JPH09289347A - Laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to irradiate a laser beam on an unused part of an optical means which forms a laser resonator by moving this means, without shifting the optical axis if the reflection surface of this means is damaged, by specifying the relation between the size of this means in its moving direction and the irradiation range of the laser beam. SOLUTION: The laser device 11 comprises a slab 14, i.e., a slab type solid- state laser medium housed in a laser resonator 17 composed of a pair of total reflection mirrors 15 to be an optical means and an output coupling mirror 16 to be an optical means for taking out a laser beam from the laser device 11. The size of the optical means in its moving direction is twice or more the size of the irradiation range of the laser beam. If damaged parts of the reflection surface of the pair of total reflection mirrors 15 and output coupling mirror 16 appear on the laser beam irradiated parts, a stage 19 supporting these mirrors 15 and 16 is moved by a screw 18a in the thickness direction of the slab 14 to irradiate the laser beam on other part than the damaged parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser device, and more particularly, to maintenance of optical means constituting a laser resonator.

[0002]

2. Description of the Related Art FIG. 13 shows a conventional slab type solid state laser device 1. Nd: YAG (Neodymium dop)
ed Yttrium Aluminum Garne
t) The slab 2 which is a slab type solid-state laser medium made of a crystal has a pair of smooth surfaces 3 and a pair of end surfaces 4. On a side portion of the slab 2, a pair of lamps 5 for optically exciting the slab 2 are provided so as to face the smooth surface 3. Further, a total reflection mirror 6 and a partial reflection mirror 7 are provided on the sides of the pair of end faces 4 so as to be at right angles to the longitudinal direction of the slab 2, and the total reflection mirror 6 and the partial reflection mirror 7 are combined. The laser light is oscillated in the laser resonator 8 thus constructed.

Usually, a total reflection mirror 6 which constitutes the resonator 8
A laser resonator 8 is provided on the reflection surface of the partial reflection mirror 7.
A coating such as a dielectric multilayer film is provided to improve the light confining effect in the inside to improve the light emission efficiency and at the same time to increase the laser proof strength of the laser resonator 8. In such a slab type solid-state laser device 1, when the slab 2 in the laser resonator 8 absorbs the excitation light having a wavelength of about 0.8 μm from the emission of the lamp 5, an inversion distribution is formed inside the slab 2. A wavelength of 1.06 which propagates in a zigzag manner while repeating total internal reflection between a pair of smooth surfaces 3 in the laser resonator 8.
The laser beam 9 of μm is oscillated. The laser light 10 of the laser light 9 that has passed through the partial reflection mirror 7 is obtained as an output outside the laser resonator 8.

Generally, in a laser device used for welding or cutting, the laser power confined in the resonator reaches several hundreds W to several times the rated output which is several KW.
Therefore, a high laser proof strength is required for a resonator mirror such as a total reflection mirror or a partial reflection mirror that constitutes the resonator. However, if the laser device continues to operate for a long time, the coating on the surface of the resonator mirror is damaged by baking, etc., and the light confinement effect and laser proof strength of the resonator are reduced, and the laser output It is necessary to periodically replace the resonator mirror with a new one because it may cause deterioration and breakage of the resonator mirror.

[0005]

However, in the work of exchanging the resonator mirror as described above, the work of adjusting the optical axis of the laser beam in the resonator after installing a new resonator mirror is a common practice. Since this is a difficult work requiring time and labor, it takes a lot of time and labor.In addition, since such an optical axis adjustment work must be performed in a state in which a laser beam with a rated output is being oscillated, a laser device is particularly required. There is a problem that handling a high-power laser beam is dangerous.

Therefore, an object of the present invention is to provide a slab-type solid-state laser device that solves these problems, and particularly to provide a slab-type solid-state laser device in which the maintainability of the resonator is greatly improved. is there.

[0007]

According to a first aspect of the present invention, there is provided a laser device, wherein the optical means forming the laser resonator, the laser medium provided in the laser resonator, and the laser medium are optically pumped, and the laser resonator is provided. A laser device comprising a light source for oscillating laser and a moving means for moving the optical means in a direction perpendicular to the optical axis of the laser light oscillated in the laser resonator, wherein the dimension of the optical means in the moving direction is It is at least twice the size of the irradiation range of the laser light.

In the laser device according to the second aspect, the optical means is a pair of total reflection mirrors having no unevenness at least in the moving direction.

In the laser device according to the third aspect, the optical means includes at least one output mirror in the resonator for extracting the laser light to the outside of the laser device.

According to another aspect of the laser device of the present invention, the optical means has at least one lens in the resonator for improving the effect of confining the laser light in the resonator.

According to another aspect of the laser device of the present invention, the laser medium is a slab type solid laser medium having a cross-sectional shape with a large aspect ratio.

In the laser device according to the sixth aspect, the slab type solid laser medium is an Nd: YAG crystal having a pair of smooth surfaces and an end surface through which laser light enters and exits.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. 1 to 3 show a laser device 1 according to the present invention.
1 is shown. The laser device 11 has a pair of smooth surfaces 12 and a pair of end surfaces 13 as a laser medium having a cross-sectional shape with a large aspect ratio, and is Nd: YAG (Neodymi).
um doped Yttrium Aluminum
Garnet) a slab 14 which is a slab type solid-state laser medium, and a pair of total reflection mirrors 15 which are optical means, and an output coupling which is an output mirror which is an optical means for extracting laser light to the outside of the laser device 11. It is provided inside a laser resonator 17 composed of a mirror 16.

The slab 14 is, for example, 25 mm in width (direction of arrow shown in FIG. 1) and 6 mm in thickness (direction of arrow shown in FIG. 2).
Of a rectangular type with an aspect ratio of 4 or more and a length of 200 mm (the direction in which the laser oscillates in FIGS. 1 and 2)
d: YAG crystal. On the other hand, the total reflection mirror 15 and the output coupling mirror 16 both have a laser resonator 17 on their reflection surfaces.
A standard product having a coating such as a dielectric multilayer film for improving the laser light confinement effect to enhance the light emission efficiency and at the same time enhance the laser resistance of the laser resonator 17 is used. Is a length 50 mm in the thickness direction of the slab 14 having a reflecting surface having a ridge line in the thickness direction of the slab 14 (the arrow direction in the slab in FIG. 2) × slab 1
4 is a concave mirror having a length of 50 mm in the width direction, and the output coupling mirror 16 is a flat plate mirror (reflecting surface is 50 mm × 50 mm) having a length of 50 mm in the thickness direction of the slab 14.

Further, since the output coupling mirror 16 is installed so that the laser output is taken out only from the upper side in the width direction of the laser light oscillated in the laser resonator 17 (direction of the arrow in the slab in FIG. 1), the laser resonator is provided. 17 is shown in FIG. 1 (slab 14
In the cross section shown in FIG. 2 (the cross section in the thickness direction of the slab 14), the unstable resonator is formed in the cross section shown in FIG. Is.

The pair of total reflection mirrors 15 and output coupling mirror 16 are fixed to stays 19 movably provided on separate pedestals 18 as moving means of the optical means, and in the thickness direction of the slab 14. It can be moved. That is, the stay 19 can slide in the thickness direction of the slab 14 with respect to the pedestal 18, and the screw 18 a is provided between the stay 19 and the pedestal 18 so as to be fixed at that position. A total reflection mirror 15 is attached to the stay 19 via a screw 20 so that the optical axis of the total reflection mirror 15 can be adjusted. The output coupling mirror 16 has the same structure, but in the illustrated example, there is no screw for adjusting the optical axis. As means of movement, in addition to screws, shims, blocks,
A combination of positioning projections and depressions can also be used. Furthermore, a pair of lamps 21 for optically exciting the slab 14 are provided on the sides of the slab 14 so as to face the smooth surface 12.

In such a laser device 11, when the slab 14 in the laser resonator 17 absorbs the excitation light having a wavelength of about 0.8 μm from the emission of the lamp 21, the slab 1
4, a population inversion is formed, and laser light 22 having a wavelength of 1.06 μm propagating in a zigzag manner while repeating total internal reflection between a pair of smooth surfaces 12 in the laser resonator 17 is oscillated. Then, the laser beam 22 is extracted by the output coupling mirror 16 in the direction of arrow 23 in FIG.

Further, by using the laser device 11 for a long period of time, as shown in FIGS. 4a to 4c and 5a to 5c, the pair of total reflection mirror 15 and the output coupling mirror 16 are coated with a reflection surface. Degraded damaged part 2
4 is generated in the laser light irradiation unit 25. In such a case, as shown in FIG. 3, the stay 19 supporting the total reflection mirror 15 and the output coupling mirror 16 is moved in the thickness direction of the slab 14 with respect to the pedestal 18 by the screw 18a to damage the damaged portion 2
If the laser beam 22 is radiated to a portion other than 4,
Since the total reflection mirror 15 and the output coupling mirror 16 are flat in the thickness direction of the slab 14, the laser resonator 17
In the case where the laser resonator 17 can be easily maintained without the optical axis inside being displaced, that is, without adjusting the optical axis, and the total reflection mirror 15 and the output coupling mirror 16 are replaced with new ones. The same effect as can be obtained. Since the thickness of the slab 14 is 6 mm as described above, the thickness of the laser light 22 is also about 6 mm, while the total reflection mirror 15 and the output coupling mirror 16 are low in cost as described above. Since a standard product is used because of the relationship, since the length of the slab 14 in the thickness direction is 50 mm,
Perform such maintenance 7 to 8 times (∵50mm / 6m
m ≈ 8.3) Can be repeated, laser resonator 1
7 can be improved in maintainability and the downtime of the laser device 11 can be greatly reduced.

Here, a laser device using a slab 14 which is a laser medium having a large cross-sectional aspect ratio will be described, and a total reflection mirror 15 and an output coupling mirror 16 which are optical means are provided in the slab 14. Although the laser device which moves in the thickness direction is shown, the same effect is exhibited in a laser device using a laser medium having another cross-sectional shape, and an optical means is provided with respect to the optical axis of the laser beam. The present invention also corresponds to a laser device provided with a moving means that moves in a direction different from this embodiment as long as it is a right angle direction.

Embodiment 2 6 to 8 show another embodiment of the laser device of the present invention. The laser resonator 27 of the laser device 26 of the second embodiment is provided with a lens 28 which is an optical means for improving the light confining effect in the laser resonator 27. The other structure is similar to that of the first embodiment. The lens 28 is a convex lens having a width of 50 mm and having a ridgeline in the width direction of the slab 14 on the surface on the slab 14 side, and the surface thereof is to reduce loss due to reflection of the laser light 29 in the laser resonator 27. Has been coated. The lens 28 is fixed to the stay 19 movably provided on the pedestal 18, which is a moving unit of the optical unit, by a screw 18a, and is movable in the thickness direction of the slab 14.

In the laser device 26 having such a structure, not only the total reflection mirror 15 and the output coupling mirror 16 but also the surface of the lens 28 as shown in FIGS. Damaged part 3 to part 30
When 1 occurs, the position of the laser light irradiation unit on the optical means can be changed as in the first embodiment. That is, the stay 19 movably provided on the pedestal 18 is moved by the screw 18a to move the lens 28 in the thickness direction of the slab 14 having a curvature, thereby refracting the optical path of the laser light 29 as shown in FIG. Let On the other hand, in order to compensate for the refraction component of this optical path, the total reflection mirror 15 on the optical path side where the laser light 29 is refracted is adjusted by the screw 20 so that the laser light 29 enters the total reflection mirror 15 vertically. At this time, the movement of the total reflection mirror 15 by the screw 18a is not always necessary. In this way, the maintenance of the laser resonator 27 can be easily performed similarly to the first embodiment without performing the optical axis adjustment as in the related art, and the total reflection mirror 1 can be performed.
5, the same effect as when the output coupling mirror 16 and the lens 28 are replaced with new ones can be obtained.

[0022]

According to the first aspect of the present invention, the laser device has the optical means constituting the laser resonator, the laser medium provided in the laser resonator, and the laser medium which is optically excited to cause laser oscillation in the laser resonator. A laser device comprising: a light source; and a moving means for moving the optical means in a direction perpendicular to the optical axis of the laser light oscillated in the laser resonator, wherein the dimension of the moving direction of the optical means is irradiation of the laser light. Since the size is more than twice the size of the range, when the reflecting surface of the optical means is damaged by using the laser device for a long time, the optical means is moved in the moving direction without shifting the optical axis. The maintenance of the laser resonator for irradiating the unused portion of the laser beam with the laser beam can be performed at least once.

In the laser device according to the second aspect, the optical means is provided with a pair of total reflection mirrors having no unevenness at least in the moving direction, so that the optical means is moved in the direction not having the unevenness of the optical means. By doing so, maintenance of the laser resonator can be easily performed without shifting the optical axis in the laser resonator.

According to another aspect of the laser device of the present invention, the optical means includes at least one lens for improving the effect of confining laser light in the resonator, so that the laser in the laser resonator is provided. The light confinement efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a side view showing a width direction of a laser device of the present invention.

FIG. 2 is a side view showing a thickness direction of the laser device of the present invention.

FIG. 3 is a side view showing a state in the thickness direction when the optical means of the laser device of the present invention is moved by the moving means.

FIG. 4 is a diagram showing a state in which a total reflection mirror, which is an optical unit of the laser device of the present invention, is damaged by laser light.

FIG. 5 is a diagram showing a state in which an output coupling mirror, which is an optical unit of the laser device of the present invention, is damaged by laser light.

FIG. 6 is a side view showing the width direction of another embodiment of the laser device of the present invention.

FIG. 7 is a side view showing another embodiment of the laser device according to the present invention in the thickness direction.

FIG. 8 is a side view showing a state in the thickness direction when the optical means of another embodiment of the laser device of the present invention is moved and adjusted by the moving means.

FIG. 9 is a diagram showing a state in which a lens, which is an optical unit of another embodiment of the laser apparatus according to the present invention, is damaged by laser light.

FIG. 10 is a side view showing a thickness direction of a conventional laser device.

[Explanation of symbols]

1, 26 laser device, 14 slab, 15 total reflection mirror, 16 output coupling mirror, 17, 27 laser resonator, 18 pedestal, 19 stay, 21 lamp.

Claims (6)

[Claims] 1. Optical means constituting a laser resonator, a laser medium provided in the laser resonator, a light source for optically exciting the laser medium to cause laser oscillation in the laser resonator, and the optical means. A laser device having a moving means for moving in a direction perpendicular to the optical axis of the laser light oscillated in the laser resonator, wherein the dimension of the optical means in the moving direction is the irradiation range of the laser light. A laser device that is more than twice the size of. 2. The laser device according to claim 1, wherein the optical means includes a pair of total reflection mirrors having no unevenness at least in the moving direction. 3. The laser device according to claim 1, wherein the optical means comprises at least one output mirror in the resonator for extracting the laser light to the outside of the laser device. 4. The laser device according to claim 1, wherein the optical unit includes at least one lens for improving a confining effect of laser light in the resonator in the resonator. 5. The laser device according to claim 1, wherein the laser medium is a slab-type solid-state laser medium having a cross-sectional shape with a large aspect ratio. 6. The slab type solid-state laser medium has a pair of smooth surfaces and an end surface through which laser light enters and exits Nd: YA.
The laser device according to claim 5, which is made of a G crystal.