JPH02281773A - Metal vapor laser oscillating tube - Google Patents

Abstract

PURPOSE:To improve an output and efficiency by installing one of discharge electrodes and a conductor member electrically conducted with an oscillating- tube box body in the clearance of a heat-insulating material and the oscillating- tube box body. CONSTITUTION:One 6 of discharge electrodes and a conductor member 19 electri cally conducted with an oscillating-tube box body 15 are mounted into the clearance of a heat-insulating material 12 and the oscillating-tube box body 15, and bellows 20A extensible in the axial direction and the circumferential direction are arranged at both end sections of the conductor tube 19. Consequent ly, even when the diameter and length of the outer tube 15 are made the same as conventional devices or the diameter of the outer tube 15 is increased or length thereof is lengthened in order to augment plasma volume, inductance can be reduced because the conductor tube 19 is set up. Accordingly, the eleva tion of an output and the improvement of efficiency can be attained simultane ously.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) This invention relates to a metal vapor laser oscillation tube.

(Prior Art) A metal vapor laser oscillation tube generally has a structure as shown in FIG. In FIG. 4, reference numeral 1 denotes a ceramic inner tube with excellent heat resistance, and a discharge buffer gas such as He, Ne, etc. is supplied from a gas supply system 3 to a discharge section 2 inside the tube, and is exhausted by a rotary pump 4. The voltage applied from the pulsed high voltage power supply 7 between the discharge electrode 5 and the discharge electrode 6 in contact with the outer tube 15 is pulsed by high voltage pulses of several KV to 10-odd KV and a repetition frequency of several KHz to 10-odd KHz. Plasma is generated by polar discharge. Metal particles 8 are arranged inside the ceramic inner tube 1, and when the metal particles 8 come into contact with the discharge plasma, the inside of the ceramic inner tube 1 is heated to an extremely high temperature state, and the metal particles 8 are evaporated.
A metal vapor is generated that becomes the laser medium. This metal vapor is uniformly distributed in the ceramic inner tube 1 at 10 to 1016 n/cI.
When excited by free electrons in the discharge plasma, it emits light with a wavelength unique to the metal, and passes through the Brewster window 9 to the output mirrors 10 placed at both ends of the ceramic inner tube 1. The light is amplified by an optical resonator constituted by a reflecting mirror 11, and output as a laser beam from the output mirror 10 side. A heat insulating material 12 is wrapped around the ceramic inner tube 1 to keep the inside at a high temperature, and these are further inserted into a protective tube 13. Ceramic inner tube 1
゜The heat insulating material 12 and the protection tube 13 are supported by the outer tube 15 via O-rings 14 at both ends, and the space between the outer tube 15 and the protection tube 13 is evacuated by the rotary pump 16 to form a vacuum insulation chamber 17. It has become.

An insulating tube 18 is inserted in the middle of the outer tube 15 to electrically isolate the discharge electrodes 5 and 6.

Incidentally, recent demands on metal vapor laser oscillator tubes include higher output and higher efficiency.

In order to increase the output, it is possible to increase the volume of the plasma and increase the input to the plasma. If the outer tube 15 is made longer or thicker in order to increase the volume of plasma, the inductance as a power supply circuit increases, the rise of the discharge current is delayed, the excitation efficiency is poor, and the oscillation efficiency is reduced.

On the other hand, in order to improve efficiency, it is conceivable to make the outer tube 15 shorter or thinner to reduce the inductance of the laser oscillation tube. Reducing the inductance speeds up the current rise time and increases efficiency. However, if the outer tube 15 is short or thin, the plasma volume will be small and high output cannot be expected.

In this way, higher output and higher efficiency have a contradictory relationship.
Conventionally, it has been difficult to simultaneously achieve high output and high efficiency.

(Problem to be solved by the invention) As mentioned above, in the conventional metal vapor laser oscillation tube,
It has been difficult to obtain high output and high efficiency.

The present invention has been made in view of the above circumstances, and its purpose is to provide a metal vapor laser oscillation tube that has high output and high efficiency.

[Structure of the Invention] (Means for Solving the Problems) In the present invention, there is provided a pipe in which metal particles are arranged, a heat insulating material provided to cover the outside of the pipe, and a gap between the pipe and the heat insulating material. and an oscillation tube housing provided so as to cover the tube, supplying discharge gas into the tube, and generating discharge plasma by applying a voltage between discharge electrodes provided near both ends of the tube. In a metal laser oscillation tube that performs laser oscillation by exciting the metal particles with free electrons in discharge plasma, one of the discharge electrodes and the oscillation tube casing are provided in a gap between the heat insulating material and the oscillation tube casing. It is characterized by disposing a conductor member that is electrically conductive with.

Furthermore, the above-mentioned structure is such that a bellows (elastic member) that can be expanded and contracted is arranged in the axial direction and the circumferential direction of the conductor member. Also,
A smooth conductor cover was installed to cover the end of the conductor member facing the discharge electrode that was not in contact with the conductor member. (Function) In the metal vapor laser oscillation tube configured in this way, a conductor member that is electrically connected to one of the discharge electrodes and the oscillation tube casing is arranged in the gap between the heat insulating material and the oscillation tube casing. Because of this, the inductance is small and the current rise time is fast (
Therefore, large output can be achieved without reducing efficiency. Furthermore, the effect of reflecting radiant heat by the conductor member increases the heat insulation effect to the outside. In addition, the Touta cover suppresses discharge that crosses the insulation material and protection tube between the internal conductor and the discharge electrode that does not come into contact with it, preventing deterioration of the insulation material and protection tube due to discharge, extending the life of the laser oscillation tube. becomes.

This enables a metal vapor laser oscillation tube with a large laser output without increasing the overall size.

(Example) Hereinafter, the present invention will be explained in detail based on the illustrated example. Incidentally, the same parts as in the prior art are given the same reference numerals, and redundant explanations will be omitted.

FIG. 1 is a schematic sectional view showing a metal vapor oscillation tube according to the present invention. As shown in FIG. 1, a conductor tube 19 made of, for example, aluminum or copper is installed concentrically outside the protective tube 13 housing the heat insulating material 12 and inside the outer tube 15, that is, inside the vacuum insulation chamber 17. Further, bellows 20 which are expandable and retractable in the axial and circumferential directions are arranged at both ends of the conductor tube 19. Both ends of the bellows 20 are electrically connected to the cathode 6 and also to the outer tube 15.

In this way, the conductor tube 19 is connected to the cathode 6 and the outer tube 15.
By providing this, it is possible to reduce the inductance and increase the plasma volume, making it possible to achieve high efficiency and large output.

That is, in the conventional metal laser oscillation tube, voltage is applied from the power source 7 to the cathode 6 through the outer tube 15 made of aluminum or the like. However, in order to reduce inductance and increase efficiency, it is necessary to shorten the length or diameter of the outer tube 15, which inevitably reduces the volume of the plasma and makes it impossible to achieve high output. There wasn't.

Here, in order to reduce only the diameter of the outer tube 15 without reducing the volume of the plasma, the volume of the heat insulating material 12 and the vacuum heat insulating chamber 17 must be reduced, resulting in an insufficient heat insulating effect, which is not practical.

According to the present invention, even if the diameter and length of the outer tube 15 are the same as conventional ones or the diameter or length of the outer tube 15 is increased to increase the plasma volume, the conductor tube 19 is provided. It becomes possible to reduce inductance, and high output and high efficiency can be achieved at the same time.

Further, since the conductor tube 19 is arranged inside the vacuum heat insulation chamber 17, the effect of reflecting radiant heat by the conductor tube 19 also provides the advantage of improving the heat insulation effect to the outside.

Note that it is possible to improve the laser output of a metal vapor laser oscillation tube by reducing the inductance L of the laser oscillation tube. R, then approximately Lo
It is expressed as clln(rr/r,). That is, r
By reducing the inductance L, the inductance L is reduced and the output efficiency of the laser is improved.

Further, although the conductor tube 19 thermally expands in the axial and circumferential directions due to the secondary radiation heat from the protection tube 13, the change in the length of the conductor tube 19 can be absorbed because the bellows 20 is arranged. Note that instead of the bellows 20, an elastic body capable of absorbing thermal expansion, such as a spring, may be used.

FIG. 2 shows a second embodiment of the invention. Note that the same parts as in the first embodiment are denoted by the same reference numerals, and redundant explanation will be omitted. As shown in FIG. 2, the conductor tube 19 itself has a bellows structure so that changes in length due to heat are absorbed by the pleats 2OA, and the same functions and effects as in the first embodiment can be obtained.

FIG. 3 shows a third embodiment of the invention. In the first and second embodiments, a protective cover 21 is installed at the end of the conductor tube 19, which is installed for the purpose of reducing the inductance of the laser oscillation tube and faces the Group 11 electrode 5, which does not come into contact with the conductor tube 19. . This protective cover 21 is made of a conductor with a smooth surface (for example, aluminum, copper, copper alloy, etc.), and this protective cover 21 alleviates the concentration of electric field strength at the end of the conductor tube 19 facing the discharge electrode 5. Insulation material 12
Therefore, discharge across the protection tube 13 can be prevented.

Therefore, the deterioration of the heat insulating material 12 and the protection tube 13 due to discharge is eliminated, and further effects and effects can be obtained, such as prolonging the life of the laser oscillation tube.

In the above embodiments, the conductor member is described as a conductor pipe having a tubular shape, but it is not limited to the tubular shape, and may have a configuration in which a plurality of conductors such as a plate shape are arranged, and various shapes may be used without departing from the gist of the present invention. It can be modified and implemented.

[Effects of the Invention] As described above in detail based on the embodiments, according to the present invention, by arranging the conductor member, it is possible to make the metal vapor laser oscillation tube highly efficient and improve the laser output. Moreover, since the conductor member is placed inside the vacuum insulation chamber, the insulation effect is improved, and efficient laser oscillation can be performed.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing a metal vapor laser oscillation tube according to a first embodiment of the present invention, FIGS. 2 and 3 are schematic sectional views showing second and third embodiments of the present invention, FIG. 4 is a schematic cross-sectional view showing a conventional metal vapor laser oscillation tube. 1...Ceramic inner tube, 3...Gas supply system, 5...
・Discharge electrode, 6...Discharge electrode, 7...Pulse high voltage power supply, 8...Metal particle, 10...Output mirror 11
... Total reflection mirror 12 ... Heat insulation material, 13 ... Protection tube, 15 ... Outer tube (oscillator tube housing) 16 ... Rotary pump, 17 ... Vacuum insulation chamber, 19 ...・Conductor tube (conductor member), 20...Bellows, 20A...Folds, 21...Protective cover〉・9ゝBite C rumor 222=:==hi9

Claims (3)

[Claims] (1) Comprising a tube in which metal particles are arranged, a heat insulating material provided to cover the outside of the pipe, and an oscillation tube casing provided to cover and maintain a gap with the heat insulating material, A discharge gas is supplied into the tube, and a voltage is applied between discharge electrodes provided near both ends of the tube to generate discharge plasma, and the metal particles are excited by free electrons in the discharge plasma. In a metal laser oscillation tube that performs laser oscillation, a conductor member that is electrically connected to one of the discharge electrodes and the oscillation tube casing is provided in a gap between the heat insulating material and the oscillation tube casing. Features metal vapor laser oscillation tube. (2) The metal vapor laser oscillation tube according to claim 1, wherein the conductor member has an elastic function that expands and contracts in accordance with thermal expansion in order to compensate for thermal expansion along the axial direction of the tube. . (3) The metal vapor laser oscillator tube according to claim 1, wherein an end portion of the conductor member facing the other discharge electrode that is not electrically conductive with the conductor member is covered with a smooth conductor member.