JPS5850786A - Lateral mode excitation type gas laser device - Google Patents

Abstract

PURPOSE:To greatly increase the maximum output power of main discharge, and attain the high power output of laser resulting in the realization of high efficiency laser oscillation, by remarkably reduce the gas flow turbulence due to a dielectric electrode. CONSTITUTION:A rectifying member 14 is mounted on the cylindrical dielectric electrode 6. Since the gas flow turbulence due to this electrode arrangement is remarkably reduced, the instability of the main discharge due to the gas flow turbulence is prevented, and the maximum output power greatly increases. Under the normal typical laser operating condition, the output power increases approx. twice, and therefore the laser output also increases approx. twice. Simultaneously, the set position for the dielectric electrode particularly in the direction of gas flow can be arbitrarily set. Since the gas flow turbulence is greatly reduced by the streamlined dielectric electrode 15, the high output and high efficiency of the laser and simultaneously the improvement of lateral mode patterns can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas circulation type laser device using a silent discharge assisted glow discharge excitation method. This is an attempt to increase the number of employees.

A typical example of a conventional laser of this type is a so-called 002 laser with three axes orthogonal to each other, in which the optical axis, main discharge, and gas flow directions are perpendicular to each other.

Figure 1 is a longitudinal cross-sectional view of a conventional device, and Figure 2 is a cross-sectional view of the conventional device taken along the line. (1) is an anode, (2) is a cathode, (
3) li insulating cathode substrate, (4) d stabilizing resistor connected to each cathode, (5) produces main discharge.

(6) is a dielectric electrode covered with a glass dielectric, (7) is a dielectric electrode (6)
and the cathode (2) i or anode port); (8) is the direction of the laser gas flow;
(9) is a discharge excitation medium, aS is a total reflection mirror, aa is a laser optical axis, and U is a laser beam.

Next, the operation will be explained. A high voltage is applied between the dielectric electrode (6), which is installed upstream of the main discharge gap between the anode (1) and the cathode (2), and the ground and the high-frequency electric current (7>K). Then, the dielectric electrode (6) and the cathode (2)
A silent discharge (hereinafter referred to as 8D) is generated between the main electrode and the anode (1). The laser gas (Co2-N2-H, mixed gas) pre-ionized by this 8D flows into the main discharge gap along the flow direction (8). 8. I)
When a DC high-voltage power supply (5) is used to apply a discharge force between the anode (1) and cathode (2) of the main discharge in a gas that is pre-ionized uniformly in the direction of the laser optical axis (2) by auxiliary discharge, , a homogeneous and high power density discharge excitation medium (9) is produced. By sandwiching this discharge excitation medium (9) and placing a total reflection mirror (1) and a partial reflection mirror (2) having an appropriate reflectance facing each other, laser oscillation occurs and a laser beam (a) is emitted from the two partial reflection mirrors (a) and (a). :1 is emitted.

Usually, the dielectric electrode (6) is a cylindrical piece made of a glass-lined iron pipe with a circular cross section.

Alternatively, a glass pipe with a thin metal wire for power supply inside is used. -Both types of electrodes are internally cooled with deionized water. In order to noticeably exhibit the effects of discharge homogenization and high power density of the 8D auxiliary discharge, an 8D power of aS~5- of that of the main discharge is required. The 8D power W follows Ohji's following relational expression.

% Formula % Here, F(V) is a function of the zero-to-peak value V of the power supply voltage, f is the power supply frequency, and C is the capacitance of the dielectric. Under typical laser operating conditions, f −1@k
Hg, V -51cv f: If assumed, the above 8
In order to input the D discharge force, a dielectric electrode (6)' with a diameter of 10 mm or more is required. however.

The dielectric material was assumed to be glass with a wall thickness of approximately 1 m.

Upstream of main discharge gear 7! If there is a dielectric electrode (6) with a diameter of 10 square meters or more, the maximum input power for the main discharge is limited due to significant disturbance of the gas flow caused by the electrode (6). In order to alleviate this restriction, there is a method in which the dielectric electrode (6) is installed far away from the main discharge gap part on the upstream side. However, 2. When this method is used, the discharge excitation medium (9) spreads too much in the gas flow direction, which also reduces the efficiency with which the oscillator picks up stimulated emission light from the medium.

Conventional laser equipment is configured as described above, so
Disturbance of the gas flow caused by the dielectric electrode limits the maximum input power for the main discharge. If the dielectric electrode was moved further upstream in order to alleviate the turbulence in the gas flow, there were drawbacks such as the inability to perform highly efficient laser oscillation.

This invention was made to eliminate the above-mentioned drawbacks of the conventional method (by significantly reducing gas flow turbulence caused by dielectric electrodes).

Significantly increases the input maximum power of the main discharge and therefore
The object of the present invention is to provide a laser device that achieves high-efficiency laser oscillation by achieving high laser output and appropriately controlling the cross-sectional shape of a discharge excitation medium.

Below, we will take up four examples of this Shinmei no Mi Q+, and explain them using each figure. , In Figure 3, the axis is a dielectric! This is a rectifying member made of an insulating material arranged to reduce the gas flow caused by the pole (6). In FIG. 4, a! 9 is a streamlined dielectric piece. In Figure 5 (, N).

The diameter is such that turbulence in the gas flow is sufficiently small during return. In FIG. 6, a'a is a plate-shaped dielectric electrode j which sandwiches a plate-shaped metal plate between dielectric materials and is arranged parallel to the gas flow direction.

In the example shown in Fig. 3, the conventional cylindrical dielectric electrode (6)
Since the rectifier member (14) is attached to -1, the turbulence of the gas flow due to this electrode arrangement is reduced to an obvious level. Therefore, the unstable rate of the main discharge due to the turbulence of the gas flow is prevented,
j! Large - Input power increases to large 1@. Under typical laser operating conditions, the input power is approximately doubled, so the laser output is also approximately doubled. At the same time, the position of the dielectric electrode, especially the position in the gas flow direction, can be set arbitrarily. That is, the discharge excitation cross-sectional shape can be controlled by the position of the electrode. This control makes it possible to obtain an excitation cross-sectional shape suitable for laser oscillation, thereby enabling highly efficient oscillation and improving the transverse mode pattern of the laser beam.

In the example shown in Fig. 4, as described in Fig. 3, the turbulence of the gas flow can be greatly reduced by the streamlined dielectric electrode α, so that the laser output and efficiency can be increased and the Yokote It is easy to see that you can try to improve the pattern.

The example shown in Fig. 5 is a conventional cylindrical dielectric electrode (6).
The dielectric electrodes (Le) each having a diameter of 1/3 and 1/3 are arranged in three rows in the gas flow direction.

In this case, since the total surface area of the small diameter dielectric electrode (IQ) is equal to the surface area of the conventional dielectric electrode (6), 8
D input power is also the same. on the other hand.

The gas flow is disturbed by the small diameter dielectric electrode al.

Since the area of the front surface facing the gas flow of the @ pole is reduced to 1/3, it is significantly reduced. therefore.

In the example shown in FIG.
It is easily seen that the same effect as desired can be obtained compared to the case of the two embodiments. In the example of Figure 5.

Although three rows of small-diameter dielectric electrode members are shown, any number of rows may be used to obtain the effects of the present invention.

The example shown in FIG. 6 is equivalent to infinitely increasing the number of rows of small-diameter dielectric electrodes OeJ in the case of FIG. 5, and is an example in which a flat dielectric electrode α1 is used. It's a good thing.

Naturally, from the viewpoint of 8D power input, the surface area of this dielectric electrode aη is set to be equal to that of the conventional dielectric electrode (6). Since the disturbance in the gas flow caused by the flat dielectric electrode a can be ignored, the above 3.
As in the example, it can be seen that the effects of the present invention can be sufficiently obtained.

In addition, in the above embodiment, the case of a shielded split type p main discharge corridor pole is described. Even if the case is a @ pole split type or the anode and cathode are integrated, the same method as in the above embodiment may be applied. Effects can be obtained.

Furthermore, in the above four embodiments, a so-called three-axis orthogonal type laser was described in which the optical axis, main discharge, and gas flow directions were perpendicular to each other.

As described above, the present invention is provided with a dielectric electrode disposed in a laser gas flow path at a downstream position and generating a non-discharge between an anode and a cathode. It is characterized by having a cross-sectional shape with low fluid resistance, which reduces turbulence in the gas flow due to the i# dielectric electrode, resulting in high output and high efficiency, as well as an excellent transverse mode pattern. This has the effect of providing a gas circulation type gas laser device.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a conventional laser device. FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1. In the figure, (l) is an anode, (2) a cathode, (3) is an insulating cathode substrate, (4 is a stabilizing resistor, (5) is a DC high voltage power supply, (an dielectric electrode, (7) is a high frequency power source, (8) is the direction of the laser gas flow, (9) is the discharge excitation medium, the trout is a total reflection mirror, the α force is a partial reflection mirror, the ring is the laser optical axis, 1
1 is a laser beam, a◆ is a rectifying member, aS is a streamlined dielectric electrode, and +1 is a small diameter dielectric electrode. aη is a flat dielectric electrode. Note that in the two figures, the same reference numerals indicate the same or corresponding parts. Applicant Makoto Ishizaka, Director of the Agency of Industrial Science and Technology - @Figure 2 Figure 3 Figure 4 Figure 115

Claims (4)

[Claims] (1) In one equipped with a dielectric electrode that is disposed within the laser gas flow path and generates a silent discharge between an anode and a cathode that are disposed downstream. A lateral excitation type gas laser device, characterized in that the dielectric electrode has a cross-sectional shape with low fluid resistance. (2) Laterally excited gas laser device 0 according to claim 1, comprising a rectifying member made of an insulating material on the downstream side of the dielectric electrode having a cylindrical cross section. (3) The dielectric electrode is composed of multiple small diameter members. A lateral excitation type gas laser device according to claim 1, wherein said gas laser device is arranged along a laser gas flow path. (4) A laterally pumped gas laser device according to claim 1, wherein the pole is formed into a flat plate shape.