JPH11201900A - Self-compensated laser cavity - Google Patents

Abstract

(57) [Problem] An object of the present invention is to prevent a decrease in the use efficiency of laser light and improve the quality of laser light with a simple structure. SOLUTION: A first reflecting device 21 having first and second reflecting surfaces 21a and 21b arranged at right angles to each other,
Third and fourth reflecting surfaces 22a, which are arranged at right angles to each other,
A second reflection device 22 having a ridge line 21c,
The laser medium 23 is disposed between the first reflection surface 21a and the third reflection surface 22a so that the laser light does not pass through the ridge lines 21c and 22c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-compensating laser resonator used for a solid-state laser device mounted on a flying object such as an artificial satellite or an aircraft, for compensating the inclination of a reflecting surface.

[0002]

2. Description of the Related Art FIG. 17 shows, for example, Springer Se.
ries in Optical Sciences
Vol. 1 "Splid-State Laser E
ngineering 4th edition "Walter Koec
1 is a configuration diagram showing a conventional laser resonator shown on page 197 of Hner (published by Springer, Germany, 1995). In the drawing, reference numerals 1 and 2 denote a pair of reflecting mirrors arranged to oppose each other to confine laser light, 3 denotes a laser medium disposed between the reflecting mirrors 1 and 4, 4 denotes a light source for exciting the laser medium 3, and 5 denotes The optical axis of the laser resonator, 6 is the optical path of the laser light traveling from the reflecting mirror 2 to the reflecting mirror 1, and 7 is the reflecting mirror 1
This is the optical path of the laser light traveling from the mirror to the reflecting mirror 2.

Next, the operation will be described. In such a laser resonator as described above, laser light reciprocates in optical paths 6 and 7,
Only laser light passing through the same optical paths 6 and 7 and maintaining the same phase state is selectively confined and amplified, and an oscillation mode is formed. When the reflecting mirrors 1 and 2 are arranged in parallel with each other, the laser light is repeatedly reflected between the reflecting mirrors 1 and 2 and reciprocates on optical paths 6 and 7 parallel to the optical axis 5. At this time,
The laser light is emitted from the laser medium 3 excited by the excitation light source 4.
Are repeatedly passed and amplified.

On the other hand, as shown in FIG. 18, when one of the reflecting mirrors 1 is inclined and the reflecting mirrors 1 and 2 are not parallel, the laser beam traveling along the optical path 6 parallel to the optical axis 5 is It is reflected on an optical path 8 which is at an angle to the axis 5. Therefore, the laser light that has reciprocated does not pass through the same optical path, and cannot form an oscillation mode.

[0005] As a means for solving such a problem, the above-mentioned "Split-State Laser Engine" is used.
FIG. 227 also shows a self-compensated laser cavity as shown in FIG. In the figure, 11 is a roof prism having a ridge line 11a parallel to the Z axis, 12 is a roof prism having a ridge line 12a parallel to the X axis, and 13 is a corner cube prism arranged opposite to the roof prisms 11, 12. The laser medium 3 is disposed between the corner cube prism 13 and the roof prism 11.

In such a laser resonator, the laser light travels on the optical axis 14 and is reflected on the roof prism 12. The laser beam reflected by the roof prism 12 is
The laser light is folded at the corner cube 13 and is transmitted through the laser medium 3 excited by the excitation light source 4 and amplified. Laser medium 3
The laser light amplified by the above is reflected on the roof prism 11 and is again amplified by the laser medium 3. After this,
The laser light returns to its original position and is confined in the laser resonator.

Next, FIG. 20 shows a roof prism 1 shown in FIG.
FIG. 4 is an explanatory diagram showing a reflection state of a laser beam incident on a laser beam 2;
In the figure, reflecting surfaces 12b and 12c sandwiching a ridge line 12a are shown.
Are fixed at right angles to each other, and have an angle of 45 degrees with the optical axis 14. The laser beam traveling on the optical path 15 parallel to the optical axis 14 and entering the roof prism 12 is 90 degrees by the reflection surface 12b and 90 degrees by the reflection surface 12c, for a total of 1
Given a change in direction of 80 degrees. The optical path 16 of the laser light reflected in this manner is also parallel to the optical axis 14. That is, the loop prism 12 reflects the incident laser light as laser light parallel to the incident laser light and traveling in the opposite direction.

Further, as shown in FIG. 21, when the roof prism 12 is inclined at an angle α about the ridgeline 12a as a center axis,
The angle change given by the reflecting surface 12b is 90-2α,
The angle change given by the reflection surface 12c is 90 + 2α, and the angle change between the laser light traveling along the optical path 15 and the optical path 16 of the laser light reflected by the roof prism 12 is 18 in total.
It becomes 0 degrees. Therefore, even when an inclination occurs with the ridge line 12a as the central axis, the loop prism 12 reflects the incident laser light as laser light that is parallel to the incident laser light and travels in the opposite direction.

Similarly, when the incident laser light is inclined with respect to the optical axis 14, the roof prism 12 converts the incident laser light into laser light parallel to the incident laser light and traveling in the opposite direction. reflect. 20 and 21, the optical path 15 and the optical path 16 are connected to the optical axis 1 for explanation.
4, but in practice, conventionally, the optical path 15
In both the optical path 16 and the optical path 16, the center of the beam coincides with the optical axis 14, and the laser light is irradiated and reflected within a range including the ridgeline 12a.

Further, as shown in FIG. 19, by arranging the ridge line 11a of the roof prism 11 and the ridge line 12a of the roof prism 12 in directions orthogonal to each other, the inclinations of the roof prisms 11, 12 are compensated for each other. , A self-compensating laser resonator is constructed.

[0011]

In the conventional self-compensating laser resonator constructed as described above, since the laser beam is applied to the area including the ridge lines 11a and 12a of the roof prisms 11 and 12, diffraction occurs. Loss occurs, and the utilization efficiency of the laser light decreases. Further, microscopically, the reflection as shown in FIG. 20 does not occur on the ridge lines 11a and 12a, and the laser light is cut off at the ridge lines 11a and 12a, so that the laser light is easily broken into two or four. The quality of the laser light is degraded. Further, when trying to realize a long optical path length with a small laser resonator, the roof prism 1
In addition to the optical elements 1 and 12, an optical element for turning back, such as the corner cube prism 13, is required, which complicates the configuration of the laser resonator.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can prevent a decrease in laser light use efficiency with a simple configuration and can improve the quality of laser light. It is an object of the present invention to obtain a self-compensating laser resonator capable of improving the laser power.

[0013]

The self-compensating laser resonator according to the first aspect of the present invention comprises first self-compensating laser resonators arranged at right angles to each other.
A first reflecting device having a second reflecting surface and a second reflecting device having third and fourth reflecting surfaces disposed at right angles to each other, and facing the first reflecting device; A laser medium provided between the first reflecting surface and the third reflecting surface;
A light source that excites the laser medium;
The second ridge line formed by the two planes including the reflection surface is included in a surface substantially orthogonal to the first ridge line formed by the two planes including the first and second reflection surfaces, and the first ridge line is formed from the laser medium by the first ridge line. The laser light emitted toward the reflection surface is divided into a first reflection surface, a second reflection surface, a third reflection surface, a fourth reflection surface, a second reflection surface, a first reflection surface, and a fourth reflection surface. Are reflected in the order of the reflection surface and the third reflection surface and are incident on the laser medium.

A self-compensating laser resonator according to a second aspect of the present invention uses first and second reflecting devices each having two plane reflecting mirrors arranged at right angles to each other.

A self-compensating laser resonator according to a third aspect of the present invention comprises two planar reflecting mirrors arranged at an interval from each other and connected to each other by a connecting member.

A self-compensating laser resonator according to a fourth aspect of the present invention comprises a prism having a laser light incident surface and two reflecting surfaces arranged at right angles to each other as first and second reflecting devices. It was used.

A self-compensated laser resonator according to a fifth aspect of the present invention has a configuration in which the first and second ridges of the prism are omitted.

A self-compensated laser resonator according to a sixth aspect of the present invention is provided with an isolator that transmits laser light in one direction only in the optical path of the laser light.

A self-compensating laser resonator according to a seventh aspect of the present invention is a laser resonator in which a partial reflecting mirror for laser output is provided on any one of the first to fourth reflecting surfaces.

The self-compensating laser resonator according to the invention of claim 8 is characterized in that any one of the P-polarized component and the S-polarized component of the laser light is applied to one of the first to fourth reflecting surfaces. Is selectively transmitted and output to the outside, and a polarization reflection means for reflecting the other is provided, and a laser beam is supplied to the polarization path with an arbitrary ratio of a P-polarized component and an S-polarized component to an optical path of the laser beam. This is provided with a polarization component adjusting means.

According to a ninth aspect of the present invention, there is provided a self-compensating laser resonator that selectively transmits one of a P-polarized component and an S-polarized component of a laser beam and reflects the other in an optical path of the laser beam. A polarization reflection means for outputting the laser light to the outside, and a polarization component adjusting means for dividing the laser light into a P polarization component and an S polarization component at an arbitrary ratio with respect to the polarization reflection means in the optical path of the laser light. It is.

The self-compensated laser resonator according to the tenth aspect selectively transmits one of the P-polarized light component and the S-polarized light component of the laser light, reflects the other light, and outputs the reflected light to the outside. An isolator that has two polarization reflection means, a Faraday rotator, and a half-wave plate and transmits laser light only in one direction, and a P-polarized component and an S-polarized component at an arbitrary ratio to the isolator. And a polarization component adjusting means provided in the optical path of the laser beam.

The self-compensated laser resonator according to the eleventh aspect of the present invention uses a half-wave plate as the polarization component adjusting means.

A self-compensating laser resonator according to a twelfth aspect of the present invention uses a birefringent element which can obtain a birefringent effect by an applied voltage as a polarization component adjusting means.

A self-compensating laser resonator according to a thirteenth aspect of the present invention includes a seeder light generating device that causes the seeder light to enter the optical path of the laser light from the polarization reflection means.

A self-compensated laser resonator according to a fourteenth aspect of the present invention is provided with a beam diameter conversion device for converting a beam diameter of a laser beam in an optical path of the laser beam.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a configuration diagram showing a self-compensating laser resonator according to Embodiment 1 of the present invention. In the figure, reference numeral 21 denotes a first reflection device having first and second reflection surfaces 21a and 21b arranged at right angles to each other, and 22 denotes third and fourth reflection surfaces 22a and 22 arranged at right angles to each other.
b, a second reflector facing the first reflector 21, and the first and second reflectors 21, 21.
For example, as shown in FIG. 2, one having two plane reflecting mirrors 27 and 28 arranged at a right angle to each other is used. FIG. 2 shows only the second reflection device 22, but the configuration of the first reflection device 21 is the same.

Further, the third and fourth reflecting surfaces 22a, 22
The second ridge line 22c formed by the first and second reflecting surfaces 2c
The first and second 21a, 21b and the third and fourth reflection surfaces 22a, 22b are included in a surface substantially orthogonal to the first ridgeline 21c formed by the first and second reflection lines 1a, 21b. I have. 23 is a laser medium provided between the first reflection surface 21a and the third reflection surface 22a, and 24 is a light source for exciting the laser medium 23.

Next, the operation will be described. The laser light traveling along the optical path L1 is amplified after passing through the laser medium 23, and is sequentially reflected by the first reflecting surface 21a and the second reflecting surface 21b, and the optical path L2 parallel to the optical path L1 is opposite to the optical path L1. Proceed in the direction. The laser light traveling on the optical path L2 is sequentially reflected by the third reflection surface 22a and the fourth reflection surface 22b, and
The light travels in an optical path L3 parallel to 2 in a direction opposite to the optical path L2. The laser light traveling along the optical path L3 is sequentially reflected by the second reflecting surface 21b and the first reflecting surface 21a, and is parallel to the optical path L3.
4 in the direction opposite to the optical path L3.

The laser light traveling along the optical path L4 is the fourth laser light.
Are sequentially reflected by the reflection surface 22b and the third reflection surface 22a, return to the optical path L1, and are further amplified by the laser medium 23. Therefore, the laser beam is applied to the ridge line 2 of the first reflecting device 21.
The laser beam is confined and amplified in the laser resonator without passing over the ridgeline 22c of the first reflection device 22 and the second reflection device 22.

In such a self-compensating laser resonator,
Since the laser light does not pass over the ridge lines 21c and 22c of the reflection devices 21 and 22, there is no loss due to the diffraction of the ridge lines 21c and 22c, and a decrease in the use efficiency of the laser light is prevented. Further, since the laser light is not cut by the ridge lines 21c and 22c, the quality of the laser light is improved. Further, the four optical paths L1 to L4 can be arranged in parallel, and the first and second optical paths L1 to L4 can be arranged.
Since no reflecting means other than the reflecting devices 21 and 22 are required, the structure of the laser resonator can be simplified and the size can be reduced. Furthermore, since the plane reflecting mirrors 27 and 28 are light in weight, the weight of the reflecting devices 21 and 22 and the entire laser resonator can be further reduced.

In the above example, the laser medium 23 is arranged on the optical path L1, but may be arranged on any of the optical paths L1 to L4. Further, a plurality of sets of the laser medium 23 and the excitation light source 24 may be arranged in a plurality of optical paths.

Embodiment 2 FIG. Also, ridge lines 21c, 22c
Since the laser light does not pass through the portion of the flat reflecting mirror 27,
The portions of the ridge lines 21c and 22c of 28 may be deleted. That is, as shown in FIG. 3, plane reflecting mirrors 29 and 30 having an area smaller than that of FIG.
The laser resonators may be connected to each other by the connecting member 31, and the size and weight of the laser resonator can be further reduced.

Embodiment 3 Next, FIG. 4 is a perspective view showing a reflecting device of a self-compensating laser resonator according to Embodiment 3 of the present invention. In this example, the reflection device 21 of FIG.
A roof prism 25 is used as 22. The roof prism 25 has a laser light incident surface 25a, two reflecting surfaces 25b and 25c arranged at right angles to each other, and a ridgeline 25d. Also, the incident surface 25a and the reflecting surface 2
The angle between 5b and 25c is 45 degrees.
Furthermore, the surfaces (the upper surface and the lower surface in the figure) other than the incident surface 25a and the reflecting surfaces 25b and 25c can have any shape and angle as long as they do not interfere with the portion through which the laser light passes. Other configurations are the same as those of the first embodiment.

Next, the operation will be described. The laser beam passes through the incident surface 25a and is totally reflected by the reflecting surface 25b. The laser light totally reflected by the reflection surface 25b is totally reflected by the reflection surface 25c, is reflected in the opposite direction parallel to the incident laser light, and is output from the incidence surface 25a.

Next, a change in the polarization state of laser light in a laser resonator using the roof prism 25 of this example as the reflection devices 21 and 22 will be considered. First, when the laser light is reflected on a plane, the polarization component oscillating in the plane containing the rays of the incident light and the reflected light is P-polarized, and the polarization component oscillating perpendicularly to the plane containing the rays of the incident light and the reflected light. S-polarized light. The laser light is reflected by the reflection surface 25b of the roof prism 25,
When reflected by 25c, a phase change is given. Since the amount of the phase change is different between the P-polarized light and the S-polarized light, for example, except for the case where the polarization state in the optical path L4 is only the P-polarized component or only the S-polarized component with respect to the reflection surface 25c,
The polarization state of the laser light in the optical path L4 changes in the optical path L1.

Here, x of any polarization in the optical path L1
The axis component is Ex, the z-axis component is Ez, and the optical paths L1 to L3
Consider the polarization state of laser light propagating to X of laser light
The axis component Ex is propagated from the optical path L1 to the optical path L3.
Reflected twice as S-polarized light by the first reflecting device 21,
The light is reflected twice as P-polarized light by the second reflection device 22. The z-axis component Ez of the laser beam is reflected twice as P-polarized light by the first reflector 21 and twice as S-polarized light by the second reflector 22 while propagating from the optical path L1 to the optical path L3. Is done.

Both the x-axis component Ex and the z-axis component Ez receive a phase change due to reflection of S-polarized light and a phase change due to reflection of P-polarized light twice each, and the amount of phase change is x-axis component Ez.
Since the amount becomes equal between x and the z-axis component Ez, the polarization state of the optical path L1 is preserved in the optical path L3. Accordingly, the optical paths L1 and L3 maintain the same polarization state with respect to the laser light having an arbitrary polarization state, and the optical paths L2 and L4 maintain the same polarization state with each other. If the optical components are arranged in the optical paths L1 and L3 or the optical paths L2 and L4 in a diagonal positional relationship, the change in the polarization state due to the reflection of the prism is canceled out, so that the design of the laser resonator is facilitated.

As described above, also when the roof prism 25 is used as the reflection devices 21 and 22, the laser beam
A self-compensated laser resonator that does not pass over c can be configured, and with a simple configuration, it is possible to prevent a decrease in the utilization efficiency of laser light and to improve the quality of laser light. In addition, the angles of the reflection surfaces 25b and 25c are hardly shifted, and a stable self-compensated laser resonator can be obtained. Furthermore, in the diagonal light path,
Since there is no change in the polarization state due to reflection at the reflection surfaces 25b and 25c, the design of the laser resonator is facilitated.

Embodiment 4 FIG. In the above example, ridge line 2
Although the roof prism 25 having 5d is shown, as shown in FIG. 5, for example, it has an incident surface 26a and reflecting surfaces 26b and 26c arranged at right angles to each other, and the reflecting surfaces 26b and 2c.
A roof prism 26 may be used in which the vicinity of a ridgeline 26d formed by two planes including 6c is cut. That is, the ridgeline 26d
In the vicinity, since the laser beam does not pass through, that portion may be deleted to form a trapezoidal cross section. Further, the cut surface 26e can have any shape and angle as long as it does not interfere with a portion through which the laser beam passes. Thus, by using the roof prism 26 in which the vicinity of the ridgeline 26d is cut, the weight and size of the entire laser resonator can be reduced.

Embodiment 5 FIG. Next, FIG. 6 is a configuration diagram showing a self-compensating laser resonator according to a fifth embodiment of the present invention. In this example, a partial reflecting mirror 32 for laser output is provided at a part of the fourth reflecting surface 22b of the second reflecting device 22, that is, at an intersection with the optical path L4. Other configurations are
This is the same as in the first embodiment.

In such a self-compensating laser resonator,
As in the first embodiment, the laser light travels in the order of the optical paths L1 to L4 and is amplified. In the partial reflecting mirror 32,
A part of the laser light is transmitted and output to the outside, and the rest is reflected and further circulates in the laser resonator. Thus, by providing the partial reflecting mirror 32 on the fourth reflecting surface 22b, a laser beam output can be obtained with a simple structure,
Further, since the number of optical components is small, loss of laser light can be suppressed.

In the above example, the partial reflecting mirror 32 is provided at a portion where the optical path L4 intersects the fourth reflecting surface 22b.
First to fourth reflecting surfaces 21a, 21b, 22a, 22
b.

Embodiment 6 FIG. Next, FIG. 7 is a configuration diagram showing a self-compensating laser resonator according to Embodiment 6 of the present invention. In the figure, reference numeral 33 denotes a half-wave plate serving as a polarization component adjusting unit disposed in the middle of the optical path L4, and reference numeral 34 denotes a polarizing reflection unit provided at a portion where the optical path L4 intersects the fourth reflection surface 22b. The polarization reflection mirror 34 transmits the P-polarized light of the laser beam and reflects the S-polarized light. Here, the component of the laser light oscillating in the plane containing the light beams of the incident light and the reflected light is P-polarized light, and the component of the laser light oscillating perpendicularly to the plane containing the light beams of the incident light and the reflected light is the S-polarized light.

In such a self-compensating laser resonator,
Since only the S-polarized laser light is reflected by the polarizing reflector 34 with respect to the polarizing reflector 34, the S
Only polarized laser light orbits inside the laser resonator.

FIG. 8 is an explanatory diagram showing a change in the polarization component of the laser beam in the self-compensating laser resonator shown in FIG. 7, and shows a state before and after the half-wave plate 33 and the polarization reflector 34. . The half-wave plate 33 has an action of rotating the polarization direction to an arbitrary angle, and can divide the laser beam into a P-polarized component and an S-polarized component at an arbitrary ratio with respect to the polarization reflecting mirror 34. Therefore, when the laser beam that has passed through the half-wave plate 33 is incident on the polarization reflecting mirror 34, the S-polarized component is reflected, and the P-polarized component is output outside the laser resonator as a laser beam.

In such a self-compensating laser resonator,
Laser light output can be obtained with a simple structure, and the loss of laser light can be suppressed because there are few optical components. Further, since the P-polarized light component and the S-polarized light component can be separated at an arbitrary ratio by the half-wave plate 33,
By selecting the wave plate 33, the ratio of the laser light output to the outside of the laser resonator can be arbitrarily changed.

In the above example, the polarization reflecting mirror 34 is provided at the portion where the optical path L4 intersects the fourth reflecting surface 22b.
First to fourth reflecting surfaces 21a, 21b, 22a, 22
b.

Further, in the above example, the polarization reflecting mirror 34 transmitting the P-polarized laser light and reflecting the S-polarized light is shown. However, it is also possible to transmit the S-polarized laser light and reflect the P-polarized light. . Further, although the half-wave plate 33 is arranged in the optical path L4, it may be arranged in any of the optical paths L1 to L4.

Embodiment 7 FIG. Furthermore, in the above example, the polarizing reflector 34 is arranged on the reflecting surface 22b so that the laser beam transmitted through the polarizing reflector 34 is output to the outside. However, for example, as shown in FIG. A polarizing reflector 34 is disposed between the half-wave plate 33 and the fourth reflecting surface 22b, and the laser light transmitted through the polarizing reflector 34 circulates in the laser resonator and is reflected by the polarizing reflector 34. The emitted laser light may be output outside the laser resonator.

Embodiment 8 FIG. Next, FIG. 10 is a configuration diagram showing a self-compensating laser resonator according to an eighth embodiment of the present invention. In the figure, 35 is provided in the middle of the optical path L4, a birefringent element as the polarization component adjusting means birefringence effect is obtained by applying voltage, as the birefringent element 35, for example, lithium niobate (LiNbO ₃₎ One having a Pockels cell is used. 36
Is a Pockels cell power supply connected to the birefringent element 35.

In such a self-compensating laser resonator,
The laser light that has passed through the polarization reflector 34 becomes P-polarized linearly polarized light, and only the P-polarized laser light is circulated in the laser resonator with respect to the polarization reflector 34. Further, the laser light circulating in the laser resonator is incident on the birefringent element 35.
When a voltage is applied to the birefringent element 35 from the Pockels cell power supply 36, the birefringent element 35 has the property of a wave plate, and can convert linearly polarized light into circularly polarized light and rotate the polarization direction. That is, the polarization reflecting mirror 34
In contrast, the laser beam can be divided into a P-polarized component and an S-polarized component at an arbitrary ratio.

As described above, the laser beam split into the P-polarized component and the S-polarized component by the birefringent element 35 is incident on the polarization reflecting mirror 34, and the P-polarized component is transmitted and circulates in the laser resonator. , S-polarized light components are output outside the laser resonator as laser light. Therefore, the P-polarized light component and the S-polarized light component can be separated at an arbitrary ratio by the applied voltage of the birefringent element 35, and the ratio of the laser light output to the outside of the laser resonator can be arbitrarily changed.

In the above example, the polarization reflecting mirror 34 that transmits the P-polarized laser light and reflects the S-polarized light is shown. However, the polarized light reflecting mirror 34 may transmit the S-polarized laser light and reflect the P-polarized light. . Further, the birefringent element 35 and the polarizing reflecting mirror 34 are arranged in the optical path L4, but may be arranged in any of the optical paths L1 to L4.

Embodiment 9 FIG. Next, FIG. 11 is a configuration diagram showing a self-compensating laser resonator according to Embodiment 9 of the present invention. In the figure, reference numeral 36 denotes an isolator provided in the middle of the optical path L4. FIG. 12 is an explanatory view for explaining the principle of the isolator of FIG. 11. The isolator 36 includes a first polarizing reflector 37, a Faraday rotator 38, a half-wave plate 39, and a second polarizing reflector 40. have. Further, each of the polarization reflection mirrors 37 and 40 reflects the S-polarized light of the laser light and transmits the P-polarized light as polarization reflection means.

In such a self-compensating laser resonator,
The laser light incident on the isolator 36 is first converted into linearly polarized light in the x-axis direction by passing through the first polarizing reflector 37. Thereafter, the laser beam is applied to the fara de rotator 3
8, the polarization direction is rotated 45 degrees from the x-axis to the z-axis. The laser light transmitted through the Faraday rotator 38 is 1
The half-wave plate 39 changes the polarization direction from the z-axis to the x-axis by 45.
Rotated by degrees. Further, the laser light transmitted through the half-wave plate 39 transmits through the second polarizing reflector 40.

Here, it is assumed that a laser beam is incident on the isolator 36 from the second polarizing reflector 40 side. Second
The laser beam transmitted through the polarizing reflector 40 is rotated by 45 degrees from the x-axis to the z-axis by the half-wave plate 39. Thereafter, the polarization direction of the laser light is rotated 45 degrees from the x-axis to the z-axis by the Faraday rotator 38. Therefore, the polarization direction of the light transmitted through the Faraday rotator 38 is the z-axis direction. Laser light having a polarization in the z-axis direction cannot be transmitted through the first polarization mirror 37, and is entirely output to the outside by the polarization mirror 37. Therefore, the isolator 36 has the function of passing laser light in only one direction.

In the laser resonator provided with such an isolator 36, the direction of the laser light circling the laser resonator can be defined in one direction, and the laser light can be stabilized.

In the above example, the polarization mirrors 37 and 4 are used.
Although a laser beam which reflects S-polarized light and transmits P-polarized light is shown as 0, a laser beam which reflects P-polarized laser light and transmits S-polarized light may be used. Further, the isolator 36 is arranged in the optical path L4, but may be arranged in any of the optical paths L1 to L4.

Embodiment 10 FIG. Next, FIG. 13 is a configuration diagram showing a self-compensating laser resonator according to Embodiment 10 of the present invention. In this example, a 波長 wavelength plate 41 is arranged upstream of the isolator 36 as in the ninth embodiment.

In such a self-compensating laser resonator,
The half-wave plate 41 allows the laser light to pass through the isolator 36.
Is divided into a P-polarized light component and an S-polarized light component at an arbitrary ratio with respect to the first polarized light reflecting mirror 37. In this case, the P-polarized light component is transmitted and circulates inside the laser resonator, and the S-polarized light component is output outside the laser resonator as laser light. Therefore, it is possible to arbitrarily adjust the ratio of the laser light output to the outside of the laser resonator while defining the circling direction of the laser light in one direction. Further, since the polarizing reflector 37 of the isolator 36 can also be used for laser output, the number of optical components can be reduced, the loss of laser light can be reduced, and the entire laser resonator can be downsized. it can.

In the above example, the polarization reflecting mirror 37 reflects S-polarized laser light and transmits P-polarized light. However, the polarizing reflector 37 reflects P-polarized laser light and transmits S-polarized light. May be. In the above example, the isolator 3
Although the 6 and 1/2 wavelength plates 41 are arranged in the optical path L4, they may be arranged in any of the optical paths L1 to L4.

Further, instead of the half-wave plate 41, a birefringent element 35 as shown in the eighth embodiment (FIG. 10) may be used. In this case, the ratio of the laser light output to the outside of the laser resonator can be arbitrarily changed by the voltage applied to the Pockels cell, while defining the direction in which the laser resonator circulates in one direction.

Embodiment 11 FIG. Next, FIG. 14 is a configuration diagram showing a self-compensating laser resonator according to Embodiment 11 of the present invention. In the figure, reference numeral 42 denotes a seeder light generator for making a single-wavelength light, that is, seeder light, enter the laser resonator.
For example, the seeder light enters the intersection of the polarization reflector 34 and the optical path L4 via an optical path (not shown) for the seeder light constituted by an optical fiber or the like. The incident seeder light is reflected by the polarization reflector 34 and travels on the optical path L4. Other configurations are the same as in the seventh embodiment.

Next, the operation will be described. The laser medium 23 is excited by the excitation light source 24 and generates laser oscillation by coupling to a stable mode of the laser resonator. However, the light initially emitted from the excited laser medium 23 is only spontaneous emission light called fluorescence,
It takes a long time to circulate this spontaneously emitted light in the laser resonator and gradually amplify it. Spontaneous emission light includes various wavelengths, and each wavelength is amplified.

Therefore, the single-wavelength seeder light generated by the seeder light generator 42 is incident on the laser resonator at the start of operation. The incident seeder light circulates inside the laser resonator and is amplified, and causes laser oscillation in the same oscillation mode as the seeder light in the circling direction. On the other hand, the light that circulates in the opposite direction to the seeder light is only spontaneous emission light, and it takes a long time for the spontaneous emission light to be amplified and cause laser oscillation. Therefore, the energy stored in the laser medium 23 is consumed by the stable mode laser oscillation circling in the same direction as the seeder light before the stable mode circulating in the direction opposite to the seeder light oscillates. It is defined in the same direction as the light.

As described above, by injecting the seeder light into the laser resonator, the direction in which the laser light circulates around the laser resonator can be defined in one direction, and a single-wavelength high-quality laser light is obtained. be able to. In addition, since the polarization reflector 34 for laser output can be used for incidence of the seeder light, the circling direction of the laser light can be defined in one direction with a small number of optical components, and the laser quality can be improved. Can be miniaturized.

Embodiment 12 FIG. Next, FIG. 15 is a configuration diagram showing a self-compensating laser resonator according to Embodiment 12 of the present invention. In the figure, reference numeral 45 denotes a beam diameter conversion device which is provided in the middle of the optical path L4 and converts the beam diameter of the laser beam.
As shown in FIG. 7, the lens has a concave lens 46 and a convex lens 47.

Here, the focal length of the concave lens 46 is -f.
1. If the focal length of the convex lens 47 is f2 and the distance between the concave lens 46 and the convex lens 47 is D, the beam diameter conversion device 4
5 is f = (− f1 × f2) / (− f1 +
f2-D). When D = f2-f1, the focal length of the beam diameter converter 45 is ∞, and when the beam diameter on the concave lens 46 side is 1, the beam diameter on the convex lens 47 side is converted to f2 / f1 times. Therefore, the beam diameter can be freely adjusted by appropriately selecting the focal lengths of the concave lens 46 and the convex lens 47.

The oscillation mode of such a laser resonator is as follows.
The oscillation mode of the laser resonator can be adjusted by adjusting the conversion magnification of the beam diameter converter 45 because it depends on the beam diameter of the laser light circulating around the laser resonator. Further, by adjusting the oscillation mode of the laser resonator, it becomes easy to adjust the shape of the beam of the laser light circling the laser resonator.

In the above example, the beam converter 45 is arranged on the optical path L4, but may be arranged on any of the optical paths L1 to L4.

[0072]

As described above, the self-compensating laser resonator according to the first aspect of the present invention has a first reflecting device having first and second reflecting surfaces arranged at right angles to each other, and a right angle to each other. And a second reflection device having third and fourth reflection surfaces disposed opposite to each other so that the ridge lines are substantially orthogonal to each other, and a laser medium is placed between the first reflection surface and the third reflection surface. Because of the arrangement, the laser light emitted from the laser medium toward the first reflection surface is reflected by the first reflection surface, the second reflection surface, the third reflection surface, the fourth reflection surface, and the second reflection surface. The surface, the first reflecting surface, the fourth reflecting surface, and the third reflecting surface are reflected in this order and incident on the laser medium, and the laser light does not pass on the ridge of the reflecting device, and therefore, there is no loss due to diffraction of the ridge. In addition, it is possible to prevent a reduction in the use efficiency of laser light. Further, since the laser light is not cut by the ridge line, the quality of the laser light can be improved. Further, the structure of the laser resonator can be simplified and downsized.

The self-compensating laser resonator according to the second aspect of the present invention uses the first and second reflecting devices each having two plane reflecting mirrors arranged at right angles to each other. Can be

In the self-compensating laser resonator according to the third aspect of the present invention, the two plane reflecting mirrors are arranged at an interval from each other and connected to each other by the connecting member. It is not necessary to fix the reflector, and the reflector can be downsized.

In the self-compensating laser resonator according to the fourth aspect of the present invention, since the prisms are used as the first and second reflecting devices, the angle of the reflecting surface is hardly shifted, and the self-compensating laser resonator is stable. Can be obtained. Further, in the optical path having a diagonal relationship, there is no change in the polarization state due to reflection on the reflection surface, so that the design of the laser resonator is facilitated.

In the self-compensating laser resonator according to the fifth aspect of the present invention, the first and second ridges of the prism are eliminated, so that the size of the reflecting device can be reduced.

In the self-compensating laser resonator according to the sixth aspect of the present invention, an isolator that transmits laser light in only one direction is provided in the optical path of the laser light. The direction can be defined, and the laser beam can be stabilized.

The self-compensating laser resonator according to the seventh aspect of the present invention has a simple structure because a partial reflecting mirror for laser output is provided on any one of the first to fourth reflecting surfaces. Laser light can be easily output.

The self-compensating laser resonator according to the invention of claim 8 is characterized in that any one of the P-polarized component and the S-polarized component of the laser beam is applied to one of the first to fourth reflecting surfaces. A polarized light reflecting means for selectively transmitting the light to the outside and reflecting the other light is provided, and the laser light is turned into a P-polarized light component and an S-polarized light component at an arbitrary ratio with respect to the polarized light reflecting means in the optical path of the laser light. Since the polarized light component adjusting means is provided, the ratio of the laser light output to the outside of the laser resonator can be arbitrarily changed.

The self-compensating laser resonator according to the ninth aspect of the present invention selectively transmits one of the P-polarized component and the S-polarized component of the laser beam and reflects the other in the optical path of the laser beam. Since the polarized light reflecting means for outputting the polarized light to the outside is provided, and in the optical path of the laser light, the polarized light component adjusting means for dividing the laser light into the P polarized light component and the S polarized light component at an arbitrary ratio with respect to the polarized light reflecting means is provided. The ratio of the laser light output to the outside of the laser resonator can be arbitrarily changed.

The self-compensated laser resonator according to the tenth aspect selectively transmits one of the P-polarized component and the S-polarized component of the laser beam, reflects the other, and outputs it to the outside. Polarization reflecting means, Faraday rotator and 1
An isolator having a half-wave plate and transmitting laser light only in one direction, and a polarization component adjusting means for dividing the laser light into a P-polarized component and an S-polarized component at an arbitrary ratio with respect to the isolator. Since it is provided in the optical path of the light, the ratio of the laser light output to the outside of the laser resonator can be arbitrarily changed, and the direction of the laser light orbiting the laser resonator can be defined in one direction, Laser light can be stabilized. In addition, since the polarized light reflecting means of the isolator is also used for outputting laser light, the number of optical components can be reduced, the loss of laser light can be reduced, efficiency can be improved, and the whole can be downsized.

The self-compensating laser resonator according to the eleventh aspect of the present invention uses a half-wave plate as the polarization component adjusting means. And can be divided into

The self-compensating laser resonator according to the twelfth aspect of the present invention uses a birefringent element capable of obtaining a birefringence effect by an applied voltage as the polarization component adjusting means. Can be easily adjusted.

In the self-compensating laser resonator according to the thirteenth aspect, the seeder light generated by the seeder light generator is made to enter the optical path of the laser light from the polarization reflection means.
The direction in which the laser light circulates around the laser resonator can be defined in one direction, and a single-wavelength high-quality laser light can be obtained. In addition, since the polarized light reflecting means for laser output can be used for incidence of the seeder light, the circling direction of the laser light can be defined in one direction with a small number of optical components, thereby improving laser quality, reducing loss and increasing efficiency. And the size of the laser resonator can be reduced.

The self-compensated laser resonator according to the fourteenth aspect of the present invention is provided with a beam diameter conversion device for converting the beam diameter of the laser light in the optical path of the laser light, so that the oscillation mode of the laser resonator is adjusted. In addition, it becomes easy to adjust the shape of the beam of the laser light circling the laser resonator.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a self-compensating laser resonator according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an example of the reflection device of FIG.

FIG. 3 is a perspective view showing a reflecting device of a self-compensating laser resonator according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing a reflecting device of a self-compensating laser resonator according to a third embodiment of the present invention.

FIG. 5 is a perspective view showing a reflecting device of a self-compensating laser resonator according to a fourth embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing a self-compensating laser resonator according to a fifth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing a self-compensating laser resonator according to a sixth embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a change in a polarization component of laser light in the self-compensating laser resonator of FIG. 7;

FIG. 9 is a schematic configuration diagram showing a self-compensated laser resonator according to a seventh embodiment of the present invention.

FIG. 10 is a schematic configuration diagram showing a self-compensating laser resonator according to an eighth embodiment of the present invention.

FIG. 11 is a schematic configuration diagram showing a self-compensating laser resonator according to a ninth embodiment of the present invention.

FIG. 12 is an explanatory diagram illustrating the principle of the isolator of FIG.

FIG. 13 is a schematic configuration diagram showing a self-compensating laser resonator according to a tenth embodiment of the present invention.

FIG. 14 is a schematic configuration diagram showing a self-compensating laser resonator according to Embodiment 11 of the present invention.

FIG. 15 is a schematic configuration diagram showing a self-compensating laser resonator according to a twelfth embodiment of the present invention.

16 is a configuration diagram illustrating an example of a beam diameter conversion device in FIG.

FIG. 17 is a configuration diagram illustrating an example of a conventional laser resonator.

18 is a configuration diagram illustrating a case where one of the reflecting mirrors in FIG. 17 is inclined.

FIG. 19 is a configuration diagram showing an example of a conventional self-compensating laser resonator.

20 is an explanatory diagram illustrating a reflection state of laser light incident on the roof prism of FIG. 19;

21 is an explanatory diagram showing a state where the roof prism of FIG. 20 is inclined.

[Explanation of symbols]

21 first reflection device, 21a first reflection surface, 21b
2nd reflection surface, 21c 1st ridge line, 22 2nd reflection device, 22a 3rd reflection surface, 22b 4th reflection surface, 22c 2nd ridge line, 23 laser medium, 24 light sources, 25, 26 roof Prism, 25a, 26a entrance surface, 25b, 25c, 26b, 26c reflection surface, 27, 2
8, 29, 30 plane reflecting mirror, 31 connecting member, 32
Partial reflection mirror, 33, 39, 41 1/2 wavelength plate (polarization component adjustment means), 34 polarization reflection mirror (polarization reflection means),
35 birefringent element (polarization component adjusting means), 36 isolator, 37 first polarization mirror (polarization reflection means), 3
8 Faraday rotator, 40 second polarizing reflector (polarizing reflector), 42 seeder light generator, 45 beam diameter converter.

Claims (14)

[Claims] 1. A first reflection device having first and second reflection surfaces arranged at right angles to each other, and a third and fourth reflection surface arranged at right angles to each other,
A second reflecting device facing the first reflecting device; a laser medium provided between the first and third reflecting surfaces; and a light source for exciting the laser medium. Wherein the second ridge formed by the two planes including the third and fourth reflecting surfaces is substantially perpendicular to the first ridge formed by the two planes including the first and second reflecting surfaces. The laser light emitted from the laser medium toward the first reflecting surface is
The first reflection surface, the second reflection surface, the third reflection surface, the fourth reflection surface, the second reflection surface, the first reflection surface, the fourth reflection surface, and the A self-compensating laser resonator which is reflected in the order of a third reflecting surface and is incident on the laser medium. 2. The self-compensating laser resonator according to claim 1, wherein each of the first and second reflecting devices has two plane reflecting mirrors arranged at right angles to each other. 3. The self-compensated laser resonator according to claim 2, wherein the two plane reflecting mirrors of each reflecting device are arranged at an interval from each other and are connected to each other by a connecting member. 4. The apparatus according to claim 1, wherein each of the first and second reflecting devices is a prism having a laser light incident surface and two reflecting surfaces arranged at right angles to each other.
A self-compensating laser resonator as described. 5. The self-compensating laser resonator according to claim 4, wherein the first and second ridge portions of the prism are omitted. 6. The self-compensated laser resonator according to claim 1, wherein an isolator that transmits the laser light in only one direction is provided in an optical path of the laser light. vessel. 7. A partial reflecting mirror for laser output is provided on any one of the first to fourth reflecting surfaces. 4. A self-compensated laser resonator according to item 1. 8. One of the first to fourth reflecting surfaces selectively transmits one of a P-polarized component and an S-polarized component of the laser beam and outputs the laser light to the outside. A polarized light reflecting means for reflecting the other is provided, and a polarization component adjustment for dividing the laser light into a P-polarized light component and an S-polarized light component at an arbitrary ratio with respect to the polarized light reflecting means in the optical path of the laser light. 7. The self-compensating laser resonator according to claim 1, further comprising means. 9. A polarization reflection means for selectively transmitting one of a P-polarized component and an S-polarized component of the laser light and reflecting the other to output to the outside is provided on an optical path of the laser light. And an optical path of the laser light is provided with polarization component adjusting means for dividing the laser light into a P-polarized component and an S-polarized component at an arbitrary ratio with respect to the polarized light reflecting means. The self-compensating laser resonator according to claim 1. 10. An optical path of a laser beam, wherein two polarization reflection means for selectively transmitting one of a P-polarized component and an S-polarized component of the laser beam and reflecting the other to output to the outside; An isolator that has a Faraday rotator and a half-wave plate and transmits laser light only in one direction, and a polarization component that divides the laser light into a P-polarized component and an S-polarized component at an arbitrary ratio with respect to the isolator 6. The self-compensating laser resonator according to claim 1, further comprising an adjusting unit. 11. The self-compensating laser resonator according to claim 8, wherein the polarization component adjusting means is a half-wave plate. 12. The self-compensated laser resonance device according to claim 8, wherein said polarization component adjusting means is a birefringent element capable of obtaining a birefringence effect by an applied voltage. vessel. 13. The self-compensated laser resonance according to claim 8, further comprising a seeder light generating device for causing the seeder light to enter the optical path of the laser light from the polarization reflection means. vessel. 14. The self-compensating type according to claim 1, wherein a beam diameter conversion device for converting a beam diameter of the laser light is provided in an optical path of the laser light. Laser resonator.