JPH06244485A - Gas laser device - Google Patents

Abstract

PURPOSE:To provide a gas laser device which can adjust the length of an optical resonator. CONSTITUTION:This device is equipped with a body 21, where a laser guide pipe 2 which is to be charged with a gas laser medium is made, a pair of electrodes 7 and 8, which are provided, fronting on the laser tube 2, respectively, on one side and the other side of the body 21 arranged in the axial direction of the laser guide tube 2, and a pair of reflective mirrors 5 and 6, which are provided opposite to the laser tube 2, respectively, on one side and the other side of the body 21 so as to form an optical resonator, and a gas laser medium is made by mixing a plurality of isotope gas at specified ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a laser formed on a main body.
The gas laser medium enclosed in the conduit is excited by a discharge to generate a laser.
The present invention relates to a gas laser device that outputs laser light.

[0002]

2. Description of the Related Art A gas laser device with a small wavelength fluctuation is
There is a so-called closed type in which a gas laser medium is enclosed in a laser conduit formed in the main body. In such a gas laser device, the laser conduit is formed in the main body before the laser conduit is filled with the gas laser medium and sealed off.
The pair of reflective mirrors forming an optical resonator, which are provided at both ends of the conduit, are positioned in the optical axis direction between a concave mirror and a flat mirror, which is an interval between these reflective mirrors. You have to adjust the captain.

Conventionally, in order to adjust the optical axis and the resonator length of such a gas laser device, the applicant of the present invention has proposed a device shown in Japanese Patent Application No. 3-123940.

That is, the conventional gas laser device is shown in FIG.
As shown in (a), it has a main body 1 formed of low expansion glass into a prismatic shape. A laser conduit 2 is formed in the main body 1 along the axial direction. This laser conduit 2
Has one end surface communicating with the first communication passage 3 and the other end communicating with the second communication passage 4. Each of the communication passages 3 and 4 is formed in an L shape, and one end of the communication passage 3 and 4 is open to one end face in the axial direction of the main body 1,
The other end has an opening on the upper surface.

A plane mirror 5 for optically closing one end opening of the first communication passage 3 is optically sealed on one end surface of the main body 1, and a concave surface for closing one end opening of the second communication passage 4 on the other end surface. Mira
6 is optically sealed. The planar mirror 5 and the concave mirror 6 form an optical resonator. On the upper surface of the main body 1, the anode 7 is provided at a portion facing the other end of the first communication passage 3.
Is provided, and the cathode 8 is provided at a portion facing the other end of the second communication passage 4.

The main body 1 is divided into a first block 1A and a second block 1B. That is, the main body 1 has the inclined surfaces 11a and 11b inclined at a predetermined angle with respect to the axis of the main body 1 in the portion of the first communication passage 3 at the one end side where the plane mirror 5 is sealed. Block 1 of 1
A and the second block 1B are divided, and after adjusting the optical axis and the resonator length of these blocks as described later, the respective inclined surfaces 11a and 11b are optically sealed.

To adjust the optical axis of the optical resonator in the gas laser device, first, the central axis of the laser conduit 2 and the concave mirror 6 are used.
The concave mirror 6 is optically sealed to the end surface of the second block 1B, and the second flat mirror 5 is optically sealed to the end surface of the first block 1A so that the center of the concave surface of the first block 1A coincides with the center of the concave surface. Then, a tunable laser light as reference light is passed from the concave mirror 6 side, and the first block 1A is rotated around the optical axis so that the amount of transmitted light from the flat mirror 5 is maximized. , Adjust the optical axis.

To adjust the resonator length, first, the reference light is fixed to an arbitrary wavelength, and the first block 1A is changed to the second block 1A.
As shown in FIG. 3B, the inclined surfaces 11a and 11b are optically sealed at a position where they are moved in parallel with respect to B and the amount of transmitted light from the plane mirror 5 is almost the same as when the optical axis is adjusted. It is done by that.

In the case of a gas laser device, the wavelength (frequency) width that can be oscillated depends on the spectral line width (natural width) of atomic transition due to the influence of irregular thermal atomic motion (Doppler effect) in plasma. ) Wider Doppler width. Then, the longitudinal mode (wavelength, which occurs within the Doppler width,
Only the frequency) is amplified and oscillates. This vertical mode interval Δν (frequency) is given by Δν = C / 2L C: speed of light, L: resonator length.

Therefore, the main body 1 is laid as described above.
If it is divided into two parts at a predetermined angle with respect to the vertical plane of the central axis of the conduit 2, the sealing positions of the respective inclined surfaces 11a and 11b of the first block 1A and the second block 1B will be determined. The oscillation wavelength (longitudinal mode) can also be changed by shifting and adjusting the resonator length.

However, according to such a configuration,
After adjusting the optical axis of the optical resonator, the first block 1A
Must be further moved in parallel to change the resonator length (oscillation wavelength). Therefore, by moving the first block 1A, the optical axis adjusted prior to the resonator length is deviated. Therefore, the resonator loss may increase and the output of the lasing laser light may decrease. In addition, the laser output may vary among individual gas laser devices.

[0012]

As described above, in the conventional gas laser device, when the resonator length is changed in order to adjust the oscillation wavelength, the optical axis of the optical resonator may be displaced. It was

The present invention has been made in view of the above circumstances. An object of the present invention is to provide a gas laser device capable of changing the oscillation wavelength without causing deviation of the optical axis. is there.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a main body having a laser conduit in which a gas laser medium is enclosed, and an axial direction of the laser conduit. A pair of electrodes provided on the one end side and the other end side of the main body so as to face the laser conduit, and one pair of electrodes on the one end side and the other end side of the main body facing the laser conduit, respectively. And a pair of reflection mirrors forming an optical resonator, wherein the gas laser medium is a mixture of a plurality of isotop gases at a predetermined ratio.

[0015]

According to the above construction, the oscillation wavelength can be changed by shifting the center wavelength (frequency) of the wavelength width (Doppler width) by changing the mixing ratio of a plurality of isotope gases constituting the gas laser medium. You can

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Incidentally, the same parts as those of the conventional configuration shown in FIG.

In the gas laser device of the present invention, the main body 21 is not divided into the first block 1A and the second block 1B as in the conventional structure, but is formed of crystallized glass such as low expansion glass. It consists of one block.
A flat mirror 5 and a concave mirror 6 as reflection mirrors constituting an optical resonator are provided on one end side and the other end side of the main body 21 in an airtight manner by adjusting the optical axes and optical sealing. There is.

The gas laser medium enclosed in the laser conduit 2 of the main body 21 is a mixture of a plurality of isotop gases at a predetermined ratio. In this embodiment, the gas laser medium is He (helium) -Ne.
In addition to the mixed gas of (neon), a mixture of isotopes of Ne ²⁰ and Ne ^{22 at} a ratio of 50% is used as the neon gas.

In the case of the gas laser device, the oscillating wavelength (frequency) width is smaller than the spectral line width (natural width) of atomic transition due to the influence of irregular temperature atomic motion (Doppler effect) in plasma. Wide Doppler width. The center wavelength (frequency) of this wavelength width (Doppler width) is different for each atom, and is slightly different in the case of isotope because the atomic weight is different.

Since the oscillating wavelength width (gain width) is determined by the sum of the gain curves of all the atoms that are laser media, the center wavelength can be shifted by changing the mixing ratio of the isotopes to be mixed. . If the center wavelength can be shifted, the oscillation wavelength (vertical mode position) can be changed.

That is, conventionally, the central wavelength of the oscillated laser light was changed by changing the resonator length, but in the present invention, the Ne gas is mixed with the isotop gas of Ne ²⁰ and Ne ^22. By using the gas laser medium
Since the oscillation wavelength is changed, the oscillation wavelength can be changed without causing deviation of the optical axis.

Conventionally, when the length of the resonator is shortened, the longitudinal mode interval becomes longer than the wavelength width and the oscillation may not occur. However, the oscillation wavelength can be changed by shifting the gain curve. Therefore, it does not stop oscillating.

Ne ²⁰ and N are added to Ne gas as a gas laser medium.
The gas laser device of the present invention in which isotope gas with e ²² is mixed at a ratio of 50%, and Ne gas is mixed with Ne ²⁰
The vertical mode of the laser output in the conventional gas laser apparatus using only the above will be described with reference to FIGS. 2 (a) to 2 (d).

FIG. 3A shows the relationship between the amplification factor of light and the frequency, curve A is the laser light oscillated from the conventional gas laser device, and curve B is the gas laser of the present invention. It is laser light emitted from the device. The Doppler width of each laser beam was about 1.5 GHz, but it was measured that the center wavelength had a shift of about 500 MHz shown by X in the figure.

FIG. 2B shows the relationship between the Q of the resonator and the frequency, and the spectrum line width indicated by C in the drawing is 10 MH.
The vertical mode interval Δν indicated by D is about 1 GHz when the resonator length L is 150 mm.

FIG. 3C shows the relationship between the conventional laser light intensity and frequency, and FIG. 7D shows the relationship between the laser light intensity and frequency according to the present invention. Conventional vertical mode has a spectrum of 1
In contrast to the monochromatic light of a book, the longitudinal mode of the present invention has an oscillation frequency divided into two spectra.

In this way, the Ne gas of the gas laser medium contains 5 isotop gases of Ne ²⁰ and Ne ²² , respectively.
It was confirmed that the center wavelength (the position of the gain curve) of the wavelength width capable of oscillating was shifted by about 500 MHz by using the mixture of 0%. Therefore, if this is utilized, the longitudinal mode, that is, the oscillation wavelength can be changed without changing the resonator length, that is, the resonator length. If the oscillation wavelength can be changed without changing the resonator length, the optical axis adjusted before the wavelength adjustment will not be displaced.

In the above-mentioned embodiment, the He--Ne gas laser uses the isotop gas of Ne ²⁰ and Ne ^{22 in} which the respective Ne gases are mixed at a ratio of 50%.
The mixing ratio of these isotope gases is not limited to 50%,
Other mixing ratios may be used, and by changing this mixing ratio, the central wavelength of the oscillating wavelength width can be changed accordingly.

The gas laser device is He--N.
Even in an Ar (argon) gas laser instead of the e-laser, the same effect can be obtained by mixing a plurality of the isotop gases.

[0030]

As described above, according to the present invention, the laser conduit medium formed in the main body is filled with the gas laser medium in which a plurality of isotope gases are mixed at a predetermined ratio.

Therefore, since the central wavelength of the oscillating wavelength width can be shifted according to the mixing ratio of a plurality of isotope gases, the oscillation wavelength can be adjusted without causing the deviation of the optical axis. Furthermore, since the oscillation wavelength can be changed without providing a mechanism for adjusting the resonator length, the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view of the overall configuration of an embodiment of the present invention.

FIG. 2 is an explanatory view of the generation of a vertical mode of laser output according to the present invention and the related art.

FIG. 3 is a sectional view of a conventional gas laser device.

[Explanation of symbols]

2 ... Laser conduit, 5 ... Plane mirror (reflection mirror), 6 ...
Concave mirror (reflection mirror), 7 ... Anode, 8 ... Cathode, 21
… Main body.

Claims (1)

[Claims] 1. A main body in which a laser conduit for enclosing a gas laser medium is formed, and the laser is provided at one end and the other end of the main body in the axial direction of the laser conduit. A pair of electrodes provided facing the conduit, and a pair of reflection mirrors forming an optical resonator provided on one end side and the other end side of the main body so as to face the laser conduit, respectively. The gas laser device is characterized in that the gas laser medium is formed by mixing a plurality of isotop gases at a predetermined ratio.