JPH0372687A - Solid-state laser device - Google Patents

Abstract

PURPOSE:To protect thermal insulation and seal from burnout caused by reflected laser rays by using a practical structure, by a method wherein a pair of light shielding members for protecting thermal insulator on both surfaces of a laser medium against laser rays reflected from a mirror are fixed between both exposed inclined end surfaces of the laser medium and each mirror, so as to independently adjust the positions in the direction perpendicular to the side surface of the laser medium. CONSTITUTION:On the right end and the left end of a clamping member 3 retaining the end portion of a laser medium 10, two kinds of long and short legs 3c for fixing light shielding members 30 are equipped; fixing holes for the legs 3c of the light shielding members 30 are formed as long holes; positions, of the light shielding member 30, in the direction perpendicular to the side surface 10b of the laser medium 10 can be finely adjusted with screws 4. Since a part of laser rays L reflected by an output mirror 22 collides against the exposed end portion 11a of a thermal insulator 11, and said part happen to be burned out, the position of the light shielding member 30 in the direction of delta is finely adjusted so as to shield the thermal insulator 11 against the reflected laser rays.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a solid-state laser device commonly referred to as a slab type laser device suitable for high-output use, which has l pairs of plate surfaces that totally reflect laser light and A laser medium formed in a slab-like body having a pair of oblique end surfaces that enter and exit, a storage container that stores the laser medium and holds both ends thereof so that both oblique end surfaces are exposed to the outside, and an oblique end surface of the laser medium. and l pairs of mirrors that are arranged opposite to each other and reflect laser light.

[Conventional technology]

As is well known, in a solid-state laser device, a laser medium such as YAG containing a laser active substance is generally formed in the shape of a mouth or throat, but if the cross-sectional shape is circular, for example, the central axis of the medium during laser oscillation is Since the internal temperature distribution with a peak and the resulting thermal distortion occur, the phase of the laser light passing through the cross section of the laser medium is shifted depending on its radial position, and the overall oscillation mode is likely to be disturbed. If the degree of damage becomes significant, the laser oscillation action will stop, so it has the disadvantage that it is not very suitable for high-power laser oscillation.

The above-mentioned slab-type solid-state laser device solves this problem by using a slab-like or plate-like object as the laser medium, and inside the device, the laser light travels in a zigzag pattern while being totally reflected by a pair of plate surfaces. Therefore, even if there is a temperature distribution in the medium, the laser light will pass through places with different temperatures, and the effect of thermal strain on the phase of the laser light will be averaged out, and the laser oscillation mode will be affected by the temperature distribution. much less frequently. Therefore, the slab-type solid-state laser device can oscillate at high output and L
・The phase of the beam in its cross section is well aligned, so it has the advantage of being able to be focused into a very small spot by optical means.

FIG. 9 illustrates the structure of this slab-type solid-state laser device. The laser medium 10 has a flat rectangular cross section.
A crystal body such as YAG or glass containing a laser active substance such as d, etc., and the laser light travels inside the medium 10 in a zigzag pattern as described above in the horizontal direction in the figure, using the pair of plate surfaces 10a as total reflection surfaces. The image enters and leaves the image at a predetermined angle known as, for example, the Brewster's angle via the beveled end surface 10c. A total reflection mirror 21 and an output mirror 2 which is a partial reflection mirror are respectively opposed to these inclined end surfaces 10c.
2 are arranged to form a laser resonant system together with the laser medium 10. Of course, the laser beam output Lo is taken out from the output ξ 22 side.

Since the laser medium 10 needs to be optically excited, a storage container 1 is provided and the laser medium 10 and a pair of excitation light sources 2 are housed therein to remove the heat generated by the excitation light source 2 and to provide the laser medium lO for high output oscillation. Since cooling is necessary to lower the temperature of the storage container 1 as much as possible, the storage container 1 is made into a closed structure and a cooling medium C such as pure water is passed through the inside of the storage container 1. This storage container l is the excitation light source 2.
It consists of a cylindrical main body part 1a having a mirror-finished elliptical inner surface that reflects excitation light EL from the main body 1a, and a pair of lid parts 1b whose inner surfaces are also mirror-finished and which close both end faces of the main body part 1a. The laser medium 10 and the excitation light source 2 are inserted into the container through the hole formed in the lid 1b, and both ends of the laser medium 10 and the excitation light source 2 are hermetically supported by the lid 1b. The laser medium 10 is held so that both inclined end faces 10c thereof are exposed to the outside, and this holding part is kept airtight by a seal 6, which is usually an O-ring, interposed between the lid part ib and the restraining member 3. dripping

Similarly, the excitation light source 2 is held at both ends by the lid part 1b with its electrode 2a protruding outside, and this holding part is interposed between the lid part 1b and another restraining member 5. It is sealed by a seal 6 similar to the above.

Note that the upper and lower halves of the inner chamber of the storage container l are occupied by the laser medium lO.
are shifted from each other in the left-right direction in the figure according to the inclined end surface 10c. Further, the outlet ports 1c for the cooling medium C are provided at the top and bottom of the main body portion 1a of the storage container 1, respectively.

The laser medium 10 receives the excitation light EL from the excitation light source 2 through its pair of plate surfaces 10a and performs a laser oscillation action, but most of the energy received from the excitation light EL is ultimately converted into heat therein. Therefore, the laser medium IO is strongly cooled by the cooling medium C to reduce the thermal distortion caused by this. Since this cooling effect is mainly performed through the pair of large plate surfaces 10a of the laser medium 10, the temperature gradient in the thickness direction, which is the vertical direction in the figure, is small, but the temperature gradient in the width direction is also small. In order to reduce this, a thermal insulation 11 is provided on the pair of side surfaces 10b as shown in FIG. The thermal insulation 11 is made by filling a silicone rubber adhesive with good thermal insulation properties between the semi-cylindrical glass or metal holder 12 and the side surface 10b as shown in the figure, and then hardening the adhesive. Alternatively, a heat insulating material such as resin and a metal holder are sequentially bonded onto the side surface 10b. As a result, the heat flow within the laser medium 10 occurs only in the vertical direction in FIG. 10, and hardly occurs in the horizontal direction, and the temperature gradient in the width direction within the laser medium 10, and therefore the thermal distortion, are substantially eliminated.

In the conventional slab-type solid-state laser device described above, thermal distortion within the laser medium is slight even during high-output laser oscillation, so a high-quality laser beam with well-aligned phases within the cross section can be extracted.

[Problem to be solved by the invention]

However, in the conventional slab-type solid-state laser device mentioned above,
There is a problem in that thermal insulation and seals near the oblique end surface of the laser medium exposed to the outside from the storage container are easily irradiated with laser light and burnt out. This will be explained below with reference to FIGS. 11 and 12.

FIG. 11 shows a state in which the laser medium 10 and the mirrors 21 and 22 that constitute the laser resonant system are extracted from FIG. 9 and viewed from the upper side of the figure in order to show how the thermal insulation is irradiated with laser light. shows. Beveled end surface 10 of laser medium 10
The laser light emitted from c should originally be perfectly parallel light, but in reality it has a slight divergence angle as shown in the figure, so part of the laser light reflected from -21 or 22 The portion hits the end surface 11a of the thermal insulation 11 exposed on both sides of the inclined end surface 10c and heats it. Of course, the proportion of the scattered laser light that causes this problem to the total luminous flux is small, but in a slab-type solid-state laser device, the energy density of the laser light is extremely high, 5 W/l111, so the interaction between the laser medium 10 and the mirror 21 or 22 is If the optical axis alignment is misaligned or misalignment occurs due to temperature changes during operation, the thermal insulation 11 will burn out within a short time.

The burnout of the thermal insulation 11 is not only a loss of itself, but also the volatile matter or evaporated matter at the time of burnout is deposited on the oblique end face 10c of the laser medium 10 that is in direct contact with it and absorbs the laser light, so that even this oblique end face is lost. The laser medium becomes unusable due to damage. If an antireflection film such as a metal oxide film is provided on the inclined end surface 10c, it is particularly susceptible to contamination by vapor deposition, and is likely to be damaged rapidly.

1. In order to show how the seal is irradiated with laser light, FIG. 12 shows the laser medium 10, U-21 and 2 from FIG.
2, the lid part 1b of the storage container, and the seal 6 interposed between it and the laser medium are extracted and shown.

As mentioned above, there is some scattered light in the laser beam, so
The seal 6 surrounding the vicinity of the oblique end surface 10c of the laser medium 10 is likely to be heated by a portion of the reflected light from the mirror 21 or 22, and in this case, the optical axis alignment between the laser medium and the paper may be misaligned, or If a misalignment occurs during use, the seal 6 will burn out within a short time.

Furthermore, in addition to the reflected light, laser light that would normally be totally reflected inside the laser medium 10 is not totally reflected at the contact portion between the laser medium 1O and the seal 6 due to the relationship between the refractive indexes of both, and is not reflected inside the seal 6. The light may enter as leakage light and burn out the seal 6.

If the seal 6 burns out, the laser medium 10 in contact with it will be locally heated and the wavefront of the laser beam passing through it will be disturbed, reducing the quality of the laser beam.In addition, the cooling medium will leak from the seal and evaporate. - The laser medium may be damaged due to thermal distortion due to the latent heat of the laser medium, or water droplets may adhere to the surface of the laser medium and the laser beam may be focused inside the medium by its lens action, resulting in partial destruction of the laser medium due to its local heating effect. be. Furthermore,
Moisture leaking through the seal deteriorates the antireflection coating on the oblique end surface 10c of the laser medium, which tends to adversely affect laser resonance conditions.

As a solution to this problem, the area of the mirrors 21 and 22 is made smaller than the cross-sectional area of the laser medium 10 to prevent scattered light from hitting the thermal insulation 11 and the seal 6 even if there is some deviation in optical axis alignment. Although it is possible to do this, it is necessary to make the area of the mirror considerably smaller, so a considerable portion of the laser beam emitted from the laser medium does not hit the mirror and is dissipated, resulting in a significant decrease in laser light output. .

Furthermore, a structure is conventionally known in which small prisms are provided at both ends of the plate surface 10a of the laser medium 10, and the laser beam enters and exits from the end face of the prism. Although this prevents thermal insulation and seals from burning out, it does complicate the structure, and as can be easily seen from FIG. 9, it becomes extremely troublesome to insert and attach the laser medium to the storage container.

The present invention solves this problem and provides a highly practical solid-state laser device that can effectively prevent burnout of the thermal insulation provided on the side surface of the slab-type laser medium and the seal interposed between the laser medium and the storage container. The purpose is to obtain.

[Means to solve the problem]

According to the present invention, the purpose of preventing the burnout of the thermal insulation described above is to create a slab having l pairs of plate surfaces that totally reflect the laser beam, a pair of thermally insulated side surfaces, and a pair of oblique end surfaces through which the laser beam enters and exits. A laser medium formed in a shape, a storage container that stores the laser medium and holds both ends thereof so that both oblique end faces are exposed to the outside, and a container that is disposed opposite to the oblique end faces of the laser medium to reflect laser light. For a laser device comprising a pair of mirrors,
A pair of light shielding members for protecting the thermal insulators on both sides of the laser medium from the laser light reflected by the mirrors are installed on the sides of the laser medium between both exposed oblique end faces of the laser medium and each mirror. This is achieved by attaching it to the storage container so that its position in the orthogonal direction can be adjusted independently.

The light shielding member in the above configuration is made of a metal plate, for example, and one side thereof is used as the edge of a light shielding curtain, so that the entire oblique end surface of the laser medium is exposed to the reflected light from the mirror, but the thermal insulation on the side surface is hidden behind the curtain. It is preferable to hide it behind. As a means for adjusting the position of the end of the curtain of the light shielding member in the direction perpendicular to the side surface of the laser medium, various mechanisms can be used as appropriate, as in the embodiments described below.

Furthermore, the purpose of preventing burnout of the seal described above is to provide a solid-state laser device with the above-mentioned basic structure with a light shielding member that protects the seal interposed between the laser medium and the storage container from the laser light reflected by the mirror. It is distantly related by being disposed outside the storage container between both exposed oblique end surfaces of the laser medium and each mirror, and carried by the laser medium.

The arrangement structure of the light shielding member in the above configuration utilizes the fact that a holder that holds thermal insulation is provided on both end faces of the laser medium, and this holder protrudes from the oblique end face of the laser medium. It is preferable to extend the light shielding member in this way and attach a light shielding member to this extended portion.

Furthermore, it is very advantageous to shape the extension of this holder in such a way that it protects the thermal insulation against light reflected from the mirror. According to this structure, in addition to the protective effect for the seal of the light shielding member, the protective effect for thermal insulation can be obtained at the same time.

However, as a result of actually using the light-shielding member to prevent burnout of this seal, the light-shielding member was heated by the scattered laser light and an oxide film was formed on its surface, and during use, the oxide film peeled off and the laser medium was tilted. There is a risk that it may stick to the end surface.

Contamination by this oxide film is not serious when the thermal insulation burns out, but it reduces laser oscillation efficiency and may damage the laser medium during long-term use. Therefore, in addition to preventing seal burnout, light shielding materials It is also necessary to prevent oxidation due to overheating.

According to the present invention, this object is to provide a solid-state laser device having the above-mentioned basic structure with a light-shielding member that protects a seal interposed between the laser medium and the storage container from the laser light reflected by the cooler. This is achieved by thermally conductive coupling with a storage container that is disposed outside of the storage container between both exposed oblique end surfaces of the laser medium and each mirror, and into which a cooling medium flows.

In this configuration as well, the holder that holds the thermal insulation on both sides of the laser medium extends so as to protrude from the oblique end surface of the laser medium, and the light shielding member is guided or positioned by the extending portion of the holder. It is advantageous to connect the light-shielding element with the storage container in a thermally conductive manner, and furthermore to form the extension of the holding body in such a way as to protect the thermal insulation against reflected light from the holder. It is very advantageous to keep it there.

Further, according to the present invention, the above-mentioned objective of preventing burnout of the seal is more reliably achieved by applying a high reflectance coating to at least the vicinity of the contact portion of the laser medium surface with the seal.

[Effect]

Protecting heat insulation and seals from burnout is inversely related to the effective use of laser beam to increase laser oscillation efficiency, and the safety factor of protection is especially important against misalignment of the optical axis within the laser resonant system that may occur during operation. Since the oscillation efficiency is likely to be sacrificed, it is desirable to have a protective means that can be adjusted at any time.

Furthermore, if a means to solve the problem is provided on the laser medium side like a conventional prism, the structure will be complicated and it will be difficult to attach the laser medium to the storage container.

In the present invention, paying attention to this point, the light shielding member of the above configuration as a heat insulation and seal protection means is arranged outside the storage container between the inclined end surface of the laser medium and the mirror,
The mounting position can be adjusted freely without complicating the structure.

When protecting the thermal insulation with this light shield, its mounting perpendicular to the side of the laser medium on which the thermal insulation is provided can be easily adjusted to maximize the utilization of the entire laser beam cross section. To be able to safely protect thermal insulation while using it.

Further, in the present invention, a pair of light shielding members for heat insulation protection are provided, and they can be adjusted independently of each other. Of course, the purpose of providing a pair of light shielding members is to protect the thermal insulation provided on each side of the laser medium, but
The reason why they can be adjusted independently is that the light shielding member is made into a diaphragm mechanism, for example, simply to make the adjustment easier.
This is because it is not possible to make sufficient adjustments to accommodate complicated optical axis deviations that may occur during operation of the solid-state laser device.

When protecting the seal with a light shielding member, the seal is supported on the laser medium outside the storage container between the mirror and the inclined end surface exposed outside the laser medium storage container. This results in
During operation of the solid-state laser device, the relative position between the light-shielding member and the oblique end face will not change, and the optical axis will not shift, making effective use of the laser beam and ensuring good seal protection while maintaining good oscillation efficiency. effect can be obtained.

In order to obtain a heat insulation protection effect as well as this seal protection effect, a holder that holds the heat insulation on both sides of the laser medium is extended from the oblique end face, and a light shielding member = 17 is attached thereto. It is very advantageous to form the projection in such a way that it is protected against reflected laser light from the mirror.

In order to protect the seal protection light shielding member itself from overheating due to scattered laser light, it must be thermally conductive to the storage container in which a cooling medium is passed through and kept at a low temperature, as described in the above configuration. By coupling the light shielding member to the cooling medium, the light shielding member is effectively cooled by the cooling medium through the storage container. In addition, by thermally conductively connecting this light shielding member to the storage container while being guided by the extension of the heat insulating holder described above, it is possible to prevent changes in the relative position of the light shielding member to the inclined end surface during operation, and to change the optical axis. It is possible to eliminate the occurrence of misalignment, maintain good laser oscillation efficiency, and obtain a reliable seal protection effect.

On the other hand, burnout of the seal due to laser light leaking into the seal from inside the laser medium/body, separate from the reflected light from the mirror, can also occur on the surface of the laser medium near the contact area with the seal. If a high reflectance coating is applied, the laser light that attempts to enter the seal outside the laser medium will be reflected into the inside of the laser medium by the coating film, so that it can be reliably prevented.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing a main part of a solid-state laser device according to the present invention, which is provided with a light shielding member 30 for thermal insulation protection, in a form compatible with FIG. 9.

This figure shows the end portion of the laser medium 10 including the oblique end surface 10c on the output coupe 22 side. It has a pair of plate surfaces 10a that also serve as cooling surfaces by a medium, and a thermal insulation 11 is provided between the pair of side surfaces 10b and a semi-cylindrical holder 12, and the end surface 11a is an inclined end surface. It is exposed on the side of 10c. As shown in FIG. 8, the laser medium 10 is inserted through a hole in the lid 1b of the storage container, and its end portion is attached to the storage container 1 so that the oblique end surface 10c is exposed to the outside.

The figure shows a restraining member 3 that supports the end of the laser medium 10 together with the lid 1b described above.
It is formed from a metal plate bent along the uneven part of b, has a window 3a in the center that exposes the oblique end surface 10c of the laser medium, and is screwed onto the lid at a plurality of mounting holes 3b. be done. The left and right ends of the holding member 3 are provided with legs 3C of two types, long and short, for attaching the light shielding member 30, and the flat plate-shaped light shielding member 30 can be screwed to the tip of each leg 3C. There is. Alternatively, the legs 3C may all have the same length and their tips are inclined, and the light shielding member 30 may be attached in a position parallel to the inclined end surface 10c of the laser medium 10. The smaller the distance between the slanted end surface 10c, which is slightly exposed from the window 3a of the restraining member 3, and the light shielding member, the more advantageous it is to protecting the thermal insulation 11. Therefore, the length of the leg 3c is set not to exceed several -. Ru.

The attachment hole 30a of the light shielding member 30 to the leg 3C is formed into a so-called long hole that is flat in the left-right direction as shown in the figure, and the side surface of the laser medium 10 of the light shielding member 30 is formed in the direction indicated by δ in the figure and with an adjustment allowance. The position in the direction perpendicular to 10b can sometimes be finely adjusted using screws 4 in this example. As for the output, a part of the laser light reflected by the laser beam 22 may hit the exposed end 11a of the thermal insulation 11 and burn it out as described above, so it is necessary to shield the thermal insulation 11 from this reflected laser beam. The position of the light shielding member 30 in the direction of δ in the figure is finely adjusted. This adjustment is from 0.1 to
It is necessary to do this with an accuracy of 0.211II11.

FIGS. 2 and 3 show one structure for increasing the accuracy of fine adjustment of the position of the light shielding member 30. FIG. In the example shown in FIG. 2, a mounting plate 31, a metal plate spring 32 formed in a chevron shape, and an adjusting screw 33 are provided, and a screw 4 is provided.
This allows the end of the leaf spring 32 to be fixed at the same time as being attached to the aforementioned leg 3C. Figure (a) is a plan view of the same, and as shown in figure (b), which is a cross section taken along the line X-X, the plate spring 32 is screwed onto the mounting plate 31 through the slightly larger hole 32a. By adjusting the extent to which the leaf spring 33 is pushed out using the screw 33, the position of the light-shielding side 32a on the left side of the figure can be finely adjusted in the direction indicated by δ.

In the example shown in FIG. 3, a U-shaped guide member 34 and both of them = 21, a metal slide plate 35 guided by a groove 34a cut inside the leg, a leaf spring 36, and a fine screw 37 are provided.
The guide member 34 is screwed to the aforementioned leg 3C at the mounting hole 34b. The screw 37 is screwed into the slide plate 35 through the leaf spring 36 and the hole 34c of the guide member 34, and by adjusting the screwing depth, the slide plate 3
The position of the light shielding side 35a of No. 5 can be finely adjusted in the direction indicated by δ with high precision.

The leaf spring 32 in FIG. 2 and the slide plate 35 in FIG. 3 both serve as light shielding members, and like the light shielding member 30 in FIG. It is preferable that the structure is made of a metal with a In either structure, the position of the light shielding member can be easily adjusted with high precision using screws or other means, and by making this adjustment as needed, the thermal insulation can be shielded from the reflected laser light from the ξ. In addition to providing safe protection, the extent to which the laser beam is blocked by the light blocking member can be minimized. The width of the laser medium is usually about 20 mm, and the light shielding member is 0.2 mm wide.
When adjusted with an accuracy of +o+, the 2- loss of the reflected laser beam is only about 2%.

FIG. 4 is a perspective view showing a main part of an embodiment of the solid-state laser device according to the present invention, in which a light shielding member 4o is provided for protecting the seal 6, in a form compatible with FIG.

FIG. 4 also shows the end portion of the laser medium 10 including the oblique end surface 10c, and the thermal insulation 11 is provided between the l pair of side surfaces of the laser medium 10 and the holder 12 as before. However, in this example, each end of the pair of holders 12 extends so as to protrude outward beyond the oblique end surface 10c of the laser medium 10, and the shape of the extending portion 12a of the bracket is as shown in the figure. It is formed so as to hide the thermal insulation 11 from the outside. As a result, the portion of the laser beam reflected from the output beam 22 that is wider than the width of the inclined end face 10c is completely blocked from entering the thermal insulation 11. Further, in this example, a light shielding member 4o is provided on the outer side of one tip of the pair of extension portions 12a.
For the sake of convenience, a small opening 12b is provided as shown in the figure.

When attaching the laser medium 10 to a storage container, as usual, the laser medium 10 is first inserted through the hole in the lid 1b of the storage container l shown in FIG. Fit a seal such as an O-ring around the periphery, and then insert the laser medium 1.
After fitting the window 3a of the holding member 3 shown in FIG. As a result, the laser medium IO is attached to the storage container 1 with the oblique end surface 10c exposed to the outside, and is elastically and cooled by the seal 6 interposed between the lid 1b and the cooling medium at each end. C is supported in a sealed manner. Also in this embodiment, the holding member 3 is the lid 1b.
It is formed into a bent plate shape to fit the external shape of the
A mounting leg for the light shielding member 40 is not provided.

The light shielding member 40 shown in FIG. 4 is attached to the extending portions 12a of a pair of holders 12 with the windows 41a formed in the light shielding portion 41 being fitted into the extension portions 12a of the pair of holders 12.
Therefore, it is positioned relative to the inclined end surface 10c. Note that in this example, the light shielding member 40 is formed in a bent shape like the restraining member 3, but it may also be in a flat plate shape. Some examples of this light shielding member 40 are shown in FIG. 5, and will be explained below with reference to this one.

The light shielding member 40 has an elongated window 41a corresponding to the cross section of the laser medium 10 including the holder 12, the upper and lower two sides of the window 41a are light shielding sides, and a pair of holders are provided at both ends 41b and 41c. It is fitted into the extending portion 12a of the body 12.

The left end 41b of the window 41a is formed in a semicircular shape according to the left extension in FIG. 4, and the right end 41c is formed in a shape that matches the notch 12b of the right extension. The light shielding member 40 is also precisely finished so that the light shielding member 40 can be accurately positioned.

As shown in FIG. 5(a) and its side surface, FIG. 5(c), protrusions 42 and 43 are provided on the back side of the left and right ends of the light shielding member 40 to enable accurate positioning.
Their inner sides are finished in the same shape as the window edges 41b and 41c. The right protrusion 43 has a punch hole 4.
3a is cut, and by simply tightening the screw 44 shown in FIG.
It can be firmly fixed at 0.

In the example of FIG. 5(a), the distance between the upper and lower light shielding sides 5 of the window 41a of the light shielding member 4o is slightly smaller than the distance between the upper and lower plate surfaces 10a of the laser medium 10, that is, the height of the oblique end surface 10c. It is finished accurately so that the light shielding member 40 is attached to the laser medium 10, and the output is so that the reflected laser light from the sheet 22 enters the inclined end face 10c but does not hit the seal 6 in contact with the plate face 10a. be done. In order to satisfy this condition, no matter how accurate the finish of the window 41a is, it is meaningless unless the light shielding member 4o is installed accurately.
Since the edges such as the periphery of 0c are chamfered by about 0.2 mm, installation of this degree can be done within the error range.

In the example of FIG. 5(C), a pair of light-shielding protrusions 41d are provided on the upper and lower sides of the window 41a of the light-shielding member 4o, and their opposing sides are used as light-shielding sides. The protrusion height of these light-shielding protrusions 41d is, for example, about 0.2 mm, and by making the interval between the opposing light-shielding sides slightly smaller than in the case of FIG. I can do it.

26- In the example of FIG. 5(d), the light shielding protrusion 41e is provided only on one side of the window 41a, and its protrusion height is made larger than that of the case of FIG. 5(C). Such a light shielding protrusion 4
1e is suitable when the rollers 21 and 22 are placed at a position inclined from the axis of the laser medium IO, as shown by line M in FIG. 12 for convenience.

Such a tilted arrangement is useful in bringing the rectangular cross-section of the laser beam, which is characteristic of slab-type solid-state laser devices, closer to a square cross-section and improving the so-called aspect ratio in its use. As can be seen from the figure, in this case, since the seal 6 in contact with one plate surface of the laser medium 10 is particularly susceptible to reflected laser light, the light-shielding protrusion 41e is provided only on one side, and the fifth Assuming that the light shielding member 40 in Figure (d) is on the output mirror 22 side, a light shielding member in which a light shielding protrusion 41e is provided above the window 41a is used on the opposite total reflection ξ 2↓ side.

FIG. 6 is a perspective view showing, in a form compatible with FIG. 9, a main part of an embodiment of the present invention in which the light shielding member 50 itself for protecting the seal is protected from overheating due to laser beam irradiation.

Laser medium 10 in this example. The seal 6 and the restraining member 3 are not significantly different from those shown in FIG. 4, and their installation is the same. Also, the light shielding member 50 protects the seal 6 from being hit by the reflected laser light from the output As a result, it is also irradiated with a part of the laser beam emitted from the oblique end surface 10c of the laser medium IO and becomes overheated.
This embodiment is designed to effectively cool the oxidation since it may be subject to significant oxidation.

The light shielding member 50 can be made of a metal material that is difficult to oxidize, such as stainless steel, from the viewpoint of preventing oxidation.
In reality, it is better to use copper or aluminum, which has good thermal conductivity, to achieve better results, and in this embodiment, it is made up of a light shielding part 51 and a connecting part 52 that is continuous with the light shielding part 51.

The light shielding part 51 is a part that is easily overheated by receiving reflected laser light, etc., so in order to increase the heat capacity, it is formed much thicker than the previous embodiment, for example, 10 wm, and in the illustrated example, the upper and lower sides of the elongated window 51a are is provided with a pair of light shielding protrusions 51d, and by fitting both ends of the window 51a into the extending portion 12a of the holder 12 protruding from the oblique end surface 10c of the laser medium 10, the oblique end surface 10c of the light shielding member 50 is sealed. The position relative to 6 can be determined accurately. Although this fitting surface requires high precision, it is desirable to place the extension portion 12a so that it can slide along this surface in order to absorb thermal expansion of the laser medium 10 during operation.

The connecting portion 52 is formed into a flat plate shape as shown in the figure, and has a hole 52a for attachment, through which the storage container l shown in FIG.
For example, the peripheral surface 1 of the protrusion that supports the excitation light source 2 of the lid 1b.
By attaching the light shielding member 50 to the storage container 1 by means of screws or the like, the light shielding member 50 is thermally conductively coupled to the storage container 1 over the entire lower surface of the coupling portion 52 thereof. In this installation or connection, the diameter of the hole 52a is set slightly larger than the installation screw, and the holder 1 of the window 51a of the light shielding part 51 is
It is desirable that no force be applied to the fitting part with the extension part 2.

FIG. 7 shows some examples of the light shielding member 50 corresponding to the previous FIG. 5. In the example shown in FIG. 5A, the window 51a of the light shielding portion 51 has flat upper and lower sides, and these sides are the light shielding sides. Both ends 51b and 51c of the window 51a shown in the figure are the portions that are fitted into the extending portion 12a of the holder 12. This side view (c) simply shows how to attach the coupling part 52 to the circumferential surface 1d of the projection of the lid 1b of the storage container 1 at the hole 52a. . Same figure (
In the example C), light-shielding protrusions 51d are provided on the upper and lower sides of the window 51a of the light-shielding portion 51, as in FIG. In the example shown in FIG. 5A, the light shielding protrusion 51e is provided only on one side of the window 51a. The functions of these light-shielding protrusions 51d and 51e are the same as in the case of FIG. 5, so the explanation will be omitted.

The light shielding member 50 in this embodiment is thermally conductively coupled to the storage container 1 through which the cooling medium C flows, as shown in FIG. 9, so that the amount of heat received from the reflected laser beam etc. The heat is quickly radiated to the cooling medium C through the cooling medium C, thereby eliminating the problem of overheating as in the conventional case.

FIG. 8 shows an embodiment of the present invention in which the surface of the laser medium 10 near the seal 6 is coated with a high reflectance coating. The figure shows a laser medium 10, a seal 6, and a coating film 60.
1, and other members are omitted. FIG. 8(a) shows an example in which a seal 6 is attached to the edge of the laser medium 10, and a high reflectance coating is applied to the surface of the laser medium 10 near the contact area between the seal 6 and the laser medium 10.

Figure 8 0)) and (C) show that the seal 6 is attached to the laser medium l.
This is an example of the case where it is arranged along the obtuse angle side of O. In FIG. 8(C), a high reflectance coating is applied only to the surface of the laser medium 10 near the seal 6, and in FIG. 8(C), the metal body on the surface of the laser medium 10 outside the seal 6 is coated. Although dielectrics and metals are suitable as materials for the coating film 60, which is a high-reflectance coating, metals are more advantageous when considering the dependence of the laser beam on the coating film 60 on the incident angle.

Note that, as shown in FIG. 6, the seal 6 is located at a position Gζ where the light from the excitation light source 2 does not directly reach, so that the coating film 50 is not deteriorated by the light from the excitation light source 2. Therefore, since the innermost part of the coating on the surface of the laser medium 10 can extend up to the inner wall surface of the storage container 1, restrictions on the width of the coating film 60 are relaxed.

As described above, in the present invention, the light shielding member 30 that protects the thermal insulation 11 and the light shielding member 40 or 5 that protects the seal 6
0. and a coating film 60, but as an application thereof, the present invention can be practiced in combination with such protection means. In addition, as can be seen from the description of the embodiments, the present invention is not limited to these examples, and can be implemented in various embodiments or specific structures to achieve greater effects.

〔Effect of the invention〕

As described above, in the present invention, the laser beam is formed in a slab-like body having a pair of plate surfaces that totally reflect the laser beam, a pair of thermally insulated side surfaces, and a pair of oblique end surfaces through which the laser beam enters and exits. A medium, a storage container that stores the laser medium and holds both ends of the medium so as to expose the internal medical end surface to the outside, and a pair of 5's that are disposed opposite to the oblique end surface of the laser medium and reflect the laser beam.
In a laser device equipped with a mirror, a pair of light shielding members each protecting thermal insulators on both sides of the laser medium from laser light reflected by the mirrors is provided between the exposed end face of the laser medium and each mirror. By attaching it to the storage container so that its position perpendicular to the side surface of the laser medium can be adjusted independently, or by protecting the seal interposed between the laser medium and the storage container from the laser light reflected by the mirror. By disposing a light-shielding member outside the storage container between the exposed end face of the laser medium and each mirror and carrying it on the laser medium, it is possible to achieve a practical structure without complicating the structure of the solid-state laser device. The structure can effectively protect thermal insulation and seals from burnout caused by reflected laser light, thereby improving the operational reliability of solid-state laser devices.

Furthermore, a light shielding member that protects a seal interposed between the laser medium and the storage container from laser light reflected by the mirror is installed on the outside of the storage container between the exposed end face of the laser medium and each mirror. 3. To further improve the operational reliability of a solid-state laser device by preventing the risk of the light-shielding member itself being overheated by reflected laser light, etc. by disposing the light-shielding member and thermally conductively coupling it with the storage container. I can do it.

In addition, not only can the seal be prevented from being burnt out by the laser beam reflected by the laser, but it can also be coated with a high reflectance coating on the surface of the laser medium near the area where it comes in contact with the seal. Burnout caused by leakage light can also be prevented.

As described above, the present invention not only makes it possible to safely protect thermal insulation, seals, and even the light shielding member itself, but also minimizes the loss of laser light within the laser resonant system, making it possible to operate slab-type solid-state laser devices with high efficiency and high performance. Capable of output operation.

Note that, since the light shielding member for thermal insulation protection according to the present invention is provided outside the container housing the laser medium, there is a possibility that the optical axis alignment within the laser resonant system may be misaligned or misaligned due to various factors during operation of the solid-state laser device. Even if this occurs, the solid-state laser device can always be operated under the best 34 conditions by correcting or fine-tuning the position of the light shielding member as needed. Since one pair of light shielding members is provided,
This is because, regardless of the manner in which the above-mentioned deviation or deviation of the optical axis occurs, the position of the dual-speed optical member can be precisely and finely adjusted to optimize the operating conditions of the solid-state laser device.

In addition, since the light shielding member for seal protection according to the present invention is supported or guided by a laser medium, there is almost no possibility that its position will be distorted or shifted during operation, and even if its position needs to be adjusted, Since the light shielding member is disposed outside the storage container, its position can be easily adjusted or corrected.

In this way, the present invention simultaneously solves the conventional problems of slab-type solid-state laser devices: preventing burnout of thermal insulation and seals, and preventing loss of laser light within the laser resonant system.
Furthermore, it is possible to provide a practical means for preventing overheating of the light shielding member as such a prevention means.

[Brief explanation of drawings]

Figures 1 to 1θ relate to the present invention; Figure 1 is a perspective view of the main parts of an embodiment of a solid-state laser device according to the present invention incorporating a light shielding member for heat insulation protection, and Figure 2 is a perspective view of the light shielding member. A plan view and a sectional view showing a structural example, FIG. 3 is a plan view showing a different structural example of the light shielding member, and FIG. 4 is a main part of an embodiment of a solid-state laser device according to the present invention incorporating a light shielding member for seal protection. 5 is a plan view and a side view showing some examples of the light shielding member, and FIG. 6 is a perspective view of the main part of the solid-state laser device according to the present invention incorporating means for preventing overheating of the light shielding member for seal protection. , FIG. 7 is a plan view and a side view showing some examples of the light shielding member, FIG. 8 is a cross-sectional view showing a state in which a high reflectance coating is applied to a laser medium, and FIG. 9 is a solid state as an object of the present invention. Cross-sectional view showing a structural example of a laser device, 1st
Figure O is a cross-sectional view showing the structure of the laser medium. FIG. 1I and subsequent figures relate to the prior art; FIG. 11 is a plan view of a laser resonant system of a solid-state laser device according to the prior art, and FIG. 12 is a side view thereof. In these figures, 1: storage container, 3c: leg for attaching light shielding member, 6: seal or O-ring, 10: laser medium, 10a: plate surface, 1
0b: side surface, lOc: oblique end surface, ll: thermal insulation, 21: total reflection mirror, 22: output mirror, 30: light shielding member, 30
a: light shielding member mounting hole, 31: mounting plate, 32: light shielding plate spring, 32a: light shielding part, 33: adjustment screw, 34: guide member, 34a: guide groove, 35: light shielding slide plate, 35a: light shielding part, 36: leaf spring, 40: light shielding member, 41: light shielding part of light shielding member, 50: light shielding member, 51: light shielding part of light shielding member,
52: Joint portion of light shielding member, 60: Coating film, C:
Cooling medium, δ: Adjustment direction or adjustment amount of light shielding member, E
L: excitation light, L: laser light, LO: q)

Claims (1)

[Claims] 1) A pair of plate surfaces that totally reflect laser light and a thermally insulated substrate 1
A laser medium formed in a slab-like body having a pair of side surfaces and a pair of oblique end surfaces through which laser light enters and exits, and a storage that stores the laser medium and holds both ends so that both oblique end surfaces are exposed to the outside. In a laser device that includes a container and a pair of mirrors that are arranged opposite to each other on an inclined end surface of a laser medium and reflect laser light, the thermal insulators on both sides of the laser medium are each protected from the laser light reflected by the mirrors. A pair of light shielding members are attached to the storage container between both exposed oblique end surfaces of the laser medium and each mirror so that the position in a direction perpendicular to the side surface of the laser medium can be independently adjusted. solid-state laser device. 2) A laser medium formed in a slab-like body having a pair of plate surfaces that totally reflect the laser beam and a pair of oblique end surfaces through which the laser beam enters and exits, and a laser medium that houses the laser medium and exposes both oblique end surfaces to the outside. In a laser device that includes a storage container that holds both ends so as to be exposed, and a pair of mirrors that are arranged opposite to the oblique end surface of the laser medium and reflect the laser beam, an intervening device is provided between the laser medium and the storage container. A light-shielding member for protecting a seal to be displayed from laser light reflected by the mirror is disposed outside the storage container between both exposed oblique end surfaces of the laser medium and each mirror, and is carried by the laser medium. A solid-state laser device featuring: 3) A laser medium formed in a slab-like body having a pair of plate surfaces that totally reflect the laser beam and a pair of oblique end surfaces through which the laser beam enters and exits, and a device that houses the laser medium and exposes both oblique end surfaces to the outside. A laser device comprising: a storage container that holds both ends of the laser medium so as to be exposed and allows a cooling medium to flow therein; and a pair of mirrors that are placed oppositely on the oblique end surface of the laser medium and reflect the laser beam. A light shielding member for protecting a seal interposed between the storage container and the storage container from laser light reflected by the mirror is disposed outside the storage container between both exposed inclined end surfaces of the laser medium and each mirror. A solid-state laser device characterized in that the laser device is thermally conductively coupled to a storage container. 4) A laser medium formed in a slab-like body having a pair of plate surfaces that totally reflect the laser beam and a pair of oblique end surfaces through which the laser beam enters and exits, and a laser medium that houses the laser medium and exposes both oblique end surfaces to the outside. In a laser device including a storage container that holds both ends so as to be exposed, and a pair of mirrors that are arranged opposite to the oblique end surface of the laser medium and reflect the laser beam, at least the portion of the laser medium surface that is connected to the storage container is A solid-state laser device characterized in that a high reflectance coating is applied near the contact portion with a seal interposed between the container and the container.