JPS6197886A - Metallic vapor laser apparatus - Google Patents

Abstract

PURPOSE:To prevent the decrease in output and to contrive the prolongation in lifetime by a method wherein metal vapor adsorption films equipped with a feeding mechanism at the laser beam outlet are arranged in parallel with Brewster windows and inside the windows. CONSTITUTION:When a ceramic tube 4 is heated by impressing pulse high voltage from a pulse high voltage source 12 to both electrodes the cathode 2 and the anode 3 and to the buffer gas, a metal 16 evaporizes and excited by electrons, then emitting excited beams. At this time, the metal vapor diffuses through the buffer gas atmosphere and is adsorbed to the metal vapor adsorption films 17 arranged at both ends of the discharge tube body 5, taken out of the Brewster windows 10 through the adsorption films 17, and outputted from the output mirror 14 side under amplification by a total reflection mirror 13 and the output mirror 14. When the output of laser beam decreases with the increase in amount of deposition with the passage of operation, the adsorption films are fed out and replaced with parts of no deposition of metallic vapor.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention has an oscillation wavelength in the visible range (wavelengths of 5106 and 5780 wavelengths), and can obtain high efficiency and high laser output. This invention relates to metal vapor laser devices such as copper vapor lasers applied to separation technology.

[Technical background of the invention and its problems] As shown in FIG.
A pulse high voltage power supply 12 is connected between the cathode 2 and the anode 3 provided at both ends of the ceramic tube 4 by supplying a buff 1 gas such as
applies a pulsed high voltage. The copper grains 16 placed inside the ceramic tube 4 are heated and evaporated by the discharge generated by this high voltage. Note that the discharge section 5 of the heat-resistant ceramic tube 4 is vacuum isolated from the heat insulating chamber 8 by an O-ring seal section 6 and a bellows 7. Further, a heat shielding plate 9 is provided on the outer peripheral surface of the ceramic tube 4.

Furthermore, Brewster windows 10 for extracting laser light are arranged at both ends of the discharge tube body 15.

The metal vapor laser device includes a vacuum evacuation system that can evacuate the discharge section 5 using a rotary pump 11, and a
A gas supply system 1 that introduces buffer gas only to Equipped with utensils.

The discharge is caused by a buffer gas supplied from the gas inlet 1 into the ceramic tube 4 and a voltage of several kV to 1 applied to both poles 2.3.
This is a pulsed bipolar discharge with several kV and a repetition frequency of several KHz to several K11 z.

The metal vapor serving as the laser medium is obtained by heating the ceramic tube 4 to about the boiling point of the metal by contact with the discharge plasma, and evaporating the metal grains 16 placed inside. This metal vapor is uniformly distributed in the ceramic tube 4 at a depth of 10" to 1
It is distributed at a density of 0" n/cd and emits excitation light by being excited by electrons in the discharge plasma. Total reflection mirrors 13 and output mirrors 14 (50% It is amplified by an optical resonator consisting of a transmittance) and is extracted as a laser beam from the output mirror 14 side.In the figure, 19 is a gas exhaust port, 20 is a cooling pipe, 21 is a conducting wire, 22 is a connecting pipe, 23 indicate insulating tubes.

In a conventional example with such a configuration, metal vapor diffuses into the buffer gas atmosphere from inside the ceramic tube 4 kept at a high temperature, and adheres to low-temperature parts such as the Brewster windows 10 at both ends, and the laser beam is transmitted to the outside. The laser tube becomes difficult to remove, the laser output decreases over time, and the life of the laser tube is shortened.

[Object of the Invention] The present invention was made in view of the above circumstances, and an object of the present invention is to provide a metal vapor laser device that does not make it difficult to extract laser light to the outside even if metal vapor adheres to the Brewster window. do.

[Summary of the Invention] In order to achieve the above object, the present invention includes a heat-resistant ceramic tube covered with a heat shielding plate and having metal grains placed therein, and vacuum-isolating the ceramic tube with an O-ring and a bellows. In a metal vapor laser device equipped with a vacuum insulation chamber, a rose gas inlet, a high voltage DC power source, and a pulsed high voltage power source consisting of a high-speed switching circuit, a metal vapor adsorption film equipped with a sending R structure at the laser beam extraction port is used. It can be placed parallel to the Brewster window and further inside the discharge tube than the Brewster window, and the total reflection mirror and the output mirror can form an optical resonator, or the Brewster window and the total reflection mirror or the output mirror can be airtight. This is a metal vapor laser device surrounded by a box held in a metal vapor laser.

[Embodiment of the Invention] An embodiment of a metal vapor laser device according to the present invention will be described below with reference to FIG. Note that parts in FIG. 1 that are the same as those in FIG. 3 are given the same reference numerals, and explanations of overlapping parts are omitted.

That is, in FIG. 1, the buffer gas (He).

An inlet 1 for introducing Ne, etc.) into a discharge section 5 in a ceramic tube 4, a pulsed high voltage power supply 12 consisting of a high voltage DC power supply and a high speed switching circuit, and a cathode 2 for generating a pulsed high voltage and discharging by this power supply 12. A heat-resistant ceramic tube 4 having an anode 3 at both ends and having metal grains 6 installed therein; a heat-insulating chamber 8 in which a discharge section 5 within the ceramic tube 4 is vacuum-isolated by an O-ring seal section 6 and a bellows 7; A heat shielding plate 9 that covers the ceramic tube 4, a discharge tube body that surrounds the ceramic tube 4 and its accessory parts, and a metal vapor adsorption device through which a laser beam that adsorbs metal vapor passes through each end of the discharge tube body 5. A film 17, a Brewster window 10 that is parallel to the adsorption film 17 and takes out the laser beam at the end, a total reflection mirror 13 that totally reflects the laser beam taken out from the discharge tube body 5, and an output mirror that outputs the laser beam. The metal vapor laser device is composed of the optical resonator formed by 14. In addition, metal vapor adsorption film 1
7 has a feeding mechanism that can be freely replaced with respect to the discharge tube main body 5.

Next, the operation of the metal vapor laser device according to the present invention will be explained.

A pulsed high voltage power supply 12 is applied between the cathode 2 and anode 3 and the buffer 7 gas at several kV to several kV, and the repetition rate is KHz to several tens of K. The tube 4 is heated to about the boiling point of the metal. Through this heating, the metal inside the ceramic tube 4, for example, the copper grains 16, is evaporated and uniformly 1014 to 10"n inside the ceramic tube 4.
Copper vapor is distributed at a density of /li. Then, when excited by electrons in the discharge plasma, excitation light is emitted. At this time, the copper vapor diffuses into the buffer gas atmosphere from within the ceramic tube 4 maintained at a high temperature and is adsorbed by the metal vapor adsorption films 17 disposed at both ends of the discharge tube body 5.

Therefore, the excitation light is transmitted through the adsorption film 17 that transmits the laser light.
is transmitted through the Brewster window 10, and is amplified by an optical resonator consisting of a total reflection mirror 13 and an output mirror 14 (50% transmittance) arranged at both ends of the discharge tube body 5.
The laser beam is extracted from the output mirror 14 side as a relay laser beam.

On the other hand, the amount of adhesion of the adsorption film 17 that adsorbs copper vapor increases as the operation progresses, so if the output of the laser beam decreases, the adsorption film 17 is used to remove the copper vapor in the same way as the film feed of a camera. By sending the copper vapor to replace the area where it is not attached at all, the cause of the decrease in laser light output due to copper vapor and adhesion can be removed, and the laser light output will be restored to its original level.

As explained above, according to the above embodiment, the laser light output does not decrease due to metal vapor adhering to the film, and as a result, the life of the entire device can be extended.

Note that the present invention is not limited to the embodiment shown in FIG. 1; for example, as shown in FIG.
Using the metal vapor laser shown in the figure, the Brewster window 10 and the output mirror 13 or output mirror 14 at each end of the discharge tube body 5 are placed in a container 18 that is kept airtight, and then the Brewster window 10 itself is sealed. By increasing the size and having a rotating rock structure, and replacing the part where metal vapor is attached due to rotation with the part that is not attached, it is possible to eliminate the decrease in the output of the laser light due to the attachment of metal vapor, and it is possible to reduce the overall efficiency of the device. It can extend the lifespan.

[Effects of the Invention] As detailed above, according to the present invention, since metal vapor adheres to the metal vapor adsorption film and can be replaced with a new film, the output of the laser device does not decrease, and the metal vapor laser The life of the device itself can be extended.

[Brief explanation of drawings]

FIG. 1 is a layout diagram showing one embodiment of a metal vapor laser according to the present invention, FIG. 2 is a layout diagram showing another embodiment of the invention, and FIG. 3 is a layout diagram showing a conventional metal vapor laser. be.

Claims (2)

[Claims] (1) A pulsed high-voltage power supply consisting of an inlet for introducing buffer gas into the discharge section, a high-voltage DC power supply, and a high-speed switching circuit, and a cathode and anode at both ends that generate a pulsed high voltage and discharge metal particles inside the high-voltage power supply. a heat-resistant ceramic tube in which a discharge portion of the ceramic tube is installed, an insulating chamber in which the discharge part of the ceramic tube is vacuum-isolated by an O-ring and a heat shield plate, and a discharge tube body comprising a heat shield plate that covers the ceramic tube;
A metal vapor adsorption film that transmits laser light is placed at each end of the discharge tube body, a Brewster window is placed parallel to the adsorption film on the laser light extraction side, and a laser beam is placed on both sides of the discharge tube body. A metal vapor laser device comprising a total reflection mirror and an output mirror arranged perpendicular to an optical axis. (2) The metal vapor laser device according to claim 1, characterized in that the metal vapor adsorption film has a length larger than the Brewster window width and is formed so as to be continuously fed out and replaced.