JPS61212079A - Laser oscillator with high power output - Google Patents

Abstract

PURPOSE:To maintain the stability of laser output, to prevent the components in a laser oscillator from being burnt and to prevent the life of the laser gas from being shortened, by inclining a transmitting window so that laser beams reflected by the transmitting window are led to and absorbed by an optical energy absorber. CONSTITUTION:Output laser beams 31 produced by a resonator 2 are directed to a transmitting window 40 provided with antireflection films on both sides thereof. Most of the beams are allowed to pass through the window and taken out in the atmosphere as output laser beams 32. The angle at which the transmitting window 40 is fixed is properly adjusted so that laser beams 33 reflected by the window 40 are absorbed by an absorber 5 through a mirror 23 constituting the resonator 2. The optical energy absorber 5 is cooled by air or water for preventing it from increasing its temperature. Since no laser beams are returned to a concave mirror 22 or a convex mirror 21, the resonance is not disturbed, and the components within the housing 1 of the laser oscillator are prevented from being burnt, and therefore any impurity gas having a tendency to shorten the life of the laser gas is not produced by burning them. Accordingly, the life of the laser gas is prevented from being shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-output laser oscillator, and particularly to a transmission window that transmits laser light from the oscillator into the atmosphere.

[Conventional technology]

FIG. 6 is a cross-sectional view showing a conventional high-power laser oscillator. In the figure, (1) is the laser oscillator housing.

(21 is a resonator that resonates the laser beam guided from the laser beam generator (not shown), which is formed inside the laser oscillator housing tll, includes a convex mirror 3υ, a concave mirror (2
). (to) is an extraction mirror that also constitutes the resonator (2) and takes out the laser beam after resonance. Gυ is the output laser beam extracted from the above-mentioned resonator (2) by the post-resonance extraction mirror (to), [4] is also installed in the oscillator housing +11, and is a double-sided anti-reflection device that guides the output laser beam Gυ into the atmosphere. This is the transmission window with a film. (to) is the output laser light that has passed through the transmission window (4) with anti-reflection films on both sides.

A conventional high-output laser oscillator is configured as described above, and the laser beam guided from the laser beam generating section (not shown) resonates in the resonator (2) and then is taken out as the output laser beam 00 by the mirror (c). Transparent window with anti-reflection coating on both sides (4)
The majority of the laser beam passes through and becomes the output laser beam, which is then guided into the atmosphere. But usually.

Approximately 0.4% of the output laser beam C (+1) is reflected by the transmission window (4) despite the anti-reflection coating.

This occurs because the antireflection film cannot always be manufactured according to theory. The reflected laser light returns to the take-out mirror, and is reflected again in the order of concave mirror (2) and convex mirror (2). Thick (although it wouldn't have been a problem if it wasn't).

If the laser beam reaches a high output, there is a risk of burning out the components inside the laser oscillator housing, such as the mirror support around the convex mirror Qυ and the concave mirror (2). In this case, the output of the twice-reflected laser beam will be approximately 4 W, which will have a large effect.

[Problem that the invention seeks to solve]

As mentioned above, in conventional high-output laser oscillators.

Approximately (L4%) of the transmission window with anti-reflection coating on both sides (output laser beam 31 at 41) is reflected and returns to the resonator (2), so the original resonance state of 2 is affected, causing problems such as fluctuations in laser output. There is a problem in that the life of the laser gas is shortened due to impure gas generated due to instability or burnout of components within the oscillator housing.

This invention was made to solve this problem, and prevents the laser output from becoming unstable due to the laser beam reflected by the two-sided anti-reflection coating transmission window, thereby preventing the components in the two oscillators from being burnt out. , The purpose of obtaining a large output laser oscillator that does not reduce the life of laser gas 〇 [A means to solve problems] In the large output laser oscillator due to this invention.

A transmission window with anti-reflection coatings on both sides is attached to the laser oscillator housing at a predetermined angle, and an absorber absorbs the optical energy of the reflected laser light that is reflected from the transmission window with anti-reflection coatings on both sides and returns into the resonator. It was designed to lead to.

[Effect]

In this invention, the laser beam reflected once by the transmission window with anti-reflection coatings on both sides is absorbed by the absorber inside the oscillator housing, thereby maintaining the stability of the laser output and preventing any influence on the operating characteristics of the laser oscillator.

[Embodiments of the invention]

An embodiment of this invention will be described below.

FIG. 1 is a sectional view of a high-power laser oscillator showing an embodiment of the present invention.

In the figure, the same reference numerals as in the prior art indicate the same or equivalent parts, and U is in the laser oscillator housing +11.

A transmission window with anti-reflection film on both sides provided in contact with the atmosphere reflects the output laser beam 01) on its surface toward the inside of the housing (1), and the optical axis of this reflected laser beam (toward) It is held so that its direction can be adjusted, and it can be installed at a predetermined angle. (5) is located on the optical axis of the reflected laser beam (to) that is reflected by the transmission window 14a with double-sided anti-reflection coating and returned toward the take-out mirror @, and is installed below the concave mirror @2. Reflected laser light (
It is an absorber that absorbs the light energy of (1) and (2) and prevents its own temperature from rising by water or air cooling.

Figure 2 also shows the output laser beam C(υ) from the resonator (21) of the high-power laser oscillator and the reflected laser beam (υ) which is reflected by the transmission window with anti-reflection coating on both sides and returns to the absorber (5). To)
FIG. 3 is a diagram showing the relationship between the optical paths of the light beams reflected by the take-out mirror @ in FIG. 2 above.

An extraction mirror (
2) is removed, the optical axes of the output laser beam 01) and the reflected laser beam (to) are extended, and the surface of the transmission window with adjustable double-sided anti-reflection coating is placed on the intersection.1! is the distance between the concave mirror and the transparent window with anti-reflection coating on both sides,
d is the diameter of the concave mirror. Also, θ is
This is the angle between the normal line to the reflective surface of the above-mentioned transmission window I40 with anti-reflection coating on both sides and the optical axis of the output laser beam Gυ and the optical axis of the reflected laser beam. window! The installation of 10 is also an angle. In the figure, (3
3a) is a laser beam reflected from the inner surface of the case of the transmission window IIO with anti-reflection coatings on both sides.

(33b) Laser light reflected from the outer surface of Iri.

Further, FIG. 5 is a diagram showing the relationship between the mounting angle θ and the reflectance at the transmission window 1411I with double-sided antireflection coatings.

Here, as an example, in the case of a transmission window 14a with double-sided anti-reflection coating using a three-layer anti-reflection coating shown in FIG. shows. In Fig. 4.

Gloss is the potassium chloride (KOI) substrate that is the base material of the transparent window 14Q with double-sided anti-reflection coating, and eill is the potassium chloride (KOI) substrate coated with diarsenic trisulfide (A).
82S5) film, 63 is the lead fluoride (pbF2) film coated on this, (to) the lead fluoride (pbF2) film coated on it,
by2) diarsenic trisulfide (
As2Bg) film.

The high output laser oscillator is constructed as described above.

The output laser beam 00 emitted from the resonator (2) is directed toward the transmission window t4G with anti-reflection coatings on both sides, and most of it is extracted into the atmosphere as the output laser beam (to) that has passed through.

Laser light reflected from the inner surface of the housing of the transmission window with anti-reflection coating on both sides (33a), and laser light reflected from the outer surface (s3b) H, Installation of the transmission window with anti-reflection coating on both sides @O By adjusting the angle θ to an appropriate angle, the light is absorbed into the absorber (5) via the take-out mirror (to) constituting the resonator (2). Therefore, the laser beam (33a) reflected from the inner surface of the casing and the laser beam (33b) reflected from the outer surface do not return to the concave mirror @ and convex mirror r21) constituting the resonator +2).

This eliminates the possibility of disturbing the resonance state, burning out the structure inside the laser oscillator housing (1), or shortening the life of the filled laser gas due to the generation of impurity gas due to burning out.

That is, in FIG. 3, in a high-output laser oscillator, the length l is usually about 10 fFl, and the size d of the concave mirror is about 100 ilI+ in diameter, so the laser beam (33a) reflected from the inner surface of the casing and In order to prevent the laser beam (33b) reflected from the outer surface from reaching the concave mirror (2), the laser beam (33b) reflected from the inner surface of the housing must be prevented from reaching the concave mirror (2).
Regarding 3a), the transmission window with anti-reflection coating on both sides - 〇In the installation, the angle θ is the quadratic condition 1020〉m. Therefore, the installation angle θ is 5 mrad, that is, 0.
It is sufficient if it is 3° or more. This is because the front and back surfaces of the transmission window 14o with double-sided anti-reflection coatings are usually at a wedge angle of about 10 minutes, so the laser beam (33a) reflected from the inner surface of the transmission window 14a with double-sided anti-reflection coatings and the outside When the laser beam (33b) reflected from the surface reaches the absorber (5), the laser beam (33b) reflected from the outer surface is about 30m1t concave mirror compared to the laser beam (33a) reflected from the inner surface. This is because the laser beam (53a) reflected from the inner surface may be affected by the laser beam (53a) because it arrives at a further distance.

Further, as an example, in the transmission window t4Q with antireflection coatings on both sides made of a three-layer antireflection coating shown in FIG. 5, the allowable reflectance is 0.2% or less, that is, the transmission window I4[I If the mounting angle θ is 20 degrees or less, stability of the laser output, prevention of burnout of the resonator t23, long life of the laser gas, etc. can be ensured.

In addition, in the above embodiment, the absorber (5) is replaced with a concave mirror (2).
), but the absorber (5) may be installed at any position on the optical axis of the laser beam reflected by the two-sided anti-reflection film-coated transmission window (un).

〔Effect of the invention〕

As described above, this invention is an absorber that absorbs optical energy of the laser light reflected from the transparent window with anti-reflection coating on both sides, which is attached to the case of the wrinkle laser emitting device, by tilting it at a predetermined angle. By guiding and absorbing the laser beam, the laser output is kept stable and the components inside the two oscillators are prevented from being burnt out.

This has the effect of preventing a decrease in the life of the laser gas.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a high-output laser oscillator which is an embodiment of the present invention, and FIGS. FIG. 3 is a diagram showing the optical path of the laser beam returning to the absorber, and FIG. 3 is a diagram showing the optical path of the laser beam when the extraction mirror is removed. FIG. 4 is a cross-sectional view showing an example of the antireflection coating of the transmission window with antireflection coatings on both sides, and FIG. Figure 6 is a cross-sectional view showing a conventional high-output laser oscillator manufactured by the company. In the figure, (
l) is the laser generator housing, (2) is the resonator, on is the convex mirror, (2) is the concave mirror, (to) is the extraction mirror, r30 is the output laser beam, (to) is the passed output laser The light (to) is the reflected laser beam, the front is the transmission window with anti-reflection coatings on both sides, and (5) is the absorber. In each figure, the numbers indicate the same or corresponding parts.

Claims (3)

[Claims] (1) In a laser oscillator that generates a high output laser,
An oscillator housing, a resonator formed within the oscillator housing that resonates the laser beam and composed of a concave mirror, a convex mirror, and an extraction mirror, and a resonator located on the optical axis of the output laser beam extracted from the resonator. It is provided in the oscillator housing to transmit most of the output laser beam and at the same time reflect a part of the output laser beam into the oscillator housing, so that the optical axis direction of the reflected laser beam is aligned with the output laser beam. A transmission window with an anti-reflection film is installed at a predetermined angle so as to face in a direction other than the optical axis of the oscillator, and the transmission window with an anti-reflection film is located on the optical axis of the laser light reflected into the oscillator housing. A high-output laser oscillator comprising: an absorber disposed within the oscillator housing to absorb optical energy of reflected laser light. (2) A high-output laser oscillator according to claim 1, wherein the mounting angle of the transmission window with an antireflection film is adjustable. (3) The installation angle of the transmission window formed by the transmission window with anti-reflection film and the plane perpendicular to the optical axis direction of the output laser beam is 0.3° to 2.
3. A high-output laser oscillator according to claim 1 or 2, wherein the laser oscillator is set in a range of 0°.