JP2674312B2 - Slab type solid state laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a solid-state laser device suitable for high output, which is commonly called a slab type, and includes a pair of plate surfaces that totally reflect laser light and a thermal insulation. A laser medium formed in a slab-like body having a pair of side surfaces that are formed and a pair of beveled surfaces through which laser light goes in and out is a cooling medium having both beveled surfaces inside a storage container that stores an excitation light source and a cooling medium. A laser beam transmitting member is hermetically attached to both openings of the storage container that are stored and held over the entire length so as to contact with the laser medium, and are opposed to both oblique end surfaces of the laser medium. The present invention relates to a slab type solid-state laser device in which a total reflection mirror and an output mirror are arranged so as to face a transmissive member.

[Conventional technology]

As is well known, in a fixed laser device, a laser medium such as YAG containing a laser active substance is generally formed in a rod shape, but if the cross-sectional shape is circular, for example, an internal portion having a peak in its central axis during laser oscillation Since the temperature distribution and thermal strain caused by it occur, the phase of the laser beam passing through the cross section of the medium is displaced depending on its radial position and the entire oscillation mode is easily disturbed. Is not suitable for high power laser oscillation.

The above-mentioned slab-type solid-state laser device solves this problem by using a slab-shaped or plate-shaped laser medium as a laser medium, and in this medium, a laser beam is made into a jig-jig shape while being totally reflected by the pair of plate surfaces. Even if there is a temperature distribution in the medium, the laser light travels while passing through locations with different temperatures, and the effects of thermal strain on the phase of the laser light are averaged as a whole, and the laser oscillation mode Is much less affected by the temperature distribution.
Therefore, the slab-type solid-state laser device has a feature that it can oscillate with a large output and can converge to a very small spot by optical means because the phase in the cross section of the laser beam is well aligned.

FIG. 9 shows a proposal previously made by the present applicant (Japanese Patent Application No.
-157561) shows the structure of a slab type solid-state laser device. The laser medium 10 is a crystal or glass such as YAG containing a laser active substance such as Nd having a flat rectangular cross section.
Is a pair of plate surfaces 10a which are total reflection surfaces and move in the left-right direction in the figure in a zigzag shape in the lateral direction of the drawing as described above, and for example, both beveled end surfaces formed at a predetermined angle known as Brewster's angle. Enter and exit via 10c. The slab type laser medium 10 houses a pumping light source 2 for optically pumping the laser medium 10, and a cooling medium C for cooling the laser medium in order to reduce internal thermal strain of the laser medium 10 and oscillate at high output, For example, in the storage container 1 having a closed structure in which CFCs flow through the inlet 1c and the outlet 1d, the slanted end face 10c is stored over its entire length so that it contacts the cooling medium in the storage container 1. Although not particularly shown, in order to reduce the temperature gradient in the width direction of the laser medium 10, the side surface 10b (10th
(Fig.) A semi-cylindrical metal holder 13 for holding a heat insulator 12 for heat insulation is provided with a screw hole, and is held by using a bolt or a stud that hermetically penetrates the side wall of the storage container body 1a. There is. The heat insulator 12 is formed, for example, by filling a silicone rubber adhesive having good heat insulation between the side surface 10b and the holder 13 and curing it, or between the side surface 10b and the holder 13. It is formed as a good heat insulating resin piece to be adhered. Further, the main body 1a of the storage container is formed in a cylindrical shape having an elliptical inner surface finished to a mirror surface that reflects the excitation EL from the excitation light source 2, and both end surfaces of the main body 1a have the inner surface finished to a mirror surface. The excitation light source 2 is closed by a pair of lids 1b that airtightly support the excitation light source 2 through the O-ring 6b. This one
An opening is formed in the pair of lid portions 1b at a position facing the oblique end surface 10c of the laser medium 10, and the O-ring 6a and the pressing member 3 are formed by the plate-shaped transmitting member 4 which transmits the laser light.
Is hermetically closed by means of and, and a total reflection mirror 21 and a partial reflection mirror 22 as an output mirror are arranged on the outside of each of the transmission members 4 so as to face the transmission member. A laser resonance system is configured with the reflection mirror 22.

By the way, in this way, the laser medium 10 is provided with the beveled surface 10
The reason why c is held in the storage container 1 so that it contacts the cooling medium C in the storage container 1 is that if the laser medium 10 is
As shown in the figure, when the inclined end surface 10c is supported so as to be exposed to the outside of the storage container 11, the airtight portion between the laser medium 10 and the storage container 11 is along the peripheral surface of the laser medium 10. Existence and for this reason total reflection mirror 21, partial reflection mirror 22
There is a problem that the O-ring 6c is irradiated by the laser light reflected from the laser medium 10 and passing through the gap between the laser medium 10 and the pressing member 13 that presses the O-ring 6c along the peripheral surface of the laser medium 10, and the O-ring is burned. If a frame-shaped shielding plate that shields the gap from reflected light is provided in order to prevent the O-ring from being burnt out, the periphery of the beveled end face of the laser medium is shielded and the laser output is reduced. The output light and the reflected light are irradiated in the vicinity of the peripheral edge to generate gas from the shielding plate, which burns on the beveled end face of the laser medium, causing another problem of damaging the laser medium. This is because the opening of the container can be closed by a laser light transmitting member having a sufficiently large area, and the airtight portion can be set sufficiently away from the optical path of the laser light.

[Problems to be solved by the invention]

In the conventional slab type solid-state laser device configured as described above, laser light (for example, wavelength λ =
Freon is used, for example, which has a low absorption of 1.06 μm and transmits laser light well. However, in order to obtain a high output as a solid-state laser device, the cooling effect is insufficient with CFC, so it is necessary to change the cooling medium to a medium having a large cooling effect such as water. However, water has a large absorption of laser light, and even if the excitation energy input from the excitation light source to the laser medium is increased, the laser light is absorbed by the water existing between the oblique end surface of the laser medium and the laser light transmitting member, There was a problem that sufficient output could not be obtained for the input.

An object of the present invention is to provide a slab-type solid-state laser device in which a laser output can be sufficiently obtained even when a laser medium is immersed in a cooling medium such that a beveled end surface is in contact with a cooling medium having large light absorption such as water. That is.

[Means for solving the problem]

In order to solve the above-mentioned problems, in the present invention, a slab having a pair of plate surfaces that totally reflect laser light, a pair of heat-insulated side surfaces, and a pair of oblique end surfaces through which laser light enters and exits. The laser medium formed in a shape is housed and held over the entire length in a container for accommodating the excitation light source and the cooling medium so that both slanted end faces contact the cooling medium, and faces both slanted end faces of the laser medium. A slab type solid-state laser in which a laser beam transmitting member is airtightly attached to both openings of the storage container, and a total reflection mirror and an output mirror are arranged outside the storage container so as to face the laser beam transmitting member. The apparatus is provided with a laser beam transmitting member, which is provided with an end face which is parallel to the slant end face of the laser medium and is substantially in contact with the entire slant end face in a state of being attached to the storage container. It shall be a device having a part. In this device configuration, a pair of transparent plates sandwiching a pair of plate surfaces of the laser medium from both sides in parallel with the plate surfaces and at a distance from the plate surfaces, and the laser between the pair of transparent plates. A slab holder for holding the medium is used to form a partitioned flow path that forms a flow of the cooling medium along the pair of plate surfaces, and after the cooling medium passes through this flow path, one of the laser media is formed. If the flow path of the cooling medium in the storage container is formed so as to pass through the facing interval between the beveled end face of the laser beam transmitting member and the facing gap between the other beveled end face of the laser medium and the laser beam transmitting member in order. It is more preferable. In addition, the flow path of the cooling medium,
A pair of transparent plates sandwiching a pair of plate surfaces of the laser medium from both sides in parallel with the plate surfaces and at a distance from the plate surfaces, and a slab holder for holding the laser medium between the pair of transparent plates. And the space inside the storage container is divided into a space that encloses the laser medium and the laser light transmitting member and a space that encloses the excitation light source, so that the cooling medium cools the laser medium and the laser light transmitting member, and then the cooling process. It is more preferable to form the excitation light source so as to be cooled in the final stage of (3). Then, the specific flow path for cooling the excitation light source at the final stage of the cooling process divides the space surrounding the laser medium and the laser light transmitting member into three parts by disposing the slab holders in the vicinity of both oblique end faces of the laser medium. At the same time, the space containing the pair of excitation light sources is divided into two spaces each containing one excitation light source with a space surrounding the laser medium and the laser light transmitting member interposed therebetween, and the cooling medium is a space between both slab holders. After flowing into the inside, a space where one beveled surface is located, a space where the other beveled surface is located, a space that encloses one excitation light source, a space that encloses the other excitation light source, or a cooling medium is formed. Flow into the space between the two slab holders, the flow path is branched into two, and the branched cooling medium has a space in which one of the slant end faces is located, a space that encloses one excitation light source, and the other. Space where the beveled surface is located, etc. Shall form a space surrounding the excitation light sources so that each pass in order. In the holding structure for holding the laser beam transmitting member in the container opening, the laser beam transmitting member has a cylindrical flange formed at the end portion of the light guide unit on the side of the total reflection mirror or the output mirror, and the laser beam transmitting member is provided outside the container. The wall surface is formed with a recess into which the laser beam transmitting member can be inserted from the light guide portion side, and the recess is formed with a peripheral surface forming a ring-shaped space between the recess and the outer peripheral surface of the cylindrical flange. A ring-shaped airtight member is interposed in the air gap, and the laser light transmitting member keeps a space between the end surface of the cylindrical flange on the light guide section side and the bottom surface of the recess and the side of the cylindrical flange opposite to the light guide section. It is preferable to have a structure in which the end face side is held so as not to be able to escape to the outside of the storage container via a buffer member.

[Action]

When the laser light transmitting member is formed as described above, the optical path length in the cooling medium between the oblique end surface of the laser medium and the laser light transmitting member is extremely small, and the laser light is output without being absorbed by the cooling medium. . That is, the slab type solid-state laser device has a large cooling effect on the laser medium,
Moreover, it is possible to provide a high-output device with extremely small output reduction.

Further, in this device configuration, a pair of transparent plates sandwiching a pair of plate surfaces of the laser medium from both sides in parallel with the plate surfaces and at a distance from the plate surfaces, and the laser between the pair of transparent plates. A slab holder for holding the medium is used to form a partitioned flow path that forms a flow of the cooling medium along the pair of plate surfaces, and after the cooling medium passes through this flow path, one of the laser media is formed. If the flow path of the cooling medium in the storage container is formed so as to sequentially pass through the facing gap between the beveled end face and the laser light transmitting member, and the facing gap between the other beveled end face of the laser medium and the laser light transmitting member, Since the cooling medium forcibly and rapidly passes through the narrow gap between the beveled end surface of the laser medium and the facing surface of the laser light transmitting member, the laser medium may occur when such a flow path configuration is not adopted. Cooling in the facing gap between the beveled surface and the facing surface of the laser beam transmitting member There is a risk of deposits such as water stains on the sloped surface of the laser medium due to the low moving speed of the body, the facing surface of the laser light transmitting member, or seizure of deposits due to the high energy density of the laser light, damage to the sloped surface or the facing surface. The surface is always kept clean and high output can be maintained stably.

And, in this way, the cooling medium which keeps the beveled end surface of the laser medium and the facing surface of the laser light transmitting member clean is also responsible for cooling the excitation light source in which a glass lamp is usually used. The space in the storage container is divided into a space that encloses the laser medium and the laser light transmitting member, and a space that encloses the excitation light source, and the cooling medium flow path cools the laser medium and the laser light transmitting member. After that, by forming the excitation light source to be cooled at the final stage of the cooling process, the lamp may not be installed properly when it is replaced at the end of its life, or the lamp may be damaged during operation due to some cause. Even if this happens, the broken glass may damage the beveled surface of the laser medium or the laser beam transmitting member, which may reduce the laser output or cause minute damage to the device. Progress in cracking by repeated thermal stress at the time of the scan operation, it is possible to remove the fear of destroying. As a specific configuration of such a flow path, as described above, the space surrounding the laser medium and the laser light transmitting member is divided into three parts by arranging the slab holders in the vicinity of both slanted end faces of the laser medium, and The space that goes through the pair of excitation light sources is divided into two spaces, each containing one excitation light source, with the space surrounding the laser medium and the laser light transmitting member sandwiched in between, and the cooling medium flows into the space between both slab holders. After that, if the flow path is configured so as to sequentially pass through the space in which one beveled surface is located, the space in which the other beveled surface is located, the space containing one excitation light source, and the space enclosing the other excitation light source, the cooling medium is formed. Since all the members to be cooled in the storage container are cooled in series and the relationship between the flow rate of the cooling medium and the cooling effect is uniquely determined, the capacity of the pump that sends the cooling medium into the storage container must be set to the required cooling level. Useless depending on the effect It can be properly determined. In addition, after the cooling medium flows into the space between the slab holders, the flow path is branched into two, and the branched cooling medium has a space in which one of the slant end faces is located and a space in which one of the excitation light sources is wrapped. If the flow path is formed so as to sequentially pass through the space in which the other slanted end face is located and the space that encloses the other excitation light source, the structure of the flow path is remarkably simple, as described in the embodiment section. The flow capacity of the flow path that is divided into two parts, and the flow capacity of the cooling medium flowing in the flow path with the larger flow resistance is the pump capacity so that the cooling effect can be obtained. By increasing the size, sufficient cooling can be obtained for the entire apparatus, and the cost increase due to the increase in pump capacity can be substantially compensated by the cost reduction due to the simplification of the flow path configuration. Therefore, when there is a margin in the pump capacity with respect to the flow rate required in the flow channel configuration for cooling all the cooled members in series, the flow channel configuration with the branch flow channel provides a cost advantage.

Further, by constructing the holding structure for holding the laser light transmitting member in the storage container as described above, the laser light transmitting member should be in contact with the hard metal surface of the storage container on its peripheral surface and in the axial direction. Without being held, damage to the surface of the laser light transmitting member is prevented, and there is no fear of applying excessive force at the time of assembling or inspecting the device, and the reliability of the device is further improved in combination with the flow passage configuration of the cooling medium. .

〔Example〕

FIG. 1 shows a first embodiment of a slab type solid-state laser device equipped with a laser light transmitting member according to the present invention. In the figure, the same members as those in FIG. 9 are designated by the same reference numerals and the description thereof will be omitted. Outlet ports 1c, 1d into which water is introduced and led out as the cooling medium C are formed in a storage container that stores the laser medium 10, the excitation light source 2 and the cooling medium C, and the water introduced from the introduction port 1c is the excitation light source. 2 and heat from the laser medium 10, are drawn out from the outlet 1d to the outside of the storage container 1, are recooled outside the storage container, and are introduced again from the inlet 1c. The laser medium 10 is cooled. The entire length of the laser medium 10 is stored and held in the storage container 1, and the opening of the storage container 1 formed at a position facing the slanted end surface 10a has a laser light transmitting member 14 according to the present invention.
It is closed airtightly via the O-ring 6a. As shown in the drawing, the laser light transmitting member 14 is mounted on the storage container 1 in parallel with the slant end face 10a of the laser medium and on the entire slant end face of the laser medium 10 and the storage container 1 with high accuracy. It has a light guide portion 14b having end surfaces 14a facing each other with a minimum gap taken into consideration. That is, the light guide section
The end surface 14a having the same area as the cross section of 14b has the laser medium 10
Has a surface sufficiently larger than the surface area of the beveled surface 10a of
The O-ring 6a and the pressing member 3 are attached to the storage container 1 sufficiently away from the optical path of the laser light. And laser medium
The laser light output from the sloped surface 10a of 10 is the sloped surface 1
It passes through water under a very short distance between 0a and the end face 14a of the laser beam transmitting member. As described above, water is a cooling medium that absorbs a large amount of laser light, but by substantially eliminating the optical path length in water through which laser light passes in this way, the output from the beveled surface 10a is almost eliminated. It can be taken out of the storage container without being killed.

2 to 4 show a second embodiment of a slab type solid-state laser device equipped with a laser light transmitting member according to the present invention. Here, FIG. 3 is a sectional view taken along the line AA of FIG.
FIG. 4 is a sectional view taken along the line BB in FIG. In this embodiment, a pair of transparent plates 8 and 8 made of an inorganic glass sandwiching a pair of plate surfaces 10a, 10a of a laser medium from both sides in parallel with the plate surfaces and at an appropriately set interval. , This one
Cooling the laser medium 10 between the pair of transparent plates 8 and 8 using a slab holder 7 that holds the laser medium in the longitudinal direction (the reciprocal traveling direction of the laser light) in the vicinity of the beveled surface 10a. A divided flow path 9 (FIGS. 2 and 3) is formed in which the medium is flowed along the plate surface 10a as shown by an arrow 25c (FIG. 3).
The cooling medium introduced from the introduction line 23 (Fig. 4) is indicated by the arrow.
The laser medium 10 is cooled through the plate surface 10a when flowing with 25a-25b-25c, further flows with an arrow 25d-25e to cool the excitation light source 2A, and then the inflow hole 15a formed in the storage container 15 ( Second
(Fig.) Passing through a minute gap between one oblique end surface 10a of the laser medium and the facing surface 14a of the laser light transmitting member 14, rising from the outflow hole 15b as shown by an arrow 25f, and cooling the excitation light source 2B. After passing through the inflow hole 15c as shown by the arrow 25g, the minute passage between the other oblique end surface 10a of the laser medium and the facing surface 14a of the laser light transmitting member 14 is passed through the flow passage 15d and the outlet conduit. twenty four
It flows into (Fig. 4) and is led out to the outside as shown by an arrow 25h.

By configuring the flow path of the cooling medium in this way, the cooling medium forcibly and at high speed passes through the minute gap between the oblique end surface of the laser medium and the facing surface of the laser light transmitting member. Since the facing surface is constantly cleaned during operation of the device and adhesion of dust etc. on the cooling medium is prevented, the high laser output obtained by miniaturizing the gap between the beveled surface of the laser medium and the facing surface of the laser light transmitting member. However, it is stably maintained without fear of being killed by deposits.

5 and 6 show a third embodiment of the present invention.
In these figures, the same members as those in FIG. 1 are designated by the same reference numerals. This embodiment shows an example of the flow channel configuration in the case where the cooling medium cools the laser medium and the laser light transmitting member, and then the flow channel of the cooling medium is formed so as to cool the excitation light source at the final stage. . FIG. 6 (a),
(B) and (c) are respectively cutting lines C-C in FIG.
It is sectional drawing which follows DD and EE.

As shown in FIG. 5, the internal space of the storage container 30 is formed by the transparent plates 8 and 8 and the slab holders 7 and 7 that support the laser medium 10 between the transparent plates 8 and 8, so that the laser medium 10, Then, it is divided into a space that encloses the laser light transmitting members 14 and 14 and two spaces that enclose the excitation light sources 2A and 2B with the space sandwiched therebetween.
Further, the space that encloses the laser medium 10 and the laser light transmitting members 14 and 14 is formed by forming the slab holders 7 and 7 as partition plates through which the laser medium 10 penetrates and arranging them near both beveled end faces 10c and 10c. A space surrounding the main body of the laser medium 10 and a beveled surface
It is divided into three spaces, 10c and 10c. Further, as shown in FIG. 6, the storage container 30 is watertightly sandwiched between the flow path plates 31A and 31B on the side surface side thereof. The flow path plates 31A, 31B are formed in a rectangular shape having a width that sufficiently covers the length of the storage container 30 in the left-right direction in FIG. Therefore, as shown in FIG. 6 (a), when the cooling medium C, here water, is fed from the inlet 32a of the flow path plate 31A, the water flows from the flow path having a rectangular cross section, which is long in the direction perpendicular to the paper surface. After flowing into the space between the slab holders 7 and 7 (Fig. 5) with the width between the slab holders in the direction perpendicular to the traveling direction of the laser light and parallel to the plate surfaces 10a and 10a of the laser medium, Face 10c, 10c
The laser medium 10 is traversed through the flow paths 32b, 32b along the direction toward the flow path having a rectangular cross section of the flow path plate 31B. Then, as shown in FIG. 6 (b), the water that has flowed into this flow path is a space 32c in which one of the slanted end faces of the laser medium 10 is located (the space 32c constitutes a part of the cooling medium flow path). Enter the space 32c (5th
(See FIG. 6) across the gap between the beveled end face 10c and the laser light transmitting member 14 and enter the flow path 32d (FIG. 6 (b)) of the flow path plate 31A. The flow path 32d extends in a direction perpendicular to the paper surface (left and right direction in FIG. 5) to a space 32e where the other beveled end surface is located, and water enters the space 32e through the flow path 32d. Space 32
The water that has entered e crosses the gap between the beveled surface 10c and the laser light transmission member 14, passes through the flow path 32f formed in the storage container, and enters the space that encloses the excitation light source 2B. Here, the water moves to the right while cooling the excitation light source 2B, passes through the flow path 32h (FIG. 6 (c)) formed in the flow path plate 31B, and enters the space surrounding the excitation light source 2A. Here, the water is guided to the left in FIG. 5 in the space while cooling the excitation light source 2A, and is led out from the flow path 32j to the outside.

When the flow path of the cooling medium is formed in this way, water cools all the cooled members in series, and the relationship between the flow rate of water and the cooling effect is uniquely determined, so it is necessary to obtain the required cooling effect. A large flow rate can be easily obtained, and the capacity of the pump that pumps water can be appropriately determined without waste.

7 and 8 show a fourth embodiment of the present invention.
This embodiment is different from the third embodiment in the case where the cooling medium cools the laser medium and the laser light transmitting member and then the flow path of the cooling medium is formed so as to cool the excitation light source in the final stage. It shows an example of the configuration of the flow path. 8 (a), (b), and (c) are sectional views taken along the cutting lines FF, GG, H-H in FIG. 7, respectively.

As in the case of the storage container 30, the storage container 33 is divided into a space that encloses the laser medium 10 and the laser light transmitting members 14 and 14 that are divided into three parts, and two spaces that enclose the excitation light sources 2A and 2B. ing. Further, as shown in FIG. 8, the storage container 33 is watertightly sandwiched by the flow path plates 34A and 34B on its side surface side.
The flow path plates 34A and 34B are formed in a rectangular shape having a width that sufficiently covers the length of the storage container 33 in the left-right direction in FIG. Therefore, as shown in FIG. 8 (a), the flow path plate 34A
When the cooling medium C, here water is sent from the light guide port 35a of
Water flows along the plate surface of the laser medium 10 from a rectangular cross-section flow path that is long in the vertical direction to the paper surface, and has a width between the slab holders 7 and 7 (Fig. 7) and a rectangular cross-section flow path of the flow path plate 34B. As shown in FIG. 7, it branches into two streams 35b and 35c while heading toward.
The branched flows 35b and 35c are directed to the spaces 35d and 35e in which the two slanted end faces of the laser medium 10 are located, respectively. Space 35d, 3
The water that has flowed into 5e traverses the gap between the beveled surface 10c and the laser light transmitting member 14, one passing through the flow passage 35f formed in the storage container into the space surrounding the excitation light source 2A, and the other flow passage. Enter the space surrounding the excitation light source 2B through 35g. Here, water cools the excitation light sources 2A and 2B, respectively, and the flow path 35j
And derived from 35k to the outside.

When the flow path of the cooling medium is formed in this way, the flow path of the cooling medium is divided into two and flows while cooling half of the laser medium main body, one laser light transmitting member, and one excitation light source in series. There may be cases where the flow resistances of the two differ from each other. In this case, it is necessary to secure the flow rate of the flow path having the larger flow resistance by increasing the pump capacity so as to obtain the required cooling effect. However, since the flow resistance imbalance is not so large in general, the increase in the pump capacity is not so large, and the increase in cost due to this is that the flow path plates 34A and 34B use the third embodiment. Since it is smaller and simpler than the flow channel plates 31A and 31B in FIG. 1, it can be substantially compensated by the cost difference of the flow channel plates.

As shown in the third and fourth embodiments, after the cooling medium cools the laser medium and the laser light transmitting member, by forming the flow path of the cooling medium so as to cool the excitation light source in the final stage, Normally, a glass lamp is used.When the life of the excitation light source is reached, the lamp may not be installed properly when it is replaced, or the lamp may break during operation for some reason. The fragments are discharged together with the cooling medium C to the outside without damaging the beveled surface of the laser medium or the laser beam transmitting member. Generally, in order to circulate the cooling medium, a cooler is used on the drain side of the container, but if a filter is provided on this, all debris is removed here. As a result, there is no risk that the laser output will be reduced due to the destruction of the lamp, or that minute scratches will propagate into and break into cracks due to repeated thermal stress during pulse operation of the device.

FIG. 12 shows a fifth embodiment of the present invention. Further, FIG. 13 shows a detailed view around the laser beam transmitting member 14 in FIG. The structure for hermetically holding the laser beam transmitting member in the container is the O-ring 6a in the groove on the bottom surface of the recess formed in the outer wall surface of the container 1 in the device configuration according to the first embodiment shown in FIG.
Then, the flange surface 14r of the laser light transmitting member 14 is applied to the O-ring 6a, the other surface 14s is pressed by the surface 3s of the pressing member 3 to compress the O-ring 6a, and the pressing member 3 is held by the bolt to hold the pressing member 3. The laser light transmitting member 14 is held so as not to be able to escape to the outside of the storage container 1 by closing until it hits. In this case, since the dimensions of each part are set so that there is a gap between the surface 1r of the storage container 1 and the flange surface 14r of the laser light transmitting member 14, the flange surface 14r of the laser light transmitting member 14 is stored. The container 1 can be protected from damage by not hitting the hard metal surface of the container 1, but the other surface 14s may come into contact with the hard surface of the pressing member 3 and be damaged. Further, the surface 1r of the storage container 1 and the laser light transmitting member
The gap between the flange surface 14r of 14 and the flange surface 14r is O
Since the ring 6a needs to be compressed by a predetermined amount, it cannot be so large, so if the work is done in the direction to eliminate the void due to a possible machining dimension error, the assembly will be performed without finding this mistake and the flange Not only the surface 14r may be damaged, but also an excessive force may be applied to the laser light transmitting member.

The embodiment of FIG. 12 shows an example of a holding structure in which the risk of damage to the laser light transmitting member is extremely reduced. According to this structure, the cylindrical flange 14 is provided at the end portion of the light guide portion 14b of the laser light transmitting member 14 on the side of the total reflection mirror or the output mirror.
c is formed, and a peripheral surface 41t having an inner diameter larger than the diameter of the cylindrical flange 14c is formed in a recess formed on the outer wall surface of the storage container 41 and into which the laser light transmitting member 14 is inserted from the light guide portion 14b side. When the laser beam transmitting member 14 is held in the storage container 41, the ring-shaped airtight member fitted in the groove having the peripheral surface 41t, here the O-ring 43 is pushed and expanded by the outer peripheral surface of the cylindrical flange 14c. The laser light transmitting member 14 is stopped at an appropriate position while deforming the cross section of the O-ring, and then a plate-shaped cushioning member 45 made of, for example, ethylene tetrafluoride is applied to the right end face of the cylindrical flange, and the cushioning is performed. The laser light transmitting member 14 is further pushed into the storage container 41 by pressing the laser light transmitting member 14 further by using the bolt 50 with the pressing member 4 via the material 45 and tightening the bolt 50 until the pressing member 4 hits the storage container 41. Airtight and cannot escape to the outside of the container It is held in. At this time, the dimensions of each part are set so that a sufficiently large gap is formed between the surface 41r of the storage container 41 and the flange surface 14r. As shown in FIG. 13, this gap can be made sufficiently large because it is not necessary to compress the O-ring by a predetermined amount on the flange surface 14r, and it is practically impossible that this gap will be eliminated due to a mistake in machining. can do. In this way, by setting the airtight portion on the peripheral surface and taking the structure in which the laser light transmitting member is held in the storage container through the cushioning material so as not to be able to escape, the entire surface of the laser light transmitting member is a solid metal surface. The contact with the laser light transmitting member is avoided, and the laser light transmitting member is not unnecessarily applied with force, and the fear of damage is eliminated.

〔The invention's effect〕

In the present invention, since the slab type solid state laser device is configured as described above, the following effects can be obtained.

In the device of claim 1, even if a cooling medium having a large cooling effect but a large light absorption is used as the cooling medium,
Since the optical path length for absorbing light is substantially eliminated, the energy of the laser light output from the slanted end face of the laser medium can be obtained outside the storage container with almost no loss, making full use of the cooling capacity of the cooling medium. In addition, it has become possible to realize a large output device.

In the apparatus of claim 2, when the cooling medium is forced to pass through a narrow gap between the slant end surface of the laser medium and the facing surface of the laser light transmitting member at a high speed, and such a flow path configuration is not provided. Caused by the low moving speed of the cooling medium in the facing gap between the beveled end surface of the laser medium and the facing surface of the laser beam transmitting member, the adhesion of water stains or the like to the beveled end surface of the laser medium or the facing surface of the laser beam transmitting member or the laser beam There is no risk of sticking of deposits due to high energy density, burn-out of the beveled surface or the opposing surface, the surface is always kept clean, and the important effect that high output can be stably maintained is obtained. .

In the device according to claim 3, the lamp is not mounted properly when the lamp is replaced when the life of the excitation light source lamp, which is usually made of glass, is exhausted, or the lamp is destroyed during operation due to some cause. Even if there is, the broken glass damages the beveled surface of the laser medium and the laser light transmitting member, which reduces the laser output,
Alternatively, it eliminates the concern that minute scratches may develop and break into cracks due to repeated thermal stress during pulse operation of the device.

In the apparatus of claim 4, the cooling medium cools all the members to be cooled in the storage container in series, and the relationship between the flow rate of the cooling medium and the cooling effect is uniquely determined. Therefore, the cooling medium is sent into the storage container. The capacity of the pump can be appropriately determined without waste according to the required cooling effect.

According to the apparatus of claim 5, although the structure of the flow passage is remarkably simplified and a difference in flow resistance may occur between the branched flow passages, a cooling medium flowing in the flow passage having the larger flow resistance is required. By increasing the pump capacity so that the flow rate can achieve a sufficient cooling effect, sufficient cooling can be obtained for the entire device, and the cost increase due to the increase in pump capacity can be reduced by simplifying the flow path configuration. Can substantially compensate for this. Therefore, if there is a margin in the pump capacity with respect to the flow rate required for the flow path configuration for cooling all the cooled members in series, a cost advantage can be obtained.

In the device according to claim 6, the laser light transmitting member is held by the peripheral surface thereof and without coming into contact with the hard metal surface of the storage container in the axial direction, thereby preventing damage to the surface of the laser light transmitting member and at the same time, the device. There is no fear that an unreasonable force will be applied at the time of assembly or inspection, and the reliability of the device will be further improved in combination with the above-mentioned cooling medium flow path configuration.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a structure of a slab type solid-state laser device having a laser light transmitting member according to the present invention according to a first embodiment, and FIGS. 2 to 4 show a laser light transmitting member according to the present invention. 2 shows a configuration of a slab type solid-state laser device provided according to a second embodiment, FIG. 2 is a longitudinal sectional view, FIG. 3 is a lateral sectional view taken along the line AA of FIG. 2, and FIG. FIG. 5 is a horizontal sectional view taken along the line BB of FIG. 3, and FIG. 5 is a longitudinal sectional view showing a structure of a slab type solid-state laser device having a laser light transmitting member according to a third embodiment of the present invention. FIG. 6 is a diagram showing a cross section of each part in FIG.
(B) and (c) are respectively C-C line and D- in FIG.
Sectional views taken along the lines D and E-E, FIG. 7 is a longitudinal sectional view showing a fourth embodiment of a slab type solid-state laser device provided with a laser light transmitting member according to the present invention, and FIG. 8 is FIG. It is a figure which shows the cross section of each part, Comprising: (a), (b), (c) is sectional drawing which follows the FF line in FIG. 7, GG line, and HH line, respectively.
FIG. 9 is a sectional view showing a structural example of a slab type solid-state laser device previously proposed by the applicant, FIG. 10 is a sectional view showing a side structure of the laser medium shown in FIG. 5, and FIG. FIG. 12 is a sectional view showing a configuration example of a slab type solid-state laser device, FIG. 12 is a sectional view showing a holding structure of a laser light transmitting member according to a fifth embodiment of the present invention, and FIG. 13 is a laser light transmitting member in FIG. It is sectional drawing which shows the details of circumference | surroundings. 1,11,15,41: storage container, 2,2A, 2B: excitation light source, 3: pressing member, 7: slab holder, 8: transparent plate, 9: flow path, 10: laser medium, 10a: beveled surface , 10b: side surface, 12: thermal insulator, 4, 14: laser light transmitting member, 14a: end face, 14b: light guide section, 14c: cylindrical flange, 21: total reflection mirror, 22: output mirror (partial reflection mirror) ), 32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h, 32i, 32j, 35a,
35b, 35c, 35d, 35e, 35f, 35g, 35h, 35i, 35j, 35k: flow path, C: cooling medium, EL: excitation light, L: laser light, 41t: peripheral surface.

Claims (6)

(57) [Claims] 1. A laser medium formed in a slab-like body having a pair of plate surfaces for totally reflecting laser light, a pair of heat-insulated side surfaces, and a pair of beveled surfaces for entering and exiting laser light. However, the laser medium is housed and held over the entire length so that both slanted end surfaces are in contact with the cooling medium and a pair of excitation light sources for irradiating both plate surfaces of the laser medium and the cooling medium. Laser light transmitting members are airtightly attached to both openings of the storage container facing both the slanted end faces, and a total reflection mirror and an output mirror are disposed outside the storage container so as to face the laser light transmission member. In the slab type solid-state laser device, the laser light transmitting member is parallel to the slant end face of the laser medium and is substantially in contact with the entire slant end face in a state of being attached to the container. end Slab type solid-state laser apparatus, comprising a light guide portion having a. 2. A slab type solid state laser device according to claim 1, wherein a pair of plate surfaces of the laser medium are sandwiched from both sides in parallel with the plate surface and at a distance from the plate surface. A cooling medium is formed by using a transparent plate and a slab holder that holds the laser medium between the pair of transparent plates to form a partitioned flow path that forms a flow of the cooling medium along the pair of plate surfaces. After passing through this flow path, one of the oblique ends of the laser medium and the laser beam transmitting member face each other, and the other oblique end face of the laser medium and the laser beam transmitting member face each other. A slab type solid-state laser device having a flow path for a cooling medium in a storage container. 3. A slab type solid state laser device according to claim 1, wherein a pair of plate surfaces of the laser medium are sandwiched from both sides in parallel with the plate surface and at a distance from the plate surface. Using a transparent plate and a slab holder that holds the laser medium between the pair of transparent plates, the space inside the container is divided into a space that encloses the laser medium and the laser light transmitting member and a space that encloses the excitation light source. The slab type solid-state laser device is characterized in that a flow path is formed so that the cooling medium cools the laser medium and the laser light transmitting member and then cools the excitation light source at the final stage of the cooling process. 4. The slab type solid-state laser device according to claim 3, wherein the space surrounding the laser medium and the laser light transmitting member is 3 minutes by arranging the slab holder near both oblique end faces of the laser medium. At the same time, the space that encloses the pair of excitation light sources is divided into two spaces that enclose the laser medium and the laser light transmitting member, and that encloses one excitation light source. After flowing into the space, the flow of the cooling medium so as to sequentially pass through the space where one beveled surface is located, the space where the other beveled surface is located, the space that encloses one excitation light source, and the space that encloses the other excitation light source. A slab-type solid-state laser device having a path formed therein. 5. The slab type solid-state laser device according to claim 3, wherein the space surrounding the laser medium and the laser light transmitting member is 3 minutes by arranging the slab holder near both oblique end faces of the laser medium. At the same time, the space that encloses the pair of excitation light sources is divided into two spaces that enclose the laser medium and the laser light transmitting member, and that encloses one excitation light source. After flowing into the space, the flow path is branched into two, and the branched cooling medium has a space in which one beveled surface is located, a space that encloses one excitation light source, and a space in which the other beveled surface is located, A slab-type solid-state laser device, wherein a flow path of a cooling medium is formed so as to sequentially pass through a space surrounding the other excitation light source. 6. The slab type solid-state laser device according to claim 1, wherein the laser light transmitting member has a cylindrical flange formed at the end portion of the light guide portion on the side of the total reflection mirror or the output mirror, and A concave portion into which the laser light transmitting member can be inserted from the light guide portion side is formed on the outer wall surface, and a peripheral surface which forms a ring-shaped space between the concave portion and the outer peripheral surface of the cylindrical flange is formed. A ring-shaped airtight member is interposed in the ring-shaped space, and the laser light transmission member maintains a space between the end surface of the cylindrical flange on the light guide portion side and the bottom surface of the recess and the anti-light guide portion of the cylindrical flange. A slab-type solid-state laser device characterized in that the slab-type solid-state laser device is held on the side end face side via a cushioning member so as not to be able to escape from the storage container.