JPH04174574A - Metallic-vapor laser device - Google Patents

Abstract

PURPOSE:To obtain a desired wick performance and, at the same time, to reduce the laser light shielding amount of the wick by providing the wick formed by coating a tungsten material in a discharge tuber. CONSTITUTION:A heat insulating material 13 is put around the outer periphery of a ceramic tube 2 and a wick 20 is provided in the tube 2 by coating the inner surface of the tube 2 with a tungsten metal from a metallic vapor source 1 to the end section of the tube 2 in the axial direction. After the tube 2 is evacuated by actuating an evacuating system, a buffer gas Ne is supplied into the tube 2 through a gas supplying tube 3. Then plasma is produced in the tube 2 by actuating a pulsative high-voltage power source and the temperature of the plasma is raised to the temperature required for laser oscillation by means of the vapor source 1. Free electrons contained in the plasma are excited by the metallic vapor front the vapor source 1 and an inverted state is produced in the tube 2, resulting in the generation of laser light. The laser light adheres to the wick 20 after the power of the laser light is raised through a laser resonator. Since the wick 20 formed by coating the inner surface of the tube 2 is thin in thickness and does not shield the laser light, the output of this metallic- vapor laser device does not drop and highly efficient laser oscillation can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a metal vapor laser device, and more particularly to a metal vapor laser device in which a discharge tube is provided with a wick that shields less laser light.

(Prior Art) A conventional metal vapor laser device is configured as shown in FIG. 3, for example. That is, in the figure, an anode 4 and a cathode 5 are connected to both ends of a ceramic tube 2 in which a metal vapor source 1 is disposed via a joining member 2a, thereby forming a discharge tube. An anode 4 and a cathode 5 in this discharge tube are each provided with an electrode flange 6.

This electrode flange 6 has a body 9 surrounding the discharge tube described above.
and is fixedly attached to the electrode support flange 7 interposed between the insulating tube 10 and the Brewster tube 11. Each of the anodes 4 and cathodes 5 is fixed to an electrode support flange 7 via an electrode flange 6.

The outer peripheral surfaces of the ceramic tube 2, anode 4, and cathode 5 are surrounded by a heat insulating material 13, and the outside of the heat insulating material 13 is covered with an insulating tube 10 having a body 9 and an insulating tube flange 19. A pair of Brewster tubes 1 are attached to each electrode support flange 7.
A window 12 is attached to each opening of the Brewster tube 11, and an a-camisole 23 and a total reflection mirror 14 are arranged outside these windows 12 to form a resonator. .

In FIG. 3, the Brewster tube 11 shown on the left side has a gas supply tube 3 that supplies neon (Ne) gas, for example.
A gas exhaust pipe 8 is also connected to the Brewster tube 11 shown on the right. A high DC voltage is applied between the left electrode support flange 7 and the insulating tube flange 19. In addition, in the same figure, reference numeral 15 indicates charging capacitor C1.
, 16 is an intermediate capacitor C2, 17 is a resistor R118 is a thyratron, and 24 is a diode D, respectively.

In the metal vapor laser device having the above configuration, laser oscillation is performed as follows.

First, a discharge buffer gas, such as neon gas, is supplied from the gas supply tube 3 into a ceramic tube 2 serving as a discharge tube in which a metal vapor source 1 is disposed. Next, a high voltage is applied between the anode 4 and cathode 5 provided at both ends of the ceramic tube 2 to form discharge plasma. This discharge plasma heats the ceramic tube 2 to a high temperature, and the metal vapor source 1
From this, vaporized metal particles (metal vapor) that become the laser medium are produced. Furthermore, this metal vapor diffuses into the ceramic tube 2 and is excited by free electrons in the discharge plasma within the ceramic tube 2. Laser light is emitted when this excited metal vapor transitions to a lower energy level.

As mentioned above, the generation of metal vapor that becomes the laser medium is achieved by activating a pulsed high voltage source and discharging it between the picture electrodes 4.5.
For example, when using copper as the metal vapor source 1, the ceramic tube 2 is heated from room temperature to 1500°C. It's heated up to.

(Problems to be Solved by the Invention) As described above, in the conventional metal vapor laser device, the metal vapor source 1 in the ceramic tube 2 is heated by the heat of the discharge plasma formed in the ceramic tube 2, and the laser oscillation is prevented. A suitable amount of metal vapor is generated.

By the way, the temperature inside the ceramic tube 2 rises due to the discharge plasma, and the heat generated thereby is dissipated not only in the radial direction through the heat insulating material 13 and radiated outward, but also in the radial direction through the opening of the Blinister tube 11. There is an axial portion that is discharged outward from the window 12, etc., and the temperature inside the ceramic tube 2 is lower than the window 12.
Because it decreases rapidly toward , it also has a mountain-shaped distribution in the axial direction.

As a result, the vapor generated from the metal vapor source 1 within the ceramic tube 2 diffuses and adheres to the low temperature portion of the ceramic tube 2 in the axial direction. A wick 20 is used to return the metal adhering to this low-temperature part to the metal vapor source 1 by the action of capillary action. When the metal vapor is copper, the wick 20 is heated to about 1000° C. to 1500° C. and is also used under high voltage discharge, so it needs to have the strength to withstand that. Additionally, a structure is required to allow the molten metal to flow through capillary action. Therefore, the wick 20 is composed of a base material 21 and a capillary tube portion 22 provided on the inner peripheral side of the base material 21, as shown in FIG.

In this way, the wick 2 has a certain degree of strength and structure.
0 is provided inside the ceramic tube 2, the laser light is blocked and the laser output is reduced. For example, inner diameter 40mm
When a wick 20 having a thickness of 2 mm was installed in a laser tube as shown in FIG. 4, there was a problem in that the laser output was reduced by about 20%.

Therefore, the present invention has been made in consideration of the above circumstances.
The purpose is to provide a metal vapor laser device that can obtain desired wick performance and has less shielding of laser light.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention generates laser light by electrical discharge machining a discharge tube in which a metal vapor source that generates metal vapor is arranged. The metal vapor laser device is characterized in that a wick coated with tungsten material is provided inside the discharge tube.

(Function) In the present invention having the above configuration, when a buffer gas is introduced into the discharge tube and discharge is started, plasma is generated and the temperature of the discharge tube gradually rises. When the metal vapor source eventually reaches a temperature at which it can generate metal vapor, the metal vapor is uniformly distributed within the discharge tube. Free electrons in the plasma collide with this metal vapor to excite the metal vapor, creating a state of population inversion inside the discharge tube and generating laser light.

Here, the metal vapor within the discharge tube adheres to the coated tungsten metal wick and is transported to the metal vapor source by capillary action due to the unevenness of the wick surface.

Therefore, since the inside of the discharge tube is coated with the wick, the oscillated laser light is not blocked by the wick and a high laser output can be obtained. Furthermore, the ceramic-coated wick will not be damaged by the strength of the discharge tube.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

Note that the same reference numerals as in FIG. 3 will be used to describe parts that are the same as or correspond to the conventional configuration.

In FIG. 1, the metal vapor laser device is provided with a ceramic tube 2 as a discharge tube, and an anode 4 and a cathode 5 are connected to opposite ends of the ceramic tube 2 via connecting portions 2a. . A pulsed secondary discharge takes place between these electrodes 4.5.

A heat insulating material 13 is arranged around the outer periphery of the ceramic tube 2, and a metal body 9 is arranged around the outer periphery.

Furthermore, a wick 20 coated with tungsten metal is provided inside the ceramic tube 2 from the metal vapor source 1 to the axial end of the ceramic tube 2 . In this case, tungsten metal is coated on the inside of the ceramic tube 2 by thermal spraying, vapor deposition or powder application.

A pair of Brewster tubes 11 are connected to the outside of the electrodes at both ends of the ceramic tube 2, the left Brewster tube 11 has a gas supply tube 3 connected to a gas supply system, and the right Brewster tube 11 has a gas exhaust tube. A gas exhaust pipe 8 connected to the system is provided respectively. The gas supply pipe 3 supplies a discharge buffer gas such as neon gas into the ceramic tube 2. Further, the gas exhaust pipe 8 is for discharging buffer gas and the like within the ceramic tube 2 to the outside.

An output mirror 23 and a total reflection mirror 14 are arranged outside the window 12 of the Brewster tube 11, respectively, and the output mirror 23 and the total reflection mirror 14 constitute a laser resonator.

Now, the above-mentioned pulsed bipolar discharge has an anode 4 and a cathode 5.
This is done by a pulsed high-voltage power supply connected to an electrode support flange 7 that supports the electrodes and passes current through them. The pulse high voltage power supply has 15 charging capacitors, 16 intermediate capacitors, and 1 resistor.
7, a circuit consisting of a thyratron 18, a diode 24, etc.

This pulsed high-voltage power supply is designed to generate a discharge current with a rise time of approximately 10 -7 seconds or less by igniting the thyratron 18 with the charge stored in the charging capacitor 15 . Thyratron 18 is a pulse discharge switching element. The pulse high voltage to be generated has a voltage of several KV to several tens of KV, and a repetition frequency of several KH2 to several tens of KV.
It is H2. In the figure, symbol A is an anode terminal, C is a cathode terminal, and G is a trigger signal introduction terminal. The rest of the configuration is the same as that in FIG. 3, so the explanation thereof will be omitted.

Next, the action will be explained.

First, an exhaust system (not shown) is operated to exhaust the inside of the ceramic tube 2, and after this exhaust, a buffer gas such as neon gas is supplied via the gas supply tube 3. Next, the pulsed high-voltage power supply is activated to generate plasma in the ceramic tube 2, and the plasma raises the temperature of the metal vapor source 1 to a temperature at which it can generate metal vapor. The temperature required for laser oscillation is, for example, approximately 1500°C in the case of metal vapor source 1 or copper.
It is. By maintaining this state, the metal vapor is uniformly distributed within the ceramic tube 2.

Free electrons in the plasma collide with this metal vapor to excite the metal vapor, and eventually the inside of the ceramic tube 2 enters a state of population inversion. In this state, laser light is generated when the excited metal vapor transitions to a lower energy level. The laser light generated within the ceramic tube 2 passes through the window 12, and passes through the output mirror 23 and total reflection mirror 1 that constitute a laser resonator.
While reflecting at 4, its amplitude increases and power increases,
Eventually, the laser beam a taken from the output mirror 23 reaches a sufficient output. Here, the generated metal vapor diffuses into the low temperature part at the end of the ceramic tube 2 and adheres to the wick 20,
The wick 20 is transferred to the metal vapor source 1 by capillary action due to the uneven surface thereof, and becomes metal vapor from the metal vapor source 1.

According to this embodiment, since the wick 20 coated on the inside of the ceramic tube 2 has a thickness of several tens of micrometers, the laser beam is not blocked, the laser output is not decreased, and highly efficient oscillation is possible. can be done. Furthermore, since the ceramic tube 2, which is a discharge tube, is coated, the strength of the ceramic can prevent damage to the wick.

〔Effect of the invention〕

As explained above, according to the present invention, desired wick performance can be obtained by reducing metal vapor consumption without causing a decrease in laser output due to shielding of laser light, and laser oscillation can be stabilized for a long time. This has the advantage that it can be carried out with ease.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the metal vapor laser device according to the present invention together with a circuit diagram, Fig. 2 is a sectional view showing the ceramic tube of Fig. 1, and Fig. 3 is a sectional view of a conventional metal vapor laser device. FIG. 4 is a sectional view showing the laser device together with a circuit diagram, and FIG. 4 is a sectional view showing the ceramic tube of FIG. 3. 1... Metal vapor source, 2... Ceramic tube (discharge tube)
, 3... gas supply pipe, 4... anode, 5... cathode,
11...Brewster tube, 13...insulation material, 20...
・Wick.

Claims (1)

[Claims] A metal vapor laser device that generates laser light by discharging and heating a discharge tube in which a metal vapor source that generates metal vapor is disposed inside, characterized in that a wick coated with tungsten material is provided on the inside of the discharge tube. metal vapor laser equipment.