JPH08274396A - Microwave excited gas laser device - Google Patents

Abstract

PURPOSE: To provide a microwave excited gas laser device which can give high electric field strength whose magnitude is constant over the overall length of a laser tube. CONSTITUTION: In a gas laser device, which excites the laser medium within a laser tube 11 by generating plasma in a laser gas by the microwave discharge within a microwave circuit, the laser tube 11 pierces a part of the microwave guide tube 12 constituting a progressive wave type resonator 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device which excites laser using microwaves, and is particularly suitable for use in a microwave excitation lamp, a microwave heating applicator and the like.

[0002]

2. Description of the Related Art An example of a conventional microwave excited gas laser device is shown in FIG. In FIG. 2, reference numerals 01 laser tube and 0
2 is a macrowave waveguide with a ridge, 03 is a microwave radiation prevention tube, 04 is a Brewster window, 05 is a laser resonator mirror, 06 is a heat exchanger, 07 is a gas circulation blower, 08 is a microwave resonator, 09 Indicate each iris.

The microwave energy generated by the microwave resonator 08 is guided to the ridged myloch wave waveguide 02 through the iris 09. The ridged microwave waveguide 02 has one end short-circuited and the other end having an aperture limited by an iris 09, and thus constitutes a microwave resonator. The microwave radiation prevention tube 03 allows the laser tube 01 to pass through the microwave waveguide 02 with a ridge without letting the energy of the microwave resonator escape to the outside.

Therefore, the microwave waveguide with ridge 02
A microwave standing wave is generated in the inside of the laser tube 01, and the ridged waveguide 02 has a structure in which the electric field strength is high in the laser tube 01 portion. The laser medium is turned into plasma to excite the laser medium to a higher level, and laser oscillation is performed by the laser resonator mirror 05. The heat exchanger 06 and the gas circulation blower 07 are provided to cool the laser medium and keep the temperature constant.

[0005]

However, in the conventional method shown in FIG. 2, the microwave waveguide 02 with a ridge is used.
The electric field strength distribution inside is not a constant strength in the axial direction of the laser tube 01, but a standing wave mode represented by the sum of the microwave electric field traveling to the left and the microwave electric field traveling to the right in the figure is generated. To do. Therefore, there is a problem in that the lowest electric field strength for laser oscillation cannot be realized at any place of the laser tube 01 at the same time.

In view of the above problems, it is an object of the present invention to provide a microwave excitation gas laser device capable of providing a high electric field strength of a constant magnitude over the entire length of the laser tube.

[0007]

A microwave-excited gas laser device according to the present invention is a gas laser device which excites a laser medium in a laser tube by generating plasma in a laser gas by microwave discharge in a microwave circuit. ,
It is characterized in that the laser tube penetrates a part of a microwave waveguide forming a traveling wave resonator. That is, in the present invention, the laser tube is penetrated inside the microwave waveguide forming the traveling wave resonator of the microwave.

[0008]

In the above structure, the traveling wave type resonator is a kind of microwave resonance circuit, and is a resonator having a mode in which the microwave propagates in one direction in the microwave waveguide arranged in an annular shape. work. Since the traveling wave type resonator does not have nodes and antinodes of the electric field strength generated by superposition of the traveling wave and the backward wave, unlike the ordinary waveguide type resonator, the time average of the electric field strength is obtained everywhere in the tube axis direction. Is constant, so that the laser tube placed therein can be excited with a constant electric field strength that is optimal for lasing over its entire length.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 schematically shows a microwave pumped gas laser device according to a preferred embodiment of the present invention. FIG.
In FIG. 1, 11 is a laser tube, 12 is a microwave waveguide with a ridge, 13 is a microwave radiation preventing tube, 14 is a Brewster window, 15 is a laser resonator mirror, 16 is a heat exchanger, 1
7 is a gas circulation blower, 19 is a microwave resonator, 21 is a microwave synthesizer, 22 is a traveling wave type resonator, 23 is a microwave monitor, and 24 is a microwave phase shifter.

Here, in the laser tube 11, the internal laser medium is excited by the electric field of the microwave waveguide 12 with a ridge which is a part of the traveling wave resonator 19, and the laser oscillation is performed by the laser resonator mirror 15. Be seen. A heat exchanger 16 and a gas circulation blower 17 are provided to cool the laser medium and keep the temperature constant as in the conventional case.

The microwave synthesizer 21 includes a microwave generated by the microwave oscillator 19 and the traveling wave type resonator 2.
It is provided for synthesizing the microwaves circulating in 3. An example of the microwave synthesizer 21 has a configuration as shown below.

The microwave synthesizer 21 is composed of two waveguides which are joined together through a partition plate 21a as shown in the section BB of FIG. Disappears and changes into a single waveguide. Here, the ratio of the cross-sectional areas of the two waveguides is determined by the traveling wave resonator 9
S ₁ , which is determined by the ratio of the magnitude of the power circulating inside the point at the point a and the magnitude at the point b.
It is determined that S ₂ = (ab): b.

Further, the microwave monitor 23 detects the phase of the microwave traveling in S _{1 of the} microwave synthesizer 21, and
The phase of the microwave traveling in S ₂ is monitored.
The microwave phase shifter 24 receives a signal from the microwave monitor 23 so that the microwave generated by the microwave oscillator 12 is added in the same phase as the microwave circulating in the traveling wave resonator 22. The equivalent length of traveling wave resonator 22 is changed to.

The microwave resonator 19 is a laser tube 1
Microwave power consumed in 1 and traveling wave type resonator 23
Since a large power equal to the loss is supplied to the traveling wave resonator 22, the traveling wave resonator 22 can have a high electric field strength of a certain magnitude.

[0016]

As described above, according to the present invention,
In a gas laser device in which plasma is generated in a laser gas by a microwave discharge in a microwave circuit to excite a laser medium, in a traveling wave resonator in which the time average of electric field strength is constant everywhere in the tube axis direction. Since the laser tube is arranged in a part, it is possible to give a high electric field strength of a certain magnitude, which is optimum for laser oscillation, over the entire length thereof.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration and an embodiment according to a first embodiment of the present invention.

FIG. 2 is a configuration explanatory view showing an example of a conventional technique.

[Explanation of symbols]

 11 Laser Tube 12 Microwave Waveguide with Ridge 13 Microwave Radiation Prevention Tube 14 Brewster Window 15 Laser Resonator 16 Heat Exchanger 17 Gas Circulation Blower 19 Microwave Oscillator 21 Microwave Synthesizer 22 Traveling Wave Resonator 23 Microwave Monitor 24 microwave phase shifter

Claims (1)

[Claims] 1. A gas laser device in which plasma is generated in a laser gas by a microwave discharge in a microwave circuit to excite a laser medium in the laser tube, wherein the laser tube constitutes a traveling wave resonator. A microwave-excited gas laser device characterized by penetrating a part of a tube.