JP2598007B2 - Pulse gas laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a laterally pumped pulse gas laser device.

(Prior Art) FIG. 5 is a cross-sectional view of an excimer laser device as a pulse gas laser device, which has an outer cylindrical container 1 and an inner cylindrical container 2, and applies a pulse laser beam between these containers 1 and 2. Discharge part 3, heat exchanger 4 and blower 5 generated
Is provided. Thereby, when the gas laser medium enclosed between the containers 1 and 2 flows into the discharge unit 3 and absorbs heat, it is cooled in the heat exchanger 4 and sent to the discharge unit 3 again by the blower 5. By the way, as shown in FIGS. 6 and 7, the discharge portion 3 has a pair of rectangular main discharge electrodes 6,
7 (i.e., the first main discharge electrode 6 and the second main discharge electrode 7) are opposed to each other, and the main discharge electrodes 6, 7
Are arranged opposite to each other along the longitudinal direction of the column. FIG. 7 shows the arrangement on the main discharge electrode 7 side as viewed from the main discharge electrode 6 side. One of the spare electrodes 8 to 17 is electrically connected to the main discharge electrode 6 through peaking capacitors 18 and 19.

When a pulse high voltage (20 to 50 kV) is applied from the high voltage power supply 20 to the discharge unit 3 in such a configuration, an arc discharge occurs between the spare electrodes 8 to 17 and ultraviolet rays are emitted. As a result, preliminary ionization occurs between the main discharge electrodes 6 and 7, and thereafter, a main discharge occurs between the main discharge electrodes 6 and 7. Thus, a pulsed laser beam is induced between the resonators (not shown) arranged on the longitudinal sides of the main discharge electrodes 6 and 7.

However, when the pulse repetition rate is gradually increased in the laser device having the above-described configuration, the laser light output is saturated at a repetition rate that is not so high. The cause is as follows. The gas laser medium is passed through the discharge section 3 at a high speed by the blower 5, and the gas laser medium is required to flow in a uniform state between the discharge section 3, particularly between the main discharge electrodes 6 and 7. However, the flow of the gas laser medium, as shown in FIG. 7, has a columnar shape of each of the spare electrodes 8 to 17, which causes a resistance of the flow of the gas laser medium to reduce the flow velocity and to cause the density of the gas laser medium. Or let me do it.
For this reason, the main discharge is prevented from being uniformly generated between the main discharge electrodes 6 and 7, and conversely, the probability of occurrence of arc discharge is increased. Therefore, as the pulse repetition rate increases, the gas laser medium between the main discharge electrodes 6 and 7 does not become uniform, and the laser light output becomes saturated.

(Problems to be Solved by the Invention) As described above, the laser beam output became saturated before the pulse repetition rate was increased, and it was not possible to obtain a pulse gas laser beam having a sufficiently high pulse repetition rate.

Therefore, an object of the present invention is to provide a pulse gas laser device capable of obtaining a high pulse repetition rate.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a first container in a discharge vessel in which a gas laser medium flows.
A pulse gas laser device comprising a main discharge electrode and a second main discharge electrode arranged opposite to each other and a plurality of preliminary electrodes for generating preionization along the longitudinal direction of the main discharge electrodes. Are formed in the shape of a flat plate, the flat plate surface is arranged in the same direction as the flow direction of the gas laser medium, and the respective tips are connected to the first main discharge electrode and the second main discharge electrode. The auxiliary electrode protruding from the first main discharge electrode side and the auxiliary electrode protruding from the second main discharge electrode are arranged so as to protrude inward from the position of each opposing surface with the electrode. A pulse gas laser device which is arranged alternately so as to overlap when viewed from the longitudinal direction of the discharge electrode and the second main discharge electrode.

(Operation) With such a pulse gas laser device, the gas laser medium flows uniformly between the main discharge electrodes, and a uniform main discharge can be generated between these main discharge electrodes. Thereby, the space between the main discharge electrodes can be narrowed and the device itself can be made compact.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same parts as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a sectional configuration diagram of a pulse gas laser device,
FIG. 2 is a layout view of the spare electrode, and FIG. 3 is a layout view of the spare electrode as viewed from above.

Each of the preliminary electrodes 40 to 48 is formed in a flat plate shape having a cross-sectional shape such as streamline, and the flat plate surface is arranged in the same direction as the flow direction of the gas laser medium.

Further, each of the tips of the spare electrodes 40 to 48 is disposed so as to protrude inward from the position of each of the opposing surfaces of the first main discharge electrode 6 and the second main discharge electrode 6, and the first The preliminary electrodes 40, 42, 44, 46 projecting from the main discharge electrode 6 side and the preliminary electrodes 41, 43, 45 projecting from the second main discharge electrode 7 side are arranged in the longitudinal direction of each main discharge electrode 6, 7. They are arranged alternately so as to overlap when viewed.

With such a configuration, the cas laser medium flowing at high speed flows between the main discharge electrodes 6 and 7 in a uniform state even when passing between the preliminary electrodes 40 to 48.

When a high-voltage pulse voltage is applied to the discharge unit from the high-voltage power supply 20 in such a state, arc discharge occurs between the spare electrodes 40 to 48, and the space between the main discharge electrodes 6 and 7 becomes Pre-ionization is uniformly performed in the longitudinal direction of the main discharge electrodes 6 and 7.

After that, the main discharges grow between the main discharge electrodes 6 and 7 from the preionization and the main discharge is uniformly generated, and a pulse laser beam is induced between the resonators (not shown).

Thus, in the above embodiment, each of the spare electrodes 40 to
The arrangement direction of the tip positions of 48 is alternately changed in the opposite direction along the longitudinal direction of the main discharge electrodes 6 and 7, and these auxiliary electrodes 40 to
48 are arranged so as to intersect with each other when viewed from the longitudinal direction of the main discharge electrodes 6 and 7, so that the space between the main discharge electrodes 6 and 7 is uniformly pre-ionized in the longitudinal direction of the main discharge electrodes 6 and 7. Thus, the main discharge can be uniformly generated, whereby the space between the main discharge electrodes 6 and 7 can be narrowed and the device itself can be made compact.

That is, the gas laser medium flowing between the main discharge electrodes 6 and 7 flows in a uniform state with a small decrease due to the loss of the flow velocity and with little disturbance of the flow velocity distribution. Moreover, the gas laser medium between the main discharge electrodes 6 and 7 can be immediately replaced with a new one without setting the flow velocity of the gas laser medium so high.

Accordingly, the probability of occurrence of arc discharge is extremely reduced, and uniform discharge can be generated between the main discharge electrodes 6 and 7.
Thus, as shown in FIG. 4, even when the pulse repetition rate is increased, the flow of the gas laser medium can be maintained in a uniform state and the pulse laser beam can be generated in a stable state.

The spare electrodes 40 to 48 have a relatively large surface area, so that the amount of heat generated at the tip portion increases at a high repetition rate. Thereby, each of the spare electrodes 40 to 48 is heated to a high temperature and does not melt off.

It is needless to say that the present invention can be applied to a TEACO ₂ laser and a high-pressure sealed TEACO ₂ laser in addition to the excimer laser.

[Effects of the Invention] As described above in detail, according to the present invention, the gas laser medium flows in a uniform state with a small decrease due to the loss of the flow velocity of the gas laser medium and a small disturbance in the flow velocity distribution, thereby generating a uniform main discharge. Can be pre-ionized uniformly in the longitudinal direction of the main discharge electrode prior to the main discharge, and furthermore, the gas laser medium between the main discharge electrodes can be immediately replaced with a new one without having to make the flow rate of the gas laser medium so high. It is possible to provide a pulse gas laser device that can make the space between the main discharge electrodes narrow and can make the device itself compact, and can obtain a high pulse repetition rate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the pulse gas laser device, FIG. 2 is a layout diagram of spare electrodes of the device, FIG. 3 is a layout diagram of the device viewed from above the spare electrodes, and FIG. FIG. 5 to FIG. 7 show the number of repetitions, and FIG. 1 ... outer cylindrical container, 2 ... outer cylindrical container, 6, 7 ...
Main discharge electrode, 10,11 …… peaking capacitor, 20 ……
High voltage power supply, 40-48 …… A spare electrode.

Claims (1)

(57) [Claims] 1. A first container in a discharge vessel in which a gas laser medium flows.
Wherein the main discharge electrode and the second main discharge electrode are arranged to face each other and a plurality of preliminary electrodes for generating preliminary ionization are arranged along the longitudinal direction of these main discharge electrodes. The plurality of spare electrodes are formed in a flat plate shape, the flat plate surface is arranged in the same direction as the flow direction of the gas laser medium, and the respective tips are formed by the first main discharge electrode and the second main discharge electrode. The auxiliary electrodes protruding from the first main discharge electrode side and the auxiliary electrodes protruding from the second main discharge electrode side are arranged so as to protrude inward from the positions of the respective opposing surfaces with the main discharge electrode. Wherein the first main discharge electrode and the second main discharge electrode are alternately arranged so as to overlap when viewed from the longitudinal direction.