JPS6197883A - Metallic vapor laser - Google Patents

Abstract

PURPOSE:To contrive to improve the reliability by preventing the decrease in vacuum-holding function even when the end of a ceramic tube comes to high temperatures, by a method wherein this end is metallized, and a bellows is brazed to the metallized part with metal. CONSTITUTION:A ceramic-tube flange 54 is brazed 53 with metal to the metallized surface 52 formed in the outer periphery at the end of the ceramic tube 4. A flange 51 for the bellows 7 is welded 56 to a cathode side container 19; next, a flange 50 on the opposite side of the bellows 7 is welded to said flange 54. This can prevent the unfavorableness such as the decrease in vacuum degree in the ceramic tube 4 and thus improves the reliability of laser oscillation.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a metal vapor laser that has an oscillation wavelength in the visible region, can obtain high efficiency and high laser output, and is applied to isotope separation technology of metallic uranium, etc. Regarding.

[Technical background of the invention and its problems]

Conventionally, a metal vapor laser is mainly composed of a discharge tube body and an external rock structure, as shown in FIG. That is, the discharge tube body is internally set up by the discharge generated by the buffer gas (He, Ne, etc.) supplied from the gas supply device 1 and the pulsed high voltage applied between the cathode 2 and the anode 3. A heat-resistant ceramic tube 4 that heats and evaporates the metal particles 16, a heat-insulating chamber 8 that vacuum-isolates the discharge section 5 by an O-ring 6 and a bellows 7, and a heat-resistant ceramic tube 4 that is housed in the heat-insulating chamber 8. , and a Brewster window 10 for extracting laser light.

The external mechanisms include a gas supply device 1 that introduces the buff 7 gas only into the discharge section 5, a vacuum exhaust system that evacuates the discharge section 5 and the heat insulation chamber 8 by separate rotary pumps 11 and 12, a high-voltage DC power source, and a A pulse high voltage power supply 13 consisting of a high-speed switching circuit, and a total reflection mirror 14
An optical resonator formed by the output mirror 15 and a water cooling pipe 18 for cooling the discharge tube body are provided.

In the above configuration, the metal vapor serving as the laser medium is obtained by heating the ceramic tube 4 to the boiling point of the metal through contact with the discharge plasma and vaporizing the metal grains 16 placed inside the ceramic tube 4. This metal vapor is uniformly distributed in the ceramic tube 4 from 1014 to 101'[α°
3], and when excited by electrons in the discharge plasma, it emits light with a wavelength unique to the metal.

Total reflection mirrors 14 placed at both ends of the discharge tube body
The light is amplified by an optical resonator consisting of an output mirror 15 and an output mirror 15.
The laser light is extracted from the output mirror 15 side. The above-mentioned discharge is caused by the voltage applied between the buffer gas introduced into the ceramic tube 4 and the electrodes 2.3 to 10 [KV], and the repetition frequency to 10 [K
Hz] is a pulsed bipolar discharge.

However, this type of conventional device has the following problems. That is, although the O-ring 6 is used to seal between the ceramic tube 4 and the bellows 7, the temperature inside the ceramic tube 4 is approximately 1400 [°C] and l
58I! It is about 300 [''C] near the area. Therefore, O
There were problems such as burning of the O-ring 6 and deterioration of the performance of the O-ring 6 due to thermal expansion of the ceramic tube 4, degrading the ability to maintain the vacuum level and adversely affecting the laser oscillation characteristics.

[Object of the Invention], 1 The present invention has been made in consideration of the above circumstances, and its purpose is to prevent the end of the ceramic tube from reaching a high temperature (several i o
It is an object of the present invention to provide a metal vapor laser which can prevent a decrease in vacuum holding performance even if the temperature reaches 00°C and can improve reliability.

[Summary of the invention]

The gist of the present invention is to connect the ceramic tube and the bellows by metal brazing instead of using a heat-sensitive O-ring.

That is, the present invention provides a laser tube container comprising a cathode container and an anode container connected by an insulating tube and Brewster windows formed at both ends thereof, and a cathode and anode disposed inside the container and connected to a pulsed high voltage power source. an anode, a ceramic tube connected to the container via a bellows, and a total reflection mirror and an output mirror placed outside the container, and metal particles placed in the ceramic tube. is evaporated by discharge heating to become metal vapor, and this metal vapor is excited by electrons in discharge plasma to generate a laser.In a metal vapor sheather, the end of the ceramic tube is metallized, and the metalized portion is heated. The bellows is brazed with metal.

[Embodiments of the invention]

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a sectional view showing a schematic configuration of a metal vapor laser according to an embodiment of the present invention. Note that the same parts as in FIG. 3 are given the same reference numerals, and detailed explanation thereof will be omitted.

This embodiment differs from the conventional device shown in FIG. 3 in the connection between the ceramic tube 4 and the bellows 7, and the configuration of other parts is the same as that in FIG. That is, one cathode-side container and an anode-side container 20 are connected via an insulating tube 17, and Brewster windows 10 are provided at both ends to form a laser tube container 23. A ceramic tube 4 in which metal grains 16 are installed in a discharge section 5 is connected to the laser tube vessel 23 via a bellows 7, and a cathode 2 and an anode connected to a pulsed high voltage power source 13 are connected to both ends of the ceramic tube 4. 3 are provided respectively. A heat shield plate 9 is arranged in the heat insulation chamber 8.

In addition, the laser tube container 23 includes a rotary pump 11.1.
2 and the gas supply device 1 are connected. Also, Brewster
A total reflection mirror 14 for reflecting the laser beam and an output mirror 15 for extracting the laser beam are arranged outside the window 10. Further, a water cooling pipe 18 for cooling is installed on the outer periphery of the laser tube container 23 .

Now, the ceramic tube 4 and the bellows 7 are connected as shown in FIG. That is, the ceramic tube flange 54 is metal-brazed to the metallized surface 52 provided on the outer peripheral surface of the end portion of the ceramic tube 4. 53 is the brazed part. First, the flange 51 of the bellows 7 is welded to the cathode side container 19. 56 is a welded portion. Next, the flange 50 on the opposite side of the bellows 7 and the ceramic tube flange 54 are welded. 55 is a welded portion.

Here, the ceramic tube 4 is a highly heat-resistant ceramic that can be used up to the boiling point temperature of the metal particles 16. The heat shield plate 9 is made of tantalum or nickel plate. Tantalum is used for electrode 2.3.

The pulsed high voltage power supply 13 consists of a high voltage DC power supply (not shown) and a high speed switching circuit (not shown).

The gas supply device 1 supplies a buffer gas such as He or Ne.

Next, the operation of the embodiment laser configured as described above will be explained. First, after the discharge section 5 and the heat insulation chamber 8 are evacuated by the rotary pumps 11 and 12, buffer gas is supplied to the discharge section 5 by the gas supply device 1. In the discharge section 5, the number of voltages supplied between the electrodes 2 and 3 from the pulse high voltage power supply 13 is ~10 [KV], and the repetition frequency is ~10 [Kt-].
A pulsed bipolar discharge is caused by the pulse of 1z).

The metal vapor serving as the laser medium is obtained when the ceramic tube 4 is heated to a high temperature by contact with the discharge plasma, and the metal grains 16 placed inside are evaporated. This metal vapor is uniformly distributed in the discharge section 5 within the ceramic tube 4 at a depth of 10"~
Distributed at a density of 10" a Ccuv3, it is excited by electrons in the discharge plasma and emits light with a wavelength unique to the metal. This light is transmitted through the Brewster window 10.
A total reflection mirror 14 and an output mirror 15 placed outside the
The light is amplified by an optical resonator consisting of the following, and is extracted as a laser light from the output mirror 15 side.

During laser oscillation, the temperature near the center of the ceramic tube 4 is extremely high, and the temperature at the ends is also quite high.

Here, since the connection between the ceramic tube 4 and the bellows 7 is made by metal brazing, the performance of the O-ring deteriorates due to high temperature and the degree of vacuum decreases, unlike when an O-ring is used in the conventional case. You can avoid inconveniences such as Further, as the temperature of the ceramic tube 4 increases, the linear expansion of the ceramic tube 4 increases, but the bellows 7 connected to the ceramic tube 4 expands to absorb the expansion due to this linear expansion.

Thus, according to this embodiment, even if the ceramic tube 4 becomes high 1, it is possible to prevent problems such as a decrease in the degree of vacuum inside the ceramic tube 4, thereby improving the reliability of laser oscillation. obtain.

Note that the present invention is not limited to the embodiments described above, and can be implemented with various modifications without departing from the gist thereof. For example, the bellows may be brazed directly to the metallized portion of the ceramic tube without brazing the flange. Further, as the metal for brazing, silver or other metal may be appropriately selected.

〔Effect of the invention〕

As explained above, according to the present invention, since the ceramic tube and the bellows are brazed with metal, the elongation of the laser tube due to high temperatures can be absorbed, and it is possible to Deterioration of vacuum maintenance performance can be prevented even under many temperature cycles, and reliability and longevity of the laser oscillation tube can be improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a metal vapor laser according to an embodiment of the present invention, FIG. 2 is a sectional view showing an enlarged configuration of the main parts of the laser, and FIG. 3 is a schematic configuration of a conventional laser. FIG. DESCRIPTION OF SYMBOLS 1... Gas supply device, 2.3... Electrode, 4... Ceramic tube, 5... Discharge part, 6... O-ring, 7...
・Bellows, 8...Insulation chamber, 9...Heat shielding plate, 10
... Brewster window, 11.12 ... Rotary pump, 13 ... Pulse high voltage generation, 14 ... Total reflection mirror, 15 ... Output mirror, 16 ... Metal particles, 17 ...Insulation tube, 18...Water cooling pipe, 19...
Cathode side container, 20... Anode side container, 23... Laser tube container, 50.51... Bellows flange, 52...
・Metallized surface, 54... Ceramic pipe flange, 5
5.56... Welded part, 53... Brazed part.

Claims (3)

[Claims] (1) A laser tube container formed by connecting a cathode container and an anode container with an insulating tube and forming a Brewster window at both ends thereof, and a cathode and anode arranged in this container and connected to a pulsed high-voltage power source. , comprising a ceramic tube connected to the container via a bellows in the container, and a total reflection mirror and an output mirror placed outside the container, and the metal particles placed in the ceramic tube are discharged. In a metal vapor laser that generates a laser by evaporating the metal vapor by heating and exciting this metal vapor with electrons in discharge plasma, the end of the ceramic tube is metallized, and the bellows is attached to the metallized portion by metal. A metal vapor laser characterized by being brazed. (2) A ceramic tube flange is brazed with metal to the end of the ceramic tube, and the bellows flange is brazed with metal to this flange. Metal vapor laser. (3) The ceramic tube is connected to the cathode container of the laser container.
Metal vapor laser as described in section.