JPH0770793B2 - Metal vapor laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a metal vapor laser device, and more particularly to a metal vapor laser using gold or copper as a metal vapor generation source sealed in a discharge tube. Involved in improving the equipment.

(Prior Art) Conventionally, in this type of metal vapor laser device, metal of gold or copper is used.
Ne, He or a mixed gas of these is pulse-discharged in a discharge tube made of ceramic or the like filled as a buffer gas, and the vapor pressure of the metal is heated to about 0.1 torr, so that it is 628 nm for gold and 510.6 for copper. The pulse laser oscillation of 57 nm and 578.2 nm is performed. The laser output is about 0.3% for gold and about 1% for copper, and it is practically important to increase the oscillation output and the oscillation efficiency of these oscillators.

By the way, as a means for increasing the oscillation output, a method of increasing the diameter of the discharge tube to obtain an output from a large volume and a method of obtaining an output from a long discharge tube can be considered. However,
The former method has a problem that the directivity of the laser beam and the discharge become unstable. The latter means has a problem that the time until the rise of the oscillation becomes long, the efficiency is lowered, and the directivity of the beam is deteriorated at the rise portion of the pulse.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned conventional problems, and has achieved improvement in oscillation efficiency without increasing the diameter or length of a discharge tube. It is intended to provide a compact and high-power metal vapor laser device.

[Structure of the Invention] (Means for Solving Problems) The present invention is designed to discharge gold, copper, or a composite metal salt thereof, which is a metal vapor generation source, in a discharge tube together with a buffer gas to excite the gold or copper. In the metal vapor laser device which outputs the laser oscillation light, the metal vapor laser device is characterized in that chromium or a complex metal salt of chromium is mixed in the discharge tube together with the metal vapor generation source.

(Operation) According to the present invention, the metal, which is a source of metal vapor, such as gold, copper, or a composite metal salt thereof, is enclosed in the discharge tube, and chromium or a composite metal salt of chromium is enclosed, so that these metals are discharged together with the buffer gas. When excited by luminescence energy of chromium, the excitation of gold or copper vapor is promoted, and when the chromium vapor is excited to an upper level level and transitioned to a lower level, the lower level level of gold or copper is Since the number of upper level levels of gold or copper can be increased in conformity with the upper level levels and the generation of population inversion can be increased, a metal vapor laser device with significantly improved oscillation efficiency can be obtained.

(Embodiment of the Invention) Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.

Reference numeral 1 in the figure is a discharge tube made of a heat-resistant insulating material such as alumina ceramics. On the outer peripheral surface of the discharge tube 1, a tubular heat insulating material 2 made of alumina ceramics fiber and a metal envelope tube 3 are concentric. It is provided in. Both ends of the outer envelope tube 3 are electrically separated by an insulating tube 3a provided midway. Discharge electrodes 4 ₁ and 4 ₂ are attached to both end surfaces of the discharge tube 1, the tubular heat insulating material 2 and the outer envelope tube 3, and these discharge electrodes 4 ₁ and 4 ₂ are respectively connected to the pulse power source 5 via lead wires. It is connected. Window holding metal flanges 6 ₁ and 6 ₂ are attached to the end faces of the angular discharge electrodes 4 ₁ and 4 ₂ , respectively. The flanges 6 ₁ and 6 ₂ respectively hold window members 7 ₁ and 7 ₂ made of quartz or the like. These outer window material 7 _1, 7 _2, and resonator mirrors _81, 82 is disposed opposite to their window member 7 _1, 7 _2. One of these resonator mirrors (eg, 8 ₁ ) partially reflects and functions as an output mirror.
₂ other mirror 8 has a function to totally reflect. Wherein the one side wall of the flange ₆₁ of, Ne, the He or these mixed gas buffer gas supply unit 9 supplies are connected via a conduit 10, and the other on the side wall of the flange 6 ₂ gas exhaust member 11
Are connected via conduit 12. A cooling pipe 14 in which cooling water is circulated by a circulation pump 13 is wound around the outer peripheral surface of the outer envelope tube 3. Then, for example, granular copper 15 and chromium 16 are enclosed in the discharge tube 1.

Next, the operation of the above-described metal vapor laser device will be described.

First, the buffer gas from the buffer gas supply unit 9 (for example,
The Ne gas) is supplied into the discharge tube 1 through conduit 10 and one of the flanges _61, the discharge tube 1 by operating the gas exhaust member 11 which is connected to the other flange 6 ₂ including flanges 6 _1, 6 ₂ Exhaust the gas inside. Further, the circulation pump 13 is operated to circulate the cooling water in the cooling pipe 14 to cool the outer envelope tube 3 and the like. Subsequently, when applied from the pulse power supply 5 a pulse voltage to the discharge electrode 4 _1, 4 _2, the Ne gas supplied into the discharge tube 1 discharge is performed, the discharge tube 1 inside generates heat. At this time, since the outside of the discharge tube 1 is surrounded by the tubular heat insulating material 2, the temperature inside the discharge tube 1 rises and becomes constant when the thermal equilibrium state is reached. Copper (C
u) 15 has a vapor pressure of 0.1 torr at 1400 ° C and 1 torr at 1600 ° C, while chromium (Cr) 16 has a vapor pressure of 0.01 torr at 1400 ° C.
It shows a vapor pressure of 0.1 torr at 50 ° C and 1 torr at 1720 ° C. Therefore, the thermal equilibrium temperature is 1400 in relation to the vapor pressures of Cu and Cr.
The pulse voltage from the power source 5 and the adiabatic condition are set so that the temperature becomes ˜1600 ° C. Under such conditions, both metal vapors of Cu and Cr exist inside the discharge tube 1 and are excited by the discharge. At this time, Cu is excited from the ground level 21 to the upper level level 22 as shown in the energy level of FIG. 2, and emits laser light 24 in the process of transition to the metastable level level 23. Since the metastable level of Cu has a longer lifetime than the upper level, the population inversion occurs only for a short time between the upper level level 22 and the metastable level level 23 due to abrupt excitation, and was emitted during this period. Laser light rises in laser oscillation between the resonator mirrors 8 ₁ and 8 ₂ , and the laser light is output from the mirror 8 ₁ which is an output mirror.

The laser output of Cu can be greatly improved by the metal vapor of Cr enclosed in the discharge tube 1 together with Cu during the above-described Cu laser oscillation. It is considered that this is because the metal vapor of Cr acts on the population inversion of Cu and the excitation of Cu as shown below. That is, the metal vapor of Cr is excited by the above-mentioned discharge, and is excited from the ground level 21 to the high energy level level 25 of 48661 to 60871 cm ^-1 , which is lower than the lower level 30.
Transition to level level 26 between 967 and 31393 cm ^-1 . This lower level level and the upper level level 22 of 30784 cm ⁻¹ of Cu are overlapped because atoms are under a high temperature state, and the energy of the lower level level 26 of Cr is transferred to Cu due to collision or the like. Therefore, it is considered that the number of states in the upper level level 22 of Cu is increased, and as a result, the above-mentioned laser oscillation is efficiently generated due to the generation of a strong population inversion of Cu. In addition, of the light emitted from the Cr excited ions, 324.544 nm, 32
Since the emission at 5.184 nm has an energy that matches the excitation from the base level 21 to the upper level level 22 of the copper vapor laser,
It is thought that it effectively acts on the excitation of Cu.

The behavior of Cr vapor with respect to the above two Cu vapors is conceivable, but in any case, by enclosing and exciting Cu15 together with Cu15 in the discharge tube 1, the laser output of Cu can be greatly improved.

In the above example, the discharge tube was filled with Cu and Cr, and 1400
Although the case of operating at a high temperature of ˜1600 ° C. has been described, a composite metal salt such as metal (Cu or Au, Cr) / AlnBrm may be used. When such a composite metal salt is used, low-temperature operation becomes possible, and the inclusion of the composite Cr salt can achieve the same improvement in laser oscillation efficiency as when using Cr alone.

In the above-mentioned embodiment, the laser oscillation of Cu vapor was described, but the same effect can be obtained for the laser oscillation of gold (Au vapor).
That is, the wavelength of light emitted from Cr in the Au vapor laser is 1
267.816 nm, 267.283 nm, 267.879n from valent Cr ions
Luminescence of 267.816 nm is obtained from m and neutral Cr, which is almost the same as the excitation energy (267.595 nm) to the upper level level of Au vapor, which enables efficient excitation of Au vapor. Becomes

A discharge tube constituting a metal vapor laser device according to the present invention,
The shape and mounting method of each member such as the discharge electrode and the window holding metal flange are not limited to those shown in FIG. 1, and it is needless to say that the design can be freely changed. Chromium or a complex metal salt of chromium may be mixed with the metal salt, or the structure may be such that it is introduced into the discharge tube in the form of vapor.

[Effect of the Invention] As described in detail above, according to the present invention, the discharge tube has a large diameter,
It is possible to improve the oscillation efficiency without increasing the length, and to provide a small-sized, lightweight, high-power metal vapor laser device effective for medical devices and the like.

[Brief description of drawings]

FIG. 1 is a sectional view of a metal vapor laser device showing an embodiment of the present invention, and FIG. 2 is an explanatory view showing energy levels of Cu and Cr. 1 ... Discharge tube, 2 ... Tubular insulation, 4 ₁ , 4 ₂ ...... Discharge electrode, 5 ...... Pulse power supply, 6 ₁ , 6 ₂ ...... Metal flange for holding windows, 8 ₁ , 8 ₂ ...... Resonance Mirror, 9 …… Buffer gas supply part, 11 …… Gas exhaust member, 14 …… Cooling pipe, 15 ……
Copper, 16 ... chrome.

Claims (1)

[Claims] 1. A metal vapor laser device for outputting gold or copper laser oscillation light by discharging gold, copper or a composite metal salt thereof, which is a metal vapor generation source, in a discharge tube together with a buffer gas to excite the laser oscillation light. A metal vapor laser device in which chromium or a composite metal salt of chromium is mixed in the discharge tube together with a metal vapor generation source.