JPH0494180A - Gas laser oscillator - Google Patents

Abstract

PURPOSE:To stably operate high repetition pulse oscillator by shielding light emission caused by electric discharge in a main electric discharging space and at preliminary ionizing electrodes and providing a shield which allows a gas laser medium to flow. CONSTITUTION:Main electric discharge is generated when preliminary ionizing electrodes 5a and 5b preliminary ionize a main electric discharging space 4 by the generation of a ultraviolet ray and when an impressing voltage on a main electric discharging electrode becomes high. Light emitted at the time of the preliminary ionization and the successive main electric discharge is shielded by a shield 17 on the upstream side. Therefore, gas laser medium in the electric discharging space 4 is ionized by the ultraviolet ray, however, the gas laser medium just before passing through the shield 17 does not receive the light irradiation and the gas laser medium is not ionized by the ultraviolet ray. The shield 17 prevents the generation of a charged particle in the space on the upper stream side than the space between the preliminary ionizing electrodes. The limitation of the ionizing space to the four main electric discharging spaces allows laser gas, which is not irradiated by light by a leading pulse, to be introduced to the electric discharging space even the flowing speed of the gas laser medium is reduced and high repetition oscillating operation is attained.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a gas laser oscillation device.

(Prior art) In order to stably obtain high-repetition pulse oscillation of a laser in a horizontal excitation type gas laser oscillator, for example, Japanese Patent Laid-Open No. 6
As disclosed in Japanese Patent Application No. 3-227067, it is currently possible to flow a gas laser medium sealed in an airtight container at high speed. By flowing at this high speed, the discharged gas laser medium after the pulse discharge is carried out is flushed away, and fresh gas laser medium is quickly replaced for the next discharge, thereby generating an appropriate main discharge. There is.

(Problem to be solved by the invention) Due to the ionizing effect of ultraviolet rays generated during main discharge and pre-ionization,
Charged particles are partially generated in the space upstream from the main discharge space, and these directly flow into the main discharge space and the pre-ionization electrode.
This lowers the discharge starting voltage between the pre-ionization electrodes, which causes a decrease in the intensity of pre-ionization, and also causes problems in which the main discharge is not uniform due to the uneven distribution of the pre-ionized gas. there were. Therefore, either the charged particles generated on the upstream side disappear before the next pulse discharge is generated, or the charged particles flow out of the gas laser medium downstream from the main discharge electrode. It had to be fast enough. However, there is a limit to the flow speed of the gas laser medium, and if the repetition of the pulse discharge operation is increased, the main discharge becomes unstable and the laser does not oscillate.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas laser oscillation device that can stably operate high-repetition pulse oscillation.

[Structure of the Invention] (Means and Effects for Solving the Problems) An airtight container enclosing a gas laser medium and provided with at least a pair of main discharge electrodes, and circulating the gas laser medium in the airtight container to a main discharge space. In the gas laser oscillation device, the gas laser oscillator is equipped with a circulation means for supplying the gas, and pre-ionization electrodes that are provided in the vicinity of the main discharge space and are provided immediately before and after the excitation to pre-ionize the main discharge space, respectively. A light shield is provided near the pre-ionization electrode between the pre-ionization electrode and the circulation means to block light emission due to discharge in the main discharge space and the pre-ionization electrode and to allow the gas laser medium to flow. , the proportion of ionized gas in the subsequent pulse start state between the pre-ionization electrodes and in the main discharge space is reduced.

(Example) Hereinafter, the present invention will be described in detail based on drawings showing examples. FIG. 1 shows an embodiment of the present invention, which has an airtight container (1) in which a gas laser medium is sealed at a predetermined pressure, and a pair of main discharge electrodes consisting of an anode (2) and a cathode (3) inside the container. are provided to form a predetermined main discharge space (4). Pre-ionization electrodes (51) consisting of a plurality of pairs of pin electrodes forming a predetermined spark gap near both sides of the main discharge space (4), that is, the side immediately before excitation and the side immediately after excitation;
(5b) is provided. These pre-ionization electrodes (5
(5b) are each equipped with a peaking capacitor (6
) are connected. The above anode (2) and cathode (3)
The main discharge circuit connected to the main discharge circuit is constructed as follows.

That is, it has a main power source (10) that generates high-voltage direct current, and its electric charge is stored in a charging/discharging capacitor (12) via an inductance (11). The charge stored in the charge/discharge capacitor (12) is applied to the cathode (3) via a thyratron (3), which is a switching element. Said charge is also applied to the peaking capacitor (6) so that pre-ionization occurs through one pin electrode connected to the anode (2).

On the other hand, in the airtight container (1), apart from the main discharge electrode, a blower (
15) is provided. In the above circulation, the gas laser medium is heated through heat exchangers (16a) and (16a) provided upstream and downstream of the gas laser medium with the main discharge space as the center.
b) is maintained at a relatively low temperature.

Between the upstream heat exchanger (16a) and the upstream pre-ionization electrode (5a), the pre-ionization electrode (5a)
A light shield (17) is provided adjacent to the side. This light shield (17) is composed of a plurality of plates made of a material that blocks ultraviolet rays, and these plates are formed in a so-called layered manner so that their ends overlap when viewed from one direction.

Note that (18) is a guide body that guides the gas laser medium into the preliminary ionization discharge space and the main discharge space and smoothes the flow of the medium through these discharge spaces.

Next, the operation of the above configuration will be explained. Air blower (15
) is driven, and the gas laser medium is circulated within the airtight container (1) and constantly supplied to the main discharge space (4). Under this circulation, the voltage charged to the charge/discharge capacitor (12) from the main power supply (10) via the inductance (11) is applied between the cathodes (3) and (4) when the thyratron (I3) is turned on. Ru. At this time, the peaking capacitor (6) is charged, and the pre-ionization electrode (5bl) is discharged to generate ultraviolet light.The generation of this ultraviolet light causes the main discharge space (4
) is pre-ionized, and when the voltage applied to the main discharge electrode increases, a main discharge occurs. Here, the light emitted during pre-ionization and subsequent (main discharge) is blocked by the light shield (17) on the upstream side.Therefore, although the gas laser medium in the discharge space (4) is ionized by ultraviolet rays, the light emitted during the main discharge is blocked by the light shield (17). ), the gas laser medium is not ionized by ultraviolet rays because it is not irradiated with the above-mentioned light.For this reason, following the preceding no-pulse discharge, by the time the subsequent pulse is discharged, the light shielding body (17) and the main discharge If the gas laser medium between the space (4) and the main discharge space (4) is made to flow downstream from the main discharge space (4), the pre-ionization electrode space and the main electrostatic space rj are generated when subsequent pulses are generated.
J(4) is now filled with a non-ionizing gas laser medium, the gas state is similar to the previous pulse condition, and the electrical breakdown voltage is not lowered by the previous pulse and a pre-ionizing discharge of sufficient intensity occurs. Ultraviolet light emission occurs, and uniform discharge within the main discharge space (4) also occurs.

A pulse discharge occurs as before.

FIG. 2 shows another embodiment of the present invention in which a light shield (2G) is formed by arranging a plurality of plate-like bodies in a substantially staggered manner.

In this example as well, the gas laser medium is placed in an airtight container (1).
The main discharge effect similar to that of the above embodiment can be obtained.

[Effect of the invention] By providing the light shielding body (17) or (20), the generation of charged particles in the space upstream from between the pre-ionization electrodes is eliminated, and the ionization space is separated from the main discharge space (4) area. By limiting this, even if the flow velocity of the gas laser medium is made low, the laser gas that has not been irradiated with light in the preceding pulse can be introduced into the discharge space, making it possible to obtain high repetition oscillation operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing another embodiment of the present invention. (1)...Airtight container (2)...Anode (3)...Cathode (5a), (5b)...Preliminary ionization electrode (15)
...Blower (circulation means)

Claims (1)

[Claims] an airtight container enclosing a gas laser medium and provided with at least one pair of main discharge electrodes; a circulation means for circulating the gas laser medium in the airtight container and supplying it to the main discharge space; In the gas laser oscillation device, the gas laser oscillator includes pre-ionizing electrodes that are provided on the side and immediately after the excitation and pre-ionize the main discharge space, in the vicinity of the pre-ionizing electrode between the pre-ionizing electrode on the side immediately before the excitation and the circulation means. A gas laser oscillation device characterized in that a light shielding body is provided to block light emission caused by discharge in the main discharge space and the preliminary ionization electrode and to allow the gas laser medium to flow.