional solid-state laser device using a semiconductor laser. In the figure, 1 is a solid laser medium such as a YAG rod. The solid laser medium 1 is inserted into a cooling sleeve 2 made of a material having a light-transmitting property and a heat resistance. A cooling medium for cooling the solid laser medium 1 is circulated in the cooling sleeve 2.

Around the cooling sleeve 2, eight prism-shaped heat sinks 3 each having a trapezoidal cross section are arranged in a ring shape with their side surfaces adjacent to each other. The heat sink 3 has an inner surface 3a facing the solid laser medium 1 side and an outer surface 3b on the opposite side, and a holder 5 holding a pair of cylindrical lenses 4 is provided on the inner surface 3a. There is.

One end of the heat sink 3 is provided with the outer surface 3
The accommodation hole 6 opened to b is formed. The other end of the accommodation hole 6 is opposed to the cylindrical lens 4 via a light guide path 7. A cylindrical mount 9 holding a semiconductor laser 8 at its tip is fitted and fixed in the accommodation hole 6.

A cooling passage 10 through which a cooling medium flows is formed in the heat sink 3, and the semiconductor laser 8 held by the mount 9 is cooled via the heat sink 3. . That is, by controlling the temperature of the semiconductor laser 8 to a predetermined temperature, the wavelength of the laser light output from the semiconductor laser 8 is maintained at a wavelength that is easily absorbed by the solid-state laser medium 1. It is like this.

Therefore, according to the above construction, the laser light output from the semiconductor laser 8 passes through the light guide path 7 and is paired with the cylindrical lenses 4 to form the solid laser medium 1 therein.
The light is condensed into a linear shape along the axis of the solid laser medium 1 to excite the outer peripheral surface of the solid laser medium 1.

By the way, according to the solid-state laser device having such a structure, the mount 9 holding the semiconductor laser 8 is embedded in the accommodation hole 6 of the heat sink 3. Therefore, in the unlikely event that the semiconductor laser 8 fails, it is impossible to replace only the semiconductor laser 8 and the heat sink 3 must be replaced. Heat sink 3
Since it is necessary to remove the cooling medium from the cooling passage 10 in order to replace the heat sink 3 with each other, it may take a lot of time and labor for that purpose, and the heat sink 3 cannot be used repeatedly, resulting in high cost. There is a thing.

Further, the laser light from the semiconductor laser 8 is condensed by a pair of cylindrical lenses 4 to excite the solid-state laser medium 1. Therefore, the lens 4 is provided on the inner surface 3a side of the heat sink 3. Had to be arranged, resulting in an increase in the number of parts and an increase in the size of the device.

[0011]

As described above, in the conventional solid-state laser device in which the solid-state laser medium is excited by the semiconductor laser, when the semiconductor laser fails, the semiconductor laser is broken. In some cases, it is not possible to exchange only the laser light, and because the laser light from the semiconductor laser is focused on the solid-state laser medium by a cylindrical lens, the number of parts and the size of the device are increased. I was invited.

It is an object of the present invention to provide a solid-state laser device which makes it easy to remove the semiconductor laser from the heat sink and replace it when the semiconductor laser fails. .

Another object of the present invention is to provide a solid-state laser device capable of focusing laser light from a semiconductor laser on a solid-state laser medium without using a cylindrical lens. is there.

[0014]

The invention described in claim 1 is a solid-state laser apparatus for exciting a solid-state laser medium with laser light output from a semiconductor laser, wherein an inner surface and an outer surface are provided. A heat sink having an inner surface facing the outer peripheral surface of the solid laser medium, and a conductor formed by opening one end on the outer surface of the heat sink and opening the other end on the inner surface. An optical path and a holding member that holds the semiconductor laser and is detachably provided on the outer surface of the heat sink so that the semiconductor laser faces the one end opening of the light guide path. To do.

According to a second aspect of the present invention, in the first aspect of the invention, the heat sink is provided with a cooling passage for circulating a cooling medium near the outer surface thereof.

According to a third aspect of the present invention, in the first aspect of the present invention, the light guide path is formed in a rectangular cross section, and the inner surface thereof reflects laser light from the semiconductor laser. It is characterized in that it is formed on the reflecting surface.

According to a fourth aspect of the present invention, in the third aspect of the invention, the light guide path has a light source image of the semiconductor laser at one end opening on the outer surface of the heat sink connected at the other end opening on the inner surface. Its cross-sectional shape is set so as to be imaged. According to a fifth aspect of the present invention, in the first aspect of the invention, the holding member is provided in close contact with the outer surface of the heat sink.

[0018]

According to the invention of claim 1, since the holding member holding the semiconductor laser is detachably provided on the outer surface of the heat sink, the semiconductor laser can be removed from the heat sink and replaced.

According to the second aspect of the present invention, since the cooling passage for circulating the cooling medium is formed near the outer surface of the heat sink, the semiconductor laser provided on the outer surface of the heat sink via the holding member is efficiently provided. The temperature can be controlled.

According to the third aspect of the present invention, the heat sink is provided with the light guide path having the rectangular cross section and the inner surface of which is formed as the reflecting surface for reflecting the laser light, so that a separate component such as a cylindrical lens is formed. The laser light can be guided to the solid-state laser medium without using.

According to the invention of claim 4, it is equivalent to arranging the semiconductor laser at the other end opening of the light guide path through which the laser light is emitted. Therefore, the laser light from the semiconductor laser is emitted. Can be effectively incident on the solid-state laser medium.

According to the invention of claim 5, the holding member is a heat
By closely contacting the outer surface of the tosink, the temperature of the semiconductor laser held by the holding member can be efficiently controlled.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The solid-state laser device shown in FIG.
A solid laser medium 21 such as a rod is provided. The solid laser medium 21 is inserted into a cooling sleeve 22 made of a material having a light-transmitting property and a heat resistance. The solid-state laser medium 2 is attached to the cooling sleeve 22.
A cooling medium for cooling 1 is circulated.

Around the cooling sleeve 22, eight heat sinks 23 in the shape of a trapezoid having a trapezoidal cross section and having a flat inner surface 23a and an outer surface 23b are arranged in a ring shape with their side surfaces adjacent to each other. There is. The heat sink 23 is formed of a material having high heat conductivity such as copper, and is arranged so that the inner surface 23a faces the solid laser medium 21 side.

A light guide path 24 is formed at an intermediate portion in the height (thickness) direction of the heat sink 23, one end of which is opened to the inner surface 23a and the other end of which is opened to the outer surface 23b. The light guide path 24 has a rectangular cross section, and its inner surface is formed with a reflecting surface 24a for efficiently reflecting laser light from a semiconductor laser 28, which will be described later, for example by gold plating. . That is, as shown in FIG. 3C, the light guide path 24 is a square tube-shaped kaleidoscope having four reflecting surfaces 24a.

On the outer surface 23b of the heat sink 23,
A flat plate-shaped holding member 25 formed to have substantially the same size as the outer surface 23b is joined to one side surface and is detachably fixed by a plurality of screws 25a. A mounting hole 26 is formed in the holding member 25 at a position corresponding to the other end of the light guide path 24 formed in the heat sink 23, and a tip of a cylindrical holder 27 is fitted and fixed therein. There is. The semiconductor laser 28 is held at the tip of the holder 27. That is, the semiconductor laser 28 is located at the other end of the light guide path 24 opened to the outer surface of the heat sink 23.

The semiconductor laser 28 is a solid laser medium 21.
The one that emits light of a wavelength that is absorbed by is used. For example, when the solid-state laser medium 21 is a YAG rod, by using AlGaAs laser as the semiconductor laser 28, the excitation efficiency can be increased.

A cooling passage 29 through which a cooling medium flows is formed in the heat sink 23. By passing the cooling medium through the cooling passage 29, the temperature of the semiconductor laser 28 held by the holding member 25 via the holder 27 is controlled by the heat sink 23. By controlling the temperature of the semiconductor laser 28, it is possible to prevent the wavelength of the laser light output from the semiconductor laser 28 from changing due to the temperature change.
It is possible to reliably output laser light having a wavelength that is easily absorbed by the laser.

Since the holding member 25 has a flat plate shape and the outer surface 23b of the heat sink 23 is also a flat surface, the holding member 25 can be tightly joined and attached to the outer surface 23b. As a result, the semiconductor laser 28 held by the holding member 25 via the holder 27 is efficiently cooled.

The cooling passage 29 is connected to the heat sink 23.
The inner surface 23a and the outer surface 23b are formed closer to the outer surface. Since the cooling passage 29 is formed near the outer surface 23b, the temperature difference between the holding member 25 provided on the outer surface 23b and the cooling medium flowing through the cooling passage 29 can be reduced, so that the semiconductor layer held by the holding member 25 can be reduced. -The temperature of the 28 can be controlled efficiently and precisely. When the cooling passage 29 is as close to the outer surface 23b as possible, the accuracy of temperature control can be improved.

The light guide path 24 has a cross-sectional shape so that the light source image of the semiconductor laser 28 located at the other end is imaged at one end. That is, FIGS. 3A to 3C
As shown in FIG. 4, the width dimension of the light guide path 24 is w, the height dimension is h, the divergence angle in the width direction of the laser light emitted from the semiconductor laser 28 is θp, and the divergence angle in the height direction is Letting θn be the number of reflections on the inner surface in the width direction of the light guide path N, and M the number of reflections on the inner surface in the height direction, N / M = (h / w) · tan (θp / 2) / tan (θn / 2) (1) is set.

By setting the light guide path 24 so that the relationship of the above equation (1) is established, the light guide path 24 is set as described above.
The light source image of the semiconductor laser 28 located at the other end of the is formed at one end. Thereby, the semiconductor laser 28
Is equivalent to installing at one end of the light guide path 24,
Laser light from the semiconductor laser 28 can be efficiently applied to the solid-state laser medium 21.

According to the solid-state laser device having such a structure, when the semiconductor laser 28 fails, the holding member 25 attached to the outer surface 23b of the heat sink 23 is removed and only the holding member 25 is removed. New semiconductor laser 28
You can replace it with one that has been attached.

Therefore, the heat sink 23 through which the cooling medium is passed through the cooling passage 29 does not have to be replaced as in the conventional case, so that the replacement work can be performed quickly and easily. In particular, since it is not necessary to remove the cooling medium in the cooling passage 29 during the replacement work, the replacement workability is greatly improved.

Further, the heat sink 23 is provided with a light guide path 24 whose inner surface is formed as a reflection surface 24a, and the light source image of the semiconductor laser 28 located at the other end of the light guide path 24 is connected at the emission end. Since it is set so as to be imaged, it is equivalent to disposing the semiconductor laser 28 at the other end of the light guide path 24.

Therefore, the laser from the semiconductor laser 28 can be used without using a cylindrical lens as in the conventional case.
Since the solid-state laser medium 21 can be efficiently irradiated with the laser light, the number of parts can be reduced and the apparatus can be downsized, and in particular, the outer diameter can be reduced.

Further, in the heat sink 23, since the cooling passage 29 for passing the cooling medium is formed near the outer surface 23b, the temperature of the cooling medium and the holding attached to the outer surface 23b cooled by the cooling medium are held. The temperature difference of the member 25 can be reduced. As a result, the cooling efficiency of the semiconductor laser 28 held by the holding member 25 can be improved and the temperature control thereof can be accurately performed.

Further, since the outer surface 23b of the heat sink 23 is a flat surface and the holding member 25 is in the form of a flat plate that is in close contact with the outer surface 23b, the heat conduction from the heat sink 23 to the holding member 25 is improved, and the holding member is held. The temperature of the member 25 can be efficiently controlled.

The present invention is not limited to the above-described embodiment. For example, a plurality of light guide paths 24 are formed in the heat sink 23 at predetermined intervals in the height direction, and a holding member 25 is arranged so as to face each light guide path 24. It is also possible to attach a plurality of semiconductor lasers 28 to each other. The point is that the number of light guide paths 24 formed in the thickness direction of the heat sink 23 depends on the length of the solid laser medium 21 in the axial direction. Should be decided.

[0040]

As described above, according to the first aspect of the present invention, when the semiconductor laser fails, the semiconductor laser can be replaced by simply removing the holding member provided on the outer surface of the heat sink. Therefore, the replacement work can be performed easily and quickly.

According to the second aspect of the present invention, the temperature difference between the temperature of the cooling medium flowing through the cooling passage and the holding member attached to the outer surface of the heat sink can be made small. Therefore, the semiconductor held by the holding member is held. Accurately control the temperature of the laser
And can be done efficiently.

According to the third aspect of the present invention, it is possible to irradiate the solid-state laser medium with the laser light from the semiconductor laser without using a cylindrical lens as in the conventional case. The size of the device can be reduced due to the reduction.

According to the fourth aspect of the invention, this is equivalent to installing a semiconductor laser on the exit side of the light guide path, so that the irradiation efficiency of the laser light from the semiconductor laser can be improved. it can. According to the invention of claim 5, the holding member is a heat
Since it is in close contact with the tosink, the heat transfer efficiency is increased and the cooling efficiency of the semiconductor laser can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of an embodiment of the present invention.

FIG. 2 is likewise a vertical cross-sectional view of the overall configuration.

3 (a) to 3 (c) are explanatory views of a light guide path.

FIG. 4 is a cross-sectional view of a conventional solid-state laser device.

[Explanation of symbols]

21 ... Solid-state laser medium, 23 ... Heat sink, 23a ... Inner surface, 23b ... Outer surface, 24 ... Light guide path, 24a ... Reflecting surface, 25 ... Holding member, 29 ... Cooling passage.

Claims (5)

[Claims] 1. A solid-state laser apparatus for exciting a solid-state laser medium with laser light output from a semiconductor laser, wherein the solid-state laser medium has an inner surface and an outer surface, and the inner surface is the outer circumference of the solid-state laser medium. A heat sink disposed so as to face the surface, a light guide path formed by opening one end on the outer surface of the heat sink and opening the other end on the inner surface, and the semiconductor laser holding the semiconductor laser. A solid-state laser device comprising: a holding member detachably provided on the outer surface of the heat sink so that the laser faces the one end opening of the light guide path. 2. The solid-state laser apparatus according to claim 1, wherein the heat sink is formed with a cooling passage for circulating a cooling medium near the outer surface thereof. 3. The light guide path is formed to have a rectangular cross section, and the inner surface thereof is formed as a reflection surface for reflecting laser light from the semiconductor laser.
The solid-state laser device described. 4. A cross-sectional shape of the light guide path is set so that a light source image of the semiconductor laser at one end opening on the outer surface of the heat sink is imaged at the other end opening on the inner surface. The solid-state laser device according to claim 3, which is characterized in that. 5. The holding member is provided in close contact with the outer surface of the heat sink.
The solid-state laser device described.