JP2000091679A - Laser wavelength adjusting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separatly conduit the adjustment of resonance optical path length from the adjustment of optical axis of an adjusting mirror provided at an end part of a laser oscillation tube. SOLUTION: A reflective internal mirror 3 is provided at an end part of a gas laser oscillation tube 1, and the mirror 3 is supported by a mirror supporter 4. The mirror supporter 4 is provided with first, second, and third flanges 5, 6, and 7, and an optical axis adjusting groove 8 is provided between the first and second flanges 5 and 6, with the reflective internal mirror 3 adjusted for optical axis using an optical axis adjusting screw 10. A resonance optical path controlling groove 9 and a piezoelectric element 11 are provided between the second and third flanges 6 and 7, and the expansion/contraction of the piezoelectric element 11 plastically deforms the resonance optical path length controlling groove 9 for resonance optical path length adjustment of the reflective internal mirror 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser wavelength adjusting mechanism, and more particularly to a mechanism for finely adjusting a position of a mirror provided at an end of a laser oscillation tube.

[0002]

2. Description of the Related Art When stabilizing the wavelength of a gas laser such as a He-Ne laser, there are cases where an external mirror is used for a laser oscillation tube and where an internal mirror is used. In the former case,
The position of the mirror is controlled by a power generating element such as PZT. However, there is a problem that the adjustment of the optical axis is difficult due to the external mirror, and the oscillation tends to be unstable. On the other hand, in the latter case, the length of the resonator is controlled by a heater, a fan, a drive current, or the like. As a laser wavelength stabilization method, there are generally a two-mode method, a Zeeman method, a Lamb dip method, a molecular saturation absorption method, and the like.
It is necessary to obtain the second derivative and the third derivative. Therefore,
From the viewpoint of responsiveness, it is desirable to use an external mirror.However, depending on the wavelength band, oscillation efficiency is poor and the external mirror cannot be used. Is an issue.

For example, in Japanese Utility Model Laid-Open Publication No. 59-39959, an adjusting mirror as an internal mirror is disposed at one end of an optical resonator, and thin mirrors having different diameters are provided on the back surface of the adjusting mirror. A configuration is disclosed in which an annular outer piezoelectric element and an inner piezoelectric element are provided on concentric circles. Opposite-phase voltages are applied to the outer and inner piezoelectric elements, respectively. When the outer piezoelectric element expands and the inner piezoelectric element contracts, the thin portion of the adjusting mirror elastically deforms due to the extension and contraction, and the position of the reflecting surface of the adjusting mirror changes, thereby changing the optical path of the optical resonator. The length (the distance between the mirror provided on the other side of the resonance tube and the adjustment mirror) can be adjusted.

[0004]

However, in order to obtain a stable resonance state at a desired resonance optical path wavelength, both the adjustment of the optical axis of the mirror on the resonance optical path and the adjustment of the distance between the mirrors (resonance optical path length) are required. In the above prior art, the reflection surface position is changed by the elastic deformation of the thin portion of the adjustment mirror, so that the reflection surface of the adjustment mirror slightly tilts with respect to the optical path when adjusting the resonance optical path length, and oscillation stops. It could be. That is, in the above-described conventional technology, the adjustment of the optical axis of the mirror and the adjustment of the resonance optical path length are not performed independently. was there.

Further, when an annular piezoelectric element is attached to the adjusting mirror, a force other than the tube axis direction (thrust direction) of the laser oscillation tube is applied to the adjusting mirror, and distortion occurs in the welding connection between the laser oscillation tube and the adjusting mirror. It is easy to be damaged and becomes unusable due to the inflow of outside air. In addition, attaching a piezoelectric element to the adjusting mirror causes a vertical downward load on the adjusting mirror, which tends to cause resonance optical path deviation, oscillation instability, and oscillation stoppage. There was also.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to adjust the mirror optical axis and the optical path length independently, and to achieve high-speed and high-precision wavelength stabilization. An object of the present invention is to provide a laser wavelength adjusting mechanism capable of realizing the laser light.

[0007]

To achieve the above object, a first aspect of the present invention is a laser wavelength adjusting mechanism for adjusting a mirror provided at an end of a laser oscillation tube, the mechanism supporting the mirror. A mirror support, first, second, and third flanges provided on the mirror support; a first groove provided between the first flange and the second flange; and a gap between the second flange and the third flange. A second groove provided in the second flange, an optical axis adjusting means provided in the second flange to adjust the optical axis of the mirror by elastically deforming the first groove, and an optical axis adjusting means provided in the third flange; An optical path length adjusting means for adjusting the position of the mirror in the tube axis direction by elastically deforming the groove.

In a second aspect based on the first aspect, the optical path length adjusting means is a piezoelectric element which expands and contracts along a tube axis of the laser oscillation tube.

In a third aspect based on the first aspect, the optical axis adjusting means is a screw provided along a tube axis of the laser oscillation tube.

A fourth aspect of the present invention is the liquid crystal display device according to the second aspect, further comprising an applying means for applying a load to the piezoelectric element along a tube axis.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 shows a configuration diagram of the present embodiment. FIG. 1A is a longitudinal sectional view, and FIG.
(B) is a rear view. A cylindrical mirror support 4 as a sleeve is provided at an end of the gas laser oscillation tube 1, and a reflective internal mirror 3 is fixed to the end of the mirror support 4 so as to seal the mirror support 4. Mirror support 4
Can be composed of, for example, Kovar. A fixed mirror is provided at the other end (left side in the figure) of the gas laser oscillation tube 1 (not shown), and the laser light oscillated in the gas laser oscillation tube 1 is repeatedly reflected between the fixed mirror and the reflection internal mirror 3. While oscillating, a part of the light is radiated outside through the fixed mirror. The distance between the fixed mirror and the reflective internal mirror 3 is the optical path length of the resonance optical path 2, and the resonance optical path length is adjusted by moving the reflective internal mirror 3 along the tube axis direction (the direction of the arrow in the figure). can do.

The mirror support 4 has a first flange 5 and a second flange 5 between the gas laser oscillation tube 1 and the reflection internal mirror 3.
A flange 6 and a third flange 7 are sequentially provided.
The first flange 5 and the second flange 6 protrude substantially perpendicularly to the tube axis direction and by substantially the same amount. Meanwhile, the third
The flange 7 has a smaller protrusion amount than the first flange 5 or the second flange 6, and the third flange 7 is different from the first flange 5 and the second flange 6, as shown in the rear view of FIG. It has a nut structure. A threaded portion is formed at the portion of the mirror support 4 where the third flange 7 is formed. By rotating the third flange 7 having a nut structure, the third flange 7 moves in the direction of the laser oscillation tube 1. I do.

An optical axis adjusting groove (first groove or thin portion) 8 is formed in the mirror support 4 between the first flange 5 and the second flange 6, and a gas laser oscillation is formed in the second flange 6. An optical axis adjusting screw 10 is provided along the tube axis of the tube 1. The distal end of the optical axis adjusting screw 10 abuts on the first flange 5, and as shown in the rear view of FIG.
The second flange 6 is provided at three symmetrical positions (positions each forming 120 degrees) at three times.

Further, the second flange 6 and the third
Between the flanges 7, a cylindrical piezoelectric element 11 such as PZT is provided along the tube axis of the gas laser oscillation tube 1 (that is, provided so as to cover the outer periphery of the mirror support 4). Both ends of the piezoelectric element 11 are connected to the second flange 6
And a third flange 7 having a nut structure.
By tightening the flange 7, a force along the tube axis direction is applied, and the entire circumference of the piezoelectric element 11 is preloaded along the tube axis direction with substantially the same force.

Further, a second flange 6 and a third flange 7
The mirror support 4 has a groove for controlling the resonance optical path length (second groove).
A groove or a thin portion 9 is provided. The depths of the optical axis adjusting groove 8 and the resonance optical path length controlling groove 9 are arbitrary.

In such a configuration, when adjusting the reflection internal mirror 3, first, the third flange 7 having the nut structure is tightened to preload the piezoelectric element 11 as described above. This preload is based on the force applied by the expansion and contraction of the piezoelectric element 11 to the mirror support 4 via the second flange 6 and the third flange 7 when a voltage is applied to the piezoelectric element 11 (specifically, this force is a resonance optical path). This causes elastic deformation of the length control groove 9). As a result of performing the preload, the reflection surface of the reflection internal mirror 3 may be deviated from the optical axis. Next, one or all of the three optical axis adjustment screws 10 provided on the second flange 6 are rotated. By operating, the optical axis adjusting groove 8 provided between the first flange 5 and the second flange 6 is elastically deformed. This elastic deformation generated in the mirror support 4 is
And the angle between the reflection surface of the reflection internal mirror 3 and the optical axis is changed, and the optical axis is adjusted. As a result of this optical axis adjustment, when the reflection internal mirror 3 is oriented perpendicular to the optical axis, laser oscillation is performed.

When the resonance optical path length is adjusted after the optical axis adjustment is completed, a voltage is applied to the piezoelectric element 11 provided between the second flange 6 and the third flange 7 to apply a voltage to the gas laser oscillation tube 1. The piezoelectric element 11 is expanded and contracted along the tube axis direction. Then, the resonance optical path length control groove 9 is elastically deformed by the expansion and contraction of the piezoelectric element 11, and this deformation causes the displacement of the reflection internal mirror 3. Since the piezoelectric element 11 expands and contracts along the tube axis direction, the reflection internal mirror 3 is displaced only along the tube axis direction, and the resonance optical path length is adjusted to a desired value.

As described above, in the present embodiment, the optical axis adjustment and the resonance optical path length adjustment can be performed independently. Since this does not occur, the optical axis adjustment and the resonance optical path length adjustment are speeded up.

<Second Embodiment> FIG. 2 shows the configuration of the present embodiment. FIG. 2A is a longitudinal sectional view, and FIG.
(B) is a rear view. In the laser wavelength adjusting mechanism shown in FIG. 1, the third flange 7 has a nut structure, and a preload along the tube axis direction is applied to the piezoelectric element 11 by tightening the nut. If the dimensions are not ensured, it becomes impossible to apply a uniform preload over the entire circumference. Therefore, in this embodiment, a screw 13 for preload is further provided on the third flange 7 of the nut structure.

This preload screw 13 is shown in FIG.
As shown in FIG. 3, three screws are provided at the three-fold symmetric position of the third flange 7 in the same manner as the three-fold optical axis adjusting screw 10 provided at the second flange 6, and these three preload screws are provided. By tightening any or all of the above, a uniform preload can be applied over the entire circumference of the piezoelectric element 11.

The procedure of the adjustment in this embodiment is the same as that in the first embodiment. First, after the third flange 7 is tightened to some extent, the preload screw 13 is tightened so that the piezoelectric element 11 is uniformly applied along the tube axis direction. Apply a suitable preload.
Thereafter, the optical axis adjustment screw 10 is operated to adjust the optical axis of the reflection internal mirror 3, and finally, a voltage is applied to the piezoelectric element 11 to adjust the resonance optical path length.

<Third Embodiment> FIG. 3 shows a configuration diagram of the present embodiment. FIG. 3A is a longitudinal sectional view, and FIG.
(B) is a rear view. The difference from the laser wavelength adjustment mechanism shown in FIG. 1 is that a cylindrical PZT support cover 12 that supports a piezoelectric element 11 such as PZT is
The piezoelectric element 11 is provided with a ZT support cover set screw 12.
Is a point that is supported inside the PZT support cover 12, and the third flange 7 is not a nut structure, and has the same protrusions as the first flange 5 and the second flange 6 (the protrusion amount is smaller in the third flange 7). ). The PZT support cover 12 has six PZTs as shown in FIG.
It is attached to the second flange 6 with a support cover set screw 120, and includes the third flange 7, the piezoelectric element 11, and the reflective internal mirror 3. On the end face of the PZT support cover 12, preload screws 13 are provided at three times symmetrical positions.
Both ends of the piezoelectric element 11 are bonded to the third flange 7 and the PZT support cover 12.

Also in this embodiment, first, the piezoelectric element 11 is uniformly preloaded along the tube axis direction by tightening the preload screw 13 provided on the PZT support cover 12. Is operated to adjust the optical axis of the reflection internal mirror 3, and further, a voltage is applied to the piezoelectric element 11 to adjust the resonance optical path length.

In this embodiment, the piezoelectric element 1
1 is not provided between the second flange 6 and the third flange 7, but is provided between the third flange 7 and the PZT support cover 12, so that the space between the second flange 6 and the third flange 7 is provided. Therefore, it is possible to shorten the entire length of the mirror support 4 and shorten the resonator length of the gas laser oscillation tube 1.

[0026]

As described above, according to the present invention, the adjustment of the optical axis and the adjustment of the resonance optical path length can be performed independently, and no force in the thrust direction is applied during the adjustment of the resonance optical path length. Wavelength stabilization can be performed at high speed and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a third embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 gas laser oscillation tube, 2 resonance optical path, 3 internal mirrors, 4 mirror support (sleeve), 5 first flange, 6 second flange, 7 third flange, 8 optical axis adjusting groove, 9 resonance optical path length control Groove, 10 Optical axis adjustment screw, 11 Piezoelectric element, 13 Preload screw.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hisaka Sakai 430 No. 1 Joyokoba, Tsukuba, Ibaraki Prefecture F-term (reference) 5F072 JJ20 KK02 KK30

Claims (4)

[Claims] 1. A laser wavelength adjusting mechanism for adjusting a mirror provided at an end of a laser oscillation tube, comprising: a mirror support for supporting the mirror; and first, second and second mirrors provided on the mirror support. A third flange, a first groove provided between the first flange and the second flange, a second groove provided between the second flange and the third flange, and a first groove provided on the second flange. Optical axis adjusting means for adjusting the optical axis of the mirror by elastically deforming the groove; and an optical path provided on the third flange for adjusting the position of the mirror in the tube axis direction by elastically deforming the second groove. A laser wavelength adjusting mechanism, comprising: a length adjusting unit. 2. The laser wavelength adjusting mechanism according to claim 1, wherein said optical path length adjusting means is a piezoelectric element which expands and contracts along a tube axis of said laser oscillation tube. 3. A laser wavelength adjusting mechanism according to claim 1, wherein said optical axis adjusting means is a screw provided along a tube axis of said laser oscillation tube. 4. The laser wavelength adjusting mechanism according to claim 2, further comprising an applying means for applying a load to said piezoelectric element along a tube axis.