JP3511964B2 - Solid state laser device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state laser device using a rod-type solid-state laser medium pumped by a laser diode, and more particularly to a cooling structure thereof.

[0002]

2. Description of the Related Art FIG. 15 is a cross-sectional view showing a conventional solid-state laser device, FIG. 16 is a perspective view showing a refrigerant passage thereof, and FIG. 17 is a view for explaining a state of a refrigerant flow. In the figure, 1 is a laser diode (hereinafter referred to as LD), 2 is a rod-type solid-state laser medium, 3 is a flow tube, 4 is a coolant channel, 6 is a coolant introduction pipe, 7 is a coolant discharge pipe, and 14 is a collector. The optical device, 15 is an optical element.

In a conventional solid-state laser device, FIG.
As shown in FIG. 3, the flow tube 3 is arranged on the outer peripheral portion of the rod-type solid-state laser medium 2 to form a cooling medium flow path between the rod-type solid-state laser medium 2 and the cooling-type cooling medium. In addition, LDs 1 for optically exciting the rod-type solid-state laser medium 2 are arranged on four sides of the rod-type solid-state laser medium 2. Excitation light emitted from the LD1 is guided through a condenser 14 to a rod-type solid-state laser medium 2 arranged in an optical element 15 for guiding the excitation light. In order to uniformly excite the rod-type solid-state laser medium 2, an LD
1 is arranged in the side 4 direction. Then, when the rod-type solid-state laser medium 2 is optically excited by the LD 1, the stimulated emission light is amplified by the resonator (not shown),
It is taken out as laser light. Although the rod-type solid-state laser medium 2 is heated by the LD 1 in a large amount, the coolant tube 4 is provided between the rod-type solid-state laser medium 2 and the flow tube 3 installed outside the rod-type solid-state laser medium 2. The rod-type solid-state laser medium 2 is formed, and the rod-type solid-state laser medium 2 is cooled by flowing a coolant such as pure water in the length direction of the rod-type solid-state laser medium 2. Such a solid-state laser device is described in, for example, Japanese Patent Laid-Open No. 10-275952.

[0004]

In the conventional solid-state laser device having the above-mentioned structure, the structure shown in FIGS.
As shown in FIG. 7, when the refrigerant flows from the refrigerant introduction pipe 6 into the refrigerant flow path 4, there is a bending pressure loss for the refrigerant to flow in the direction of the hatched portion 8 of the refrigerant flow path 4 in the figure. Therefore, it becomes difficult for the portion 8 to flow, and becomes a stagnation portion 8 in which the flow velocity decreases as compared with other portions. For this reason, even if the rod-type solid-state laser medium 2 is excited by the LD 1 from three directions or more in a substantially axially symmetric manner, the flow velocity is reduced in the stagnation portion 8, so that the heat transfer coefficient in this portion is reduced, and the portion is sufficiently cooled. It becomes very hot. As described above, there is a problem that the temperature distribution of the rod-type solid-state laser medium 2 is decentered in the direction of the stagnation portion 8 where the temperature becomes high because the temperature distribution is not axisymmetric and becomes non-uniform.

As described above, in the rod-type solid-state laser medium 2 in which the temperature distribution is not axially symmetrical but nonuniform, the convex lens action generated when the temperature is increased due to excitation becomes nonuniform, so that the optical axis of the obtained laser beam is There was a problem of deviation. This means that the optical axis deviates from the center line of the rod-type solid-state laser medium 2, and there is a problem that a sufficient output cannot be obtained. Further, since the roundness of the obtained laser beam is lowered, for example, when processing is performed with this laser beam, there is a problem that the processing performance is anisotropic depending on the processing direction.

Further, in such a solid-state laser device whose temperature distribution is non-axisymmetric, the amount of eccentricity of the temperature distribution changes according to the input energy, so that the optical axis of the oscillated laser beam is input. There was a problem of deviation depending on energy.

Further, due to such deviation of the temperature distribution, it is difficult to adjust when a plurality of laser media are arranged in series for laser operation, and the optical axis of the laser light is the center of the rod type solid laser media. There was a problem that sufficient output could not be obtained because of deviation from the line. Also, when trying to guide the obtained laser beam to the optical fiber, after adjusting the optical fiber to the laser position with low input, gradually increasing the input energy, according to the deviating laser beam. However, there is a problem that adjustment is difficult because the position of the optical fiber must be adjusted.

The present invention has been made in order to solve the above-mentioned problems of the conventional ones, and a first object thereof is to prevent the eccentricity of the temperature distribution of the rod-type solid-state laser medium and to provide an output. It is an object of the present invention to provide a solid-state laser device capable of obtaining a laser beam having a high circularity and having a high circularity and whose optical axis does not change due to input energy. A second object is to provide a solid-state laser device in which the output does not decrease and the adjustment is easy even when a plurality of laser media are arranged in series for laser operation. A third object is to provide a solid-state laser device that can be easily adjusted even when an optical fiber is guided.

[0009]

In the solid-state laser device according to the present invention, a rod-type solid-state laser medium is formed, and a cooling medium flow path is formed so as to surround the rod-type solid-state laser medium and the rod-type solid-state laser medium. Cylindrical flow channel body, and a coolant introducing means that is provided in the tubular flow channel body and introduces a coolant into the coolant flow channel
And a cylindrical flow path body portion that introduces a refrigerant from the refrigerant introduction means into the refrigerant flow path, and is sandwiched between an inner cylindrical tube and an outer cylindrical tube.
The inner cylindrical tube having a donut-shaped accumulation part
Greater Then Tomo than the outer diameter of the outer diameter of the coolant channel of the
The direction along the central axis of the tubular flow passage body of the inner cylindrical tube
The length in the direction of the cylindrical flow path body of the outer cylindrical tube.
By making it shorter than its length along the axis.
The circle in which the refrigerant flows from the reservoir to the refrigerant channel.
Forming an annular passage and introducing refrigerant into the reservoir
The direction is eccentric with respect to the central axis of the tubular flow passage body .

[0010]

[0011]

[0012]

The rod type solid laser medium is excited by a laser diode from at least three directions on the side surface.

Further, a plurality of rod type solid laser media are arranged in series.

Further, the output light from the rod type solid laser medium is introduced into the optical fiber.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is a vertical cross-sectional view showing the configuration of a main part of a solid-state laser device according to a first embodiment of the present invention, in which the main part of the solid-state laser device is cut along a plane passing through a central axis of a coolant channel. FIG. 2 is a perspective view showing the refrigerant flow path of FIG. 1, and FIG. 3 is a diagram for explaining the flow of the refrigerant. In the figure, 1 is an LD and 2 is a rod-type solid-state laser medium. The cross section taken along the line AA of FIG. 1 is shown in FIG.
The LD 1 is arranged in four directions of the rod-type solid-state laser medium 2 in this embodiment as well, which is the same as the conventional one shown in FIG. 5, and the rod-type solid-state laser medium 2 can be excited substantially in axial symmetry. Note that, in FIG. 1, the axial length of the rod-type solid-state laser medium 2 is reduced for convenience of space.
Although not shown, a condenser 14 and an optical element 15 are provided between the LD 1 and the rod-type solid-state laser medium 2 as in FIG. These are the same in the following figures. Reference numeral 3 denotes a flow tube that surrounds the outer circumference of the rod-type solid-state laser medium 2. The flow tube 3 has a cylindrical shape and substantially entirely surrounds the rod-type solid-state laser medium 2 in the longitudinal direction. Reference numeral 5 is a block for fixing the flow tube 3, the position of the rod-type solid-state laser medium 2 is fixed by the end plate 51, and the holding plate 52 and the O-ring 5 are provided.
A portion of the rod-type solid-state laser medium 2 is sealed by 3.

In this embodiment, the flow tube 3 and the block 5 form a cylindrical flow passage body which surrounds the outer circumference of the rod type solid laser medium 2 and forms a coolant flow passage 4 between the rod type solid state laser medium 2 and the rod type solid state laser medium 2. I am configuring. Reference numeral 6 denotes a refrigerant introducing means, that is, a refrigerant introducing pipe, which is provided in the block 5 and introduces a refrigerant such as pure water into the refrigerant passage 4. In the present embodiment, the introduction direction of the refrigerant is a cylindrical passage body, that is, a flow tube. It is arranged so as to be eccentric with respect to the central axis of 3 and serves as a stagnation reducing means. Reference numeral 7 denotes a refrigerant outlet pipe which is provided in the block 5 and which leads out the refrigerant from the refrigerant passage 4. The cooling medium supplied from the cooling medium introducing pipe 6 flows through the cooling medium flow path 4 formed between the rod-type solid laser medium 2 and the block 5 and the flow tube 3, and directly cools the rod-type solid laser medium 2 therebetween. . The refrigerant that has passed through the refrigerant passage 4 is discharged from the refrigerant outlet pipe 7.

In the present embodiment, the rod-type solid laser medium 2 is excited by the LD 1 up to the vicinity of the coolant introduction pipe 6, and the rod arranged in the stagnation portion 8 of the coolant generated in the coolant flow path by the coolant introduction pipe 6. The LD 2 is excited up to the solid laser medium 2 portion. For example, when showing specific numerical values, the diameter of the rod-type solid-state laser medium 2 is 4 mm, the diameter of the flow tube 3 is 5 mm to 6 mm, the diameter of the refrigerant introduction pipe 6 is 3.5 to 4 mm, and the block of the refrigerant introduction pipe 6 is shown. The distance L from the connection part to 5 to the excitation part of the rod-type solid-state laser medium 2 is 15 mm or less, and the flow velocity of the refrigerant is 5 m / sec to 7 m.
/ Sec.

In the solid-state laser device configured as described above, the refrigerant introduced from the refrigerant introduction pipe 6 into the refrigerant passage 4 becomes a swirling flow in the refrigerant passage 4, so that the stagnation portion 8 is formed.
The region of is rotated in the circumferential direction as shown by the diagonal lines in FIG. Therefore, the influence of the stagnation portion 8 is averaged in the circumferential direction, and the influence of the stagnation is equalized as an average in the axial direction. Furthermore, by swirling the refrigerant, stagnation becomes difficult to grow, and the stagnation itself can be reduced. Therefore, the stagnation itself and the influence of the stagnation are reduced, and the refrigerant flow path 4 and the rod-type solid-state laser medium 2 can obtain a temperature distribution that is substantially axisymmetric. As a result, the convex lens action that occurs when the rod-type solid-state laser medium 2 is excited and the temperature rises becomes axially symmetric, and the optical axis of the obtained laser beam does not deviate, so the problem of output reduction seen in the prior art also occurs. Disappear. Further, since a laser beam having a high roundness can be obtained, a solid-state laser device having a small anisotropy depending on the processing direction can be obtained when used for processing. It should be noted that the refrigerant smoothly flows out while maintaining the swirling direction near the introduction portion.
The refrigerant outlet pipe 7 may be arranged so as to be eccentric with respect to the central axis of the flow tube 3 so as to flow out to, and the swirling of the refrigerant can be maintained up to the discharge port, so that the pressure loss can be reduced. The pumping by the LD 1 is not limited to four directions, but the rod-type solid-state laser medium 2 can be pumped uniformly if it is three or more directions.

Embodiment 2. FIG. 4 is a vertical cross-sectional view showing the configuration of the main part of the solid-state laser device according to the second embodiment of the present invention, in which the main part of the solid-state laser device is cut along a plane passing through the central axis of the coolant channel. In FIG. 4, LD1 of FIG. 1 is omitted. This also applies to the following figures. In the figure, reference numeral 50 denotes a spiral groove formed on the inner surface of the block 5 to which the refrigerant introduction pipe 6 is connected, which serves as a stagnation reducing means.

In the solid-state laser device having such a structure, the refrigerant introduced from the refrigerant introducing pipe 6 into the block 5 is swirled by the spiral groove 50 when flowing inside the block 5 by the spiral groove 50. As described above in the first embodiment, the effect of stagnation is made uniform in the circumferential direction as an average in the axial direction, and a temperature distribution that is substantially axisymmetric can be obtained. As a result, as in the case of the first embodiment, the convex lens action that occurs when the rod-type solid-state laser medium 2 is excited and the temperature rises becomes axisymmetric, and the optical axis of the obtained laser beam does not deviate. The problem of output reduction seen in the technology is also eliminated. Further, since a laser beam having a high roundness can be obtained, a solid-state laser device having a small anisotropy depending on the processing direction can be obtained when used for processing.

Embodiment 3. FIG. 5 is a vertical cross-sectional view showing a configuration of a main part of a solid-state laser device according to a third embodiment of the present invention, in which a main part of the solid-state laser device is cut along a plane passing through a central axis of a coolant channel. In the figure, reference numeral 30 denotes a spiral groove formed on the inner surface of the flow tube 3, which serves as a stagnation reducing means. Also in the present embodiment, as in the case of the second embodiment, the refrigerant is the refrigerant flow path 4 formed between the flow tube 3 and the rod-type solid-state laser medium 2.
When flowing through, the spiral groove 30 gives a swirl component to form a swirl flow. Therefore, the effect of stagnation as an average in the axial direction is made uniform in the circumferential direction, and a temperature distribution that is substantially axisymmetric can be obtained, and the same effect as in the case of the second embodiment can be obtained.

Needless to say, the second embodiment and the third embodiment may be carried out at the same time.

Fourth Embodiment FIG. 6 is a vertical cross-sectional view showing a configuration of a main part of a solid-state laser device according to a fourth embodiment of the present invention, in which a main part of the solid-state laser device is cut along a plane passing through a central axis of a coolant channel. FIG. 7 is a perspective view showing the coolant flow path of FIG. 6, and FIG. 8 is a diagram for explaining the flow of the coolant. In the figure, reference numeral 60 designates a reservoir portion or header provided in the block 5 to which the refrigerant introduction pipe 6 is connected,
It is a means to reduce stagnation. Reference numeral 70 denotes a reservoir portion, that is, a header provided in the block 5 to which the refrigerant outlet pipe 7 is connected. In such a configuration, since the reservoir 60 is provided, the flow of the refrigerant introduced from the refrigerant introduction pipe 6 is made uniform in the reservoir 60, and as shown in FIG. In addition, the size of the stagnation portion 8 is reduced, and the deviation of the temperature distribution can be reduced.
In particular, when the outer diameter D2 of the reservoir 60 was 1.5 times or more the diameter D1 of the refrigerant flow path 4, the deviation of the temperature distribution could be effectively reduced. If the reservoir 70 on the refrigerant outlet pipe 7 side is provided, when the refrigerant flows out from the refrigerant flow path 4 to the refrigerant outlet pipe 7, the influence of shifting the axial symmetry of the flow can be further reduced. , You don't have to.

Embodiment 5. FIG. 9 is a vertical cross-sectional view showing a configuration of a main part of a solid-state laser device according to a fifth embodiment of the present invention, in which a main part of the solid-state laser device is cut along a plane passing through a central axis of a coolant channel. FIG. 10 is a diagram for explaining how the refrigerant flows. In the fourth embodiment,
Although the inner diameter of the pool portion 60 is the same as the outer diameter D1 of the coolant channel, it may be larger than the outer diameter D1 of the cooling water channel as shown in FIG. In the case of such a configuration, the difference between the flow pressure loss for equalizing the flow of the refrigerant in the reservoir 60 and the pressure loss for flowing into the coolant passage 4 can be further increased, and thus the reservoir 60 The flow of the refrigerant in the inside is made more uniform in the circumferential direction, and the deviation of the temperature distribution can be further reduced.

Sixth Embodiment 11 is a perspective view showing a refrigerant flow path, showing a configuration of a main part of a solid-state laser device according to a sixth embodiment of the present invention, and FIG. 12 is a view for explaining a refrigerant flow state. In this embodiment, the first embodiment and the fifth embodiment are realized at the same time.
A block portion 60 connected to is provided with a pool portion 60, and the refrigerant introduction pipe 6 is arranged such that the refrigerant introduction direction is eccentric to the central axis of the flow tube 3. Further, the block 5 to which the refrigerant outlet pipe 7 is connected is also provided with the pool portion 70, and the refrigerant outlet pipe 7 is arranged so that the refrigerant outlet direction is eccentric to the central axis of the flow tube 3. There is.

In the solid-state laser device configured as described above, when the coolant is introduced into the coolant channel 4, the pool portion is formed.
Since the flow is made uniform at 60, the area of the stagnation portion 8 can be made smaller as shown in FIG. 12, and the central axis of the flow tube 3 can be made smaller than in the case shown in the first embodiment. You can further set the direction of introduction of the refrigerant to be able to provide greater eccentricity for, in order that can be given a greater turning moment is averaged by the temperature distribution in the circumferential direction, deviation of the temperature distribution Can be further reduced. The reservoir 70 on the side of the refrigerant outlet pipe 7 may be omitted in the same manner as described in the fifth embodiment. When the refrigerant outlet pipe 7 is arranged eccentrically with respect to the central axis of the flow tube 3 so that the refrigerant smoothly flows out to the refrigerant outlet pipe 7 while maintaining the swirling direction near the inlet portion, Since the swirling of the refrigerant can be maintained up to the discharge port, the pressure loss can be reduced, but it is not always necessary to make it eccentric.

In this embodiment, the case where the first embodiment and the fifth embodiment are carried out at the same time is shown.
The second and third embodiments may be used instead of the first embodiment, and the fourth embodiment may be used instead of the fifth embodiment, and similar effects can be expected.

Embodiment 7. FIG. 13 is a diagram showing the structure of the solid-state laser device according to the seventh embodiment of the present invention. In the figure, 9 is a rear mirror, 10 is an output mirror, and 11 is a laser beam. In this embodiment, a plurality, for example, 3
The individual rod-type solid-state laser media 2 are arranged in series between the rear mirror 9 and the output mirror 10 and used for laser oscillation. Although not shown in the figure, as in the case shown in FIG. 15, the LD 1, the condenser 14, and the optical element 15 are arranged around each rod-type solid-state laser medium 2, and each rod-type solid-state laser medium is arranged. The laser head is configured to extract the laser beam 11 by exciting the laser beam 2 substantially uniformly, and further includes the coolant flow path 4 and the stagnation reducing means according to any one of the first to sixth embodiments.

In the solid-state laser device configured as described above, since the stagnation of the coolant flow path can be reduced and the temperature distribution of the rod-type solid-state laser medium 2 can be made axially symmetric, laser oscillation can be performed without shifting the optical axis. This makes it possible to make adjustments easily and take out the output sufficiently.

Embodiment 8. FIG. 14 is a diagram showing the configuration of the solid-state laser device according to the eighth embodiment of the present invention. In the figure, 12 is an optical fiber, and 13 is a light guiding optical system such as a lens. In this embodiment, the laser beam 11 emitted from the rod-type solid-state laser medium 2 is guided by the optical guiding system 13.
Is used to guide light to the optical fiber 12. Although not shown in the figure, as in the seventh embodiment, the LD 1, the condenser 14, and the optical element 15 are arranged around each rod-type solid-state laser medium 2, and each rod-type solid-state laser medium is arranged. Two
To constitute a laser head for extracting the laser beam 11 substantially uniformly, and further includes the coolant flow path 4 and the stagnation reducing means of any of the first to sixth embodiments.

In the solid-state laser device configured as described above, since the stagnation of the coolant flow path can be reduced and the temperature distribution of the rod-type solid-state laser medium 2 can be made axially symmetric, laser oscillation can be performed without shifting the optical axis. Therefore, the position where the light is guided to the optical fiber 12 does not deviate, and the adjustment becomes easy.

In each of the above-described embodiments, as shown in FIG. 15, in the mode in which the excitation is uniform from the side by the LD and is excited from three or more directions, the excitation can be uniform in the circumferential direction. Since the heat generation can be made uniform,
In particular, the temperature distribution can be made uniform.

[0034]

As is evident from the foregoing description, the solid-state laser apparatus according to the present invention, the refrigerant flow path between the rod type solid state laser medium, the rod-type solid-state laser medium surrounds the outer periphery of 該Ro head type solid laser medium And a coolant introducing means that is provided in the tubular flow passage and introduces a refrigerant into the refrigerant flow passage.
And a cylindrical flow path body portion that introduces a refrigerant from the refrigerant introduction means into the refrigerant flow path, and is sandwiched between an inner cylindrical tube and an outer cylindrical tube.
The inner cylindrical tube having a donut-shaped accumulation part
Greater Then Tomo than the outer diameter of the outer diameter of the coolant channel of the
The direction along the central axis of the tubular flow passage body of the inner cylindrical tube
The length in the direction of the cylindrical flow path body of the outer cylindrical tube.
By making it shorter than its length along the axis.
The circle in which the refrigerant flows from the reservoir to the refrigerant channel.
Forming an annular passage and introducing refrigerant into the reservoir
Since the direction is eccentric with respect to the central axis of the tubular flow passage body, the flow of the refrigerant introduced from the refrigerant introduction pipe is made uniform in the accumulation portion, and the size of the stagnation in the refrigerant flow passage is increased. Can be reduced. Therefore, the influence of stagnation can be reduced and cooling can be made uniform, and the temperature distribution of the rod-type solid-state laser medium can be made axially symmetrical. As a result, the output does not decrease, the roundness is high, and the injection is high. A laser beam whose optical axis does not change due to energy can be obtained.

[0035]

[0036]

[0037]

Since the rod-type solid-state laser medium is excited by the laser diode from at least three sides of the side surface, the excitation can be made uniform in the circumferential direction and the heat generation state can be made uniform. The temperature distribution can be made uniform.

Further, even when a plurality of rod-type solid-state laser media are arranged in series, the adjustment is easy and the output can be sufficiently extracted.

Further, even when the output light from the rod type solid laser medium is introduced into the optical fiber, the adjustment can be easily performed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a configuration of a main part of a solid-state laser device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a refrigerant channel of FIG. 1 according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining the flow of the refrigerant according to the first embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing a configuration of a main part of a solid-state laser device according to a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing a configuration of a main part of a solid-state laser device according to a third embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view showing a configuration of a main part of a solid-state laser device according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view showing a refrigerant channel of FIG. 6 according to a fourth embodiment of the present invention.

FIG. 8 is a diagram for explaining the flow of the refrigerant according to the fourth embodiment of the present invention.

FIG. 9 is a vertical cross-sectional view showing a configuration of a main part of a solid-state laser device according to a fifth embodiment of the present invention.

FIG. 10 is a diagram for explaining the flow of the refrigerant according to the fifth embodiment of the present invention.

FIG. 11 is a perspective view showing a configuration of a main part of a solid-state laser device according to a sixth embodiment of the present invention and showing a coolant channel.

FIG. 12 is a diagram for explaining the flow of the refrigerant according to the sixth embodiment of the present invention.

FIG. 13 is a diagram showing a configuration of a main part of a solid-state laser device according to a seventh embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of a main part of a solid-state laser device according to an eighth embodiment of the present invention.

FIG. 15 is a cross-sectional view showing the configuration of a conventional solid-state laser device.

FIG. 16 is a perspective view showing a coolant channel in a conventional solid-state laser device.

FIG. 17 is a diagram for explaining the flow of the refrigerant in the conventional solid-state laser device.

[Explanation of symbols]

1 LD, 2 rod type solid laser medium, 3 flow tube, 4 coolant channel, 5 block, 6 coolant inlet pipe, 7 coolant outlet pipe, 60, 70 accumulation part, 8 stagnation part, 9 rear mirror, 10 output mirror, 11 Laser beam, 12 optical fiber, 13 light guiding optical system, 14 optical element, 15 condenser, 30, 50 spiral groove.

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-6-237030 (JP, A) JP-A-9-83045 (JP, A) JP-A-9-232652 (JP, A) JP-A-11- 46024 (JP, A) JP 7-131092 (JP, A) JP 63-204679 (JP, A) JP 60-136385 (JP, A) JP 61-284981 (JP, A) JP 8-321650 (JP, A) JP 2-209779 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01S 3/00-3/30 JISST file (JOIS ) WPI (DIALOG)

Claims (4)

(57) [Claims] And 1. A rod-type solid-state laser medium, a tubular passage body forming a refrigerant passage between the rod-type solid-state laser medium surrounds the outer periphery of the rod type solid state laser medium, the cylindrical passage a refrigerant introducing unit for introducing the refrigerant into the refrigerant flow path provided on the body, provided in a tubular passage body portion for introducing a refrigerant into the refrigerant flow path from the refrigerant introduction section, the inner cylinder tube and the outer cylindrical tube Sandwiched between
And an outer diameter of the inner cylindrical tube larger than the outer diameter of the refrigerant passage.
And the central axis of the tubular flow path body of the inner cylindrical tube
The length in the direction along the
It should be shorter than the length in the direction along the central axis of the channel body.
By forming a ring-shaped passage through which the refrigerant flows from the pool portion to the coolant channel , and to the pool portion
The direction of introduction of the refrigerant is eccentric with respect to the central axis of the tubular flow passage body.
Solid-state laser apparatus which is characterized in that is. 2. The solid-state laser device according to claim 1 , wherein the rod-type solid-state laser medium is excited by a laser diode from at least three directions on a side surface. 3. A plurality of solid-state laser apparatus according to claim 1 or 2 rod type solid state laser medium, characterized in that arranged in series. 4. The output light from the rod-type solid-state laser medium is introduced into an optical fiber.
3. The solid-state laser device according to any one of 3 above.