JPH079401Y2 - Linearly polarized internal mirror type gas laser tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a structure of a Brewster window of a linearly polarized internal mirror type gas laser tube.

[Conventional technology]

The internal mirror type gas laser tube is composed of a vacuum envelope, a laser tube, a pair of mirrors arranged at both ends on the axis of the laser tube at right angles to the laser tube, an anode and a cathode. Here, when an appropriate voltage is applied to the anode and the cathode, electric discharge occurs in the laser capillary and a laser medium is generated. A pair of mirrors arranged at both ends on the axis of the laser tube constitutes an optical resonator, and resonates the laser medium generated by the discharge. In this way, laser oscillation occurs and laser output light is obtained. However, the laser output light obtained here is unpolarized. In order to obtain linearly polarized laser output light, it is necessary to insert and fix a glass face plate at Brewster's angle on the axis of the laser tube in the optical resonator composed of a pair of mirrors.

As a conventional linearly polarized internal mirror type gas laser tube, a laser thin tube end is polished to Brewster's angle, and a glass face plate is attached to the polished surface by using a fusion seal or an adhesive agent with a low melting point glass, A special holder was placed on the axis of the thin tube, and a glass plate was mechanically fixed to the holder at Brewster's angle. However, in the former, the Brewster window generally serves as a vacuum seal, which requires a highly accurate polishing surface, a sealing process is required, and the latter has a complicated structure. However, all of them are expensive, and are not suitable for mass production and cost reduction of gas laser tubes.

As a structure that solves the above-mentioned drawbacks, by utilizing the difference in thermal expansion of substances, the glass face plate that will be the Brewster window is mechanically dimensioned accurately at a specific temperature higher than the ambient temperature where gas laser tubes are normally used. Hold and fix without applying any force within the range of, and when this temperature drops to around the operating temperature of the gas laser tube, the glass face plate and the internal holder that installs it at Brewster's angle, and the positional relationship of the composite of these There is a Brewster window holding structure in which a difference in thermal expansion is generated between the glass face plate and an external holder for fixing the glass face plate, a compressive force is applied to the glass face plate, and the glass face plate is mechanically firmly fixed.

This is suitable for mass production and cost reduction, but mechanical stress is inevitably applied to the mirror, which may cause problems such as complicated laser modes and low laser output. is there.

[Problems to be solved by the device]

In contrast to the conventional linearly polarized internal mirror type gas laser tube described above, the present invention has excellent mass productivity, low cost, and the Brewster window does not apply stress to the mirror. The purpose is to

[Means for Solving the Problems]

The gas laser tube of the present invention comprises a metal support at least at one end of the envelope or at one end of the laser capillary, and at the end of the metal support, a sealing tray is provided, and one end face is brewed inside the sealing tray. A glass face plate sandwiched between two cylindrical inner holders processed to have a star angle and installed at Brewster's angle with respect to the optical axis of the laser oscillation light is provided, and the cylindrical inner holder and the glass face plate are provided. The laser tube end structure is provided with a metal plate having an opening in the center fixed to the end of the enclosing dish in a pressed state and a mirror fixed to the metal plate.

[Embodiment 1] Hereinafter, the present invention will be described in detail with reference to embodiments. FIG. 1 is a sectional view of a laser tube showing an embodiment of the present invention, and FIG. 2 is an enlarged view of a glass face plate mounting portion which is a portion A in FIG. In both figures, 1 is a cylindrical metal support which can be bent and deformed, 2 is a metal support which is integrally attached to the metal support by brazing or the like, and is an enclosing plate which serves as an external holder for the Brewster window.
Is a low-melting glass for vacuum-tightly fixing and fixing the metal plate 5 having the mirror of 4 and the opening at the center to the enclosure plate of 2;
6 and 8 are internal holders such as metal and glass whose one side is cut at Brewster's angle for holding and fixing the glass face plate of 7 at Brewster's angle, 9 is an envelope for maintaining vacuum, 10
Is a cathode, 11 is a laser capillary, 12 is a cathode introducing rod, and 13 is an anode.

Next, a method of holding and fixing the glass face plate according to the present invention will be described. First, a thin tube 11 having an anode 13 welded thereto is fused to an envelope 9 having a cathode introduction rod 12 connected to a cathode 10 welded thereto, and the metal support 1 and the enclosure tray 2 are brazed at both ends thereof by brazing or the like. Make a sticky thing. Next, this is placed vertically so that the enclosing dish 2 faces upward, and the inner holder 8, the glass face plate 7, the inner holder 6, the metal plate 5, the mirror 4, and the low melting point glass 3 are placed in this order in this order. Incorporate these. In this case, as the material of the enclosing tray 2, a material having a thermal expansion coefficient larger than that of the glass plates of the internal holders 6 and 8 and 7 is used, and the mirror 4 is placed on the metal plate 5. It is located in

After assembling in the above order as shown in FIG. 2, the low melting glass 3 is melted by heating the part A shown in FIG. 1 to a specified temperature of about 500 ° C. Then, the internal holding bodies 6 and 8 at a temperature at which the low melting point glass 3 which is cooled and melted solidifies
The mirror 4, the metal plate 5, and the enclosing tray 2 are fusion-bonded to each other with one surface thereof in contact with a position equal to the sum of the axial lengths of the glass face plate 7. Further, when the gas laser tube is cooled to around the normal temperature where it is normally used, the glass face plate 7 is axially moved by the mirror so that the thermal expansion coefficient of the composite of the enclosing tray 2, the inner holder 6, the glass face plate 7 and the inner holder 8 is increased. It receives compressive force due to the difference. Due to this compressive force, the glass face plate 7 is strongly sandwiched from both sides by the inner holders 6 and 8 to the end face of Brewster angle of each inner holder, and the position is firmly fixed without moving.

[Embodiment 2] FIG. 3 is a longitudinal sectional view of Embodiment 2 of the present invention. In this figure, only part A of Example 1 in FIG. 1 is drawn. The difference from the first embodiment shown in FIG. 1 is that the metal support 21 is directly welded to the envelope 9. In addition, the enclosure tray 2 of the first embodiment is a straight pipe-shaped enclosure pipe 22 in the second embodiment, which is positioned by mating with the metal support 21 and is integrally attached by brazing or the like. The end surface of the enclosing pipe 22 on the mirror side is substantially flush with the surface of the metal plate 5, and the low melting point glass 3 has a structure capable of enclosing the mirror 4, the enclosing pipe 22, and the metal plate 5 at the same time. Since the second embodiment has a simple structure and a small number of parts, it has an advantage that it can be manufactured at low cost.

[Effect of device]

According to this invention, the internal holders 5 and 7 can be manufactured at low cost by pressing metal or molding glass, and the glass face plate does not need to have a special shape such as an ellipse or a circle, and can be cut into a rectangle. You can use what you did. Further, since the glass face plate can be fixed to the Brewster's angle at the same time when the low melting point glass is attached to hermetically seal the mirror, the steps can be omitted, which is suitable for mass production.

Further, since no stress is applied to the surface of the mirror, the precision of the flatness of the mirror surface is not deteriorated, and the laser output has a good mode and the output power is high.

[Brief description of drawings]

FIG. 1 is a sectional view of a linearly polarized internal mirror type gas laser tube showing an embodiment of the present invention, and FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 is a vertical sectional view showing a part of the second embodiment of the present invention. 1 ... Metal support, 2 ... Encapsulation dish, 3 ... Low melting glass, 4 ... Mirror, 5 ... Metal plate, 6 ... Internal holder,
7 ... glass face plate, 8 ... internal holder, 9 ... envelope,
10 …… Cathode, 11 …… Laser capillary, 12 …… Cathode introduction rod, 13
…… Anode, 13 …… Mirror, 21 …… Metal support, 22 …… Enclosed pipe.

Claims (1)

[Scope of utility model registration request] 1. An envelope, a laser thin tube which is partially or wholly installed inside the envelope, a cathode which is installed inside the envelope at an end of the laser thin tube, and provided on the laser thin tube. A gas laser tube having at least one anode and a miller provided at both ends of the envelope or at the end of the envelope and at the end of the laser capillary, respectively, at least at one end of the envelope or at one end of the laser capillary. A metal support is provided, and an enclosing dish is fixed to an end portion of the metal support, and inside the enclosing dish, two cylindrical inner parts, one end surface of which is cut to Brewster's angle, on the metal support side. The glass face plate sandwiched between the holders is installed at Brewster's angle, and on the side far from the metal support, in the state of pressing the cylindrical inner holder and the glass face plate, an opening is made in the center. The metal plate it has is fixed to the inner end of the enclosing tray, Farther relative to the metal support of the metal plate, linearly polarized internal mirror type gas laser tube mirror is fixed.