JPH03218081A - Copper-vapor laser device - Google Patents

Abstract

PURPOSE:To make the wavelengths of green and yellow colors selectable with a Cu-vapor laser device by providing at least one convex lens and pinhole plate between resonators of an oscillator so that the intensity distribution of the laser beam of the device can be made to a circular form instead of an annular form and the spreading angle of the beam can be made narrower. CONSTITUTION:When only green laser light of 510.6nm in wavelength is to be oscillated, a fine-movement stage 6a is adjusted so that the interval between convex lenses 5 and 6 can become equal to the sum of the focal distances of the lenses 5 and 6 against green light and another fine-movement stage 7d is adjusted so that the distance between the lens 5 and pinhole plate 7 can become 598.7 mm (equal to the focal distance of the lens 5). As a result, the green laser light emitted from a laser tube 2 is focused on the pinhole of the plate 7 after passing through the lens 5 and becomes parallel rays after passing through the lens 6. The parallel rays oscillate while they make reciprocal movement between an output mirror 3 and totally reflecting mirror 4 and are emitted from the mirror 3 after oscillation. Only yellow light of 578nm can also be made to oscillate in the same way.

Description

[Detailed description of the invention] [Application fields of Industry 7] The present invention relates to copper vapor laser devices.

[Conventional technology]

Conventionally, copper vapor laser devices have used unstable resonators that can reduce the divergence angle of the oscillation beam. For example, this type of device is shown in, for example, the 50th Japan Society of Applied Physics Academic Lecture Proceedings Volume 3 (Autumn 1989), page 858 (30pZK-2).

[Problem to be solved by the invention]

The above-mentioned conventional technology does not give consideration to the beam intensity distribution and the oscillation wavelength of the oscillation beam, and has the following two problems. First, an unstable resonator oscillates as a beam with a donut-shaped intensity distribution with the center missing, so even if this beam is passed through an amplifier, amplified light cannot be obtained from the center of the beam. There wasn't. Second, copper vapor lasers are typically green (approximately 510 nm) and yellow (578 nm).
However, with unstable resonator type oscillators, it has not been possible to selectively oscillate these two wavelengths unless special measures are taken.

Therefore, in order to adjust the output ratio of the green and yellow laser beams, it was necessary to provide an optical element having wavelength selectivity outside the oscillator.

A first object of the present invention is to provide a copper vapor laser device having a solid beam whose beam intensity distribution is not toroidal. A second object of the present invention is to provide a copper vapor laser equipment capable of emitting a beam with a small divergence angle. A third object of the present invention is to provide a copper vapor laser device in which the oscillation output of the two wavelengths of green and yellow can be adjusted.

[Means for solving problem a]

In order to achieve the above object 1.2, at least one convex lens and a pinhole plate are provided between the resonators of the oscillator composed of a total reflection mirror and an output mirror. Furthermore, in order to achieve the third object, at least one of the convex lens and the pinhole plate is movable in the axial direction of the laser.

[Effect]

A convex lens placed between the resonators condenses the laser light in the resonator, but only the laser light with a small beam divergence can pass through the pinhole plate and resonates, so the oscillating laser light The beam divergence angle becomes smaller. Since this oscillation light has a solid beam intensity distribution, when it enters the amplifier, the entire excitation medium generated in the amplifier can efficiently contribute to the generation of laser light.

Furthermore, when the laser beam is focused by a convex lens,
Its focal length changes depending on the wavelength of the laser light. Therefore, since the focal positions of the laser beams of the two wavelengths are different, by moving and adjusting the pinhole plate, these two wavelengths can be adjusted.
The amount of light that each of the two wavelengths of laser light passes through the via hole plate changes, and as a result, the oscillated laser output of these two wavelengths can be adjusted.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIG. A copper vapor laser oscillator 1 has a resonator constructed of a laser tube 2 filled with copper vapor as a laser medium, an output mirror 3, and a total reflection mirror 4. Usually, this copper vapor laser oscillator 1 is
Green laser light with wavelength 5 1 0.6 nm and wavelength 5
A 78 nm yellow laser beam can be emitted at the same time. Between the laser tube 2 and the total reflection mirror 4, a convex lens 5,
6, and a pinhole plate 7 is placed between them.

The convex lens 6 and the pinhole plate 7 are fixed on fine movement stages 6a and 7a, respectively, which can be finely adjusted in the optical axis direction. The pinhole plate 7 is made of a body that has a large heat dissipation effect, and is plated black to suppress reflection of laser light. The convex lens 6 has a design wavelength of 54 1 n
The focal length at m is 600 mm, and the focal length of the convex lens 5 is 200 me+, and both are made of quartz. Therefore, the focal lengths at a wavelength of 510.6 nm are approximately 598.7 m and 199.6 ms, respectively, and the focal lengths at a wavelength of 578 nm are approximately 602.
6no, 2 0 0.9nn. Therefore, when oscillating only green laser light with a wavelength of 510.6 nm, the fine movement stage 6a is adjusted so that the distance between the convex lenses 5 and 6 is equal to the sum of their respective focal lengths for green light, and the convex lens Fine movement stage 7a is adjusted so that the distance between pinhole plate 7 and pinhole plate 7 is 598.7 m. With this adjustment, the focal length of the convex lens 5 is 6 for yellow laser light with a wavelength of 578 nm.
0 2.6-, so the component that passes through the hole in the pinhole plate 7 and resonates almost disappears. Furthermore, even if the light that passes through this hole passes through the convex lens 6, the distance between the convex lenses 5 and 6 is shorter than the sum of their respective focal lengths for yellow light, so the convex lens 6 Of the yellow light traveling leftward in the figure, the light returned by the output mirror 3 does not return in parallel, and a laser resonator cannot be assembled for this yellow light, making laser oscillation impossible.

On the other hand, if only yellow laser light is to be oscillated, the distance between the convex lenses 5 and 6 should be 803.5 m.
The distance between the convex lens 5 and the pinhole plate 7 is set to 60
By adjusting the distance to 2.6 m, a laser resonator can be built only for yellow light, and only yellow light will oscillate.

By the way, the pinhole diameter of this pinhole plate 7 is about 0.6m, so the focal length is about 600+
*The condensed light size when condensed by the convex lens is 0.
Only laser light with a diameter of 6 mm or less can be generated. As a result,
The divergence angle of the laser beam is approximately 1 mrad. A very small laser beam 8 as below is oscillated.

The beam intensity distribution of this laser beam 8 is different from that of a laser beam generally oscillated from an unstable resonator, and is not ring-shaped but solid-shaped, so when it passes through the amplifier 9, the excitation medium generated in it energy can be efficiently extracted and amplified. As a result, the beam intensity distribution of the amplified light 10 is also solid, resulting in high output.

Furthermore, since the amplifier 9 generally has a larger inner diameter than the laser tube 2 of the oscillator 1, the oscillation light 8 is
Although it is necessary to increase the beam diameter, here, the beam diameter is oscillated by two convex lenses 5 and 6 provided in the oscillator, and the beam diameter expander is not needed.

Next, the configuration of an oscillator section in another embodiment of the present invention will be explained with reference to FIG. In the copper vapor laser oscillator 20, an output mirror 22 is placed on the left side of the laser tube 2, and a convex lens 6, a pinhole plate 7, and a convex mirror 25 are placed on the right side as shown in the figure.

The convex lens 6 has a focal length of 2 for a wavelength of 510.6 nm.
This is a 00mm aspherical lens made of quartz glass.

The concave mirror 25 has a radius of curvature of 2001In. The pinhole plate 7 is placed 200 ml from the mirror 25.

The convex lens 6 is fixed on a fine movement stage 6a, and can be finely adjusted in the optical axis direction, that is, in the left and right directions in the figure. Now, when oscillating only green light with a wavelength of 510.6 nm, the distance between the convex lens 6 and the pinhole plate 7 is 200i.
The fine movement stage 6a is adjusted so that n. In addition, in this embodiment, in order to facilitate oscillation of only green light, a dichroic mirror 2 that transmits almost 100% of green light and has a reflectance of 90% or more for yellow light is used.
6 is placed between the resonators. This allows selective laser oscillation of green light to be performed more efficiently.

In this embodiment, compared to the embodiment shown in FIG. It can be made much shorter. As a result, output mirror 2
The length occupied by parts other than the laser tube 2 between the output mirror 3 and the concave mirror 25 is much shorter than the length occupied by parts other than the laser tube 2 between the output mirror 3 and the total reflection mirror 4 in FIG. Laser output is improved.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

A copper vapor laser device with a solid beam intensity distribution can be provided.

In addition, we can provide a copper vapor laser device that can emit a beam with a small divergence angle. Furthermore, it is possible to provide a copper vapor laser device in which the oscillation output of two wavelengths, green and yellow, can be adjusted.

Furthermore, since it is not necessary to use a diffraction grating, which is generally used as a wavelength selection element, to select green and yellow wavelengths, optical loss can be reduced, and as a result, laser output can be improved.

Finally, even if the beam diameter becomes larger, it can be handled simply by increasing the diameter of the convex lens, etc., and as a result, the laser tube of the oscillator can be made thicker so that the beam diameter of the oscillated light can be increased to a diameter that fits the amplifier. .

This configuration eliminates the need for a beam expander commonly used between the oscillator, intensifier, and amplifier, and in the case of copper vapor lasers, the laser pulse width changes depending on the inner diameter of the laser tube. Therefore, it is possible to eliminate the need for a pulse width adjuster or the like that was required between the oscillator and the amplifier.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing another embodiment of the present invention. ■, 20...Copper vapor laser oscillator, 5, 6...Convex lens, 7 Pinhole plate, 25...Convex mirror, 6a, 7a...Fine movement stage, 26...Dichroic mirror 1/No. 2 Hard U

Claims (1)

[Claims] 1. A copper vapor laser device characterized in that at least one convex lens and one pinhole plate are provided in an oscillator of a barrel vapor laser. 2. The copper vapor laser according to claim 1, wherein said at least one is two. 3. The copper vapor laser device according to claim 2, wherein the two convex lenses and one pinhole plate are provided between the output mirror of the oscillator and the laser tube. 4. A copper vapor laser oscillator characterized in that the total reflection mirror is constituted by a concave mirror, and at least one convex lens and one pinhole plate are provided. 5. The copper vapor laser device according to claim 1, 2, 3 or 4, further comprising means for moving at least one of the convex lens and the pinhole plate in the axial direction of the laser beam.