JPH0126198B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention provides an unstable resonator type pulsed laser device,
In particular, it relates to the pulsed laser output configuration of unstable resonators.

Conventionally, there has been a laser device of this type as shown in FIG. In Figure 1, 1 is the main body of the unstable resonator type laser device, 2 and 3 are arranged with an appropriate gap A, and a glow (or silent)
A pair of discharge electrodes for discharging, 4 a power source for the discharge, 5 a gas circulation device that circulates and supplies a discharge medium mainly composed of carbon dioxide gas cooled to an appropriate temperature to the gap A; 6 is a concave mirror that is a total reflection mirror, and 7 is a convex mirror that is a total reflection mirror.The concave mirror 6 and the convex mirror 7 have their optical axes aligned with each other, and are placed facing each other with an appropriate distance between them. Form. Reference numeral 8 denotes an aperture which is a total reflection mirror that is located between the concave mirror 6 and the convex mirror 7 on the optical axis C, is inclined at 45 degrees, and has a circular opening in the center when viewed from the direction of the optical axis C. Plane mirrors 9 and 10 are plane mirrors that are total reflection mirrors for changing the direction of laser light, and 11
12 is a convex lens for focusing the laser beam, 12 is a processing head that holds the convex lens 11, 13 is a workpiece, and 14 is a processing table that can arbitrarily move the workpiece within a plane perpendicular to the optical axis. show.

Next, the operation will be explained. The above-mentioned discharge medium B is circulated and supplied to the gap A by the gas circulation cooling device 5, and electricity is supplied from the power source 4 to cause a glow (or silent) discharge between the discharge electrodes 2 and 3, thereby discharging the gap A. The medium is excited and infrared light with a wavelength of approximately 10.6μ, which is characteristic of carbon dioxide gas, is generated. This is amplified in an unstable resonator composed of a concave mirror 6 and a convex mirror 7, and oscillates a laser beam. The laser beam is guided in a ring mode in the direction of the optical axis D by the plane mirror 8 with an aperture, further changed its direction from the direction of the optical axis to the direction of the optical axis by the plane mirrors 9 and 10, and is converted to a large energy density by the convex lens 11. The light is focused on the workpiece 13
is irradiated to cut it.

Generally, when cutting metal materials, etc., if a continuous output laser beam is used, the cut surface becomes dirty due to large heat input, and precise cutting cannot be performed. On the other hand, it is known that pulse cutting allows for highly accurate cutting and results in a very clean cut surface. However, in the case of the laser device shown in Fig. 1, the response speed of the output laser light is slow due to the slow response of the power supply 4, and the oscillation beam diameter is large and the discharge volume is large, so the passage time of the laser medium gas is short. long,
High-speed pulse output of several hundred Hz or more was impossible.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional ones, and it involves providing a through hole in the center of the concave mirror constituting the unstable resonator, and providing a second pulse laser device on the same optical axis. The object of the present invention is to provide a laser device capable of injecting the pulsed laser light obtained from these into the unstable resonator through the through hole of the concave mirror, and using this as a trigger to generate a high output pulsed laser light. .

An embodiment of the present invention will be described with reference to the drawings. In FIG. 2, 6' is a concave mirror with a small hole, which is a total reflection mirror having a through hole in the center, and 16 is a second laser device that outputs a pulsed laser beam. Other parts are the same as in FIG. 1, and the same numbers indicate the same parts.

In the embodiment shown in FIG. 2, the pulsed laser beam emitted from the pulsed laser device 16 is injected into an unstable resonator consisting of a concave mirror 6', a convex mirror 7, etc. through a through hole of a concave mirror 6' with a small hole. , the traveling direction coincides with the optical axis C. Therefore, as shown in FIG. 3, the pulsed laser beam gradually moves away from the optical axis while repeating reflection between the concave mirror 6' with a small hole and the convex mirror 7, and finally forms an unstable resonator at the plane mirror 8 with a hole. be led outside. During this time, due to the glow (or silent) discharge between the discharge electrodes 2 and 3, the laser light repeatedly collides with the excited carbon dioxide molecules in the discharge medium B, and the laser light is amplified, and the ring mode A
It is output as a high-power laser beam. That is, the pulsed laser beam serves as a trigger to output a high-power laser beam, but its pulse response speed is the same as that of the pulsed laser beam.

Furthermore, if a silent discharge excitation pulsed laser, which is a pulsed laser with a high speed response, is used as the pulsed laser device, a high output pulsed laser of 0 to 3 KHz can be output. By setting the output coupling ratio M of the unstable resonator to a large value, a pulsed laser output with a higher output and better quality beam can be obtained.

As described above, according to the present invention, a through hole is provided at the center of a concave mirror constituting an unstable resonator, a second pulse laser device is provided on the same optical axis, and a pulse laser beam is injected through the through hole. However, since the structure is such that it can output high-output pulsed laser light using this as a trigger, a high-performance laser device can be obtained for precision cutting of the workpiece.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional unstable resonator type laser device, Fig. 2 is a block diagram showing an unstable resonator type laser device of the present invention, and Fig. 3 is a block diagram showing the unstable resonance shown in Fig. 2. FIG. 3 is a diagram for explaining the optical system of the device. In the figure, 6 is a concave mirror with small holes, 7 is a convex mirror, and 16 is a second pulse laser device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A pair of discharge electrodes arranged with a gap in between and forming a discharge in the gap, means for circulating and supplying a discharge medium containing carbon dioxide gas as a main component between the pair of discharge electrodes, An unstable resonator is constituted by a concave mirror and a convex mirror that amplify light generated by excitation of the discharge medium by discharge, and an opening is provided at a predetermined tilt angle on the optical axis between the concave mirror and the convex mirror, and in the center. A device for obtaining a laser output from the apertured plane mirror of a total reflection mirror having an aperture, wherein a through hole is provided at the center of the concave mirror constituting the unstable resonator, and
A second pulsed laser device injects pulsed laser light from outside the unstable resonator through the through hole, and emits high-output pulsed laser light using the pulsed laser light from the second pulsed laser device as a trigger. Unstable resonator type pulse laser device that outputs.