JP2003008118A - Solid-state laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve luminance and start characteristic of a laser beam emitted from a solid-state laser. SOLUTION: The solid-state laser is provided with a rod-like solid-state laser medium which emits or amplifies a laser beam of a prescribed wavelength in its lengthwise direction upon absorbing stimulation light, and a holding member which holds the laser medium. The holding member has a tunnel section for passing the laser beam and, at the same time, is positioned so that its axial center may become coincident with that of the laser medium. In the tunnel section, in addition, an aperture is provided to converge the laser beam emitted form the laser medium.

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, and more particularly to a solid-state laser device capable of improving the brightness of laser light and improving the rising characteristics of laser light.

[0002]

2. Description of the Related Art FIG. 11 is a partial sectional view showing a solid-state laser device disclosed in Japanese Utility Model Laid-Open No. 6-44160. This solid-state laser device 100, as shown in FIG.
A rod-shaped solid-state laser medium 101, a pumping light source (not shown), total reflection mirrors (not shown) and partial reflection mirrors (not shown) arranged at both ends of the solid-state laser medium 101, and The tool main body tubular portions 102 and 102 are roughly configured, and these jig main body tubular portions 102 and 102 are the solid-state laser medium 10.
It is attached to both ends of 1. The solid-state laser device 100 having such a configuration is housed in the water tank 103, and both ends of the solid-state laser medium 101 are connected to the water tank 103.
Of the support holes 104, 104 are projected to the outside. As a result, the solid-state laser device 100 has the support holes 104, 1
It is supported stably by 04. The solid-state laser device 100 is configured to be cooled by a water flow 105 flowing in the water tank 103. When the solid-state laser device 100 having such a configuration is used for work, the solid-state laser medium 101 is excited by the excitation light source, and the fluorescence generated by the excitation is resonated between the reflecting mirrors to generate solid-state laser medium as laser light. Output from the emission end of 101. Then, the laser light emitted from the emission end in this way is guided to the workpiece through the optical fiber and used for cutting, welding, marking, etc. of the workpiece.

When processing, welding, or cutting a material using the solid-state laser device 100, first, at the time of rising or at a low output, as shown by a dotted line in FIG. Output end 10 of 101
It is emitted straight from 1a. At this time, the laser light 110
The energy that is not converted into heat is heat as the laser medium 10
1 and, as a result, a temperature gradient is generated from the central portion of the laser medium 101 toward the side surface of the cooled laser medium 101 as described above. Since the refractive index of the medium generally depends on the temperature, a so-called thermal lens is generated in the laser medium 101 due to this temperature gradient. Here, when the temperature dependence of the refractive index has a positive value, the laser medium 101 has a characteristic of a convex lens with respect to light. Therefore, since the temperature gradient gradually increases as the excitation increases, the laser light 110 gradually shifts to the state shown by the broken line in the figure.
Further, since the temperature gradient becomes large at the time of high output, the laser beam 110 is rapidly converged as shown by the solid line in the figure, and is used for the above-mentioned various operations.

By the way, in order to process, weld or cut a material using the laser light 110, the laser light 110 is thin,
Moreover, there is a demand for a solid-state laser device with high brightness that can maintain a thin distance for a long time. To meet this demand, a solid-state laser device in which the diameter of the solid-state laser medium 101 is thin, or a solid-state laser device having a structure in which an aperture for blocking the laser light 110 having a certain beam diameter or more is arranged in the optical path is used. There is.

A solid-state laser device having the above-mentioned aperture in the optical path will be described with reference to FIG. In this method, when the aperture 111 is arranged apart from the laser medium 101, in order to obtain the laser light 110 having high directivity and high brightness at the time of high output of the laser light 110, It is necessary to narrow the laser light 110 by reducing the aperture diameter of the aperture 111.

[0006]

However, as described above, when the diameter of the laser medium 101 is reduced in order to obtain the laser light 110 having high brightness, there are the following problems. That is, as the volume of the laser medium 101 becomes smaller, the laser output that can be taken out decreases with the same excitation density. Further, when the diameter of the laser medium 101 is further reduced, the thickness through which the excitation light is transmitted becomes short and the excitation light passes through without being absorbed.
The extraction efficiency of laser light is reduced. Further, when the diameter of the laser medium 101 is reduced, the thermal lens effect is increased, so that there is a problem that the maximum output of laser light is reduced.
Further, as described above, when the aperture 111 is used and the aperture diameter of the aperture 111 is reduced in order to obtain the laser light 110 having high brightness, there are the following problems.
That is, in order to obtain a laser beam with high brightness, the aperture 1
When the aperture diameter of 11 is reduced, as shown in FIG. 12, the laser light 110 travels straight from the emission end 101a of the laser medium 101 at low output or when the laser light 110 rises (indicated by a dotted line in the figure). In order to radiate, as shown in FIG.
The light is blocked at 11. As a result, as shown in FIG. 14, when the laser beam 110 rises, a large output cannot be immediately obtained, and a time delay occurs until a predetermined high output is obtained. This poses a serious problem in high-speed processing, short-time repeated processing, and the like. That is, when the laser light 110 rises, the laser medium 10
When abrupt excitation is performed on the laser medium 1 from a cold state, it takes several hundred milliseconds to several seconds until a steady temperature gradient is formed in the laser medium 101. Even if the output is high, the thermal lens is not generated. As a result, the diameter of the emitted laser light 110 becomes large, and most of the laser light 110a (shown in FIG. 13) is blocked by the aperture 111, and high output cannot be obtained. In order to prevent this phenomenon, so-called feedback correction must be performed, in which the output corresponding to the laser light 110a shielded by the aperture 111 must be additionally output only at the rising time. Therefore, there is a problem that not only a dedicated device for the above-mentioned feedback correction is required, but also an extra load is applied to the excitation light source to output the extra light, and the life of the light source is shortened.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a solid-state laser device capable of improving the brightness of laser light and improving the rising characteristics.

[0008]

In order to solve the above-mentioned problems, the invention described in claim 1 is a rod-shaped solid-state laser which absorbs excitation light and generates or amplifies laser light of a predetermined wavelength in the longitudinal direction. A solid-state laser device comprising a medium and a holding member for holding the solid-state laser medium, wherein the holding member is arranged in such a manner as to have an axis common to the solid-state laser medium, It is characterized in that it has a tunnel portion for passing the laser light emitted from the medium, and that the tunnel portion is provided with an aperture for narrowing down the laser light passing through the tunnel portion.

A second aspect of the present invention relates to the solid-state laser device according to the first aspect, wherein the side surface of the aperture is a ring-shaped side surface, the side surface facing the solid-state laser medium is positive or negative. The feature is that it is an inclined surface.

According to a third aspect of the present invention, there is provided a rod-shaped solid-state laser medium that absorbs pumping light and generates or amplifies laser light having a predetermined wavelength in the longitudinal direction, and an aperture that narrows down the laser light. In the solid-state laser device, the diameter of the solid-state laser medium is D, the aperture diameter of the aperture is d, and the distance between the aperture and the solid-state laser medium is L.
In other words, the aperture diameter d of the aperture is D / 2 ≦ d ≦
It is characterized in that it is set to a size having 4D / 5 and the aperture is set to a position having 0 ≦ L ≦ 2D.

According to a fourth aspect of the present invention, a rod-shaped solid-state laser medium that absorbs excitation light and generates or amplifies laser light of a predetermined wavelength in the longitudinal direction, and an aperture that narrows down the laser light are provided. The solid-state laser device is characterized in that an annular side surface of the aperture facing the solid-state laser medium is a positive or negative inclined surface.

According to a fifth aspect of the present invention, there is provided a solid-state laser device including a rod-shaped solid-state laser medium that absorbs excitation light and generates or amplifies laser light having a predetermined wavelength in the longitudinal direction. It is characterized in that the peripheral portion of the end face of the medium for emitting the laser light is chamfered.

The invention according to claim 6 is the solid-state laser device according to claim 5, wherein the diameter of the chamfered end face is d, and the diameter of the center of the solid-state laser medium in the longitudinal direction is D. At this time, D / 2 ≦ d ≦ 4D / 5 is set.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The description will be specifically made using the embodiment. First Embodiment FIG. 1 is a partial cross-sectional view showing the structure of a solid-state laser device according to a first embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of the solid-state laser device, and FIG. FIG. 4 is a diagram for explaining an operation of the solid-state laser device at the time of rising, FIG. 4 is a diagram for explaining a rising characteristic of the solid-state laser device,
FIG. 5 is a diagram for explaining the operation of the solid-state laser device. As shown in FIG. 1, the solid-state laser device 1 of this example includes a solid-state laser medium 2 and a holding member 3 that supports the solid-state laser medium 2. An aperture 4 for narrowing down the laser light passing through is formed. The solid-state laser device 1 is housed and cooled in a water tank (not shown) as in the prior art.

The solid-state laser medium 2 is formed in a rod shape, one end of which serves as a laser light emitting end 5 and the other end of which serves as a laser light reflecting end (not shown). The solid-state laser medium 2 absorbs the excitation light and generates or amplifies the laser light of a predetermined wavelength in the longitudinal direction, and emits it from the emitting end 5 to the outside. The solid-state laser medium 2 is, for example, a base material YAG (yttrium aluminum garnet) and a laser oscillating element N.
It is formed by adding d (neodymium), absorbs excitation light, and generates or amplifies laser light of a predetermined wavelength. The solid-state laser medium has a diameter D of about 5 mm and a length of about 100 mm to 200 mm.

The holding member 3 is formed in a cylindrical shape and has a tunnel portion 6. This holding member 3
A screw portion 7 is formed on the outer peripheral surface of the. Holding member 3
Has an inner diameter capable of fitting the emission end 5 side of the laser medium 2 in a state where its own axis L coincides with the axis of the laser medium 2. The holding member 3 is formed using copper having high heat dissipation as a base material, and the surface thereof is plated with gold having high corrosion resistance. The aperture 4 is formed by protruding a part of the inner peripheral surface of the holding member 3 in the direction of the axis L of the holding member 3,
The opening diameter d is smaller than the diameter of the tunnel portion 6. This aperture 4 has a rectangular ring-shaped cross section. As a result, the aperture 4 is moved to the holding member 3
The so-called laser light is narrowed down so that only the laser light corresponding to the opening diameter d of the laser light passing through the tunnel portion 6 is passed. Aperture 4 is
In this embodiment, the diameter D of the solid-state laser medium 2 is
The same distance L (5 mm) from the emission end 5 of the solid-state laser medium 2 is provided. The aperture diameter d of the aperture 4 is the diameter D of the solid-state laser medium 2.
4/5, that is, 4 mm. The holding member 3 is attached to the solid-state laser medium 2 by the holding cap 8.
Is attached to the output end 5 side of. A screw portion 9 is formed on the inner peripheral surface of the holding cap 8. Then, after the emitting end 5 side of the laser medium 2 is fitted into the holding member 3, the screw portion 7 of the holding member 3 is screwed into the screw portion 9 of the holding cap 8 so that the holding member 3 is laser-driven. It is attached to the emitting end 5 side of the medium 2. An O-ring 10 is provided between the holding member 3 and the holding cap 8 to keep the inside of the holding member 3 watertight.

Next, the operation of the solid-state laser device 1 of this example will be described with reference to FIGS. First, the solid-state laser medium 2 absorbs the excitation light, generates or amplifies the laser light 11 having a predetermined wavelength in the longitudinal direction, and emits it from the emitting end 5 to the outside. When the output power of the laser light 11 is low or when it rises, the laser light 11 is radiated to the outside from the emitting end 5 of the laser medium 2 in a straight traveling state as shown by a dotted line in FIG. At that time, the laser light 11 is narrowed down by the aperture 4. That is, as shown in FIG. 3, the laser light 11 a in a portion corresponding to the opening of the aperture 4 can pass through the aperture 4, but the laser light 11 b outside the opening is blocked by the aperture 4. By the way, as shown in FIG. 2, the aperture 4 is arranged closer to the emission end 5 side of the laser medium 2 than the aperture 111 of the conventional technique, and the opening thereof is the opening of the conventional aperture 111. The diameter is sufficiently larger than the diameter. Therefore, as shown in FIG. 3, the aperture 4 of this example can transmit a large amount of the laser light 11a when the laser light 11 rises. Therefore, when compared with the conventional technique shown in FIG. 14, the solid-state laser device 1 of this example can immediately secure a sufficiently large output when the laser beam 11 rises, as shown in FIG. Therefore, if the solid-state laser device 1 is
ON such as high-speed machining and short-time repetitive machining
Even if it is used for work with many OFF operations, it is not necessary to perform feedback correction as in the conventional case, or it is possible to cope with work with many ON and OFF operations with slight correction.
After that, when the excitation of the solid-state laser medium 2 progresses, the output of the laser light 11 increases and at the same time, the energy not converted into the laser light 11 increases. The energy that is not converted to the laser light 11 causes a temperature gradient from the center of the laser medium 2 toward the side surface that is cooled as described above, and causes a convex lens effect. Then, as shown by the solid line in FIG. 2, the laser light 11 converges and the brightness is increased, so that it is used for work such as processing.

Here, the opening diameter d of the aperture 4 is
The brightness of the laser beam 11 can be further improved by narrowing the value a little more than the above value, while the aperture diameter d is sufficiently larger than the aperture diameter of the conventional aperture 111. It is possible to suppress the decrease in the output at the time of rising as low as possible. At this time, the laser light reflected by the side surface 12 (shown in FIG. 1) of the aperture 4 is repeatedly reflected in the holding member 3 and disappears as heat, but the heat at that time has high heat dissipation. It is discharged to the outside of the holding member 3 through the holding member 3 formed of a copper material. Corrosion of the holding member 3 due to reflection of the laser light 11 or the like is prevented by gold plating on the surface of the holding member 3. In addition, the holding member 3 and the aperture 4 are integrally formed in this manner, so that the solid-state laser device 1 installs heat generated by the laser beam 11b (shown in FIG. 3) shielded by the aperture 4. Since it disappears efficiently in the existing water tank, it is not necessary to provide a waste heat device dedicated to the aperture as in the conventional case.

Particularly, in this example, since the aperture 4 is provided close to the emission end 5 side of the laser medium 2,
It has the following effects. That is, as shown in FIG. 5, in order to improve the brightness by narrowing the laser beam 11 from a to b in the figure, the aperture diameter of the aperture 4 is set to be only m.
It is sufficient to reduce the diameter from to n. In this way, when narrowing the laser beam 11 from a to b, it is sufficient to reduce the aperture diameter of the aperture 4 from only m to n.
When the laser beam 11 rises, the aperture 4
The amount of light shielded by is small, and therefore, it is possible to suppress the decrease in output at the time of rising of the laser beam 11 as much as possible. As described above, since the aperture 4 is provided close to the laser medium 2, the aperture diameter of the aperture 4 can be made large, and therefore, the output at the time of rising of the laser beam 11 can be kept sufficiently large. ,
The brightness of the laser light 11 can be efficiently improved.

Second Embodiment FIG. 6 is a partial sectional view showing the structure of a solid-state laser device according to the second embodiment of the present invention, and FIG. 7 is a diagram for explaining the operation of the same structure. . In this example, the side surface 22 of the aperture 21 facing the emitting end 5 of the laser medium 2 is shown.
Is inclined at an acute angle with respect to the axis L of the holding member 3 (the inclined surface inclined toward the acute angle is defined as the inclined surface toward the positive side). With such a configuration, as shown in FIG. 7, the aperture 2 is radiated from the emitting end 5 of the laser medium 2.
The reflected light 23 reflected by the side surface 22 of the laser
There is a small percentage that the light directly returns to the emission end 5 side. That is, the reflected light 23 from the side surface 22 is repeatedly reflected in the holding member 3 to gradually reduce its energy.
As described above, the reflected light 23 from the side surface 22 rarely returns to the emitting end 5 side of the laser medium 2 while holding a large amount of energy, so that the pumping operation of the solid laser medium 2 is not hindered. Therefore, the optical damage of the O-ring 10 can be suppressed. In particular, as shown in FIG. 7, if the tilt angle between the side surface 22 of the aperture 21 and the axis L is 45 ° or less, the reflected light 23 reflected by the side surface 22 returns directly to the laser medium 2 side. Since the ratio is reduced as much as possible, the destabilization of the laser output due to the returning light and the optical damage of the O-ring 10 can be more effectively avoided, and the solid-state laser device 1 can be highly reliable.

In this example, the return light from the side surface 22 of the aperture 21 does not return to the emission end 5 side of the solid-state laser medium 2 so much. Therefore, as compared with the first embodiment, the aperture 21 is further provided with a laser beam. Even if it is provided close to the exit end 5 side of the medium 2, it is possible to suppress the adverse effect of the return light from the side surface 22 of the aperture 21 as low as possible. Therefore, as compared with the first embodiment described above, the aperture 21
Since the opening diameter of can be set to a larger diameter, both the characteristics at the time of rising of the laser light and the brightness can be further improved. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof is omitted.

Third Embodiment FIG. 8 is a partial cross-sectional view showing the structure of a solid-state laser device according to the third embodiment of the present invention. Aperture 31 in this example
Has an obtuse angle between the side surface 32 and the axis L of the holding member 3. Here, the inclined surface to the obtuse side is defined as the inclined surface to the negative side. With this structure, the laser light reflected by the side surface 32 does not directly return to the emitting end 5 side of the solid-state laser medium 2. That is, the energy of the reflected light from the side surface 32 is gradually reduced by being repeatedly reflected on the inner peripheral surface of the holding member 3. As described above, the reflected light from the side surface 32 rarely returns to the emission end 5 side of the laser medium 2 while holding a large amount of energy, so that the pumping operation of the solid laser medium 2 is not hindered. Therefore, the optical damage of the O-ring 10 can be suppressed. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof is omitted.

Fourth Embodiment FIG. 9 is a partial sectional view showing the structure of a solid-state laser device according to a fourth embodiment of the present invention, and FIG. 10 is a diagram for explaining the operation of the same structure. The solid-state laser medium 41 of this example is
As shown in FIG. 9, the side surface 4
A chamfered portion 44 is formed by chamfering the peripheral edge portion between 2 and the emission end 43. The chamfered portion 44 has a smaller diameter from the side surface 42 side toward the emission end 43 side. The diameter d of the emitting end 43 is set to 4/5 of the diameter D of the laser medium 41 at the center in the longitudinal direction.

Next, the operation of this embodiment will be described with reference to FIG. First, when the laser light output is low or rising, the laser light that has reached the emission end 43 from within the laser medium 41 travels straight from the emission end 43, as indicated by the broken line in FIG. On the other hand, laser medium 4
The laser light that has reached the chamfered portion 44 from inside 1 is emitted to the outside. Next, at the time of high output of the laser light, since the thermal lens is formed in the laser medium 41, the laser light reaching the emitting end 43 from within the laser medium 41 is indicated by a solid line in the figure. It converges as shown. On the other hand, the laser light that has reached the chamfered portion 44 from inside the laser medium 41 is emitted outward as indicated by the solid line in the figure. That is, the laser light that has reached the chamfered portion 44 from the inside of the laser medium 41 is emitted outward at both the low output and the high output of the laser light, and is not used for processing, welding, and cutting of the material, The same action and effect as in the case where an aperture having the same opening diameter as the diameter d of the emission end 43 is provided in contact with the emission end 43 is exhibited. By the way, in the rod-shaped laser medium 41, thermal energy that is not converted into laser light is generated in the laser medium 41 as heat, and due to thermal expansion at this time, the thermal energy is generated in the peripheral portion between the side surface 42 and the emission end 43. Stress tends to concentrate. Due to this stress, so-called cracks are likely to occur in the peripheral portion, and the cracks are likely to progress inside. However, in this example, the chamfered portion 44 is
Therefore, such a crack phenomenon does not occur. or,
When the chamfered portion 44 is provided on the laser medium 41 as in this example, it is not necessary to separately provide an aperture, so that the structure is simplified and not only the adjustment of the mounting position of the aperture with high accuracy becomes unnecessary. ， The entire device is downsized.
The same components as those in the first embodiment are designated by the same reference numerals and the description thereof is omitted.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific structure is not limited to this embodiment, and the design change and the like without departing from the gist of the present invention. Even this is included in this invention. For example, in the above-described embodiment, the case where the aperture d of the apertures 4, 21, 31 is 4/5 of the diameter D of the laser medium 2 has been described.
By the way, if the aperture d of the apertures 4, 21, 31 is greatly reduced to this value or less, the ratio of the light shielding to the laser light at the time of rising of the laser light increases, so that the dimension d of the apertures of the apertures 4, 21, 31 becomes It is preferable to set the diameter D of the laser medium 2 to 1/2 or more and 4/5 or less. Further, in the fourth embodiment, the diameter d of the emitting end 43 is
Was set to 4/5 of the diameter D at the center in the longitudinal direction of the laser medium 41, but for the same reason as above, the diameter d of the emitting end 43 is set to 1/2 or more and 4/5 or less of the diameter D. It is possible to

Further, in the above description, the apertures 4, 2
1 and 31 have been described in the case where they are formed at the same distance as the diameter D of the laser medium 2 from the emitting end 5 of the laser medium 2, that is, at the position of L = D, but the positions of 0 ≦ L ≦ 2D Even if formed, the same effect is exhibited. When the inclination angle of the side surfaces 12, 22, 32 of the apertures 4, 21, 31 with respect to the axis L is set to 45 ° or more and 90 ° or less, the side surface 1 of the apertures 4, 21, 31 is set.
The laser beams reflected by 2, 22, and 32 are repeatedly reflected in the holding member 3 and, as a result, disappear as heat in the holding member 3, which adversely affects optical equipment around the solid-state laser device. There is no such thing. Also, the holding member 3
By providing the laser light absorbing material on the inner peripheral surface and the side surfaces 12, 22, 32, it is possible to prevent the phenomenon in which the laser light is repeatedly reflected in the holding member 3 and to prevent the laser output from being hindered by the returning light. Also, the O-ring 10
It also prevents optical damage.

Further, by forming the inner peripheral surface of the holding member 3 and the side surfaces 12, 22, 32 of the apertures 4, 21, 31 to be rough surfaces, the laser light is applied to the inner peripheral surface of the holding member 3 and the laser light. Sides 12, 22, 3 of apertures 4, 21, 31
The diffuse reflection at 2 spreads widely in many directions. For this reason, the reflected light does not concentrate on a partial portion, and the holding member 3 and the apertures 4, 21, 3 are not affected.
1 is less likely to cause optical adverse effects. As described above, since the optical adverse effect due to the reflected light can be prevented, such an optical adverse effect can be ignored and the aperture can be provided at the optimum position. Further, if a reflection film is coated on the outer surface of the emission end 5 of the laser medium 2, the return light from the side surfaces 12, 22, 32 of the apertures 4, 21, 31 will not proceed into the laser medium 2. Therefore, the excitation phenomenon in the laser medium 2 is not adversely affected. The laser mediums 2 and 41 are
As base materials, YLF (yttrium lithium fluoride), YVO4 (yttrium vanadate), GG
G (gadolinium gallium garnet), GSGG
(Gatrinium scandium gallium garnet) or an amorphous material such as glass or ceramic, and Yb (ytterbium), Ho (holmium), Tm (thulium), Cr (chromium), Ti are used as laser oscillation elements.
(Titanium) can be used. Further, although copper is used as the member of the holding member 3 in the above-described embodiment, brass, brass, stainless steel, alumina, or ceramic can be used.

[0028]

As described above, according to the present invention, since the aperture for narrowing the laser beam is provided in the holding member for supporting the laser medium, the aperture is arranged close to the laser medium side. Can be done. Therefore, since the aperture diameter of the aperture can be made large, not only a large output can be secured at the time of rising of the laser light, but also the laser light can be made to have a high brightness only by making the aperture diameter of the aperture slightly smaller. Particularly, when the diameter of the solid-state laser medium is D, the aperture diameter of the aperture is d, and the distance between the aperture and the solid-state laser medium is L, the aperture diameter d of the aperture is D / 2 ≦ d ≦ 4D / 5. Size, and this aperture is 0
By setting the position so as to satisfy ≦ L ≦ 2D, not only a large output can be secured at the time of rising of the laser light, but also the laser light can have high brightness. Further, according to the present invention, since the peripheral portion of the end face for emitting the laser light is chamfered, the laser medium itself can be provided with the effect of the aperture. Therefore,
Not only does it require no separate aperture, but there is no need to adjust the position during installation, resulting in an extremely simple structure. Moreover, since the side surface of the aperture facing the solid-state laser medium is an inclined surface, the reflected light of the laser light from the side surface rarely returns directly to the laser medium side. As described above, since the laser light rarely returns to the laser medium side while maintaining a large output, there is an adverse effect on the excitation phenomenon of the laser medium due to the return light of the laser light and optical damage such as an O-ring. Can be prevented as much as possible.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing the configuration of a solid-state laser device that is a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the solid-state laser device.

FIG. 3 is a diagram for explaining the operation of the solid-state laser device when the laser beam rises.

FIG. 4 is a characteristic diagram showing a rising characteristic of laser light in the solid-state laser device.

FIG. 5 is a diagram for explaining the operation of the solid-state laser device.

FIG. 6 is a partial cross-sectional view showing the configuration of a solid-state laser device that is a second embodiment of the present invention.

FIG. 7 is a diagram for explaining the operation of the solid-state laser device.

FIG. 8 is a partial cross-sectional view showing the configuration of a solid-state laser device that is a third embodiment of the present invention.

FIG. 9 is a partial cross-sectional view showing the configuration of a solid-state laser device that is a fourth embodiment of the present invention.

FIG. 10 is a diagram for explaining the operation of the solid-state laser device.

FIG. 11 is a partial cross-sectional view showing the configuration of a conventional solid-state laser device.

FIG. 12 is a diagram for explaining the operation of the solid-state laser device.

FIG. 13 is a diagram for explaining the operation of the solid-state laser device when the laser beam rises.

FIG. 14 is a characteristic diagram showing a rising characteristic of the solid-state laser device.

[Explanation of symbols]

2, 41, 101 laser medium 3 holding member 4,21,31 aperture Side of 12, 22, 32 aperture 44 Chamfer D Diameter of laser medium d Aperture opening diameter L Distance between the emitting end of the laser medium and the aperture

Claims (6)

[Claims] 1. A solid-state laser device comprising a rod-shaped solid-state laser medium that absorbs pumping light and generates or amplifies laser light of a predetermined wavelength in the longitudinal direction, and a holding member that holds the solid-state laser medium. The holding member has a tunnel portion that is arranged in a manner to have an axis common to the solid-state laser medium, and that allows the laser light emitted from the solid-state laser medium to pass therethrough. Is a solid-state laser device having an aperture for narrowing down the laser light passing through the tunnel portion. 2. The solid-state laser according to claim 1, wherein a side surface of the aperture that is a ring-shaped surface and that is on a side facing the solid-state laser medium is a positive or negative inclined surface. apparatus. 3. A solid-state laser device comprising a rod-shaped solid-state laser medium that absorbs excitation light and generates or amplifies laser light of a predetermined wavelength in the longitudinal direction, and an aperture that narrows down the laser light. Letting D be the diameter of the solid-state laser medium, d be the aperture diameter of the aperture, and L be the distance between the aperture and the solid-state laser medium, the aperture diameter of the aperture is D / 2 ≦ d ≦ 4D / 5. The solid-state laser device is characterized in that it is set to a size to be provided and the aperture is set to a position to satisfy 0 ≦ L ≦ 2D. 4. A solid-state laser device comprising: a rod-shaped solid-state laser medium that absorbs excitation light and generates or amplifies laser light of a predetermined wavelength in the longitudinal direction; and an aperture that narrows down the laser light. The solid-state laser device according to claim 3, wherein an annular side surface of the aperture facing the solid-state laser medium is a positive or negative inclined surface. 5. A solid-state laser device comprising a rod-shaped solid-state laser medium that absorbs excitation light and generates or amplifies laser light of a predetermined wavelength in the longitudinal direction, and emits the laser light of the solid-state laser medium. A solid-state laser device characterized in that a peripheral portion of an end face to be made chamfered. 6. The diameter of the chamfered end surface is d,
6. The solid-state laser device according to claim 5, wherein D / 2 ≦ d ≦ 4D / 5 is set, where D is the diameter of the center of the solid-state laser medium in the longitudinal direction.