JPS59145585A - Laser oscillator - Google Patents

Abstract

PURPOSE:To obtain a laser oscillator, an optical system thereof is simple, an output coupling mirror therein is not deteriorated and deformed while durability and reliability thereof are excellent, by forming a total reflection plane for laser rays at the central section of the internal surface of the output coupling mirror and extracting laser rays, the section of laser-ray intensity distribution thereof forms a ring shape. CONSTITUTION:A total reflection plane 202 obtaned through the evaporation of gold, etc. is formed at the central section of the inner surface of an output coupling mirror 2, and the section of output rays 41 takes a doughnut shape that the center section is removed. The output coupling mirror 2 is formed in simple constitution of which a substance such as gold is evaporated at the central section only by one layer, and laser rays do not pass through the central section because of a total reflection mirror, and the generation of heat, a deformation and a breakdown can be reduced largely. Accordingly, since the total reflection plane is formed at the central section of the internal surface of a resonator in the output coupling mirror constituting an optical resonator in a laser oscillator and ring-shaped laser rays are extracted, the deterioration and deformation of the inner surface of the output coupling mirror remarkably lowering the reliability of the laser oscillator can be reduced, and durability and reliability are improved while an optical system can be simplified in an unstable resonator.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a laser oscillator.

Configuration of conventional example and its problems Figure 1 shows an example of a conventional stable resonator, where 1 is a total reflection mirror, 2 is an output coupling mirror, 3 is the resonator body, 4 is an output beam, 4
0 is the cross section of the output light beam 4, and 401 is the output intensity distribution, which is an example of the fundamental mode. In this example, the energy is concentrated at the center of the output coupling mirror 2, and although the outer periphery is cooled by the holder, the center is difficult to cool, which can easily cause the surface film to break or the base material to deform. becomes unstable.

FIG. 2 is an enlarged sectional view of the output coupling mirror 2 of the conventional stable resonator shown in FIG. In the figure, 200 is the base material;
2o3 is a percent reflective film, and 204 is an antireflective film. The percent reflection film 203 of the output coupling mirror is 2%Se,
! : It is obtained by alternately depositing multiple layers of different materials such as PbF, etc., the laser beam surface strength and adhesion strength with the base material 200 are weak, the energy density is particularly high in the center, and the cooling effect is also poor. In many cases, the bag started to break from that part.

FIG. 3 is a schematic principle diagram of a conventional unstable resonator. 1
20 is a total reflection mirror, and 21 is a transmission window. Reference numeral 41 denotes a ring-shaped cross section of the output light beam. In this configuration, total reflection mirror 2
Since the optical adjustment of 0 becomes complicated within the resonator, it is practically
As shown in the figure, a donut-shaped total reflection mirror 201 is built in,
An output beam 41 having a doughnut-shaped cross section is obtained in a direction perpendicular to the main body.

The feature of an unstable resonator is that by increasing the effective inner diameter of the resonator, a large amount of power can be input for discharge excitation and a high output laser beam can be obtained. 20. Donut mirror (total reflection mirror) 201. Transparent window 2
Three optical components (No. 1) are required on the output extraction side.

As described above, the conventional method has drawbacks such as deterioration of the output coupling mirror and the large number of optical components used, which causes output and mode instability.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to provide a laser oscillator with a simple optical system, no deterioration or deformation of the output coupling mirror, and excellent durability and reliability. shall be.

Structure of the Invention The present invention achieves the above object by forming a total reflection surface that reflects the laser beam at the center of the output coupling mirror constituting the optical resonator of the laser oscillator. The present invention provides a laser oscillator that outputs a laser beam whose intensity distribution has a ring-shaped cross section.

DESCRIPTION OF EMBODIMENTS FIG. 5 shows an embodiment of the optical resonator of the present invention, (a)
shows a stable resonator, and (b) shows an unstable resonator.

The same parts as in FIG. 1 are given the same numbers and their explanations are omitted, but the feature of the present invention is that a total reflection surface 202 obtained by, for example, gold vapor deposition is formed in the center of the inner surface of the output coupling mirror 2. The cross section of the output light beam 41 is donut-shaped with the center section missing.

FIG. 6 is an enlarged sectional view of the output coupling mirror 2 of the stable resonator shown in FIG. 6(a). In the figure, 200 is ZxSe
204 is PbF, 204 is an antireflection film such as ThF4, and 202 is a total reflection surface obtained by gold vapor deposition.

The output coupling mirror 2 of this embodiment has a simple structure, with just a layer of material such as gold deposited on the center part, and since it is still a total reflection mirror, the laser beam does not pass through this center part, causing heat generation and deformation. , the damage and damage can be greatly reduced.

Effects of the Invention As described above, the present invention provides a total reflection surface at the center of the inner surface of the resonator of the output coupling mirror constituting the optical system of the laser oscillator to extract a ring-shaped laser beam. ,
This makes it possible to reduce the deterioration and deformation of the inner surface of the output coupling mirror, which significantly reduces the reliability of the laser oscillator, thereby improving durability and reliability. It has the advantage of being easy to use.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a conventional stable resonator; Figure 2 is a sectional view of the output coupling mirror of the stable resonator shown in Figure 1;
Figure 4 is a schematic principle diagram of a conventional unstable resonator, Figure 6
The figures are block diagrams of the laser oscillator of the present invention, in which (a) shows a stable resonator, (b) shows an example of an unstable resonator, and Fig. 6 shows the stable resonator shown in Fig. 6 (8L). FIG. 3 is a cross-sectional view of the output coupling mirror of FIG. 1... Total reflection mirror, 2... Output coupling mirror, 3
...Resonator main body, 40, 41 ... Output beam, 20 ... Total reflection mirror, 21 ... Transmission window, 200 ... Base material, 201...Doughnut-shaped total reflection mirror, 202...Total reflection surface. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 ＼ Shen Figure 3 Figure 4 201 Figure 5 20? Figure 6 397-

Claims (1)

[Claims] A total reflection surface that reflects the laser beam is formed at the center of the output coupling mirror inside the resonator constituting the optical resonator, and a laser beam with a ring-shaped cross section of the laser beam intensity distribution is extracted. Characteristic laser oscillator.