JPH07321390A - Solid state laser rod - Google Patents

Abstract

PURPOSE:To produce high output for a long term without causing deterioration of O-ring or the optical end face. CONSTITUTION:The part close to the opposite end faces 2 of a cylindrical solid state laser rod 1 subjected to grey finish is subjected to optical polishing 3. An 0-ring 5 is arranged on the optically polished surface 3 and a holder 7 is fixed through a cap 6 to the solid state laser rod 1. The optically polished surface 3 is applied with a multilayer dielectric coating. The O-ring 5 serves as a seal for the cooling water. Since the oscillated light 8 is totally reflected on the optically polished surface 3 and the multilayer dielectric coating, the 0-ring 5 and the end face 2 are not subjected to damage caused by scattering of the laser light 8.

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 rod, and more particularly, to a holder having a cylindrical surface with a grain finish and an O-ring for sealing the cooling water flowing outside in contact with the cylindrical surface. Relates to a solid-state laser rod in which both ends are attached.

[0002]

2. Description of the Related Art Conventionally, in a solid-state laser oscillator, in order to seal the optical end surface of a solid-state laser rod, for example, a YAG rod, from cooling water, an O-ring is formed on the surface of the rod, which is finished in the sand, for example, in the sand of No. 400. Installed.

When this solid-state laser rod is used for a high-power laser, for example, a laser oscillator of 1 kW or more, the oscillated laser light is scattered by the grains on the surface of the solid-state laser rod,
When it hits the O-ring, it causes deterioration of the O-ring.

As a method for solving this, Japanese Patent Laid-Open No. 1-22
In 45583, the O-ring for sealing is covered with a fluorine-based resin to prevent the laser light from hitting the O-ring to generate gas and go out.

[0005]

In the above-mentioned conventional solid-state laser rod, an O-ring is attached to a grain-finished cylindrical surface in order to seal cooling water. Therefore, when used in a high-power laser oscillator, oscillation occurs. The generated laser light scatters on the sand and hits the O-ring, resulting in deterioration of the O-ring. Therefore, if it is used for a long period of time, there is a drawback that the optical end face of the laser rod is damaged due to water leakage or gas generation.

Further, in a solid-state laser rod for a low-power laser, especially in TEMoo, a cylindrical surface is used as optical polishing, but this optical polishing is only for the portion which is optically excited, and the excitation light is focused around. Since it is applied for the purpose, it has no effect on the prevention of O-ring deterioration.

Further, in the above-mentioned method of covering the O-ring with the fluorine-based resin, the scattering of the laser beam is unavoidable. Therefore, even if the O-ring is prevented from being deteriorated, water accompanying the deterioration of the fluorine-based resin is also prevented. However, there is a drawback that it cannot solve the damage of the rod optical end face due to the generation of gas or gas.

It is an object of the present invention to provide a solid state laser rod which does not deteriorate the O-ring when used in a high power oscillator and therefore does not suffer damage to the optical end face.

[0009]

In the solid-state laser rod of the present invention, the portions near both ends of the cylindrical surface including the portion contacting the O-ring are optically polished.

The optical-polished cylindrical surface includes a dielectric coating.

The dielectric coating may include a multi-layer dielectric coating composed of a plurality of dielectric layers having different refractive indexes.

The multi-layer dielectric coating comprises a layer of magnesium fluoride and zirconium oxide.

[0013]

Since the optical polishing is applied to the portions near both ends of the cylindrical surface including the portion contacting the O-ring, the laser light is reflected by the optical polishing surface and does not scatter, so that it is used in a high power oscillator. Also does not deteriorate and damage the O-ring and the end face.

The one having a dielectric coating on the optically polished surface has a higher reflectance, and in particular, the one having a multi-layer dielectric coating causes total reflection even when the incident laser beam exceeds the critical angle. It has a great effect of preventing deterioration and damage of the O-ring and the like.

[0015]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 (a) is a side view of an embodiment of the solid-state laser rod of the present invention, FIG. 1 (b) is a front view of FIG. 1 (a),
FIG. 7C is a vertical cross-sectional view showing a state where a holder is attached to the solid-state laser rod of FIG.

The solid-state laser rod 1 is a YAG rod and is used in a solid-state laser oscillator. Optical polishing 3 is applied to the cylindrical surface of the solid-state laser rod 1 from both end surfaces 2 except for both end surfaces 2 in the axial center direction within 10 mm. The optical polishing 3 is polished to a surface accuracy of 10Å or 1 nm, and magnesium fluoride (Mg
A multilayer dielectric coating consisting of a layer of F ₂ ) and a layer of zirconium oxide (ZrO) is applied. Here, the magnesium fluoride layer and the zirconium oxide layer have different refractive indexes.

The remaining portion of the cylindrical surface of the solid laser rod 1 is grained 4. The grain finish surface 4 is finished to have a roughness of 400, for example.

An O-ring 5 for sealing cooling water is placed on the dielectric-coated optical polishing surface 3, and a holder 6 is attached to the solid-state laser rod 1 by a cap 6.
It is fixed to.

When the solid-state laser oscillator is in an oscillating state, a laser beam 8 is oscillated in the axial direction of the solid-state laser rod 1, and the laser beam 8 is totally reflected by the optical polishing surface 3 and the dielectric coating layer. Does not hit Therefore, even if the O-ring 5 is used for a long period of time, the O-ring 5 is not deteriorated, and therefore there is no water leakage or gas generation due to the deterioration of the O-ring 5, so that the end face 2 near the optical polishing surface 3 is not damaged. The optical polishing surface 3 cannot totally reflect the laser light 8 incident at an angle exceeding the critical angle, but since the multilayer dielectric coating on the optical polishing surface 3 totally reflects this incident light, the laser light is scattered. Does not occur.

In the solid-state laser rod of this embodiment, optical polishing and dielectric coating are applied to the portions near both ends including the portion contacting the O-ring of the cylindrical surface, so that the laser light is totally reflected and is not scattered. Therefore, since the O-ring and the end face are not deteriorated and damaged, there is an effect that the high-power oscillator can be used for a long time.

[0022]

As described above, according to the present invention, since the laser light is not reflected and scattered by the optical polishing surface by performing optical polishing on the portions near both ends of the cylindrical surface, the O-ring and the optical end surface are deteriorated and damaged. The effect is that it can be used for a long period of time by being used in a high-power oscillator without being made to operate.

Further, by providing a dielectric coating on the optically polished surface to increase the reflectance of laser light, and particularly by applying a plurality of multilayer dielectric coatings having different refractive indexes, incident laser light exceeding a critical angle can be obtained. Since the light is totally reflected, the effect of preventing deterioration of the O-ring and the like is further improved.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a solid-state laser rod of the present invention, in which (a) is a side view, (b) is a front view, and (c) is a longitudinal sectional view showing a state in which a holder is attached. Is.

[Explanation of symbols]

 1 Solid Laser Rod 2 End Face 3 Optical Polishing Surface 4 Grain Finished Surface 5 O Ring 6 Cap 7 Holder 8 Laser Light

Claims (4)

[Claims] 1. A solid-state laser rod in which a cylindrical surface is grained, and holders for mounting an O-ring for sealing cooling water flowing outside in contact with the cylindrical surface are attached at both ends, A solid-state laser rod, wherein optical polishing is applied to a portion near both ends of the cylindrical surface including a portion contacting the O-ring. 2. The solid-state laser rod according to claim 1, wherein a dielectric coating is applied on the optically polished cylindrical surface. 3. The solid-state laser rod according to claim 2, wherein the dielectric coating is a multi-layer dielectric coating including a plurality of dielectric layers having different refractive indexes. 4. The multilayer dielectric coating comprises layers of magnesium fluoride and zirconium oxide.
The solid-state laser rod described.