JPH07135365A - Metal vapor laser - Google Patents

Abstract

PURPOSE:To provide a highly efficient high output metal vapor laser having long service life by increasing the plasma resistance and throwing power efficiently into a plasma from a power supply thereby increasing the laser output. CONSTITUTION:A discharge tube 2 encapsulating a buffer gas is discharged to heat a laser medium metal 3 placed in the discharge tube 2 thus producing metal vapor which is then pumped to cause laser oscillation. In such metal vapor laser 21, at least one kind of rare gas 7, hydrogen gas 8, and oxygen gas 13 are employed as the butter gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal vapor laser device, and more particularly, to discharge a discharge tube filled with a buffer gas to heat a laser medium metal placed in the discharge tube to generate metal vapor. The present invention relates to a metal vapor laser device that excites this metal vapor to cause laser oscillation.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional metal vapor laser device 1. In FIG. 2, the metal vapor laser device 1 includes a discharge tube 2, and inside the discharge tube 2, a laser medium metal 3, a laser tube 4, and a pair of opposed electrodes 5 and 5 are installed. A discharge power supply 6 is connected to the pair of opposed electrodes 5, 5. To the discharge tube 2, a cylinder 7 for supplying a rare gas, a cylinder 8 for supplying a hydrogen gas, and a rotary pump 9 are connected to the discharge tube 2. The amount of rare gas supplied from the cylinder 7 to the discharge tube 2 is adjusted by the valve 11, and the amount of hydrogen gas supplied from the cylinder 8 to the discharge tube 2 is adjusted by the valve 10 and the valve 12.

Oscillation of laser light is performed as follows. After the valve 10 is closed and the valve 11 is opened to appropriately guide the rare gas to the discharge tube 2, the electrodes 5 and 5 are discharged to heat the laser medium metal 3 to generate metal vapor. By appropriately adjusting the gas pressure and continuing the discharge, the metal vapor is excited and laser oscillation occurs.

By the way, it is known that the laser output is increased by adding hydrogen gas to the buffer gas after laser oscillation (K. Hayashi, et al., Jp.
nJAppl.Phys.vol.31 (1992), L1689). This increase in output is because the plasma resistance in the discharge tube 2 increases due to the addition of hydrogen gas, and the power is efficiently supplied from the power source 6 to the plasma in the discharge tube 2. Also, hydrogen gas has the effect of lowering the gas temperature due to its thermal dissociation,
It is considered that the lower gas temperature lowers the lower laser level density and increases the laser output.

[0005]

However, in the future, there is a high possibility that a metal vapor laser device with a higher output than ever will be required, and the output obtained by adding hydrogen gas to the buffer gas is not always sufficient. I couldn't say that.

Therefore, an object of the present invention is to solve the above problems of the prior art, to easily increase the laser output, and to provide a metal vapor laser device with high output, high efficiency and long life.

[0007]

In order to achieve the above object, a metal vapor laser device according to the present invention discharges a discharge tube filled with a buffer gas and heats a laser medium metal placed in the discharge tube. In a metal vapor laser device that generates metal vapor and excites the metal vapor to cause laser oscillation, at least one or more kinds of rare gas, hydrogen gas, and oxygen gas are used as the buffer gas.

Further, in the ratio of the hydrogen gas and the oxygen gas, it is preferable that the oxygen gas has a smaller partial pressure ratio than the hydrogen gas.

Further, it is preferable that the hydrogen gas and the oxygen gas are added to the discharge tube at the same time, or the hydrogen gas is added before the oxygen gas.

Further, it is preferable to add hydrogen gas and oxygen gas after the metal vapor is generated.

[0011]

[Function] When oxygen gas is added to the discharge tube in addition to the rare gas and hydrogen gas as the buffer gas, the oxygen gas is a negative gas. Further, the plasma resistance is increased, and the electric power from the power supply to the plasma can be efficiently supplied. However, when only oxygen gas is added, the electrodes and the like are rapidly oxidized, resulting in a device with a short life. Therefore, by adding hydrogen gas at the same time or first, it is possible to prevent the electrodes and the like from being oxidized by the reducing action of hydrogen gas, and it is possible to extend the life of the device. Further, by adding hydrogen gas together with oxygen gas, it is possible to increase the laser output by utilizing the effect of lowering the gas temperature due to thermal dissociation of hydrogen gas.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the metal vapor laser device according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic structure of an embodiment of the present invention. The same components as those of the metal vapor laser device shown in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, a metal vapor laser device 21 according to this embodiment is shown. In the present embodiment, in addition to the cylinder 7 for supplying the rare gas and the cylinder 8 for supplying the hydrogen gas into the discharge tube 2, a cylinder 13 for supplying the mixed gas of the rare gas and the oxygen gas to the discharge tube is provided. There is. A stop valve 14 and a flow rate adjusting valve 15 are connected between the discharge tube 2 and the cylinder 13, and the oxygen gas supplied to the discharge tube 2 is controlled by opening and closing the stop valve 14 and the flow rate adjusting valve 15. .

With the valves 10 and 14 closed and only the rare gas used as the buffer gas being introduced into the discharge tube 2, the discharge tube 2 is discharged to heat the laser medium metal 3 to generate metal vapor. This metal vapor is excited to cause laser oscillation. After the laser oscillation, the valves 10 and 14 are opened and the flow rate adjusting valves 12 and 15 are appropriately adjusted to supply hydrogen gas and oxygen gas into the discharge tube 2. The plasma resistance can be maximized by finely adjusting the amounts of hydrogen gas and oxygen gas using the flow rate adjusting valves 12 and 15.

In order to efficiently carry out the reducing action by hydrogen gas, oxygen gas is made to have a smaller partial pressure ratio than hydrogen gas. In addition, the hydrogen gas is added at the same time as or before the addition of the oxygen gas, so that the reducing action by the hydrogen gas is efficiently performed.

Further, if hydrogen gas or oxygen gas is added when metal vapor is not generated, the discharge tends to become unstable. Therefore, hydrogen gas or oxygen gas is added after the metal vapor is generated.

At least one selected from neon, helium, argon and xenon may be supplied as the rare gas. The plasma resistance can be further increased by using two or more kinds of rare gases.

Next, the operation of this embodiment will be described. If only oxygen gas is added to the discharge tube 2, the electrodes 5 and the like will be rapidly oxidized, resulting in a device with a short life. Therefore, by adding hydrogen gas at the same time or first, it is possible to suppress the oxidation of the electrodes 5 and the like due to the reducing action of hydrogen gas. Further, by adding hydrogen gas together with oxygen gas, the gas temperature due to thermal dissociation of hydrogen gas can be lowered.

According to the structure of this embodiment, in addition to the cylinder 7 for supplying the rare gas and the cylinder 8 for supplying the hydrogen gas,
Since the cylinder 13 for supplying the mixed gas of the rare gas and the oxygen gas to the discharge tube 2 is provided, the plasma resistance is increased as compared with the case where only the hydrogen gas is added, and more electric power can be supplied to the plasma. Further, it is possible to suppress the oxidation of the electrodes and the like due to the reducing action of the hydrogen gas that is added at the same time, so that the life of the device can be extended. Further, by adding hydrogen gas together with oxygen gas, it is possible to increase the laser output by utilizing the effect of lowering the gas temperature due to thermal dissociation of hydrogen gas.

Further, even when many kinds of buffer gases are used, by mixing all or some of the buffer gases, the number of cylinders can be reduced and the apparatus can be simplified.

In the present embodiment, the vertical excitation type is shown as the shape of the opposing electrodes 5 and 5, but the present invention is not limited to this, and it is needless to say that the present invention can be applied to a lateral excitation type metal vapor laser device. Yes.

[0023]

As described above, according to the structure of the present invention, oxygen gas is added to the discharge tube in addition to the rare gas and the hydrogen gas as the buffer gas, so that the hydrogen gas is added more than the case where only the hydrogen gas is added. Further, the plasma resistance can be increased, and the electric power from the power supply to the plasma can be efficiently supplied. Further, by adding hydrogen gas and oxygen gas to the rare gas as the buffer gas, it is possible to prevent oxidation of the electrodes and the like. As a result, a highly efficient and long-life metal vapor laser device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a metal vapor laser device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a conventional metal vapor laser device.

[Explanation of symbols]

 2 Discharge tube 3 Laser metal medium 4 Laser tube 5 Electrode 6 Discharge power supply 7 Rare gas cylinder 8 Hydrogen gas cylinder 9 Rotary pump 10, 11, 14 Stop valve 12, 15 Flow control valve 13 Mixed gas cylinder of rare gas and oxygen gas 21 Metal vapor Laser equipment

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01S 3/22 M (72) Inventor Kazuo Hayashi 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Prefecture 1 Share Corporate Toshiba Research and Development Center (72) Inventor Tomoko Ogawa 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Stock Company Toshiba Research and Development Center (72) Inventor Etsuga Noda Sachi-ku, Kawasaki-shi, Kanagawa Komukai Toshiba Town 1 Stock Company Toshiba Research and Development Center

Claims (1)

[Claims] 1. A metal vapor laser device for discharging a discharge tube filled with a buffer gas, heating a laser medium metal placed in the discharge tube to generate metal vapor, and exciting the metal vapor to cause laser oscillation. 2. A metal vapor laser device according to claim 1, wherein at least one kind of rare gas, hydrogen gas, and oxygen gas are used as the buffer gas.