JPS5889886A - Laser oscillator - Google Patents

Abstract

PURPOSE:To enhance the stability of a resonator, by shielding a mirror position adjusting mechanism, from atmosphere and providing said mechanism in a container of a system having laser gas in the opetical resonator, thereby preventing the fluctuation of mirror surfaces. CONSTITUTION:The mirror position adjusting mechanism is built in the inside of a main body flange 101 and a main body cap 102, and shielded from the atmosphere. When the mirror position adjustment has been finished, the main body cap 102 is attached, the air inside the optical resonator is exhausted, the laser gas having a specified pressure is supplied, and the laser oscillation is performed. The pressure difference hardly occurs on both surfaces of the mirror from the time the mirror position adjustment was finished and to the time of the laser oscillation. Therefore, the surfaces of the mirror are not fluctuated, and are not misaligned from the time the adjustment was finished.

Description

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

Normally, the position of the mirror in a gas laser oscillator is adjusted using a visible laser beam or a telescope in the atmosphere. During laser oscillation, the outer surface of the mirror or mirror holder is at atmospheric pressure (760 Torr), and the inner surface is under the laser gas pressure. (for example, 30 Torr), and the mirror receives an external force equal to the product of the differential pressure and the cross-sectional area, so the mirror surface changes slightly and the optical axis changes, which changes the output, beam cross-sectional shape, and beam mode to achieve the best characteristics. It was difficult to maintain stable conditions.

FIG. 1 shows a conventional mirror position adjustment mechanism 911, which will be explained using an example of a total reflection mirror.

In the figure, 1 is the base of the optical resonator, with 7 runs on the main body and 1 on the base of the optical resonator.
02 to which Q1 is fixed is a laser tube with 7 lunges 20
1 to the main body flange 1o1. 202
03 is a total reflection mirror held in the mirror holder 4. 0401 is an airtight O-ring, 402
is the coolant nozzle. 6 is a mirror receiver 7 lange, and 6 is a fine adjustment screw for adjusting the mirror position. Reference numeral 7 designates a flexible joint made of bellows, which in this figure also serves as a tension spring connecting the flange 101 of the main body 7 and the flange 5 of the mirror holder 7.

In such a conventional structure, air is introduced into the optical resonator, and under atmospheric pressure, a visible laser beam or the like is irradiated onto the total reflection mirror 3 from the direction of arrow a, and while observing the reflected light, the fine adjustment screw 6 is used to Adjust the mirror position, but the gas pressure inside the butterfly optical resonator is low (e.g. 30 Torr) during laser oscillation.
Therefore, the atmosphere pushes the mirror toward the laser tube, displacing the mirror and shifting the optical axis from the center of the optical resonator, resulting in a decrease in laser output. A part of the beam is cut and the cross-sectional shape, which should be circular, becomes elliptical. The beam mode changes.

The beam ψ approaches or hits a part of the inner wall of the optical resonator, causing a local temperature rise, causing thermal distortion and causing loss of stability over time, or in the worst case, internal damage. It had drawbacks such as self-destruction.

Misalignment of the mirror surface due to the influence of atmospheric pressure can be caused by compression or bending of the surrounding parts and parts that hold the mirror due to the atmospheric pressure, or by the fact that the fine adjustment screw 6 is
This is because the elements that determine the position and angle of the mirror surface vary non-uniformly, such as when the abutting surface in contact with the flange 101 deforms.7 These variations occur every time the oscillator is started and stopped, and the resonator Because the pressure inside changes), the amount increases, so even if the mirror &[g'11i t
-[Long-term stability cannot be obtained even under the gas pressure of 1 o'clock, and it is necessary to readjust the mirror every short period of time to ensure maximum output, optimal mode, etc. 0 Multi-stage folding When doing this, the number of mirror position adjustment mechanisms increases, which has a significant impact.

The present invention aims to solve these problems by using mirror 4t.
trttt1vertical The mechanism is installed inside the mirror that has the laser gas of the optical resonator, and the mirror (vertical [/j!7#(
The purpose of this is to prevent subsequent fluctuations in the mirror surface and improve the stability of the resonator.

An embodiment of the present invention will be described in detail below.

FIG. 3 shows an embodiment of the present invention, and a mirror position adjustment mechanism is incorporated into a main body flange 1o1 and a main body cap 102, and is isolated from the atmosphere.

A fine adjustment screw 6 for adjusting the tilt of the mirror is attached to the view mirror holder 7 lunge. A fixed plate 8 has a compression spring 9 set between it and the mirror holder 7 and the flange 5. The mirror holder 4 is cooled using the liquid supply and drainage tube 4o3 (actually 2
(Although there are books, one ld is shown in the figure) is connected from b to b' through the outer periphery of the mirror receiving flange 6, and is fixed to the main body 7 flange 101 together with the fixing plate 8 with screws on the fixing base 404. The liquid that has passed through the zero fixing table 404 passes through the entire cooling liquid nozzle 406 and is connected to the outside of the container. It has a structure that can sufficiently absorb minute movements of the mirror holder when adjusting the mirror position. Conversely, even if an external force is applied to the nozzle 406, the fixed base 404
Since it is fixed to the main body 7 lunge 101, there is no influence on the inclination of Mi2-. Further, a reinforcing column 400 is provided at the center of the machine so that the mirror holder 4 will not be deformed by the pressure of the coolant, and the coolant is designed to flow around the outer circumference of the column.

O-rings 103 and 406 are used to maintain airtightness, while 602 acts as a buffer to press the mirror against the nest.0503 is a vent that eliminates the pressure difference on both sides of the mirror. It is opened for In this practical example, unlike the bellows 3 in FIG. 1, there is no part that moves while maintaining airtightness, so the seal structure is simple.

The position adjustment of the mirror in the apparatus of this embodiment is carried out in the following steps. First, the main body cap 102 is removed, and the position of the mirror including the inside of the resonator is adjusted under atmospheric pressure.

The details of the sheep are the same as explained in the conventional example, and the explanation will be omitted. When the mirror is finished, the main body cap 102 is attached, the inside of the optical resonator is evacuated, and laser gas at a predetermined pressure is supplied to perform laser oscillation. Since there is almost no pressure difference on both sides of the C vent 503i (a slight pressure difference occurs when gas flows), the mirror surface will not fluctuate and will not go out of order from the time the adjustment is completed. Also, if necessary, correct the mirror position adjustment. If it is desired to perform this, the functions can be further expanded by providing a fine adjustment driver motor 1 as shown in FIG. 62 is an airtight O-ring, 10
is a gap provided so that the thrust load of the driver 61 does not affect mirror alignment.

Furthermore, if the output of the laser is small, liquid cooling is not necessary, so the liquid cooling system can be omitted.

However, the same can be applied to the output coupling mirror section. An example thereof is shown in FIG.

Adjust the door so that the beam can pass through the center of mirror holder 4Fi.
A transmission window 1 formed in the center of the nut-shaped main body cap 102 is made of a material with high transmittance for the laser beam.
04 is fixed with a stop plate 1-O6 via an airtight O-ring 106. 107 is a cooling liquid nozzle. Also 31. is the output coupling mirror.

As described above, the present invention isolates the mirror position adjustment mechanism from the atmosphere and provides it in a container of a system containing the laser gas of the optical resonator, and the mirror position adjustment mechanism is always under pressure within the optical resonator. Therefore, it is possible to overcome the drawbacks of conventional structures and ensure long-term stability under optimal conditions7.
The mirror position adjustment mechanism can also protect against indoor dust.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an example of a mirror position adjustment mechanism of a conventional laser oscillator, Fig. 2 is an enlarged sectional view of its part, -3.
The figure is a sectional view of a mirror position adjustment mechanism of a laser oscillator according to an embodiment of the present invention, and FIGS. 4 and 6 are partial sectional views of the mirror position adjustment mechanism of a laser oscillator according to an embodiment of the present invention. . 1...! 9. Base, 2. Fist... Laser tube, 3.
...Total reflection mirror, 4 axes...Mirror holder, 6.-
・＠-・Mirror holder 7 lange, 6...0 fine adjustment screw,
7・Φ・・・Bellows, 8・QΦΦ・Fist fixing plate, 9・
...Φ compression spring, 404...-!・・Fixed stand, 40
6...φ・Cooling liquid nozzle, 102・0...Body cap, 61...Fine adjustment screwdriver, 31・
...ΦΦ・Output coupling mirror, 104...Transmission window. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] A laser oscillator, characterized in that a mirror position adjustment mechanism is isolated from the atmosphere and provided in a container of a system containing a laser gas of an optical resonator.