JPH0760910B2 - Gas laser device - Google Patents

Description

The present invention relates to a gas laser oscillator, and more particularly to a lateral excitation type oscillator.

(Prior Art) An excimer laser oscillator, which is one of the lateral excitation methods, will be described as an example. Conventionally, this device has a pair of arcuate discharge electrodes in a closed container in which a rare gas such as a halogen gas flows. Installed opposite to each other, ultraviolet rays, X before main discharge
After pre-ionization of lines, corona, etc., main discharge of large current is performed on the discharge electrode, and amplified laser light is emitted by an optical resonator provided with a hermetically sealed container in between.

Most of the discharge products generated during discharge in the above structure are excluded from the discharge region by the flow of the rare gas that is the gas laser medium, but some are attached to the surface of the discharge electrode or the discharge is generated. Retain later. For this reason, when the repetition time becomes long, it is difficult for the next discharge to become a uniform discharge, and there is a phenomenon in which the discharge shifts to an arc discharge where the laser amplification effect cannot be obtained. In order to deal with such a problem, JP-A-59
In Japanese Patent Laid-Open No. 188189, there is proposed a technique in which a semi-cylindrical discharge electrode is mounted on a rotating body and rotated.

(Problems to be Solved by the Invention) In this technique, rotation causes wind between the discharge electrodes to facilitate replacement of the gas laser medium, but during rotation, no voltage is applied at the timing when the discharge electrodes face each other in parallel. There was a problem that it was difficult to adjust the dynamic balancing so that high-speed rotation could be maintained because the discharge was not stable and the shape was complicated. It is an object of the present invention to provide a gas laser device capable of stably discharging at high speed and repeating the discharge for a long time.

[Structure of Invention]

(Means and Actions for Solving Problems) The present invention has been made in order to achieve the above-mentioned object, and includes a closed container holding a gas laser medium and a closed container provided in the closed container so as to face each other. In a gas laser device comprising a discharge electrode for discharging a gas laser medium for discharging and an optical resonator for resonating a laser beam generated by the excitation, at least one of the discharge electrodes is formed by combining truncated cones with their axes aligned. A gas laser device having a shape and discharging between the other discharge electrode while rotating about the axis. Moreover,
A voltage is preferably applied to the rotating discharge electrode by contact with the rotating electrode surface.

In the gas laser device of the present invention, as described above, one of the discharge electrodes is formed by combining the truncated cones with their axes aligned to each other, so that the axes can be stably rotated about the axes. In addition, since the portion of the electric field between the discharge electrodes has nothing to do with the rotational position of the discharge electrodes, pulse discharge can be performed at any time during rotation without timing of discharge.

(Example) Hereinafter, the present invention will be described with reference to the drawings illustrating an example.

In FIGS. 1 and 2, there is a closed container (1) in which an anode (2) and a cathode (3) forming discharge electrodes are arranged in parallel at a predetermined interval. The anode (2) has a semi-cylindrical shape, while the cathode (3) has a shape in which truncated cones are combined with their axes aligned as shown in FIGS. 3 (a) and (b). Each is connected to a high-voltage pulse power source (4) provided outside the closed container (1). Further, a total reflection mirror (5) and an output mirror (6) are provided near both sides outside the hermetically sealed container (1), and these are a transmissive window (7) formed on the both sides.
Optical resonators are formed facing each other through a) and (7b). A shaft (8) is coaxially inserted and fixed to the cathode (3), and the shaft (8) is attached to the inner surfaces of the both sides of the closed container (1). ) Is rotatably supported by. One of the shafts (8) projects outside the closed container (1) and is connected to a drive shaft (11a) of a drive body (motor) (11) via a joint (10). One shaft connected to the drive shaft (11a) is airtightly inserted into the closed container (1). The rotatably supported cathode (3) is in contact with a conductive contact (12) connected to the high voltage pulse power supply (4). By the way, a mixed gas of a halogen gas and a rare gas is sealed as a gas laser medium in the closed container (1) at a predetermined pressure and is circulated in a direction orthogonal to the optical axis of the optical resonator by a blower (not shown). Then, it is made to flow from the direction shown by the arrow (a) to the discharge section (15) in a cooled state through a heat exchanger (not shown). Also,
Anode (2) and cathode (3) near the discharge section (15)
A preliminary electrode (not shown) is provided to assist the electric discharge by.

In the above structure, the cathode (3) is rotated by the driving body (11) at a rotation speed of 1500 to 1800 rpm, and the cathode (3) and the anode (2) are driven by the high voltage pulse power supply (4) at 30 to 50 KV and pulse rising. Is applied with a steep voltage of several tens of ns, and discharge is performed with a discharge current of several tens of KA. Therefore, in repeating the pulsed discharge, the surface of the cathode (3) faces the cathode (2) by contacting the gas laser medium in which a new surface, which is different from the discharge surface performed immediately before by rotation, is constantly flowing. . Therefore, even if the impure gas or the discharge product stays on the surface of the discharged cathode, the surface does not become the electrode surface for the next discharge, and the impure gas or the discharge product is It will be removed during one rotation.
In this case, the gas laser medium does not flow through the closed container (1) as in this embodiment, but TE (Transvesely Excite).
d) Pulse gas laser or TEA (Trnsversely Excited Atom)
Even in a system in which a gas laser medium does not flow in a laser or the like, a wind is generated by rotation, and discharge products and the like are removed by this wind, and a new electrode surface always contributes to the discharge, which is almost the same operation as the above-mentioned embodiment.

Although the example of the laser oscillating device has been shown in the above-mentioned embodiment, the same effect can be obtained in the case of using the amplifying device.

〔The invention's effect〕

The present invention has a shape in which at least one of the discharge electrodes is formed by combining truncated cones with their axes aligned to each other, and the discharge is performed between the discharge electrodes and the other while rotating about the axis as a rotation axis. Since it is a circular electrode, the distribution of the electric field between the discharge electrodes has no relation to the rotation position of the discharge electrodes, and pulse discharge can be performed at any time during rotation without timing of discharge. Further, in an electrode having a shape in which the diameter of the truncated cone increases from the central portion in the axial direction toward the end portion as shown in FIG. Since it can be set larger than that, discharge is prevented from being concentrated in the central part of the electrode. On the other hand, in the electrode combined with the multi-staged truncated cone as shown in FIG. 3 (b), it is possible to form a portion having a large discharge power density corresponding to the number of the truncated cones. Then, it is possible to make uniform the main discharge by compensating for the non-uniformity of preliminary ionization due to the pin electrodes arranged to face each other.

[Brief description of drawings]

1 is a schematic vertical sectional view showing an embodiment of the present invention, FIG. 2 is a schematic horizontal sectional view showing an embodiment of the present invention, and FIGS. 3 (a) and 3 (b) are discharge electrodes of the present invention. It is the schematic which showed the shape of. (1) ... closed container (2) ... anode (discharge electrode) (3) ... cathode (discharge electrode) (5) ... total reflection mirror optical resonator (6) ... output mirror optical resonator (8) ) …… Axis (11) …… Drive body (12) …… Contact

Claims (2)

[Claims] 1. A hermetically sealed container holding a gas laser medium, discharge electrodes provided in the hermetically sealed container so as to oppose each other to excite the gas laser medium, and an optical resonator for resonating laser light generated by the excitation. In a gas laser device provided with, at least one of the discharge electrodes has a shape in which truncated cones are combined with their axes aligned with each other, and the discharge is performed between the discharge electrodes while rotating while using the axes as a rotation axis. A gas laser device characterized by the above. 2. The gas laser device according to claim 1, wherein a voltage is applied to the rotating discharge electrode by contact with the rotating electrode surface.