JP3751176B2 - Solid state laser equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid-state laser device, and more particularly, to a solid-state laser device that can easily adjust an optical axis and can stably generate a high-quality laser beam with high output.
[0002]
[Prior art]
FIG. 6 is a cross-sectional view showing an example of a conventional solid-state laser device. In FIG. 6, 2 is a laser cavity for exciting a solid laser medium, 3a and 3b are partial reflection mirrors and total reflection mirrors for performing laser oscillation, and 4 is a laser cavity and reflection mirror arranged in a predetermined optical axis direction. Is the base. The laser cavity 2 is fixed to the base 4 through the bottom surface of the housing 7 so as to face a predetermined optical axis direction. Inside the housing 7 of the laser cavity 2, a laser rod 10 made of a solid laser medium such as Nd: YAG (Nd: Yttrium Aluminum Garnet), an arc lamp 13 for irradiating the laser rod with excitation light, and an excitation to the laser rod A condenser 16 for efficiently collecting light, a laser rod 10 and flow tubes 12 and 14 for cooling the lamp 13 are accommodated. Further, both end portions of the laser rod 10 are fixed to the side plate 7 a of the housing 7 by the rod holder 5.
[0003]
The operation of the solid-state laser device shown in FIG. 6 is as follows. The excitation light emitted from the lamp 13 is condensed on the laser rod 10 by the condenser 16, and energy is injected (pumped) into the laser rod 10. Then, laser oscillation occurs in the resonator constituted by the laser rod 10 and the reflecting mirrors 3a and 3b installed on both sides thereof, and a laser beam is emitted from the partial reflecting mirror 3a. Only a part of the energy injected into the laser rod 10 is converted into laser light, and the rest is converted into thermal energy. Therefore, in order to cool the laser rod 10 and the lamp 13, cooling water is caused to flow in the flow tube 12 enclosing the laser rod 10 and the lamp 13 through a water channel provided inside the side plate 7a of the housing.
[0004]
[Problems to be solved by the invention]
In order to take out the laser output stably and efficiently, the alignment between the optical axis of the laser rod 10 and the reflecting mirrors 3a and 3b is important, and it is necessary to adjust the optical axis deviation to several mrad or less. In the solid-state laser device shown in FIG. 6, both ends of the laser rod 10 are fixed to a metal or acrylic casing 7, but the casing 7 is directly exposed to excitation light and cooling water leaking from the condenser 16. Therefore, it tends to cause elongation and warping due to thermal expansion / contraction. For this reason, the position of the laser rod 10 is shifted with the temperature change of the housing 7, and the optical axis of the laser rod 10 is unstable. If the optical axis of the laser rod 10 is unstable, it is difficult to adjust the optical axis between the laser rod 10 and the reflecting mirrors 3a and 3b, and the output of the laser also becomes unstable.
[0005]
In particular, in a solid-state laser device that uses a plurality of laser rods arranged in series, such as multistage cascade oscillation, the optical axes of the laser rods must be matched with high accuracy. Since the optical axis fluctuates, adjustment is very difficult, and there is a problem that the output becomes unstable and decreases.
[0006]
In order to improve such problems, Japanese Patent Application Laid-Open No. 9-36461 discloses a solid-state laser device as shown in FIG. In the laser apparatus shown in FIG. 7, since both end portions of the laser rod 10 are directly fixed to the base 4 by the holder block 6 outside the housing 7, the axial displacement of the laser rod 10 due to thermal expansion / contraction of the housing 7 is achieved. Can be suppressed.
[0007]
However, also in the solid-state laser device shown in FIG. 7, the stability of the optical axis of the laser rod 10 is not sufficient for the following reason. In the solid-state laser device shown in FIG. 7, the casing 7 is directly fixed to the base 4 independently of the laser rod 10, so that when the casing 7 undergoes thermal expansion / contraction, an excitation light source inside the casing 7. The relative position between the condenser, the flow tube, etc. and the laser rod 10 is shifted. For this reason, the central axis of the pumping light distribution formed by the pumping light source or the condenser deviates from the central axis of the laser rod 10, and the temperature distribution of the laser rod 10 becomes asymmetric with respect to the central axis. Further, when the central axis of the flow tube is deviated from the central axis of the laser rod 10, the cooling of the laser rod 10 becomes non-uniform, and the temperature distribution of the laser rod 10 becomes asymmetric with respect to the central axis. Since a lens action is generated in the laser rod 10 by a refractive index distribution based on an in-plane temperature distribution perpendicular to the central axis, if the temperature distribution in the laser rod 10 is asymmetric with respect to the central axis, The optical axis of the lens formed in (1) is oriented in a direction deviated from the central axis of the laser rod. Therefore, the optical axis of the laser rod 10 becomes unstable due to the thermal expansion / contraction of the housing 7 even though the central axis of the laser rod 10 itself is hardly shifted.
[0008]
Further, in the solid-state laser device shown in FIG. 6 or FIG. 7, since the housing 7 of the laser cavity 2 is fixed to the base 4, the laser cavity 2 can be used to replace a member near the bottom surface of the laser cavity 2. You need to remove yourself from the base. For this reason, it is necessary to adjust the alignment again after replacing the member, and there is a problem that it takes a long time to replace the member in the laser cavity 2.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a solid-state laser device in which optical axis adjustment is easy, output is stable, and maintenance such as replacement of members in a laser cavity is easy. .
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, there is provided (a) a laser rod, an excitation light source for irradiating the laser rod with excitation light, and an excitation light focused on the laser rod. In a solid-state laser device comprising: a laser cavity having a condenser; and (b) a base for installing the laser cavity in a predetermined optical axis direction. , Fixing both side surfaces adjacent to both end portions of the laser rod of the housing, projecting rod holding members that hold both end portions of the laser rod from both side surfaces of the housing, and is fixed on both sides, a solid state laser, wherein the housing when the unpinned for the post of both sides of the housing is allowed to support the rod holding member so as to be rotatable on the post It is the location.
[0011]
Thereby, not only the axial deviation of the laser rod due to the thermal expansion / contraction of the housing can be suppressed, but also the optical axis deviation based on the change of the lens action due to the temperature distribution in the laser rod can be suppressed. In addition, since the laser cavity casing can be rotated around the laser rod, the members in the laser cavity can be easily replaced.
[0012]
The invention according to claim 2 is characterized in that a rod holding member for holding both ends of the laser rod is supported by the support column by fitting. Thereby, the position of the laser rod can be defined with high accuracy in the height direction and the horizontal direction.
[0013]
The invention according to claim 3 is characterized in that the support column is detachably attached to the base, and a fitting groove for positioning is provided on the support column or the base. Thereby, the position of the column can be accurately reproduced, and the optical axis of the laser rod can be defined with high accuracy.
[0014]
Furthermore, the invention described in claim 4 is characterized in that a sub-base that supports the pair of support columns and is movable in the optical axis direction on the base is provided between the support columns and the base. And As a result, the position of the laser cavity in the optical axis direction can be adjusted, and the resonator length of the laser device can be easily adjusted.
[0015]
In addition, the invention according to claim 5 is characterized in that a fitting groove extending in an optical axis direction is provided in the sub-base or the base. Thereby, the position of the laser cavity can be adjusted in the optical axis direction without shifting the optical axis of the laser rod.
[0016]
The invention according to claim 6 is characterized in that the invention according to claims 1 to 5 is applied to a solid-state laser device in which a plurality of laser cavities are installed on a single base. Thereby, in the cascade type solid-state laser device having a plurality of laser cavities, the optical axes of the respective laser cavities can be matched to facilitate the optical axis adjustment.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a sectional view showing a solid-state laser apparatus according to Embodiment 1 of the present invention. In FIG. 1, 2 is a laser cavity and 4 is a base for fixing the laser cavity. In the figure, the reflecting mirror is omitted. A laser rod 10 made of a solid laser medium such as Nd: YAG, a semiconductor laser 15 as an excitation light source, a condenser 16, and a flow tube 12 are attached to the housing 7 of the laser cavity 2. The laser rod 10 is held by a rod fixing plate 5, and the rod fixing plate 5 is fixed to the outside of the housing 7. The solid-state laser device shown in FIG. 1 uses the semiconductor laser 15 as the excitation light source, but the basic operation as the laser device is the same as when a lamp is used as the excitation light source.
[0018]
In the present embodiment, the laser cavity 2 is fixed to the base 4 as follows. A pair of support columns 8 for supporting the laser cavity is provided on the base 4. As shown in FIG. 2, the support 8 is provided with a fitting hole 8a for fitting the rod fixing plate 5 and fixed to the base 4 by means such as screwing. The rod fixing plate 5 is fitted into the fitting hole 8a of the support column 8, and the side plate 7a of the housing 7 is fixed to the side surface of the support column 8 by screwing or the like.
[0019]
In the solid-state laser device shown in FIG. 1, since both ends of the laser rod 10 are fixed to the support column 8, it is difficult to cause an axis shift due to thermal expansion / contraction of the housing 7. Further, for the following reason, the optical axis deviation based on the lens action in the laser rod 10 hardly occurs. First, since the side plate 7a of the housing 7 is fixed to the support column 8, expansion and contraction of the housing 7 in a plane parallel to the side plate 7a, that is, a plane perpendicular to the central axis of the laser rod 10 is suppressed. Is done. Further, since the casing 7 is fixed symmetrically with respect to the central axis of the laser rod, even when the casing 7 is expanded or contracted, it is expanded symmetrically with respect to the central axis of the laser rod 10.・ It will shrink. For this reason, the central axis of the excitation light distribution formed by the condenser 16 and the excitation light source 14 fixed to the housing 7 is not easily displaced from the central axis of the laser rod 10. Further, the central axis of the flow tube 12 fixed to the housing 7 is also difficult to shift from the central axis of the laser rod 10. Therefore, the symmetry of the temperature distribution in the laser rod 10 is maintained with respect to the center axis of the rod, and the optical axis deviation based on the lens action formed in the laser rod 10 is suppressed.
[0020]
In the solid-state laser device shown in FIG. 1, the housing 7 can be rotated around the laser rod 10 by removing a screw or the like that fixes the side plate 7 a of the housing to the support column 8. For this reason, even when the condenser or the semiconductor laser 15 attached to the housing 7 is in a position where it is difficult to replace, the optical axis of the laser rod 10 can be obtained by rotating the housing 7 around the laser rod 10. The replacement work can be performed while maintaining the above.
[0021]
Further, when the laser cavity 2 itself is detached from the base 4 and replaced, the replacement work can be performed while the one support column 8 is fixed to the base 4, so that the optical axis adjustment after replacement is relatively easy. .
[0023]
Embodiment 2. FIG.
FIG. 3 is a cross-sectional view showing the support and base of the solid-state laser device according to Embodiment 2 of the present invention. In the present embodiment, in order to improve the positioning accuracy of the column 8 when the column 8 is attached to and detached from the base 4, key grooves (= fitting grooves) 4 a and 8 b are provided in the column 8 and the base 4, and the column 8 A key 9 is inserted between the base 4 and the base 4. Thereby, the positioning of the support column 8 becomes accurate, and the optical axis of the laser rod 10 can be defined with high accuracy in the height direction and the horizontal direction. Therefore, the optical axes of the laser rod 10 and the reflecting mirror can be easily adjusted, and the alignment state of the optical axes can be reproduced with high accuracy and the output of the solid-state laser device can be stabilized. In this embodiment, the key groove is provided on both the support column 8 and the base 4, but a key groove may be provided on one side and a protrusion corresponding to the key may be provided on the other side.
[0024]
Embodiment 3 FIG.
FIG. 4 is a perspective view showing a solid-state laser apparatus according to Embodiment 3 of the present invention. This embodiment provides a configuration for enabling position adjustment of the laser cavity 2 in the optical axis direction when a laser beam having a beam quality different from the initial one is obtained by changing the resonator length of the laser device. Is. In the laser apparatus shown in the first or second embodiment, the screw hole for fixing the support column to the base is determined at a predetermined position, so that the position of the laser cavity 2 in the optical axis direction could hardly be adjusted. . Therefore, in the present embodiment, a sub-base 18 is further provided between the base 4 and the support 8 of the solid-state laser apparatus shown in Embodiment 2, and the support 8 is fixed at a predetermined position on the sub-base 18. Can be adjusted with respect to the base 4 in the optical axis direction. For example, as shown in FIG. 4, an oblong hole 18c for screwing is formed in the sub-base 18 so that it can be fixed at an arbitrary position in the optical axis direction. Further, the key 11 is fitted into the key grooves 18b and 4a provided on the lower surface of the sub base 18 and the upper surface of the base 4 to suppress the deviation of the optical axis due to the movement of the sub base. According to such a configuration, since the position of the laser cavity 2 can be freely adjusted without shifting the optical axis, it is possible to provide a solid-state laser device that allows easy adjustment of the resonator length and little output fluctuation.
[0025]
Embodiment 4 FIG.
FIG. 5 is a top view showing a solid-state laser apparatus according to Embodiment 4 of the present invention. In the present embodiment, an example in which the present invention is applied to a cascade type solid-state laser device in which a plurality of laser cavities 2 are arranged on one base 4 will be described. In FIG. 5, each laser cavity 2 has the same configuration as that of the third embodiment. That is, each laser cavity 2 is fixed to the sub base 18 via the support column 8, and the position of the sub base 18 can be adjusted in the optical axis direction along the key groove 4a provided on the upper surface of the base. Further, optical elements other than the laser cavity such as the reflecting mirrors 3a and 3b are also fixed by using the key groove 4a so that the optical axis can be easily adjusted with high accuracy. According to such a configuration, the optical axes of the individual laser cavities 2 can be matched with high accuracy, and the position adjustment of the laser cavities 2 in the optical axis direction can be performed without shifting the optical axes. It is possible to provide a cascade type solid-state laser device in which the adjustment of the length is easy and the output fluctuation is small.
[0026]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
According to the first aspect of the present invention, both side surfaces of the laser cavity casing are fixed to the pair of support columns disposed on the base, and both ends of the laser rod or both ends are held from both side faces of the casing. Since the rod holding member is protruded and held by the support column, it is possible to provide a solid-state laser device that suppresses the optical axis shift of the laser rod, easily adjusts the optical axis, and has a stable output. Further, since the laser cavity housing can be rotated around the laser rod, it is easy to replace the members in the laser cavity.
[0027]
According to the second aspect of the present invention, the laser rod is positioned in the height direction and in the horizontal direction because both ends of the laser rod or the rod holding member that holds the both ends are held by the support by fitting. The output of the solid-state laser device can be made more stable by defining with high accuracy.
[0028]
Furthermore, according to the third aspect of the present invention, since the support column is detachably attached to the base and the fitting groove for positioning is provided on the support column or the base, the optical axis of the laser rod is defined with high accuracy. The output reproducibility when disassembling and assembling the solid-state laser device can be improved.
[0029]
Furthermore, according to the invention described in claim 4, since the sub-base movable on the base in the optical axis direction is provided, the position of the laser cavity in the optical axis direction can be adjusted, and the resonator length can be adjusted. An easy solid-state laser device can be provided.
[0030]
In addition, according to the invention described in claim 5, since the sub-base or the fitting groove extending in the optical axis direction is provided in the base, the position of the laser cavity can be adjusted in the optical axis direction without shifting the optical axis. Therefore, it is possible to provide a solid-state laser device in which the resonator length can be easily adjusted and the output is stable.
[0031]
According to the invention described in claim 6, since the invention described in claim 1 is applied to the cascade solid-state laser device in which a plurality of laser cavities are installed on a single base, the optical axis can be easily adjusted and output can be achieved. It is possible to provide a stable cascade type solid-state laser device.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a solid-state laser apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view showing a support and a base of the solid-state laser apparatus according to Embodiment 1 of the present invention.
FIG. 3 is a cross-sectional view showing a support and a base of a solid-state laser apparatus according to Embodiment 2 of the present invention.
FIG. 4 is a perspective view showing a solid-state laser apparatus according to Embodiment 3 of the present invention.
FIG. 5 is a top view showing a solid-state laser apparatus according to Embodiment 4 of the present invention.
FIG. 6 is a cross-sectional view showing an example of a conventional solid-state laser device.
FIG. 7 is a side view showing another example of a conventional solid-state laser device.
[Explanation of symbols]
2 laser cavity, 3a and 3b reflector, 4 base, 5 rod fixing plate, 7 housing, 8 struts, 10 laser rod, 12 and 14 flow tube, 13 and 15 excitation light source, 16 collector, 18 sub-base.

Claims (6)

(A) a laser cavity in which a laser rod, an excitation light source for irradiating the laser rod with excitation light, and a condenser for condensing the excitation light on the laser rod are disposed in the housing; ) In a solid-state laser device comprising a base for installing the laser cavity in a predetermined optical axis direction,
Fixing both side surfaces adjacent to both ends of the laser rod of the housing to a pair of support columns disposed on the base,
A rod holding member that holds both ends of the laser rod is protruded from both side surfaces of the housing, and the rod holding member is fixed to both side surfaces of the housing, and the both side surfaces of the housing are fixed to the support columns. A solid-state laser device , wherein the rod holding member is supported by the support so that the case can be rotated when the is released . 2. The solid state laser device according to claim 1, wherein a rod holding member for holding both ends of the laser rod is supported by the support column by fitting.   2. The solid-state laser device according to claim 1, wherein the support column is detachably attached to the base, and a fitting groove for positioning is provided on the support column or the base.   2. The solid-state laser device according to claim 1, wherein a sub-base that supports the pair of support columns and is movable in the optical axis direction on the base is provided between the support columns and the base.   5. The solid-state laser device according to claim 4, wherein a fitting groove extending in an optical axis direction is provided in the sub-base or the base.   6. The solid-state laser device according to claim 1, wherein a plurality of laser cavities are installed on a single base.

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