JPH01214182A - Metal steam laser device - Google Patents

Abstract

PURPOSE:To increase laser oscillation capacity by inserting a cylindrical second electrode between a plasma tube and a first electrode for preventing powder and impurities within a heat-insulating material from being mixed into plasma tube by improving flow of buffer gas into the heat-insulating material. CONSTITUTION:If a second electrode 15 is inserted between a plasma tube 9 and a first electrode 12a, internal electric field of the electric field 15 becomes smaller and the electric field in axial direction is centered at a plasma tube 9 with improved steam density at the further depth, thus enabling excitation to be performed actively. As a result, oscillation efficiency can be improved. Also, since a proper gap 8 is provided between electrodes 12a and 15, flow of buffer gas supplied from one part of a supporting flange to the other into a heat-insulating material 10 can be made smoothly. Furthermore, discharge of powder within the heat-insulating material 10 and impurity gas to the outside of the main unit 1 can be performed fully. Thus, by keeping the concentration of impurities within the plasma tube 9 to be low, discharge can be stably maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a metal vapor laser device using metal vapor as a laser medium.

(Prior Art) In recent years, copper vapor lasers have come into use that have an oscillation wavelength in the visible range (wavelengths of 5106A and 5783A) and that produce high-efficiency, high-gain, high-repetition, and high-output laser light.

FIG. 2 shows a schematic configuration of a laser device for producing this type of metal vapor laser. That is, the metal vapor laser device shown in FIG. A buffer gas supply device 4 for supplying gas, a supply power supply 5 for supplying power to apply voltage to the electrode 12 in the main body 1 to cause discharge, and a supply power supply 5 for supplying power to cause a pulse discharge in the plasma tube 9. It is comprised of a discharge circuit 6, an exhaust device 7 that exhausts the inside of the plasma tube 9, and a cooling device 8 that cools the main body 1, support flange 16, and the like.

The main body 1 has an internal structure including a plasma tube 9 made of heat-resistant ceramic in the center, a fiber-based heat insulating material 10 wrapped around the tube 9, and a quartz or glass protection tube 11 provided around the outer periphery of the heat insulating material 10. It's a thing. The head portion of the main body 1 is composed of a portion in which a cylindrical first electrode 12 made of heat-resistant metal such as molybdenum is installed, and an assembly in which a window 13 for extracting laser light is installed.

Window 13 is attached to support flange 16 and forms a Brewster tube.

Note that reference numeral 14 is a metal vapor source; for example, copper is used in a copper vapor laser. The oscillation principle of this metal vapor laser device is that a discharge is generated between the electrodes 12 of both cylinders in the glass protection tube 11 to which buffer gas is supplied by the supply power source 5 and the discharge circuit 6, and a heat insulating material 10 is wrapped around the outer circumferential surface. When the plasma tube 9 is heated and the metal vapor source 14 disposed inside the plasma tube 9 fills the plasma tube 9 with metal vapor as a laser medium and excites it with discharge plasma, the emitted excitation light is emitted as described above. Laser resonator mirror 2.
The laser output is obtained by amplifying the resonance between the three.

In a metal vapor laser that requires maintaining the plasma tube 9 at a high temperature and emitting metal vapor within the plasma tube 9 for a long period of time, the health of the plasma tube 9 and
The important point is to form a structure that is designed to obtain stable discharge.

(Problems to be Solved by the Invention) In the conventional metal vapor laser device, as shown in FIG. A gap A is provided to absorb the liquid. Further, the terminal end of the first electrode 12 is fixed to a support flange 16. However, in this conventional laser device, the first electrode 12 and the plasma tube 9
There is a problem in that powder of the heat insulating material 10 and other impurities are blown out from the gap A provided between the plasma tube 9 and the plasma tube 9, making the discharge unstable. Furthermore, in order to maintain stable discharge within the plasma tube 9, it is necessary to prevent impurities from entering the plasma tube 9 as much as possible. Therefore, it is necessary to smoothly discharge the impurity gas in the heat insulating material 10 to the outside of the main body 1. Therefore, the structure in which the terminal end of the first electrode 12 is fixed to the support flange 16 as in the conventional example impedes the flow of buffer gas, so there is room for improvement.

The present invention has been made in view of the above problems, and provides a metal vapor laser device that can improve the integrity of the plasma tube and the stability of discharge in a metal vapor laser device that requires maintaining the inside of the plasma tube at a high temperature. The purpose is to

[Configuration of the Invention (Means for Solving the Problems) A plasma tube filled with metal vapor evaporated by a discharge caused between a pair of cylindrical first electrodes; In a metal vapor laser device comprising an optical resonator formed by forming a laser resonator using metal vapor as a laser medium, the plasma tube and a first?1! A metal vapor laser device comprising a cylindrical second electrode inserted between the electrode and the electrode.

(Function) By inserting the second electrode between the first electrode and the plasma tube, the flow of the buff 7 gas to the heat insulating material becomes smooth, and furthermore, powder of the heat insulating material and impurities are not mixed into the plasma tube. It becomes difficult. This reduces the impurity concentration within the plasma tube and stabilizes the discharge, thereby making it possible to obtain high and stable laser output.

(Example) An embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a schematic configuration of the main parts of an embodiment of the present invention. The same parts as the conventional device shown in FIG. It is omitted. Further, explanations of overlapping parts will also be omitted.

The difference between this embodiment device and the conventional example is that the oscillation tube body 1
and a support flange 16 that supports the window 13, and a cylindrical second electrode 15 is inserted between the tip of the first electrode 12a and the plasma tube 9. The second electrode 15 has its tip in contact with the tip of the plasma tube 9, and its opposite end is connected to the main electrode 12.
It is formed to have a slightly smaller diameter than the first electrode 12a so as not to contact the first electrode 12a. Further, a gap B is provided between the other end of the second electrode 15 and the first electrode 12a.

Therefore, in the above embodiment, the discharge occurs at the first electrode 12a.
Occurs between. In the conventional example, the electric field in the axial direction is also limited to the first electrode 1.
It is thought that it is evenly distributed between the two. However, as in the present invention, the second electrode 15 is connected to the plasma tube 9 and the first electrode.
When inserted between the second electrode 12a and the second electrode 12a, the internal electric field of the second electrode 15 becomes smaller, and the axial electric field is concentrated in the deep part of the plasma tube 9 where the vapor density is high, actively excitation. This is advantageous in improving the oscillation efficiency. Moreover, the first electrode 12a and this second electrode 12a
Since a suitable gap B is provided between the electrodes 15, the buffer gas supplied so as to flow from one side of the support flange 16 to the other can smoothly flow into the heat insulating material 10.

Furthermore, the impurity gas in the heat insulating material 10 can be sufficiently discharged to the outside of the main body 1, and by keeping the impurity concentration in the plasma tube 9 low, it is possible to maintain stable discharge.

Note that the lifespan of the oscillation tube body 1 is mostly due to the plasma tube 9.
is determined by the lifetime of the metal vapor source 14 located within. Since this metal vapor is condensed at the low temperature part at the end of the plasma tube 9, if a sintered metal such as tantalum or tungsten is used for the second electrode 15, the metal vapor will return to a high temperature at this part due to its heat pump action. It is expected that the product life will be greatly increased by being recycled to the parts.

[Effects of the Invention] The metal vapor laser device according to the present invention prevents powder and impurities in the heat insulating material from entering the plasma tube by the second electrode inserted between the first electrode and the plasma tube. By improving the flow of buffer gas into the material and lowering the impurity concentration, it is possible to maintain stable discharge. Furthermore, the laser oscillation ability can be greatly increased due to the effect of concentrating the electric field in the plasma tube with high metal vapor concentration.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of a metal vapor laser device according to the present invention, and FIG. 2 is a longitudinal sectional view showing a conventional metal vapor laser device with an end block. 1...Oscillator tube body 2.3...Resonator mirror 4...Buffer gas supply device 5...
...Power source 6...Discharge circuit 7...Buffer gas exhaust device 8...
...Cooling device 9...Plasma tube 10...
...Insulating material 11...Protection tube 12...Main electrode 13...-Window 14...・Metal vapor source 15...Second electrode 16...-Support flange ASB...Gap Applicant Toshiba Corporation Patent attorney Sasa Suyama -

Claims (1)

[Claims] A plasma tube is formed between a pair of cylindrical first electrodes, the inside of which is filled with metal vapor evaporated by the generated discharge, and a laser resonator is formed using the metal vapor filled in this plasma tube as a laser medium. What is claimed is: 1. A metal vapor laser device comprising an optical resonator, characterized in that a cylindrical second electrode is inserted between the plasma tube and the first electrode.