JPH04236476A - Metal vapor laser - Google Patents

Abstract

PURPOSE:To reduce a time for starting up to a laser oscillation and labor, to increase the life of a laser and to improve reliability by sorting light emission beam of hydrogen atoms from a discharge light to be emitted at the time of discharging in buffer gas, and detecting its intensity. CONSTITUTION:In a metal vapor laser 21 for generating metal vapor by heating a metal piece 9 mounted in a vacuum vessel 3 by heat of discharging to excite the vapor to oscillate a laser light, it is a feature that light sorting and detecting means 33 for sorting light emission beam of hydrogen atoms from a light emitted at the time of discharging for heating the piece 9 and detecting the intensity of the beam of the atoms, and a voltage controller 27 inputting the intensity of the beam of the atoms detected by the means 33 to raise the voltage of a discharge power source when the intensity of the beam of the atoms is constant or reduced, are provided.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal vapor laser device which generates metal vapor by discharging and heating a laser medium metal in a buffer gas and oscillates laser light by exciting the metal vapor.

0003

[Prior Art] FIG. 6 shows a conventional metal vapor laser device 1.
It is shown. This metal vapor laser device 1 includes a vacuum vessel 3 filled with a buffer gas, a plasma tube 11 disposed within the vacuum vessel 3, a pair of cylindrical discharge electrodes 5 disposed within the plasma tube 11, 7, a heat insulating material 13 disposed between the inner wall of the vacuum vessel 3 so as to cover the outer periphery of the plasma tube 11, a power supply 15 for applying voltage to the electrodes 5 and 7, and a heat insulating material 13 disposed at both ends of the vacuum vessel 3. mirror 17,
19 (However, the reflectance of mirror 17 is lower than that of mirror 19,
Part of the incident light is transmitted. ). Further, a metal piece 9 which is a laser medium metal is installed on the plasma tube 11.

When oscillating laser light with the metal vapor laser device 1 having the above configuration, a voltage is applied between the electrodes 5 and 7 by the discharge power supply 15 to cause discharge in a buffer gas. The metal piece 9 is heated and vaporized by this discharge, and metal vapor is generated. Then, the metal vapor is transferred to the electrode 5,
It is excited by discharging with a voltage applied between 7 and causes the mirrors 17 and 19 of the resonator to oscillate laser light.

The metal piece 9 is made of a metal with low vapor pressure and high operating temperature, such as gold or copper.
Heated from 0°C to 1700°C.

However, when metal vapor is generated by the above-mentioned discharge heating, gas (mostly water) is released from the heat insulating material 13 and the plasma tube 11 into the buffer gas inside the plasma tube 11, which prevents the discharge of the buffer gas. As a result, the discharge becomes unstable. Therefore, the discharge is temporarily stopped, the buffer gas inside the plasma tube 11 is discharged, and after a new buffer gas is filled in the plasma tube 11, the discharge is started again. While repeating these operations, the discharge voltage applied to the electrodes 5 and 7 is gradually increased, and the voltage is increased until the heat necessary to evaporate the metal piece 9 is obtained, causing discharge.

However, when the heat insulating material 13 placed around the plasma tube 11 is new, a large amount of gas (mostly water) is released into the buffer gas by discharge heating, so the metal piece 9 is Because voltage is applied until the heat necessary for vaporization is obtained, it takes time to oscillate the laser beam.

Furthermore, even if the buffer gas in the plasma tube 11 is sufficiently discharged, sealed, and the voltage increased, if the laser beam oscillation is stopped and the laser beam is to be oscillated again, it is necessary to In order to evaporate the moisture generated in the plasma tube 11, the discharge time becomes long, and it takes time for the laser beam to oscillate.

Furthermore, if the discharge is started again after the laser oscillation is temporarily stopped, the discharge becomes unstable when voltage is applied, and the discharge concentrates on a part of the electrode, leading to damage to the electrode and the plasma tube, which may cause damage to the metal vapor laser device. It was shortening my lifespan.

0010

SUMMARY OF THE INVENTION As described above, conventional metal vapor laser devices require a lot of time and effort until the laser beam is oscillated. Additionally, the device had a short lifespan and lacked reliability.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a metal vapor laser device that can reduce the start-up time and labor required for laser beam oscillation, and can extend the life of the device.

[Configuration of the invention]

[0013]

[Means for Solving the Problems] In order to achieve the above object, the invention as set forth in claim 1 selects the emission line of a predetermined atom from the light emitted during the discharge to heat the laser medium metal, and an optical selection detection means for detecting the intensity of the emission line; and the intensity of the emission line of a predetermined atom detected by the optical selection detection means is input, and when the intensity of the emission line of the predetermined atom is constant or decreases, the discharge power source The present invention is characterized in that a voltage control device for increasing the voltage is provided.

The invention according to claim 2 is characterized in that the predetermined atom according to claim 1 is a hydrogen atom.

[0015]

According to the present invention having the above structure, the light emission line of hydrogen atoms is selected by the optical selection detection means, and the intensity of the emission line of the selected predetermined atom, for example, the hydrogen atom, is detected. This detection result is input to the voltage control device. Based on this result, the voltage control device increases the voltage of the discharge power source when the intensity change of the emission line of a predetermined atom is constant or decreases.

In this case, when the voltage of the discharge power supply is increased, the emission intensity of the emission line of hydrogen atoms becomes stronger, but gradually decreases after a certain period of time. This time becomes shorter as the amount of gas (mostly water) released from the heat insulating material etc. into the buffer gas decreases, indicating that so-called bake-out has been sufficiently performed. Further, when the amount of gas released from the heat insulating material is large, it takes a long time for the emission intensity of the emission line of hydrogen atoms to decrease, indicating that the bakeout is insufficient.

Therefore, measuring the increase or decrease in the intensity of the emission line of hydrogen atoms during discharge can be used as an indicator of the degree of burnout, and as mentioned above, when the change in the intensity of the emission line of hydrogen atoms is constant or decreasing, the discharge power supply Increase voltage. By automatically repeating this process, it is possible to reduce the start-up time and labor required for laser beam oscillation. Furthermore, by increasing the voltage increase rate in small increments, concentration of discharge can be prevented as much as possible, and the life of the device can be extended.

[0018]

[Embodiment] Next, an embodiment of a metal vapor laser device according to the present invention will be described with reference to FIGS. 1 to 5. In addition, Figure 6
Components that are the same as those of the metal vapor laser device 1 shown in FIG.

First Embodiment As shown in FIG. 1, the metal vapor laser device 21 of this embodiment is provided with optical selection detection means 33 and a voltage control device 27 for controlling the discharge power source 15. The optical selection and detection means 33 includes a spectrometer 23 that receives the discharge light that has passed through the mirror 17, separates it, and selects the hydrogen spectrum, and detects the hydrogen emission line that has been selected by the spectrometer 23 and converts it into an electrical signal. It is composed of a light receiver 25 that performs the conversion. The electrical signal output from the light receiver 25 is input to a voltage control device 27 that controls the discharge power source 15.

Activation of the metal vapor laser device 21 having the above configuration will be explained with reference to the flowchart shown in FIG. In step 101, the initial voltage V1 is set by the discharge power supply 15.
is applied between the discharge electrodes 5 and 7. This initial voltage V1 causes a discharge within the plasma tube 11, and the discharge light passes through the mirror 17 and enters the spectroscope 23. The discharge light incident on the spectrometer 23 is spectrally divided and the emission line Hβ of hydrogen atoms (
4816 angstroms) are selected. In step 103, the selected emission line Hβ of the hydrogen atoms is sent to the light receiver 25.
The light intensity is measured, and in step 105 it is determined whether the light intensity is constant or has decreased. If the light intensity has decreased, the discharge voltage V1 is changed to V2 in step 107.
to rise to. If the light intensity of the hydrogen atom emission line is increasing in step 105, the intensity of the hydrogen atom emission line included in the discharge light is repeatedly detected in step 103.

After the discharge voltage V1 is increased to V2, it is determined in step 109 whether or not the laser beam is oscillated, and if the laser beam is oscillated, the process ends. If the laser beam is not oscillating, steps 103 and subsequent steps are repeatedly executed. Then, as shown in Fig. 3, the discharge voltage is set to V2.
, V3 to V7 to oscillate laser light.

In this example, Hβ (4816 angstroms) of hydrogen atoms is used as the emission line of hydrogen atoms, but other lines, namely Hα (6563 angstroms), Hγ (4102 angstroms), and H
δ (3970 angstroms) may also be used.

Therefore, in the metal vapor laser device of this embodiment, when the intensity of the emission line of hydrogen atoms is constant or decreases as shown in FIG. The start-up time and labor required for oscillation can be reduced, and the life of the device can be extended.

[0024] Furthermore, since the rate of increase in voltage is carried out in small increments, stable discharge can be achieved, the life of the device can be extended, and reliability can be improved.

Second Embodiment Next, a second embodiment will be explained based on FIG. 5. This example is another example of how to extract light emitted by discharge.

As shown in FIG. 5, the metal vapor laser device 31 of this embodiment has one end disposed inside the resonator, that is, between the mirror 19 and the end of the vacuum vessel 3, and the other end. A glass fiber 33 connected to a spectrometer is provided. This glass fiber 33 extracts a part of the light between the mirrors 17 and 19 and guides it to the spectroscope 23 .

By using this glass fiber 33, a part of the discharge light can be extracted from any part, and moreover, the extracted discharge light can be guided to the spectrometer 23 regardless of its path.

In each of the above embodiments, the light leaking from behind the mirror 17 and a part of the light between the mirrors 17 and 19 are extracted, but the light caused by the discharge can be extracted by any other method. It's okay.

Furthermore, in each of the above embodiments, the timing for increasing the discharge voltage is determined by extracting hydrogen atoms (H) and their strength, but other elements such as oxygen (O), hydroxyl group (OH), aluminum (Al ), magnesium (M
g), silicon (Si), carbon (C), water (H2), oxygen molecules (O2), nitrogen molecules (N2), and nitrogen (N) may be taken out and their strengths determined.

Furthermore, when selecting each atom, the impurity to be measured (the above-mentioned atoms) may be arbitrarily selected depending on the temperature of the metal vapor.

[0031]

Effects of the Invention As explained above, the metal vapor laser device according to the present invention can select the emission line of hydrogen atoms from the light emitted during the discharge to heat the laser medium metal, and can also control the intensity of the emission line of the hydrogen atoms. an optical selection detection means for detection, and a voltage that increases the voltage of the discharge power supply when the intensity of the hydrogen atom emission line detected by the optical selection detection means is input and the intensity of the hydrogen atom emission line remains constant or decreases. Since a control device is provided, it is possible to reduce the start-up time and labor required until the laser beam oscillates, and the excellent effects of improving reliability can be obtained.

[Brief explanation of the drawing]

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

FIG. 2 is a flowchart showing the startup operation of the metal vapor laser device.

FIG. 3 is a diagram showing changes in intensity of emission lines of hydrogen atoms.

FIG. 4 is a diagram showing a state in which the metal vapor laser device is automatically started up.

FIG. 5 is a configuration diagram showing a second embodiment of the metal vapor laser device according to the present invention.

FIG. 6 is a configuration diagram showing a conventional metal vapor laser device.

[Explanation of symbols]

5, 7 Discharge electrode 9 Metal piece 11 Plasma tube 15 Discharge power supply 17, 19 Mirror 21, 31 Metal vapor laser device 23 Spectrometer 25 Photo receiver 27 Voltage control device

Claims (2)

[Claims] 1. A vacuum container filled with a buffer gas, a pair of electrodes disposed within the vacuum container, and a discharge power source that applies a voltage between these electrodes to cause discharge in the buffer gas, In a metal vapor laser device that heats a laser medium metal placed in the vacuum container by electric discharge in a buffer gas to generate metal vapor, and excites this metal vapor to oscillate a laser beam, the metal vapor in the buffer gas an optical selection detection means for selecting the emission line of a predetermined atom from the light emitted during discharge and detecting the intensity of the emission line of the predetermined atom; A metal vapor laser device comprising: a voltage control device for increasing the voltage of the discharge power source when an intensity is input and the intensity of the emission line of a predetermined atom is constant or decreases. 2. The metal vapor laser device according to claim 1, wherein the predetermined atom is a hydrogen atom.