JPH05121797A - Gas laser oscillation device - Google Patents

Abstract

PURPOSE:To enable a gas laser oscillation device to recover its output without breaking the airtightness of an airtight chamber due to the dismount of a mirror by a method wherein a hold/drive mechanism which moves a holding member in parallel with the side wall of the airtight chamber is provided. CONSTITUTION:When a gas laser oscillation device is lessened in output due to the contamination of a mirror 28, a pressing nut 36 screwed to the thread 35a of four adjustment rods 35 is loosened, and then an adjustment nut 37 is screwed into the adjustment rod 35. By this setup, the holding member 27 is displaced in a direction (shown by an arrow a) so as to approach the side wall 21a of the airtight chamber 21 compressing a bellows 25 as it resists the restoring force of the bellows 25. The holding member 27 moves in the widthwise direction of the side wall 21a or a direction (an arrow b) vertical to the optical axis O1 of laser rays L in parallel with the side wall 21a. By this setup, the mirror 28 is made to move in the widthwise direction to enable its one end in the widthwise direction to get out of the optical axis O1 of laser rays L, and the other new part of the mirror 28 or an uncontaminated part of the mirror 28 where no discharge product is attached is located on the optical axis O1 of laser rays L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal mirror type gas laser oscillation in which an output mirror forming an optical resonator and a highly reflective mirror are integrally provided with an airtight container filled with a gas laser medium. Regarding the device.

[0002]

_2. Description of the Related Art F ₂ laser, excimer laser or T
In a gas laser oscillating device such as an EACO ₂ laser which is filled with a gas laser medium at a pressure higher than atmospheric pressure and used, an optical resonator is provided integrally with the airtight container. There is a so-called internal mirror type.

6 and 7 show a conventional internal mirror type gas laser oscillator. That is, reference numeral 1 in the figure is an airtight container having a gas laser medium filled therein. A pair of main electrodes 2 are arranged in the airtight container 1 so as to face each other at a predetermined interval. These main electrodes 2 are connected to a high voltage power source 3, respectively. When a high voltage is applied to the main electrodes 2 to generate a discharge, the gas laser medium is excited by the discharge to generate laser light L.

A first light transmitting portion 4 is formed on each side wall of the laser light L of the airtight device 1 in the direction of the optical axis.
An axial end of a bellows 5 is hermetically attached to the outer surface of the side wall corresponding to the first light transmitting portion 4. The other end of the bellows 5 is airtightly joined to one side surface of the plate-shaped holding member 6. As shown in FIG. 7, the holding member 6 has a second
The transparent portion 7 is formed. A mirror 8 forming an optical resonator is hermetically held by a fixing flange 9 on the outer surface of the holding member 6 corresponding to the second light transmitting portion 7.

Screw rods 11 are screwed into the four corners of the holding member 6, respectively. A ball portion 12 is provided at one end of the screw rod 11, and the ball portion 12 is rotatably supported by a support portion 13 provided on the outer surface of the side wall. A knob 14 is provided at the other end of the screw rod 11, and the tilt of the mirror 8 held by the holding member 6 can be adjusted by rotating the screw rod 11 by the knob 14.

By the way, in the gas laser oscillator having such a structure, a large amount of discharge products are generated in the discharge space between the main electrodes 2 because the discharge is repeatedly ignited between the pair of main electrodes 2. Is inevitable. This discharge product is attached to the inner surface of the mirror 8 by propagating by a shock wave at the time of discharge, mixing in the gas laser medium and causing a chemical reaction by the laser light L.

For this reason, the portion of the mirror 8 which is exposed to the laser light L is smeared in black, and the dirt becomes a seed to accelerate the dirt, resulting in a decrease in the output of the laser light L and dirt. The heat energy of the light L may be absorbed and the mirror 8 may be damaged.

In order to remove the stains on the mirror 8, the mirror 8 must be removed from the holding member 6 and cleaned, so that the airtight state of the airtight container 1 is destroyed. Therefore, every time the mirror 8 is cleaned, the airtight container 1 is evacuated and gas is discharged.
Since it is necessary to replace the laser medium, it may take time to restart the laser oscillation.

[0009]

As described above, conventionally, when the mirror forming the optical resonator becomes dirty, the mirror had to be removed for cleaning or replacement.
Since the airtight state of the airtight container is destroyed, it takes a lot of time and labor to restart the laser oscillation.

The present invention has been made in view of the above circumstances, and an object thereof is to recover the output without removing the mirror from the airtight container when the mirror becomes dirty and the output decreases. Another object of the present invention is to provide a gas laser oscillating device.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an airtight container filled with a gas laser medium, and an electric discharge generated between the airtight container and facing each other. A pair of main electrodes for exciting the gas laser medium, a light transmitting portion formed on both side walls of the airtight container corresponding to the optical axis direction of the laser light, and the light transmitting portion facing the light transmitting portion. A holding member that is disposed on the outer surface side of the side wall and holds a mirror that forms an optical resonator, and one end of the holding member is joined to the outer surface of the side wall around the transparent portion, and the other end of the holding member A bellows, which is joined to the periphery of the mirror and has its axis inclined at a predetermined angle with respect to the optical axis of the laser beam, and the bellows is compressed in the axial direction to hold the holding member as described above. A direction that approaches the outer surface of the side wall and intersects the optical axis Characterized by comprising a holding drive mechanism not to exceed the predetermined movement position is moved to and.

[0012]

According to the above construction, when a part of the mirror is contaminated, the holding member is moved in parallel with the side wall of the airtight container by the holding drive mechanism, so that the uncleaned part of the mirror is removed. -It can be located on the optical axis of the light.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

1 to 4 show a first embodiment of the present invention. In FIG. 4, reference numeral 21 is an airtight container in which a gas laser medium is enclosed at a pressure higher than atmospheric pressure. Inside the airtight container 21, a pair of main electrodes 22 are arranged facing each other with a space therebetween. One of these main electrodes 22 is a high voltage power source 2
3 is connected to the plus side, and the other is connected to the minus side. When a high voltage is applied to the pair of main electrodes 22, the main discharge that excites the gas laser medium is ignited between them, and the laser light L is generated.

The side walls 21a of the airtight container 21 on one end side and the other end side along the optical axis O.sub.1 direction of the laser light L are provided with _first light transmitting portions 24 each having an opening. There is.
As shown in FIG. 1, the axis O ₂ is attached to the portion of the outer surface of the side wall 21a corresponding to the periphery of the first light transmitting portion 24.
One flange 25a of the metal bellows 25 is hermetically bonded and fixed to the optical axis O ₁ of the light L at an angle θ. The other flange 25b of this bellows 25
Is a rectangular plate-shaped holding member 2 on which the second light transmitting portion 26 is formed.
7 is joined and fixed to a portion of one side surface of the No. 7 corresponding to the periphery of the second through hole 26. In other words, this bellows 25
Has a pair of flanges 25a, 25b provided at both ends of a bellows-shaped main body 25c, which are inclined in advance in the same direction at an angle θ with respect to the axis O ₂ of the main body 25c.

The inner diameter of the bellows 25 has the above-mentioned first and second dimensions.
The diameter of the second light transmitting portions 24 and 26 is sufficiently larger than the inner diameter of the second light transmitting portions 24 and 26, and the pair of light transmitting portions 24 and 26 communicate with each other through the inner space of the bellows 25.

A peripheral portion of one surface of the mirror 28 is joined to the other side surface of the holding member 27 in a state of closing the second light transmitting portion 26 via a first O-ring 29. A second O-ring 3 is provided around the other surface of the mirror 28.
The presser flange 32 is joined via 1. The pressing flange 32 is attached and fixed to the holding member 27 with a screw 33. An optical resonator is formed by a pair of mirrors 28 (one is a highly reflective mirror and the other is a partially reflective mirror) provided on one end side and the other end side of the airtight container 21 in the optical axis direction. And this optical resonator is used to seal the airtight container 2
The laser light L generated within 1 is amplified.

As shown in FIG. 3, elongated holes 34 are formed at the four corners of the holding member 27 along the direction of inclination of the bellows 25. Each long hole 34 has an adjustment rod 35.
One end portion where the male screw 35a is formed is inserted.
A holding nut 36 joined to one side surface of the holding member 27 and an adjustment nut 37 joined to the other side surface are screwed to the male screw 35a. The other end of each of the adjusting rods 35 is connected to a mounting portion 38 provided on the outer surface of the side wall 21 a of the airtight container 21.

In the gas laser oscillator having the above structure,
At first, the bellows 25 is extended the most and a pair of mirrors
28 so that they face each other in parallel. In the state where the bellows 25 is extended, one end in the width direction of the mirror 28 is located on the optical axis O ₁ of the laser light L.

When the high voltage power supply 23 is operated in such a state and a high voltage is applied between the pair of main electrodes 22, the gas laser medium is excited by the main discharge generated between the main electrodes 22 and laser. The light L is generated. The laser light L is repeatedly reflected and amplified between a pair of mirrors 28, and is oscillated and output from one mirror 28 having a low reflectance.

When such laser oscillation is repeated, the discharge products adhere to the portion of the mirror 28 located on the optical axis O ₁ of the laser light L and are contaminated. The output is reduced and the mirror 28 is damaged.

Therefore, when the mirror 28 becomes dirty and the output is reduced, the holding nut 36 screwed to the male screws 35a of the four adjusting rods 35 holding the holding member 27 is loosened, and then the adjusting nut. Screw in 37. As a result, the holding member 27 is displaced in the direction approaching the side wall 21a of the airtight container 21 shown by the arrow a in FIG. 1 while compressing the bellows 25 against the restoring force.

Further, since the bellows 25 is provided so that its axis O ₁ is inclined with respect to the axis O ₂ of the laser light L at an angle θ, it is held by compressing the bellows 25. The member 27 is not only in the approach direction indicated by the arrow a, but also in the width direction of the side wall 21a indicated by the arrow b.
It also moves parallel to the side wall 21a in the direction orthogonal to the optical axis O ₁ .

If the holding member 27 is moved in parallel, as shown in FIG.
As shown in FIG. 5, the mirror 28 also moves in the width direction, and one end side in the width direction is displaced from the optical axis O ₁ of the laser light L, and the laser light L
A new portion of the mirror 28, that is, a clean portion on which the discharge products are not attached, is located on the optical axis O _{1 of} . Therefore, if the holding member 27 is fixed and the laser light L is output in that state, the laser light L will generate a pair of mirror lights L-2.
Since the discharge products of No. 7 are reflected at the portions where they are not attached, there is no reduction in output and no damage to the mirror 27.

That is, according to the gas laser device having the above-mentioned configuration, even if the mirror 27 is contaminated with discharge products, the output can be recovered without removing the mirror 27 from the airtight container 21. ..

FIG. 5 shows a second embodiment of the present invention. In this embodiment, a spacer 42 having a taper surface 41 is provided on the outer surface of the side wall 21a of the airtight container 21 and on one side surface of the holding member 27 facing the side wall 21a.
The taper surfaces 41 of these spacers 42 are parallel and spaced apart and face each other, and are inclined at a predetermined angle with respect to the side wall 21a. Further, each spacer 42 has a side wall 21a.
A communication hole 42a corresponding to the first light-transmitting portion 24 formed in and the second light-transmitting portion 26 formed in the holding member 27 is formed.

To the taper surface 41 of each spacer 42, flange portions 43b provided at both ends of a bellows-shaped main body portion 43a of the bellows 43 are joined and fixed. The flange portion 43b is provided substantially at right angles to the axis of the main body portion 43a.

With this structure, the bevel 43 has its axis inclined with respect to the optical axis O ₁ of the laser light L in accordance with the inclination angle of the taper surface 41 of the spacer 42. Since the holding member 27 can be provided in parallel with the side wall 21a of the airtight container 21, the holding member 27 can be moved parallel to the width direction of the side wall 21a. That is, by using the spacer 42, it is possible to use an ordinary bezel 43 in which the flange portion 42b is provided at a substantially right angle to the main body portion 42a.

[0029]

As described above, according to the present invention, the axis lines of the bellows for holding the mirrors for the optical resonators, which are respectively provided on the one end side and the other end side in the axial direction of the airtight container, are arranged in the radial direction.
The light is inclined at a predetermined angle with respect to the optical axis.

Therefore, if the portion of the mirror located on the optical axis of the laser light is contaminated by the discharge product, the bellows are compressed to move the mirror in parallel and generate the discharge. Since a clean part without any object can be located on the optical axis of the laser light, the mirror is removed and the airtight condition of the airtight container is destroyed every time the mirror becomes dirty and the output decreases. You can measure the output recovery without.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a mirror holding structure showing a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a state in which the bellows is also compressed.

FIG. 3 is an end view of the airtight container.

FIG. 4 is a plan view of the airtight container, which is also partially sectioned.

FIG. 5 is an enlarged cross-sectional view of a mirror holding structure showing a second embodiment of the present invention.

FIG. 6 is a plan view of a conventional airtight container.

FIG. 7 is an enlarged sectional view of the holding structure of the mirror.

[Explanation of symbols]

21 ... Airtight container, 22 ... Main electrode, 24 ... First light transmitting part,
25 ... Bellows, 27 ... Holding members, 28 ... Millers, 35
... adjusting rod (holding drive mechanism), 36 ... press nut (holding drive mechanism), 37 ... adjusting nut (holding drive mechanism).

Claims (1)

[Claims] 1. An airtight container filled with a gas laser medium, and a pair of main electrodes which are arranged facing each other in the airtight container and excite the gas laser medium by an electric discharge generated therebetween. A light transmitting portion formed on both side walls of the airtight container corresponding to the optical axis direction of the laser light, and an optical resonator provided on the outer surface side of the side wall facing the light transmitting portion. A holding member holding a mirror to be formed, one end of which is joined to the outer surface of the side wall around the light-transmitting portion and the other end of which is joined to the surrounding of the mirror of the holding member, and an axis line is formed into the laser beam. And a direction in which the bevel is compressed in the axial direction to make the holding member approach the outer surface of the side wall and the optical axis intersects. Move in the same direction and do not exceed the specified movement position. A gas laser oscillator comprising a holding and driving mechanism.