JPH02148777A - Metal vapor laser oscillation tube - Google Patents

Abstract

PURPOSE:To obtain a laser output having a high efficiency by disposing an outer tube made of a heat resistant material concentrically with the outside of an inner tube and providing means for uniformly heating the center and the vicinities of both ends of the inner tube at temperatures at the time of oscillation of a laser on the outer surface of the outer tube. CONSTITUTION:When a laser oscillation is conducted, an outer tube 8 is evacuated by a pump 19, and discharging buffer gas is supplied from a gas supply source 20. A heater 26 is electrified, a high voltage pulse is applied from a pulse high voltage power source 14 between an anode 2 and a cathode 3 disposed with metal particles 21 through an outer tube 8, side plates 13a, 13b to generate a discharging plasma to vaporize the particles 21, thereby generating metal vapor to become a laser medium. The metal vapor is excited by free electrons, a laser oscillation is generated by an output mirror 17 and a totally reflecting mirror 18, and a laser light is output from the mirror 17. In this case, a ceramic tube 25 is uniformly heated by the heater 26 which is densely would in the vicinities of both ends and roughly wound in the vicinity of the center.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a metal vapor laser oscillator tube, and more particularly to a transversely pumped metal vapor laser oscillator tube.

(Prior Art) This type of laser generating Jti tube is configured as shown in FIG. 5, for example. That is, in the inner tube 1 made of ceramic with excellent heat resistance, a metal positioning member 4a is provided with an anode 2 and a cathode 3 made of plate-shaped molybdenum or the like, respectively, integrally arranged along the axial direction.

4b is arranged. The positioning member 4a is fixed to the inner tube 1 with screws 5, and the positioning member 4b is fixed to the inner wall surface 1 of the inner tube 1.
It is pressed against a. Also, on the outside of the inner tube 1, the inner tube 1
A protective tube 7 filled with a heat insulating material 6 to maintain the temperature at a high temperature is disposed, and an outer tube 8 made of a conductor is disposed outside the protective tube 7.

The inner tube 1 is supported by the outer tube 8 via heat insulating plates 9a and 9b, and the protective tube 7 into which the inner tube 1 is inserted is fitted with O-rings 10a and 1.
It is supported by the outer tube 8 via 0b. A vacuum heat insulating chamber 11 is formed between the protective tube 7 and the outer tube 8 by evacuation by a rotary pump 12. In addition, the outer tube 8 and the anode 2
．． The anode 3 is connected via lead plates 13a and 13b, and receives lQi voltage pulse (
The voltage is several KV to 10-odd KV, and the repetition frequency is several KH2.
~10-odd KHz) is applied between the anode 2 and the cathode 3 via the outer tube 8. The outer tube 8 is provided with an insulating tube 15 that electrically isolates the anode 2 side and the cathode 3 side.

Further, Brewster windows 15a and 1 are provided on both end surfaces of the outer tube 8.
6b is attached, and an output mirror 17 and a total reflection mirror 18 are arranged on the outside thereof, respectively. The inside of the outer tube 8, which is sealed with Brewster windows 16a and 16b attached to both ends, is evacuated by a rotary pump 19 and maintained in a vacuum state, and a discharge buff 7 gas such as To 1e and Na is supplied from a gas supply source 20. is supplied.

Conventional metal vapor laser light (The cinnabar tube is configured as described above, and in order to perform laser oscillation, the inside of the outer tube 8 is maintained at a high vacuum by exhausting the rotary pump 19, and He is supplied from the gas supply source 20. Then, a high voltage pulse is applied from the high voltage power source 14 to the outer tube 8 and the lead plate 13a between the anode 2 and the cathode 3, where the desired metal particles 21 are arranged in advance. , 13b, a discharge plasma is generated between the anode 2 and the cathode 3, vaporizing the metal particles 21, and producing metal vapor that becomes the laser medium. The metal is uniformly distributed at a density of 1014 to 1QI5n/cm:l, and when excited by the free electrons in the IIl electric plasma, it emits light with a wavelength unique to the metal.

16b, and is amplified by an optical wave oscillator composed of an output mirror 17 and a total reflection mirror 18 disposed on the outside thereof, and is output as a laser beam from the output mirror 17 side.

(Problems to be Solved by the Invention) In the conventional laser oscillation tube described above, the laser oscillation tube
Since plasma discharge is performed by applying a high voltage between the pole 2 and the cathode 3, the inside of the inner tube 1 reaches a high temperature of about 1500°C. By the way, since both ends of the inner tube 1 are open, the heat inside the inner tube 1 escapes to the outside from both ends, so the temperature inside the inner tube 1 is lower near both ends than near the center.

For this reason, the effective high temperature region (approximately 1500°C) that contributes to the discharge between the anode 2 and cathode 3 during laser oscillation is only near the center of the inner tube 1, so the effective high temperature region becomes narrow.
It had the disadvantage that it could only produce 1q of efficient laser output.

The present invention was made for the purpose of solving the above-mentioned problems, and provides a metal vapor laser oscillation tube that can make the temperature inside the inner tube almost uniform, widen the effective lOi temperature range, and obtain efficient laser output. I am trying to do that.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention supplies a discharge buffer gas into a first tube made of a heat-resistant material in which metal particles are arranged, and A discharge plasma is generated by applying a high voltage between an anode and a cathode disposed in the tube 1 to vaporize the metal particles, and the vaporized metal particles are excited by free electrons in the discharge plasma to generate a laser beam. In the laser oscillation tube that performs oscillation, a second tube made of a heat-resistant material is arranged approximately concentrically with the first tube outside the first tube, and the second tube is made of a heat-resistant material.
A heating means is disposed on the outer peripheral surface of the first tube so that the temperature near the center and both ends of the first tube becomes substantially uniform when the laser beam is emitted.

(Function) According to the present invention, the temperature in the axial direction of the first tube becomes substantially uniform due to the heating by the heating means when the laser is installed.
The effective high QCn region contributing to the discharge between the anode and the cathode can be widened, and efficient laser output can be obtained.

(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 seam 11 oscillation tube according to a first embodiment of the present invention. As shown in this figure, a protective tube 7 and an outer tube 8 are arranged concentrically outside a first tube (hereinafter referred to as an inner tube) 1 made of ceramic. The inner tube 1 is connected to the outer tube 8 via ring-shaped heat insulating plates 9a and 9b.
The storage tube 7 is supported by the outer tube 8 via O-rings lQa and 10b.

The inner tube 1 includes two short tubes 22a made of ceramic, which is the same material as the inner tube 1, and whose axial directions are substantially aligned.

22b is disposed so as to be freely movable in the axial direction. Short tube 22
a and 22b are formed to have a slightly smaller diameter than the inner tube 1, and a gap is provided between the inner tube 1 and the short tubes 22a and 22b.
Positioning members 23a and 2 are located inside of 2a and 22b.
An anode 2 and a cathode 3 fixed to 3b are supported facing each other (see FIG. 2).

The positioning members 23a, 23b are fixed to the short tubes 22a, 22b with screws 24.

Further, 11 is a vacuum insulation chamber formed by the exhaust of the rotary pump 12, 13a and 13b are lead plates connecting the anode 2 and the cathode 3 and the outer tube 8, and 141 is a high voltage pulse applied between the anode 2 and the cathode 3. 15 is an insulating tube, 16a and 16b are Brewster windows, 17.18 is an output mirror and a total reflection mirror, 19 is a rotary pump that evacuates the inside of the outer tube 8, and 20 is between an anode 2 and a cathode 3. This is a gas supply source for supplying a buffer gas such as He for discharge.

In addition, the present invention provides a second tube (hereinafter referred to as a ceramic outer tube) 25 made of ceramic and substantially concentric with the inner tube 1 between the inner tube 1 and the protective tube 7, so that the protective tube 7 and the ceramic A heat insulating material 6 for keeping the inner tube 1 at a high temperature between the outer tube 25
At the same time, a heater 26 having a square cross section is wound around the outer peripheral surface of the ceramic tube 25 along the axial direction. The heater 26 is wound tightly near both ends and loosely wound near the center so that the temperature near the center and both ends of the inner tube 1 is approximately uniform due to the heat generated during laser emission. . As described above, in this embodiment, the heater 26 is wound around the outer peripheral surface of the ceramic outer tube 25 as a heating means for the inner tube 1.

The metal vapor laser oscillation tube according to the present invention is constructed as described above, and when performing laser emission, the inside of the outer tube 8 is maintained at a high vacuum by exhausting the rotary pump 19, and He is supplied from the gas supply source 20. A discharge buffer gas such as or Ne is supplied. Thereafter, the heater 26 is energized, and a high voltage pulse is applied from the pulsed high voltage power source 14 to the outer tube 8,
By applying voltage via lead plates 13a and 13b,
A discharge plasma is generated between the anode 2 and the cathode 3 to vaporize the metal particles 21 to generate metal vapor that becomes a laser medium. Then, this metal vapor is excited by free electrons in the discharge plasma generated between the rJA electrode 2 and the cathode 3, amplified by an optical co-concentrator consisting of an output mirror 17 and a total reflection mirror 18, and then The laser beam is oscillated from the 17 side.

At this time, the ceramic outer tube 25 is heated by the heat generated by energizing the heater 26, which is wound tightly near both ends of the ceramic tube 25 and loosely wound near the center, and the inner tube 1 inside the ceramic tube 25 is heated. It is heated so that the temperature near the center and near both ends becomes substantially uniform.

At this time, by winding the heater 26 in the axial direction on the outer peripheral surface of the ceramic outer tube 25, the temperature distribution on the surface where the heater 26 is wound and the surface where it is not wound becomes approximately uniform, and Since the cross section of the heater 26 is square, the effective contact area with the ceramic outer tube 25 is increased, and the inner tube 1 can be heated efficiently.

Therefore, an effective high temperature region (approximately 1500° C.) that contributes to the discharge between the anode 2 and the cathode 81i3 during laser oscillation extends to the vicinity of both ends of the inner tube 1, allowing highly efficient laser oscillation. In addition, during laser emission, the temperature between the anode 2 and cathode 3 becomes high due to discharge, so thermal expansion occurs in the inner tube 1, anode 2, cathode 3, and short tubes 22a and 22b. tube 2
Since the inner tube 1 and the short tubes 22a, 22b are made of the same material (ceramic), the thermal expansion in the circumferential direction occurring in the inner tube 1 and the short tubes 22a, 22b is equal, and the gap in the circumferential direction is always kept constant.
Thermal expansion in the axial direction that occurs in the anode 2 and the cathode 3 is caused by the movement of the short tubes 22a and 22b, which support the anode 2 and the cathode 3 via the positioning members 23a and 23b, in the axial direction within the inner tube 1. Absorbed.

In this way, by forming the inner tube 1 and the short tubes 22a, 22b from the same ceramic material, the inner tube 1, the short tubes 22a, 22b,
Even if thermal expansion occurs between the inner tube 1 and the inner tube 1, damage to the inner tube 1 can be prevented. Also, anode 2
Even if axial thermal expansion occurs in the cathode 3, the short tubes 22a, 2
Since thermal expansion of the anode 2 and cathode 3 can be absorbed by moving 2b in the axial direction, the accuracy of the relative position of the anode 2 and cathode 3 can be ensured.

FIG. 3 is a schematic cross-sectional view showing a metal vapor laser oscillation tube according to a second embodiment of the present invention. In this example, a heater 26a having a rectangular cross section is arranged along the axial direction on the outer peripheral surface of the ceramic outer tube 25 and is thick near both ends and thin near the center.
It has a structure in which it is wound. Other configurations are as shown in Figure 1.
This is similar to the example.

In this way, in this example, the heater 26a is made thicker near both ends of the ceramic outer tube 25 and thinner near the center, so that the heat generated by energizing the heater 26a is proportional to its thickness. The inner tube 1 is heated so that the area near the center and near both ends 419 are substantially uniform.

FIG. 4 is a schematic cross-sectional view showing a metal vapor laser oscillation tube according to a third embodiment of the present invention. In this example, heaters 26b and 26c each having a rectangular cross section and having a large heat capacity near both ends and a small heat capacity H) near the center along the axial direction on the outer peripheral surface of the ceramic outer tube 25 are separately provided. It has a structure in which it is wound in a circular motion. The configuration of the frame is similar to that of the first embodiment shown in FIG.

As described above, in this example, by winding the heater 26b, which has a large heat capacity near both ends of the ceramic outer tube 25, and the heater 26c, which has a small heat capacity near the center, the inner tube 1 can be moved near the center during laser oscillation. It is heated so that the temperature near both ends becomes substantially uniform.

Therefore, in the second and third embodiments as well, the effective high temperature region (approximately 1500°C) that contributes to the M electric current between the anode 2 and cathode 3 during Lepe oscillation extends to the vicinity of both ends of the inner tube 1, resulting in high efficiency. Laser oscillation can be performed.

In addition, as another embodiment of the present invention, the ceramic outer tube 2
A configuration may also be used in which coils are wound around both ends of the coil 5 and energized. In this case, during laser oscillation, the vicinity of both ends of the inner tube 1 is heated by the heat generated by the coil, so the temperature near the center and both ends of the inner tube 1 become approximately uniform, allowing high-efficiency laser oscillation as described above. It can be performed.

Although each of the above-mentioned embodiments is a case of a horizontally excited metal vapor laser oscillation tube, it is also applicable to a vertically excited metal vapor laser oscillation tube.

[Effects of the Invention] As described above in detail based on the embodiments, according to the present invention, the temperature within the inner tube is approximately equalized by the heating means during laser oscillation, and an effective high temperature region is widened. This enables efficient and stable laser emission.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a metal vapor laser emitting tube according to the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. A schematic sectional view showing an embodiment. FIG. 5 is a schematic sectional view showing a conventional metal vapor oscillator tube. 1...Inner tube (first tube) 2...g! Pole 3... Cathode 7... Protection tube 8... Outer tube 14... Pulse high voltage power supply 17... Output mirror 18... Total reflection mirror 20.
...Gas supply source 21...Metal particles 22a, 22b=
・Short tube

Claims (5)

[Claims] (1) A discharge buffer gas is supplied into a first tube made of a heat-resistant material in which metal particles are arranged, and a discharge plasma is generated by applying a high voltage between an anode and a cathode arranged in the first tube. In a laser oscillation tube that vaporizes the metal particles and excites the vaporized metal particles with free electrons in the discharge plasma to generate laser oscillation, there is a tube provided on the outside of the first tube approximately concentrically with the tube. A second tube made of a heat-resistant material is arranged, and heated on the outer peripheral surface of the second tube so that the temperature near the center and both ends of the first tube becomes substantially uniform during laser oscillation. A metal vapor laser oscillation tube characterized in that a heating means is provided. (2) As the heating means, a heater is used which is wound around the outer circumferential surface of the second tube in the axial direction, densely wound near both ends and loosely wound near the center. 1) The metal vapor laser oscillation tube described above. (3) As the heating means, a heater is wound around the outer peripheral surface of the second tube in the axial direction, the heater being thick near both ends and thin near the center. metal vapor laser tube. (4) As the heating means, a heater having a large heat capacity near both ends and a small heat capacity near the center is wound around the outer peripheral surface of the second tube in the axial direction. The metal vapor laser oscillation tube according to item (1). (5) The first tube and the second tube are made of ceramic.
4) The metal vapor laser oscillation tube described above.