JPH11330602A - Ion laser oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ion laser oscillator which is simplified in structure. SOLUTION: Two transparent flat plates 2a and 2b comprising an etalon E are each coated with coatings 3a and 3b which are different from each other in spectral transmittance properties. The coatings 3a and 3b are equal in transmittance to light of prescribed oscillation wavelength but different from each other in transmittance to light of other wavelengths. By this setup, the device functions as an etalon to light of the prescribed wavelength, but light of the other wavelengths is reflected from one of the two transparent flat plates 2a and 2b, so that a loss occurs in a resonator to restrain the oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion laser oscillator, and more particularly to an ion laser oscillator having an etalon that suppresses frequency fluctuation of an oscillation wavelength.

[0002]

2. Description of the Related Art In an ion laser oscillator having a plurality of oscillation wavelengths, two types of elements, a prism and an etalon, must be used in combination in order to oscillate an output with a single oscillation wavelength and no minute wavelength fluctuation. There is.

FIG. 4 is a configuration diagram showing a conventional ion laser oscillator with single wavelength oscillation and small minute wavelength fluctuation.

[0004] In the ion laser oscillator shown in FIG. 4, since there are a plurality of oscillation wavelengths, a laser beam from a laser light source 5 is incident on a prism 4 installed on the optical axis, and the wavelength dispersion characteristics of the prism 4 are utilized. A predetermined oscillation wavelength is selected from a plurality of oscillation wavelengths to oscillate.

[0005] Furthermore, one surface is perpendicular to the optical axis.
Transparent flat plates 2a and 2b having three to three layers of coatings 3a and 3b are arranged via a spacer 1 so as to be parallel and opposed to each other, and a resonator called an etalon is formed in the laser oscillator.

The etalon coatings 3a and 3b are shown in FIG.
As shown in (1), the etalon functions as a narrow-band filter in which a transmission band and a non-transmission band are periodically repeated over a wide wavelength range.

The oscillation line selected by the prism 4 fluctuates at a minute wavelength level, but by arranging the etalon in the laser oscillator, fluctuation at the frequency level is suppressed, and oscillation with little fluctuation is obtained. Can be

[0008]

By the way, a prism can separate a plurality of oscillation wavelengths, but it cannot suppress minute fluctuations in wavelength. Further, the etalon alone can suppress minute wavelength fluctuations, but cannot separate oscillation wavelengths separated by nm.

For this reason, as shown in FIG. 4, in the conventional ion laser oscillator, in order to obtain oscillation having a single wavelength and without minute wavelength fluctuation, a prism and an etalon are used in combination, and the oscillation wavelength is controlled by the prism. And it is necessary to suppress the fluctuating frequency by using an etalon, and there is a problem that the structure becomes complicated.

An object of the present invention is to provide an ion laser oscillator having a simplified structure and improved performance.

[0011]

In order to achieve the above-mentioned object, an ion laser oscillator according to the present invention is an ion laser oscillator having an etalon, wherein the etalon has a small wavelength fluctuation in a specific oscillation wavelength band. In addition to the etalon's original function of suppressing, the etalon also has a function of selecting an oscillation wavelength in other oscillation wavelength bands.

Further, the etalon has a pair of transparent flat plates, and the pair of transparent flat plates is coated with each other, and the coating has the same spectral transmittance in a specific wavelength range. And has a characteristic of exhibiting a different spectral transmittance in other wavelength ranges.

The pair of transparent flat plates are arranged so as to be orthogonal to and parallel to the optical axis of the ion laser oscillator.

Further, among the coatings applied to the pair of transparent flat plates, one of the coatings uses a coating having a small change in spectral transmittance with respect to the oscillation wavelength, and the other coating uses a multilayer film, It is set so that both spectral transmittances are equal at a specific oscillation wavelength.

When a multilayer film is used as the coating, the thickness of the coating of each layer is set to an even multiple of λ / 4 (where λ is the oscillation wavelength), so that a specific oscillation can be achieved. It is formed as a film whose spectral transmittance increases with wavelength.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a configuration diagram showing an ion laser oscillator according to Embodiment 1 of the present invention, and FIG. 2 is a graph showing spectral transmittance characteristics on a transparent flat plate used in Embodiment 1 of the present invention. FIG.

In FIG. 1, the ion laser oscillator according to the present invention has an etalon E as a basic configuration. The etalon E has an essential function of suppressing the minute wavelength fluctuation in a specific oscillation wavelength band. In addition, it has a function of selecting an oscillation wavelength in other oscillation wavelength bands.

On two transparent flat plates constituting the etalon E,
Coatings 3a and 3b having mutually different spectral transmittance characteristics
Is applied. These coatings 3a and 3b show the same transmittance at a predetermined oscillation wavelength, but show different transmittances at other wavelengths. As a result, at a predetermined oscillation wavelength, the etalon has a function as an etalon, but at other oscillation wavelengths, light is reflected by the coating of one of the transparent flat plates, which causes loss in the resonator and suppresses oscillation. .

Next, a specific example of the present invention will be described as a first embodiment.

As shown in FIG. 1, a pair of transparent flat plates 2a and 2b constituting an etalon E having an ion laser oscillator having a plurality of oscillation wavelengths are provided. Reference numeral 5 denotes a laser light source that causes a laser beam to enter the etalon E.

The pair of transparent flat plates 2a and 2b are orthogonally arranged on the optical axis of the ion laser oscillator and are arranged in parallel with a certain interval with the spacer 1 interposed therebetween.

Further, the pair of transparent flat plates 2a and 2b are
Coating of multilayer film 3a, 3 on opposing surfaces facing each other
b is given.

As shown in FIG. 2, the coatings 3a and 3b have a specific oscillation wavelength (in the case of FIG. 2, near the oscillation wavelength Z0).
Have the same spectral transmittance, and the other oscillation wavelengths have different spectral transmittance characteristics.

In the case of the coatings 3a and 3b shown in FIG. 2, titanium oxide and silicon oxide are alternately λ /
Vacuum deposition, ion plating,
The film is formed using a film forming method of ion beam sputtering.

The difference between the one coating 3a and the other coating 3b is only the ratio of the film thickness of the whole coating, and the same film material and the same number of film layers.

In the first embodiment of the present invention, the etalon E
2 are coated with coatings 3a, 2a having different spectral transmittance characteristics from each other as shown in FIG.
3b is applied. Coatings 3a, 3b shown in FIG.
Has the same spectral transmittance in the vicinity of a specific oscillation wavelength, in the case of FIG. 2, the oscillation wavelength Z0, and has a characteristic of different transmittances in other oscillation wavelengths.

Therefore, the etalon E has an original function of the etalon, which suppresses minute wavelength fluctuation in a specific oscillation wavelength band at a specific oscillation wavelength. In addition, the etalon E has a function as a so-called resonator, in which, at an oscillation wavelength other than a specific oscillation wavelength, light is reflected by the coating of one of the transparent flat plates, thereby causing loss in the resonator and suppressing oscillation. Demonstrate.

(Embodiment 2) FIG. 3 is a characteristic diagram showing a spectral transmittance characteristic on a transparent flat plate used in Embodiment 2 of the present invention.

In the coatings 3a and 3b according to the second embodiment of the present invention shown in FIG. 3, one of the coatings 3a and 3b forming a pair is one of the coatings 3a and 3b.
Uses a coating having a small change in spectral transmittance with respect to the oscillation wavelength, and the other coating 3b or 3
“a” uses a multilayer film and has a specific oscillation wavelength (in the case of FIG. 3,
In the vicinity of the oscillation wavelength Z0), both are set to have the same spectral transmittance.

When a multilayer film is used as the other coating 3b or 3a, the coating thickness of each layer is λ
By setting the film thickness to an even multiple of / 4 (where λ is the oscillation wavelength), a film whose spectral transmittance increases at a specific oscillation wavelength as shown in FIG. 3 can be formed.

Thus, the etalon E used in the second embodiment of the present invention has an etalon function at a specific oscillation wavelength, and cancels the etalon function at other oscillation wavelengths. Has become.

Etalon E used in Embodiment 2 of the present invention
In addition, not only does the etalon function to suppress minute wavelength fluctuations when the laser light is transmitted, it also has the wavelength selection function of the prism, so only the etalon can be used at a specific oscillation wavelength. There is an advantage that an output without minute fluctuation can be obtained.

[0034]

As described above, according to the present invention, the same transparent transmittance is obtained only at a specific oscillation wavelength by applying a coating having different spectral transmittance characteristics to the transparent flat plate constituting the etalon. Therefore, the function of selecting the oscillation wavelength obtained by using the conventional prism can be added to the etalon.

Therefore, the oscillation wavelength can be selected and the minute wavelength fluctuation can be stabilized using only the etalon, and a prism is not required, the number of parts can be reduced, and optical loss such as scattering is reduced. And the size of the oscillator can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an ion laser oscillator according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing spectral transmittance characteristics on a transparent flat plate used in Embodiment 1 of the present invention.

FIG. 3 is a characteristic diagram showing a spectral transmittance characteristic on a transparent flat plate used in Embodiment 2 of the present invention.

FIG. 4 is a configuration diagram showing an ion laser oscillator according to a conventional example.

FIG. 5 is a characteristic diagram showing spectral transmittance characteristics on a transparent flat plate used in a conventional example.

[Explanation of symbols]

 1 Spacer 2a, 2b Transparent flat plate 3a, 3b Coating on transparent flat plate E Etalon

Claims (5)

[Claims] 1. An ion laser oscillator having an etalon, wherein the etalon adds to the etalon's original function of suppressing minute wavelength fluctuations in a specific oscillation wavelength band and oscillates in other oscillation wavelength bands. An ion laser oscillator having a function of selecting a wavelength. 2. The etalon has a pair of transparent flat plates, and each of the pair of transparent flat plates is coated, and the coating has the same spectral transmittance in a specific wavelength range. 2. The ion laser oscillator according to claim 1, wherein the ion laser oscillator has characteristics of showing different spectral transmittances in other wavelength ranges. 3. The ion laser oscillator according to claim 2, wherein said pair of transparent flat plates are arranged so as to be orthogonal to and parallel to an optical axis of said ion laser oscillator. . 4. A coating applied to the pair of transparent flat plates, one of which uses a coating having a small change in spectral transmittance with respect to an oscillation wavelength, the other coating uses a multilayer film, 3. The ion laser oscillator according to claim 2, wherein both the spectral transmittances are set to be equal at a specific oscillation wavelength. 5. When a multilayer film is used as the coating, the thickness of the coating of each layer is set to an even multiple of λ / 4 (where λ is an oscillation wavelength), whereby a specific oscillation is achieved. The ion laser oscillator according to claim 4, wherein the film is formed as a film whose spectral transmittance increases with wavelength.