JPH04243174A - Ion laser tube - Google Patents

Abstract

PURPOSE:To prevent deterioration of a discharge base and a decrease in insulation by engaging a cylindrical member of alumina ceramic with a central opening of a disclike member. CONSTITUTION:A disclike member 7 has a central opening 10, and a cylindrical member 9 of alumina ceramic is forced into the hole 10. Further, the member 7 has a plurality of openings 11 around the opening 10. A discharge path 12 is formed on the axis of a laser tube with the opening formed by the inner wall of the member 9 of the ceramics engaged with the opening 10 of the member 7. The plurality of openings 11 form a gas return passage 13 for making gas between a cathode 2 and an anode 3 uniform. A cylindrical connecting member 8 is formed of aluminum nitride similarly to the member 7. Both are brought into close contact with one another with low melting point glass, and hermetically sealed therein. Further, a coolant passage is provided in the outside of the tube for forced cooling.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ion laser tubes, and more particularly to the structure of laser tubes.

0002

2. Description of the Related Art Laser beams have excellent directivity and can concentrate energy density, so they are applied to a wide range of fields such as processing of metal materials, medical equipment, and even communication using optical fibers. Generally, gas lasers, liquid lasers, and solid-state lasers are known as laser light sources, depending on the form of the laser medium. Among these, gas lasers use an optical system to resonate emitted light from discharge-excited gas atoms or ions. It causes laser oscillation.

Ion lasers such as argon or krypton, which are a type of gas laser, can obtain many oscillation lines in the visible and ultraviolet regions, and have high output, so they can be used for laser spectroscopy such as holography, Raman spectroscopy, and even pigmentation. It is used as a light source for laser excitation. Ion lasers have high output, but the discharge current density during laser oscillation is 50
The power consumption reaches 0A/cm2, and the power consumption is extremely high at 50W/cm per unit length of the discharge tube. Under such discharge conditions, the temperature of the laser tube that maintains the gas discharge becomes extremely high, so the material used therefor must have excellent heat resistance. In addition, in the ion laser, a cooling channel is provided on the outer periphery of the laser tube as a countermeasure against the above-mentioned temperature, but the laser tube itself is also required to have excellent conductivity in order to improve its cooling effect.

Conventionally, as an ion laser tube that can meet the above requirements, a cylindrical Be material having electrically insulating properties and excellent thermal conductivity is used as a laser tube disposed between an anode and a cathode.
Those using O (beryria), AlN (aluminum nitride), etc. are known. In addition, there is also an ion laser tube in which the discharge path and part of the envelope of the laser tube are constructed by alternately connecting graphite disk-shaped members and cylindrical insulating members in the axial direction of the laser tube. Are known.

[0005]

[Problems to be Solved by the Invention] In the above-mentioned cylindrical ceramic laser tube, when aluminum nitride is used as the ceramic material, the discharge channel wall is sputtered by the plasma generated in the laser tube, resulting in decomposition of the aluminum nitride. There was a problem that nitrogen gas was generated due to Also, beryllia has the problem of being a polluting substance, difficult to handle, and expensive.

On the other hand, even in an ion laser tube in which a disc-shaped graphite member and an insulating member are connected, the graphite on the discharge channel wall is sputtered, and the sputtered graphite powder deteriorates the insulation between the cathode and anode. There was a problem with causing it. When the above-mentioned problems caused by nitrogen gas or graphite powder occur, the laser tube cannot maintain a good discharge state, the laser light output gradually decreases, and finally the laser oscillates no longer.

On the other hand, although beryllia solves the above problems, it has the problem of being a polluting substance, difficult to handle, and expensive. There is a need for an ion laser tube that solves both of these problems, is easy to handle, is inexpensive, and has excellent performance that further extends the life of the laser tube.

[0008]

[Means for Solving the Problems] The present invention constitutes a laser thin tube section by alternately connecting ceramic disc-shaped members with an opening in the center that serves as a discharge path and ceramic cylindrical connecting members. , an ion laser tube having an anode and a cathode on both sides thereof, characterized in that a cylindrical member made of alumina ceramics is fitted into a central opening of a disc-shaped member.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to the drawings. FIG. 1 shows a cross-sectional view of an embodiment of a water-cooled ion laser tube of the present invention. The laser tube of the present invention includes a laser tube cathode section 2 that accommodates a coiled cathode 4, a laser tube anode section 3 that accommodates a cylindrical anode 5, and a laser tube that is sandwiched between the laser tube cathode section 2 and the anode section 3. It is mainly composed of a central part 1. The laser tube cathode section 2 and anode section 3 are formed and processed from a glass material, and each has a Brewster window 6 mounted on the end side wall on the axis of the laser tube.

The central portion 1 of the laser tube includes a disc-shaped member 7 made of aluminum nitride and a cylindrical connecting member 8 in the axial direction of the laser tube.
It has a structure in which these are connected alternately and coaxially. Each disc-shaped member 7 has a central opening 10, into which a cylindrical member 9 made of alumina ceramics is tightly fitted. Furthermore, each disc-shaped member 7 has a plurality of apertures 11 around the central aperture 10. The aperture formed by the inner wall of the alumina ceramic cylindrical member 9 fitted into the central aperture 10 of the disc-shaped member 7 forms a discharge path 12 on the axis of the laser tube. Moreover, the plurality of openings 11 are
A gas return path 13 is formed to equalize the gas pressure between the cathode section 2 and the anode section 3.

The cylindrical connecting member 8 is made of aluminum nitride similarly to the disc-shaped member 7, and both are closely adhered to each other with low melting point glass to maintain an airtight interior. Further, although not shown in the drawings, a cooling channel is provided on the outside of the laser tube to enable forced cooling. As described above, the laser tube material is required to have electrical insulation, excellent thermal conductivity, and sputter resistance.

[0012] The reason why alumina ceramics was selected as the laser tube material is that when Ar ion irradiation is performed and the sputter resistance is compared with beryllia using the ion thinning method, the sputter hole cross-sectional area [×103 μm2] and the sputter hole depth are This is because it is comparable to beryllia in terms of size [μm], etc., and is a harmless substance and inexpensive. On the other hand, in terms of thermal conductivity, alumina ceramics is about an order of magnitude inferior to beryllia, and it is necessary to reduce the temperature gradient during operation, so consideration must be given to making the wall thickness as thin as possible. Needless to say.

[0013]

[Effects of the Invention] As explained above, in the ion laser tube of the present invention, since the discharge path in direct contact with plasma is formed of an alumina ceramic member, deterioration of the discharge body and decrease in insulation, which have been problems in the past, can be avoided. It can be prevented. Therefore, the present invention can significantly extend the life of the laser tube, and its industrial value is extremely high.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of an ion laser tube of the present invention.

[Explanation of symbols]

1 Laser tube central portion 2 Laser tube cathode portion 3 Laser tube anode portion 4 Cathode 5 Anode 6 Brewster window 7 Disk-shaped member 8 Cylindrical connection member 9 Alumina ceramics cylindrical member 10
Central opening 11 Opening 12 Discharge path 13 Gas return path

Claims (1)

[Claims] Claim 1: A laser capillary section is constructed by alternately connecting a ceramic disc-shaped member with an aperture serving as a discharge path in the center and a ceramic cylindrical connecting member, and an anode and a cathode are arranged on both sides of the laser capillary section. 1. An ion laser tube comprising: an alumina ceramic cylindrical member fitted into the central opening of each disc-shaped member.