JPH0789591B2 - Carbon dioxide laser device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a high-power carbon dioxide laser device, and more particularly to improvement of polarization characteristics of its output laser light.

[Technical background of the invention]

Conventionally, a high-power carbon dioxide laser device is shown in FIGS.
As shown in the figure, the end mirror 1 and the output mirror 2 constitute a resonator 3. In FIG. 3, a randomly polarized laser light 4 as shown in FIG. 3B is obtained, and in FIG. 4 a linearly polarized laser light 6 as shown in FIG. Is getting A method of converting the linearly polarized laser light 6 into circularly polarized light is shown in FIG.

[Problems of background technology]

In a conventional carbon dioxide gas laser device, as shown in FIG. 4, a Brüster window 5 is provided, and the polarization of the laser resonance light is changed by the difference in the transmittance due to the difference in the polarization plane of the light of the Brüster window 5. I had decided on the plane. However, when the laser output becomes high and the wavelength becomes long at 10.6 μm like a carbon dioxide gas laser, a general glass material is not used and it is necessary to use a special material (ZnSe or the like). When the resonance energy becomes high, the energy passing through the Brewster window 5 increases, and the energy absorbed by the Brewster window 5 increases accordingly. For this reason, this Brüster window material may be subjected to optical thermal strain, causing the configuration of the resonator 3 to be disturbed, resulting in a reduction in laser output and a change in oscillation transverse mode.

Further, as shown in FIG. 5, the conversion of the linearly polarized laser light 6 into the circularly polarized laser light 8 was also performed using the 1/4 wavelength plate 7. In addition to causing the same problems as the Uster window 5, it may be destroyed due to the heat load.

[Object of the Invention]

It is an object of the present invention to provide a carbon dioxide gas laser device which solves the above-mentioned conventional problems and is capable of obtaining a high-power carbon dioxide gas laser beam of clean circularly polarized light.

[Outline of Invention]

According to the present invention, an end mirror and an output mirror are provided at both ends of a tube having an L-shaped tube axis, and inside the tube, an incident angle and a reflection angle are 30 degrees to near the output mirror.
An integrated carbon dioxide gas laser resonator with a bending reflection mirror that bends the optical axis to 60 degrees, and an incident angle of 45 degrees on the optical path near the output mirror of this resonator. A carbon dioxide laser device consisting of a 1/4 wavelength conversion mirror.

Example of Invention

The carbon dioxide gas laser device of the present invention is as shown in FIG. 1. When the same parts as those in the conventional example are designated by the same reference numerals, the resonator 3 outputs the end mirror 1 and the output to the both ends of the tube having the L-shaped tube axis. It is composed of a mirror 2. A bending reflection mirror 9 is disposed near the output mirror 2 at a corner inside the resonator 3 so that the incident angle and the reflection angle are 30 ° to 60 °, for example 45 °. Has been done. Further, a 1/4 wavelength conversion mirror 10 set at an incident angle of 45 ° is provided outside the resonator 3, that is, on the optical path near the output mirror 2.

During operation, the folding reflection mirror 9 determines the plane of polarization of the laser light at resonance. This is determined because the reflectance differs depending on the P-polarized light and the S-polarized light and the oscillation gain is high in the carbon dioxide laser. The characteristic curves of reflection in the P-polarized light and the S-polarized light are shown in FIG. Next, the 1/4 wavelength conversion mirror 10 causes the linearly polarized laser beam 6 emitted from the resonator 3 to undergo a rotation action of the plane of polarization by the 1/4 wavelength conversion mirror 10, and becomes a circularly polarized laser beam 8. To be converted.

〔The invention's effect〕

According to the present invention, one bending reflection mirror 9 is provided inside the resonator without giving a large heat load to the optical components, particularly the Brüster window 5 and the quarter-wave plate 7, as in the conventional case. 1/4 wavelength conversion mirror 10 immediately after laser emission
Circularly polarized carbon dioxide laser light can be easily obtained by providing each one, and the effect of applying the laser light to processing or the like is great.

Further, in the present invention, since the above-mentioned functions are concentrated near the output mirror 2, all the functions can be unitized. Furthermore, because of the integrated structure, the linear polarization plane and the quarter-wave conversion mirror 10
The positional relationship with and could be set with mechanical accuracy. Due to this integrated structure, the circularly polarized light (the function of converting linearly polarized light into circularly polarized light) is not affected by the rotation at the output mirror unit.

Further, according to the present invention, the basic optical axis of the laser resonator can be made parallel to the optical axis after being circularly polarized, and when the coaxial optical axis is further aligned, two more folds are required. It is possible to use the bending reflection mirror 9. In this case, the 1/4 wavelength conversion mirror 10 may be two 1/8 wavelength conversion mirrors.

The present invention can be applied not only to a single-axis resonator but also to a multi-folded resonator.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a carbon dioxide gas laser device according to an embodiment of the present invention, FIG. 2 is a characteristic curve diagram showing reflection characteristics in P-polarized light and S-polarized light, and FIGS. FIG. 5 is a schematic configuration diagram showing two examples of the gas laser device, and FIG. 5 is an explanatory diagram showing a method of converting linearly polarized laser light into circularly polarized laser light by a 1/4 wavelength plate. 1 …… End mirror, 2 …… Output mirror, 9 …… Bending reflection mirror, 10 …… 1/4 wavelength conversion mirror.

Claims (1)

[Claims] 1. An end mirror and an output mirror are respectively provided at both ends of a tube having an L-shaped tube axis, and inside the tube, near the output mirror, an incident angle and a reflection angle are 30 degrees to 30 degrees.
An integrated carbon dioxide gas laser resonator with a bending reflection mirror that bends the optical axis to 60 degrees, and an incident angle of 45 degrees on the optical path near the output mirror of this resonator. Carbon dioxide laser device consisting of 1/4 wavelength conversion mirror.