JPH05315678A - Optical resonator for orthogonal gas laser - Google Patents

Abstract

PURPOSE:To provide an optical resonator for an orthogonal gas laser, offering good symmetry in mode pattern and capable of producing high power. CONSTITUTION:An optical resonator for an orthogonal gas laser has a structure as shown in Fig. (a), in which a rear mirror Mr, a first fold mirror Mb1, a second fold mirror Mb2, and a first mirror Mp1 for changing optical path are arranged in a first plane S1 having an angle of a with a flow of gas; and a second mirror Mp2 for changing optical path, a third fold mirror Mb3, a fourth fold mirror Mb4, and an output mirror Mo are arranged in a second plane S2 parallel to the first plane S1. Fig. (b) shows an alternative structure, in which a rear mirror Mr, a fifth fold mirror Mb5, a sixth fold mirror Mb6, and a third mirror Mp3 for changing optical path are arranged in a fourth plane S4 having an angle of beta with a flow of gas; and a fourth mirror Mp4 for changing optical path, a seventh fold mirror Mb7, a eighth fold mirror Mb8, and an output mirror Mo are arranged in a fifth plane 85 parallel to the fourth plane S4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of an optical resonator of an orthogonal gas laser oscillator.

[0002]

2. Description of the Related Art A folded optical path in an optical resonator of an orthogonal gas laser oscillator is provided on a plane parallel to a gas flow because a discharge gap is generally narrow as shown in FIG. In the case of using a high-frequency discharge for excitation, a relatively stable discharge can be obtained even if the discharge gap is widened.
Some are provided on a plane inclined by 5 degrees.

The one in which the folding optical path is provided on a plane parallel to the gas flow has a large output, but the transverse mode pattern of laser light (hereinafter simply referred to as mode pattern) is shown in FIG.
It becomes asymmetric as shown in (b). When the folding optical path is provided on a plane perpendicular to the gas flow, the mode pattern is relatively symmetrical, but the output is small.

[0004]

As described above, when the folding optical path is provided on a plane parallel to the gas flow, the mode pattern becomes asymmetric. One of the reasons is that the temperature of the gas flow is However, as shown in FIG. 4 (c), the discharge increases from the entrance to the exit of the discharge part, the refractive index of the light changes, and the phase of the light passing through this part changes according to the distance from the entrance. It seems to do. When the folding optical path is provided on a plane perpendicular to the gas flow, the mode patterns are relatively symmetrical because the distance from the entrance of the discharge part is the same. The present invention has been made in view of such a point, and an optical resonator of an orthogonal gas laser oscillator capable of reducing the asymmetry of the mode pattern by rotating the optical axis of the folded optical path by a certain angle. It is intended to be provided.

[0005]

In order to achieve the above object, the invention according to claim 1 provides a plurality of gas laser oscillators in which the gas flow direction of the laser gas and the longitudinal direction of the optical resonator are orthogonal to each other. The rear mirror and the plurality of folding mirrors provided at the end of the first plane that includes the folding optical path and forms a predetermined angle α with the gas flow, and the end of the second plane that includes the plurality of folding optical paths and is parallel to the first plane. The output mirror and the plurality of folding mirrors that are provided and the third plane, which is respectively provided at the same side ends of the first plane and the second plane and whose optical path direction is perpendicular to the longitudinal direction of the optical resonator, It is composed of a first optical path plane changing mirror and a second optical path plane changing mirror each of which is changed by 45 degrees with respect to the first plane and the second plane.

According to a second aspect of the present invention, in the gas laser oscillator in which the gas flow direction of the laser gas and the longitudinal direction of the optical resonator are orthogonal to each other, the gas flow direction includes a U-shaped folded optical path and forms a predetermined angle β with the gas flow. Rear mirror and two folding mirrors provided at the ends of the four planes, and output mirrors and two foldings provided at the ends of the fifth plane that intersects the fourth plane at a right angle, including the U-shaped folding optical path Within the sixth plane, which is provided at the same side end of the fourth plane and the fifth plane and is perpendicular to the longitudinal direction of the optical resonator, the mirror and the fourth plane and the fifth plane, respectively. It comprises a fourth optical path plane changing mirror and a fifth optical path plane changing mirror which are changed by 45 degrees.

[0007]

With this structure, the invention of claim 1 rotates the optical axis by 90 degrees by the mirror for changing the optical path plane, and the invention of claim 2 further rotates by 180 degrees by the folding mirror of the U-shaped arrangement. Therefore, the asymmetry of the mode pattern based on the difference between the upstream and downstream distances of the gas flow is reduced, and the mode becomes low-order. Also, the laser output is increased because the gas flow is effectively used.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 (a) shows the invention of claim 1 in which the predetermined angle α formed by the first plane and the second plane with the gas flow is 90 degrees. As shown, the rear mirror Mr, the first folded mirror Mb1, and the second folded mirror Mb are provided at the end of the first plane S1.
2 and the first optical path changing mirror Mp1 are arranged, and the optical path is Z-shaped. Further, the second optical path surface changing mirror Mp2, the third folding mirror Mb3, the fourth folding mirror Mb4 and the output mirror Mo are arranged at the end of the second plane S2, and the optical path is similarly Z-shaped.

The first optical path changing mirror Mp1 and the second optical path changing mirror Mp2 are respectively a first plane S1 and a second plane S.
The second plane S whose optical path direction is perpendicular to the longitudinal direction of the optical resonator
Within 3, the first plane S1 and the second plane S2 are respectively changed by 45 degrees and guided to the other plane, and the optical paths of both planes are rotated by 45 degrees about the optical axis.

FIG. 3B shows the invention of claim 2 in which the fourth plane S4 is used.
, The predetermined angle β formed by the fifth plane S5 with the gas flow is 45 degrees. As shown in the figure, the rear mirror Mr, the fifth folding mirror Mb5, the sixth folding mirror Mb6 and the third optical path changing mirror Mp3 are arranged at the end of the fourth plane S4, and the optical path is U-shaped. There is. In addition, at the end of the fifth plane S5, the fourth optical path changing mirror Mp4 and the seventh folding mirror Mp are provided.
b7, the eighth folding mirror Mb8 and the output mirror Mo are arranged, and the optical path is also U-shaped.

The third optical path changing mirror Mp3 and the fourth optical path changing mirror Mp4 are respectively a fourth plane S4 and a fifth plane S.
A sixth plane S in which the optical path direction of 5 is perpendicular to the longitudinal direction of the optical resonator.
Within 6, the angle is changed by 45 degrees with respect to the fourth plane S4 and the fifth plane S5, and the light is guided to the other plane, and the optical paths of both planes are rotated by 45 degrees about the optical axis.

FIG. 2 shows the first aspect of the present invention including the first plane and the second plane.
This is an example in which the predetermined angle α formed by the plane and the gas flow is 0 degree, that is, parallel. This Fig. 2 is a clockwise rotation of Fig. 1 (a).
Since it has been rotated by 0 degrees, the description of the mirror of each part is omitted.

FIG. 3 shows the rotation of the optical axis of the optical path of each plane in the three embodiments in the direction of the arrow. 1A is a cross-sectional view of the optical path of FIG. 1A. In the Z-shaped optical path of the first plane (hereinafter referred to as the Z path), the optical axis does not rotate relatively, so that the arrow indicates the same direction, for example, the horizontal right direction. However, since the optical axis rotates 90 degrees when moving to the Z pass of the second plane, the arrows are both vertically upward in the Z pass of the second plane. 2B is a cross-sectional view of the optical path of FIG. 2, and the horizontal rightward arrow attached to the optical axis of the Z path of the first plane is rotated by 90 degrees in the Z path of the second plane as described above. Vertical upward. 1C is a transverse cross section of the optical path of FIG. 1B, and a vertically downward arrow attached to the rear mirror Mr of the fourth plane changes the third optical path surface by a U-shaped path (optical path) of the same plane. The mirror Mp3 is vertically upward, the fourth optical path changing mirror Mp4 is horizontal left when moving to the fifth plane, and the output mirror Mo is horizontally rightward by the U-shaped path of the same plane and makes one revolution. .

As described above, when the optical axis is rotated, the symmetry of the mode pattern is improved, and the low-order modes are easily generated. The laser light output from these resonators is 45
It is a linear deflection of a degree and can be easily changed to a circular deflection.

[0015]

As can be understood from the above description, since the present invention has the constitutions described in the claims,
A mode pattern with good symmetry can be obtained. Also, a low-order mode can be obtained. Further, the laser output is increased by effectively utilizing the gas flow. Therefore, it is possible to improve processing accuracy in cutting processing and the like.

[Brief description of drawings]

FIG. 1 (a) is an explanatory diagram of an embodiment of claim 1 of the present invention. FIG. 1 (b) is an explanatory diagram of an embodiment of claim 2 of the present invention.

FIG. 2 is an explanatory diagram of another embodiment of claim 1 of the present invention.

FIG. 3 is an explanatory diagram showing the rotation of the optical axis of the optical path of each plane according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram of modes of an optical resonator of a conventional orthogonal gas laser oscillator.

[Explanation of symbols]

 Mo output mirror Mr rearmira Mb1 to Mb8 folding mirror Mp1 to Mp4 optical path changing mirror

Claims (2)

[Claims] 1. A gas laser oscillating device in which a gas flow direction of a laser gas and a longitudinal direction of an optical resonator are orthogonal to each other, the gas laser oscillating device being provided at an end portion of a first plane including a plurality of folded optical paths and forming a predetermined angle α with the gas flow. Rear mirror and a plurality of folding mirrors, and an output mirror and a plurality of folding mirrors provided at an end of a second plane including the plurality of folding optical paths and parallel to the first plane, and the same side of the first plane and the second plane. A first optical path plane changing mirror which is provided at each end of the optical path plane and which changes the optical path direction by 45 degrees with respect to the first plane and the second plane within a third plane perpendicular to the longitudinal direction of the optical resonator; An optical resonator of an orthogonal gas laser oscillator comprising a second optical path plane changing mirror. 2. A gas laser oscillator in which a gas flow direction of a laser gas and a longitudinal direction of an optical resonator are orthogonal to each other, and the gas laser oscillation device is provided at an end portion of a fourth plane including a U-shaped folded optical path and forming a predetermined angle β with the gas flow. The rear mirror and the two folding mirrors, the output mirror and the two folding mirrors provided at the end of the fifth plane that includes the U-shaped folding optical path and intersects the fourth plane at a right angle, the fourth plane, A fourth optical path provided on each of the same side ends of the fifth plane and changing the optical path direction by 45 degrees with respect to the fourth plane and the fifth plane within a sixth plane perpendicular to the longitudinal direction of the optical resonator. An optical resonator of an orthogonal gas laser oscillator comprising a plane changing mirror and a fifth optical path plane changing mirror.