JP6678956B2 - Laser device, laser amplifier and laser oscillator - Google Patents

Description

  The present invention relates to a laser device, a laser amplifier and a laser oscillator.

  Patent Document 1 discloses a laser medium unit capable of reducing the influence of heat generation of a laser gain medium. This laser medium unit has a cooling medium flow path through which a cooling medium for cooling the laser gain medium flows. The cooling medium flow path is arranged so that the cooling medium flows from a region having a high intensity to a region having a low intensity in the intensity distribution in the irradiation region of the pump light with respect to the laser gain medium.

JP, 2014-22568, A

  The position and orientation of the laser medium with respect to the optical path are preset. The position and orientation are set so that desired laser characteristics can be obtained. Therefore, if the position and orientation of the laser medium with respect to the optical path deviate, desired laser characteristics may not be obtained.

  Therefore, an object of the present invention is to provide a laser device, a laser amplifier, and a laser oscillator that can stably obtain desired laser characteristics.

  A laser device according to an aspect of the present invention includes a first substrate, a laser medium body that is brought into an excited state by being irradiated with excitation light, and a laser medium that is fixed to the first substrate. A medium body holding member that holds the laser medium body, the medium body holding member includes a fixing portion fixed to the first substrate, and a deformable portion that is in contact with the laser medium body and is elastically deformable. , And is configured to transfer the heat generated in the laser medium body to the first substrate via the deforming portion and the fixing portion.

  In the laser device, the heat generated in the laser medium body is transferred to the first substrate by the medium body holding member. Therefore, it is possible to make the temperature of the laser medium body uniform and stabilize the characteristics of the laser medium body. Further, the laser device holds the laser medium body by a medium body holding member that is elastically deformable. Therefore, the load of stress on the laser medium body is suppressed while maintaining the relative positional relationship between the first substrate and the laser medium body, so that the laser medium body is held in a physically stable state. be able to. As a result, the displacement of the laser medium body with respect to the optical path is reduced, so that desired laser characteristics can be stably obtained.

  The above laser device further includes a positioning member that is fixed to the first substrate and that abuts on the laser medium body, and the laser medium body is brought into an excited state by being irradiated with excitation light. A medium and an optical medium that is placed on the first substrate and transmits the excitation light, the first main surface being in contact with the first substrate, and the second main surface facing the first main surface. A laser having a main surface, a first side surface to which the laser gain medium is joined, and an optical medium having a second side surface that allows pumping light to pass therethrough, and in a direction including a direction normal to the first side surface. When the gain medium moves, the deforming portion may elastically deform along the normal direction of the first side surface. According to this configuration, the heat generated in the laser gain medium is discharged to the first substrate via the deforming portion that is in contact with the laser gain medium. Therefore, since excessive heating of the laser gain medium is suppressed, the temperature of the laser gain medium can be stabilized at a predetermined temperature. Further, since the deformable portion in contact with the laser gain medium is elastically deformed to allow a change in the distance between the fixed portion and the laser gain medium, the laser medium body can be held in a structurally stable state. it can. As a result, desired laser characteristics can be suitably obtained.

  The above laser device is connected to the second substrate that is in contact with the second main surface and the first substrate and the second substrate, respectively, and the first substrate is thermally connected to the second substrate. And a first heat conducting section connected to the. According to this configuration, the first substrate and the second substrate are thermally connected to each other, so that it is possible to reduce the temperature difference between the first substrate and the second substrate. Therefore, it is possible to suppress the generation of stress due to the temperature difference between the components.

  The above laser device includes one end connected to the first substrate and the other end connected to the second substrate, and presses the first substrate against the laser medium body and lasers the second substrate. An elastic member that generates a tensile force that presses the medium body may be further included. According to this configuration, the contact pressure between the laser medium body and the first and second substrates increases, so that the heat generated in the laser medium body can be suitably transferred to the first and second substrates. Further, when the thickness of the laser medium body increases due to the temperature rise of the laser medium body, the distance between the first and second substrates is expanded or expanded so as to correspond to the increase in thickness due to the tensile force of the elastic member. Can be reduced. Therefore, generation of stress acting on the laser medium body can be suppressed.

  The above laser device is connected to a cooling unit for cooling the optical medium and the laser gain medium, a second heat conducting unit connected to the cooling unit, one end connected to the second heat conducting unit, and a second substrate. And a third heat conducting part having the other end, and the third heat conducting part may have a natural frequency lower than the frequency of the vibration generated by the cooling part. According to this configuration, since the natural frequency of the third heat conducting section is lower than the frequency of the vibration generated in the cooling section, this vibration is damped in the third heat conducting section. Therefore, the influence of vibration on the laser medium body can be suppressed, and desired laser characteristics can be stably obtained.

  A laser amplifier according to another embodiment of the present invention is any one of the above laser devices, an incident optical system for making a laser beam to be optically amplified enter an optical medium included in the laser device in an optical path coaxial with excitation light, An output optical system that outputs laser light amplified by a laser medium body included in the laser device and emitted from the laser medium body in an optical path coaxial with the excitation light in a direction different from the optical path of the excitation light. Since the laser amplifier includes the above laser medium unit, the positional deviation of the laser medium body with respect to the optical path is reduced. Therefore, a desired laser amplification characteristic can be stably obtained.

  A laser oscillator according to yet another aspect of the present invention includes any one of the above laser devices and an optical resonator in which a laser medium body included in the laser device is arranged on a resonance optical path. Since the laser oscillator includes the above laser medium unit, the positional deviation of the laser medium body with respect to the optical path is reduced. Therefore, desired laser characteristics can be stably obtained.

  According to the present invention, a laser device, a laser amplifier, and a laser oscillator that can stably obtain desired laser characteristics are provided.

FIG. 1 is a diagram showing a configuration of a laser amplifier according to one embodiment. FIG. 2 is a cross-sectional perspective view showing the configuration of the laser device shown in FIG. FIG. 3 is an exploded perspective view showing the configuration of the laser medium unit shown in FIG. FIG. 4 is an exploded perspective view showing the configuration of the laser medium body shown in FIG. FIG. 5 is a diagram showing how the medium holding block is deformed. FIG. 6 is a diagram showing a configuration of a laser resonator according to another mode. Part (a) of FIG. 7 and part (b) of FIG. 7 are views showing a medium holding unit according to a modification.

<First Embodiment>
Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

  FIG. 1 is a diagram schematically showing a configuration of a laser amplifier including a laser device according to an embodiment of the present invention. The laser amplifier 1 amplifies the laser light L2 (seed light) to be amplified, which is provided from the seed light source unit 100. The laser amplifier 1 includes an excitation light source unit 2, a mirror unit 3, and a laser device 4. The excitation light source unit 2 emits excitation lights L1a and L2a. The mirror unit 3 transmits the excitation lights L1a and L1b and reflects the laser light L2. The laser device 4 is excited by the excitation lights L1a and L1b provided from the excitation light source unit 2 and amplifies the laser light L2 provided from the seed light source unit 100.

  The excitation light source unit 2 includes a light source 2a that provides the excitation light L1a and a light source 2b that provides the excitation light L1b. The optical path of the excitation light L1a intersects the optical path of the laser light L2 provided from the seed light source unit 100. The light sources 2a and 2b output light having a wavelength that can excite the laser medium unit 8 of the laser device 4. The wavelengths of the excitation lights L1a and L1b are different from the wavelength of the laser light L2. As the light sources 2a and 2b, for example, a semiconductor laser can be adopted. The excitation light source unit 2 may include a condensing optical system (not shown) that condenses the excitation lights L1a and L1b.

  The mirror unit 3 is arranged on the optical path of the excitation lights L1a and L1b between the excitation light source unit 2 and the laser device 4. The mirror unit 3 has a mirror 3a that functions as an incident optical system and a mirror 3b that functions as an output optical system. The mirrors 3a and 3b may be dichroic mirrors that transmit light having a predetermined wavelength and reflect light having a wavelength different from the predetermined wavelength. In addition, the mirrors 3a and 3b are arranged at symmetrical positions when the laser amplifier 1 is viewed in a plan view. With such a symmetrical arrangement, more power can be supplied to the laser medium unit 8 evenly. Since the excitation lights L1a and L1b are mostly absorbed in the laser medium unit 8, there is almost no excitation lights L1a and L1b that pass through the laser medium unit 8 and are emitted to the outside.

  The mirror 3a is arranged at the intersection of the optical path of the excitation light L1a and the optical path of the laser light L2. The mirror unit 3 transmits the excitation light L1a from the light source 2a and makes the excitation light L1a incident on the laser device 4. Further, the mirror 3 a reflects the laser light L 2 from the seed light source unit 100 and makes the laser light L 2 incident on the laser device 4. The optical path of the excitation light L1a after passing through the mirror 3a and the optical path of the laser light L2 after being reflected by the mirror unit 3 are coaxial. In FIG. 1, the excitation light L1a and the laser light L2, which are shown to be parallel to each other, mean that they are coaxial.

  The mirror 3b reflects the amplified laser light L2 emitted from the laser device 4 in a direction intersecting the optical path of the excitation light L1b. Further, the mirror 3b transmits the excitation light L1b from the light source 2b and makes the excitation light L1b incident on the laser device 4.

  Next, the laser device 4 will be described. FIG. 2 is a cross-sectional perspective view showing the configuration of the laser device 4. The laser device 4 includes a frame 6, a chamber 7, a laser medium unit 8, and a cooling unit 9.

  The frame 6 holds the chamber 7 and the cooling unit 9 in place. The frame 6 includes a bottom plate 11, an intermediate plate 12, a top plate 13, a spacer 14, and a vibration isolator 16. The bottom plate 11 has a disk shape, and the chamber 7 is placed on the main surface 11a. A plurality of spacers 14 are arranged on the main surface 11 a of the bottom plate 11. On the main surface 11 a of the bottom plate 11, the plurality of spacers 14 are arranged at equal intervals so as to surround the chamber 7.

  The intermediate plate 12 is arranged on the upper end side of the spacer 14. That is, the chamber 7 and the spacer 14 are arranged between the bottom plate 11 and the intermediate plate 12. The length of the spacer 14 is longer than the height of the chamber 7. Therefore, a gap is formed between the chamber 7 and the intermediate plate 12.

  The intermediate plate 12 has a ring shape and has a through hole 12b into which a part of the cooling unit 9 is inserted. A plurality of vibration isolation parts 16 are arranged on the upper surface 12 a of the intermediate plate 12. The vibration isolation units 16 are arranged at equal intervals around the central axis of the intermediate plate 12. The top plate 13 is arranged on the upper end side of the vibration isolation unit 16.

  The top plate 13 supports the cooling head 17. A cooling head 17 is arranged at the center of the main surface 13 a of the top plate 13. The cooling head 17 can be, for example, a GM refrigerator driven based on the Gifford McHon cycle. The cooling head 17 generates vibration during its operation. This vibration is damped by the vibration isolation unit 16 arranged between the top plate 13 and the intermediate plate 12. A bellows 18 is arranged between the top plate 13 and the chamber 7.

  The chamber 7 is a container that houses the laser medium unit 8, and is arranged on the bottom plate 11. A laser medium unit 8 and one end of a cooling unit 9 are arranged in the chamber 7. Further, the chamber 7 has a first window 7a and a second window 7b. The first window 7a provided on the side wall of the chamber 7 allows the excitation light L1a and the laser light L2 to pass therethrough. The first window 7a is formed on the optical path from the light source 2a to the laser medium unit 8. Further, the second window 7b provided on the side wall of the chamber 7 at another place allows the excitation light L1b and the laser light L2 to pass therethrough. The second window 7b is formed on the optical path from the laser medium unit 8 to the light source 2b.

  The laser medium unit 8 is excited by the excitation lights L1a and L1b provided from the excitation light source unit 2 and amplifies the laser light L2 provided from the seed light source unit 100. The laser medium unit 8 is placed on the bottom surface of the chamber 7. The detailed structure of the laser medium unit 8 will be described later.

  The cooling unit 9 cools the laser medium unit 8. The cooling unit 9 includes a cooling head 17 (cooling unit), a cryo heat absorption unit 19 (second heat conduction unit), and a plurality of heat conduction units 21A (third heat conduction unit). As an example, the cooling unit 9 cools the laser medium unit 8 to about 100K to 200K.

  The cryo endothermic portion 19 is a columnar member, the upper end of which is connected to the cooling head 17, and the lower end of which is connected to the heat conducting unit 21A.

  The heat-conducting unit 21A has an upper end connected to the cryo-heat absorbing portion 19 and a lower end connected to the laser medium unit 8. The heat transfer unit 21A has a copper net 21a and a fixed plate 21b. The upper end of the copper net 21a is sandwiched between the lower end of the cryo endothermic portion 19 and the fixed plate 21b, and is physically and thermally connected. The lower end of the copper net 21a is sandwiched between the laser medium unit 8 and the fixed plate 21b, and is physically and thermally connected. The copper net 21a is formed of copper or a copper alloy having good thermal conductivity. The copper net 21a is formed by weaving thin copper wires, and has lower rigidity than a plate-shaped copper plate. In other words, the copper net 21a is a member that thermally connects the laser medium unit 8 and the cryo endothermic portion 19, and is a member that is not expected to have a mechanical supporting force. Therefore, the heat exhausting portion 31 and the upper heat sink 26 (second substrate) are structurally configured to be hung on the frame 6 via the cryo heat absorbing portion 19.

  According to this configuration, the vibration generated in the cooling head 17 is transmitted to the cryoheat absorbing portion 19, but is damped in the heat conducting unit 21A having the copper net 21a. Specifically, since the rigidity of the copper net 21a is low (that is, the natural frequency of the copper net 21a is small), based on the frequency response curve of mechanical vibration, the vibration generated in the cooling head 17 having a frequency higher than the natural frequency is generated. Is attenuated.

  Next, the laser medium unit 8 will be described in detail. As shown in FIG. 3, the laser medium unit 8 includes a laser medium body 22, a heat insulating sheet 23, a lower heat sink 24 (first substrate), an upper heat sink 26 (second substrate), and a positioning block 27. (Positioning member), medium body holding blocks 28A, 28B, 28C (medium body holding member), tension spring 29 (elastic member), and heat conducting unit 21B (first heat conducting portion).

  The lower heat sink 24 is a plate-like member having a rectangular shape in a plan view, and is placed on the bottom surface of the chamber 7 via a heat insulating sheet 23 made of ceramic or the like. Therefore, since the heat transfer from the chamber 7 to the lower heat sink 24 is suppressed, the temperature of the laser medium unit 8 can be controlled appropriately. The lower heat sink 24 is a metal material having good thermal conductivity, and is formed of, for example, copper or a copper alloy. In the following description, “good thermal conductivity” means that the thermal conductivity of the member is higher than that of the laser medium body 22, that is, the laser gain media 33A, 33B, 33C and the optical medium 32. Means that.

  The laser medium body 22 is mounted on the lower heat sink 24. Specifically, the lower surface of the laser medium body 22 physically contacts the main surface 24 a of the lower heat sink 24. The position of the laser medium body 22 on the main surface 24a is maintained by the positioning block 27 and medium body holding blocks 28A, 28B, 28C. The detailed relationship between the laser medium body 22, the positioning block 27, and the medium body holding blocks 28A, 28B, 28C will be described later.

  An upper heat sink 26 is placed on the laser medium body 22. Specifically, the upper surface of the laser medium body 22 physically contacts the lower surface 26 a of the upper heat sink 26. The upper heat sink 26 is a plate-shaped member having a rectangular shape in a plan view, and has the same shape as the lower heat sink 24. The main surface 26b of the upper heat sink 26 is provided with a disc-shaped heat exhausting section 31. The lower end of the heat transfer unit 21A is connected to the heat exhaust unit 31. The upper heat sink 26 is a metal material having good thermal conductivity, and is made of, for example, copper or a copper alloy.

  The tension spring 29 is provided on the back surface of the lower heat sink 24 and the upper heat sink 26. The lower end (one end) of the tension spring 29 is connected to the lower heat sink 24, and the upper end (other end) is connected to the upper heat sink 26. The tension spring 29 generates a force that pulls the upper heat sink 26 toward the lower heat sink 24. The laser medium body 22 is sandwiched between the lower heat sink 24 and the upper heat sink 26 by these tension springs 29.

  Further, three heat conducting units 21B are provided on the back surfaces of the lower heat sink 24 and the upper heat sink 26. The heat transfer unit 21B has the same configuration as the heat transfer unit 21A. The lower end of the heat transfer unit 21B is connected to the back surface of the lower heat sink 24, and the upper end is connected to the back surface of the upper heat sink 26. The lower heat sink 24 and the upper heat sink 26 are thermally connected to each other by these heat conducting units 21B.

  As shown in FIG. 4, the laser medium body 22 is a solid-state laser medium body, and includes an optical medium 32 and laser gain media 33A, 33B, and 33C.

  The optical medium 32 is a transparent member made of yttrium-aluminum-garnet (YAG), and the optical medium 32 transmits the excitation lights L1a and L1b and the laser light L2. The optical medium 32 is a thin flat plate having a trapezoidal shape in a plan view. The optical medium 32 has four side surfaces 32a, 32b, 32c, 32d. The side surfaces 32a, 32b, 32c, 32d are flat surfaces. When the optical medium 32 is viewed in a plan view, the side surface 32c (first side surface) and the side surface 32d (second side surface) are parallel to each other. For example, the side surface 32d is referred to as a lower bottom and the side surface 32c is referred to as an upper bottom. You can also The side surface 32a (first side surface) and the side surface 32b (first side surface) can also be called a trapezoidal leg. Further, the optical medium 32 has a first main surface 32e and a second main surface 32f. The first main surface 32e contacts the main surface 24a of the lower heat sink 24. The second main surface 32f, which faces the first main surface 32e, contacts the lower surface 26a of the upper heat sink 26.

  A laser gain medium 33A is connected to the side surface 32a, a laser gain medium 33B is connected to the side surface 32b, and a laser gain medium 33C is connected to the side surface 32c. On the other hand, the side surface 32d is a light incidence / emission surface on which the pump lights L1a and L1b are incident and the amplified laser light L2 is emitted. That is, the laser gain medium is not connected to the side surface 32d.

  The laser gain media 33A, 33B, 33C are joined to the optical media 32 by, for example, a ceramic composite technique. The size and plan view shape of the laser gain mediums 33A, 33B, 33C depend on the shapes and sizes of the side surfaces 32a, 32b, 32c and the diameters of the excitation lights L1a, L1b incident on the laser gain media 33A, 33B, 33C. Can be set accordingly. The laser gain media 33A, 33B and 33C may be larger than the irradiation regions of the pump lights L1a and L1b incident thereon. Examples of the size and plan view shape of the laser gain media 33A, 33B, 33C include rectangles and squares. The laser gain media 33A, 33B, 33C are YAG doped with Yb as an active element. The laser gain media 33A, 33B, 33C are excited by the pump lights L1a, L1b. The excited laser gain media 33A, 33B, 33C can output emitted light. One example of emitted light is stimulated emission light. This stimulated emission light contributes to the optical amplification of the laser light L2.

  The positioning block 27 is physically fixed to the lower heat sink 24 (see FIG. 3). The side surface 27 a of the positioning block 27 contacts the side surface 32 d of the optical medium 32. Therefore, the movement of the optical medium 32 in the direction of the normal line N1 of the side surfaces 27a and 32d is restricted. The height of the positioning block 27 is lower than the height of the optical medium 32. That is, a gap is formed between the positioning block 27 and the upper heat sink 26. The positioning block 27 is a metal material having good thermal conductivity, and is formed of, for example, copper or a copper alloy.

  The medium body holding blocks 28A, 28B, 28C are different only in the positions where they are arranged, and have the same shape as a single body. Hereinafter, the medium body holding block 28C will be described in detail, and the description of the medium body holding blocks 28A and 28B will be omitted.

  The medium body holding block 28C is a heat conducting member having good heat conductivity, and is made of copper as an example. The medium holding block 28C has a fixed portion 34 and a deformable portion 36. The fixing portion 34 has a rectangular parallelepiped shape and is fixed in a state of being in physical contact with the lower heat sink 24. Therefore, the medium holding block 28C is thermally connected to the lower heat sink 24. The height of the medium holding block 28C is lower than the height of the optical medium 32. That is, a gap is formed between the medium holding block 28C and the upper heat sink 26.

  A deforming portion 36 is provided on the side surface of the fixed portion 34 facing the laser gain medium 33C. The deformable portion 36 is formed integrally with the fixed portion 34. Therefore, the deformable portion 36 is thermally connected to the fixed portion 34. The deforming portion 36 has a plurality of comb teeth 36a extending from the side surface of the fixed portion 34 toward the laser gain medium 33C. The tip of the deforming portion 36 (that is, the tip of the comb tooth 36a) contacts the laser gain medium 33C. Therefore, the deforming portion 36 is thermally connected to the laser gain medium 33C. Therefore, the laser gain medium 33C is thermally connected to the lower heat sink 24 via the deforming portion 36 and the fixing portion 34 of the medium holding block 28C.

  The side surface of the fixed portion 34 faces the main surface 33a of the laser gain medium 33C. More specifically, the side surface of the fixed portion 34 is parallel to the main surface 33a of the laser gain medium 33C. The comb teeth 36 a extend in a direction inclined with respect to the side surface of the fixed portion 34. In other words, the extending direction A1 of the comb teeth 36a is inclined with respect to the normal direction N2a of the side surface of the fixed portion 34. Therefore, the extending direction A1 of the comb teeth 36a is also inclined with respect to the main surface 33a of the laser gain medium 33C which is parallel to the side surface of the fixed portion 34. That is, the extending direction A1 of the comb teeth 36a is also inclined with respect to the normal direction N2b of the main surface 33a of the laser gain medium 33C.

  Here, as shown in FIG. 5, when the force F along the normal direction N2a of the fixed portion 34 (or the normal direction N2b of the laser gain medium 33C) acts on each of the tips 36b of the comb teeth 36a. Assume Focusing on one of the comb teeth 36a, the direction FA of the force F is inclined with respect to the extending direction A1 of the comb teeth 36a. Then, the comb teeth 36a can be regarded as a leaf spring having a cantilever structure in which the base end portion 36c on the fixed portion 34 side is a fixed end and the tip end 36b on the laser gain medium 33C side is a free end. According to the cantilever structure, the comb teeth 36a can be flexibly elastically deformed with respect to the force acting on the free end (the tip 36b). When the entire deformable portion 36 having the plurality of comb teeth 36a is viewed, the tips of the plurality of comb teeth 36a come into contact with the laser gain medium 33C. When the laser gain medium 33C moves in the normal direction N2b of the main surface 33a of the laser gain medium 33C, bending deformation occurs in each of the comb teeth 36a. That is, the deforming section 36 allows the laser gain medium 33C to move in the normal direction N2b.

  Therefore, the medium body holding block 28 functions as a heat transfer path that transfers the heat generated in the laser medium body 22 to the lower heat sink 24, and also functions as a physical buffer that allows the deformation of the laser medium body 22.

  By the way, in the laser medium unit 8 used in the laser amplifier 1, it is necessary to cool the Yb: YAG crystal used as the laser gain medium to about 100K during its operation. Therefore, the laser medium unit 8 of the laser amplifier 1 is exposed to an environment of about room temperature during maintenance, for example, while being cooled at about 100K during its operation. Thus, in the laser medium unit 8 exposed to the cryogenic environment and the room temperature environment, thermal expansion and thermal contraction of the components occur. Repeated thermal expansion and thermal contraction of these components may cause misalignment of the laser medium unit 8.

  Therefore, it is conceivable to configure the holding member of the laser medium unit 8 so that the laser medium does not shift even when thermal expansion and thermal contraction occur. However, according to such a configuration, when the laser medium unit 8 is exposed to a room temperature environment, that is, when the laser medium unit 8 causes thermal expansion, deformation due to thermal expansion is not allowed. Therefore, a stress may occur in the laser medium unit 8.

  Therefore, in the laser medium unit 8, the positioning block 27 is fixed to the lower heat sink 24. Therefore, since the positioning block 27 can regulate the movement of the optical medium 32, it is possible to suppress the optical axis shift of the optical medium 32 and the laser gain media 33A, 33B, and 33C connected to the optical medium 32 by the positioning block 27. On the other hand, since the medium body holding blocks 28A, 28B, 28C have the deforming portion 36, the thermal deformation caused by the difference in the coefficient of thermal expansion between the components forming the laser medium unit 8 and the temperature change is allowed. . Therefore, it is possible to suppress the generation of thermal stress that occurs in the components forming the laser medium unit 8. Moreover, since the medium holding blocks 28A, 28B, 28C are formed of copper having good thermal conductivity, the heat generated in the laser gain mediums 33A, 33B, 33C is transferred to the lower heat sink via the deforming portion 36 and the fixing portion 34. You can tell 24. Therefore, the heat generated during the operation of the laser medium unit 8 is preferably discharged, and the heat distribution inside the optical medium 32 and the laser gain media 33A, 33B, 33C can be made uniform. As a result, the laser medium unit 8 suppresses the occurrence of optical misalignment of the laser gain media 33A, 33B, and 33C, suppresses the occurrence of internal stress, and the optical medium 32 and the laser gain media 33A, 33B and 33C. Since the heat distribution in (3) is made uniform, the states of the optical medium 32 and the laser gain media 33A, 33B, 33C can be thermally and structurally stabilized. Therefore, desired laser characteristics can be stably obtained.

  The laser medium body 22 is sandwiched between the lower heat sink 24 and the upper heat sink 26. The lower heat sink 24 and the upper heat sink 26 are thermally connected to each other by the heat conducting unit 21B. Therefore, the heat generated in the laser medium body 22 and discharged to the lower heat sink 24 is transferred to the upper heat sink 26 via the heat conducting unit 21B. Then, it is discharged from the heat exhausting portion 31 of the upper heat sink 26 toward the cooling unit 9 via the heat conducting units 21A and 21B and the cryo heat absorbing portion 19. Therefore, the heat generated in the laser medium body 22 can be efficiently discharged.

  Further, the lower heat sink 24 and the upper heat sink 26 are attracted to each other by a tension spring 29 to sandwich the laser medium body 22. According to this configuration, the deformation of the laser medium body 22 in the thickness direction is allowed by the extension of the tension spring 29. Therefore, the holding state of the laser medium body 22 can be further stabilized.

  Further, the laser medium unit 8 is connected to the cryoheat absorbing section 19 via the heat conducting unit 21B. The heat conducting unit 21B has a natural frequency lower than the frequency of vibration generated by the cooling head 17. Therefore, the vibration generated in the cooling head 17 is damped in the heat transfer unit 21B. That is, the vibration generated in the cooling head 17 does not affect the laser medium unit 8. Therefore, the states of the optical medium 32 and the laser gain media 33A, 33B, 33C can be further stabilized. Therefore, stable laser characteristics can be suitably obtained.

<Second Embodiment>
FIG. 6 is a diagram schematically showing the configuration of the laser oscillator according to the second embodiment. The laser oscillator 1A shown in FIG. 6 generates the laser light L3 by being supplied with the excitation lights L1a and L2a. The laser oscillator 1A includes an excitation light source unit 2, a mirror unit 3A, and a laser device 4. Since the pumping light source unit 2 and the laser device 4 have the same configurations as the pumping light source unit 2 and the laser device 4 of the first embodiment, detailed description thereof will be omitted.

  The mirror unit 3A is arranged on the optical path of the excitation lights L1a and L1b between the excitation light source unit 2 and the laser device 4. The mirror unit 3A has mirrors 3c, 3d, 3e. The mirror 3c is arranged on the optical path of the excitation light L1a emitted from the light source 2a. The mirror 3c transmits the excitation light L1a and reflects the laser light L3 as the emission light generated by the laser device 4.

  The mirror 3d is arranged on the optical path of the excitation light L1b emitted from the light source 2b. The mirror 3d transmits the excitation light L1b and reflects a part of the laser light L3. The mirrors 3c and 3d form an optical resonator. In other words, the mirrors 3c and 3d are arranged so that the laser light L3 is repeatedly reflected between the mirrors 3c and 3d. The laser medium unit 8 is arranged in the resonance optical path between the mirrors 3c and 3d.

  The mirror 3e is arranged between the mirror 3d and the light source 2b. The mirror 3e transmits the excitation light L1b emitted from the light source 2b and reflects a part of the laser light L3 transmitted through the mirror 3d in a direction different from the optical path of the excitation light L1b. Therefore, the laser light L3 reflected by the mirror 3e is the output light.

  Since the laser oscillator 1A includes the laser device 4, the laser medium body 51 can be held in a physically stable state. As a result, the positional deviation of the laser medium body 51 with respect to the optical path is reduced, so that desired laser characteristics can be stably obtained.

  The present invention has been described in detail above based on the embodiments. However, the present invention is not limited to the above embodiment. The present invention can be variously modified without departing from the gist thereof.

  For example, as shown in part (a) of FIG. 7, the laser medium unit 8B may include a cylindrical laser medium body 51. The cylindrical laser medium body 51 has one end supported by the medium body holding portion 52A and the other end supported by the medium body holding portion 52B. The medium body holding portions 52A and 52B are fixed to the heat sinks 53A and 53B, respectively. As shown in part (b) of FIG. 7, the medium body holding portion 52A has a fixed portion 54 fixed to the heat sink 53A and a deformable portion 56 capable of elastic deformation. The deforming portion 56 has a plurality of comb teeth 56a extending in an arc shape from the inner peripheral surface of the cylindrical fixing portion 54 toward the center. The comb teeth 56a are provided at equal intervals around the central axis of the fixed portion 54. The outer peripheral side of the comb teeth 56 a is a fixed end fixed to the fixed portion 54. The inner peripheral side of the comb teeth 56 a is a free end that is in contact with the laser medium body 51. The deformable portion 56 is elastically deformable in the diameter direction of the fixed portion 54 (that is, the diameter direction of the laser medium body 51). Therefore, when the laser medium body 51 generates heat and the diameter of the laser medium body 51 increases, the deforming portion 56 allows the diameter change. Therefore, the laser medium body 51 can be held in a structurally stable state. Thereby, desired laser characteristics can be stably obtained.

  Further, for cooling the laser medium unit 8, for example, liquid nitrogen may be used.

DESCRIPTION OF SYMBOLS 1 ... Laser amplifier, 1A ... Laser oscillator, 2 ... Excitation light source part, 3 ... Mirror part, 4 ... Laser device, 6 ... Frame, 7 ... Chamber, 8 ... Laser medium unit, 9 ... Cooling unit, 11 ... Bottom plate, 12 ... intermediate plate, 13 ... top plate, 14 ... spacer, 16 ... vibration isolation unit, 17 ... cooling head (cooling unit), 18 ... bellows, 19 ... cryo heat absorption unit (second heat conduction unit), 21A ... heat conduction unit ( 3rd heat-conducting part), 21B ... Heat-conducting unit (first heat-conducting part), 21a ... Copper net, 21b ... Fixing plate, 22 ... Laser medium body, 23 ... Insulating sheet, 24 ... Lower heat sink (first substrate) , 26 ... Upper heat sink (second substrate), 27 ... Positioning block (positioning member), 28A, 28B, 28C ... Medium body holding block (medium body holding portion), 29 ... Tension spring (elastic member), 31 ... Discharge Heat part, 3 ... optical medium, 33A, 33B, 33C ... laser gain medium, 34 ... fixed part, 36 ... deformable part, 36a, 56a ... comb teeth, 51 ... laser medium body, 52A, 52B ... medium body holding part, 53A, 53B ... Heat sink, L1a, L1b ... Excitation light, L2 ... Laser light.

Claims (7)

A first substrate,
A laser medium body that is excited by being irradiated with excitation light,
A medium body holding member which is fixed to the first substrate and holds the laser medium body with respect to the first substrate,
The medium body holding member has a fixing portion fixed to the first substrate, and a deformable portion that is in contact with the laser medium body and is elastically deformable, and is generated in the laser medium body. A laser device configured to transfer heat to the first substrate via the deforming portion and the fixing portion. A positioning member fixed to the first substrate and abutting on the laser medium body;
The laser medium body is a laser gain medium that is excited by being irradiated with the excitation light, and an optical medium that is mounted on the first substrate and transmits the excitation light. 1st main surface which contact | abuts to the 1st board | substrate, the 2nd main surface which opposes the said 1st main surface, the 1st side surface with which the said laser gain medium is joined, and the said excitation light are passed. An optical medium having a second side surface,
The deformable portion elastically deforms along a normal direction of the first side surface when the laser gain medium moves in a direction including a normal direction of the first side surface. The laser device described. A second substrate in contact with the second main surface;
The first heat conducting unit connected to each of the first substrate and the second substrate, and thermally connecting the first substrate to the second substrate, further comprising: The laser device described.   The first substrate includes one end connected to the first substrate and the other end connected to the second substrate. The first substrate is pressed against the laser medium body and the second substrate is connected to the laser beam. The laser device according to claim 3, further comprising an elastic member that generates a tensile force that is pressed against the medium body. A cooling unit for cooling the optical medium and the laser gain medium;
A second heat conducting section connected to the cooling section;
A third heat conducting part having one end connected to the second heat conducting part and the other end connected to the second substrate,
The laser device according to claim 3, wherein the third heat conducting unit has a natural frequency lower than the frequency of vibration generated by the cooling unit. A laser device according to any one of claims 1 to 5,
An incident optical system that makes laser light to be optically amplified enter an optical medium of the laser device in an optical path coaxial with excitation light,
An output optical system that outputs the laser light amplified by a laser medium body included in the laser device and emitted from the laser medium body in an optical path coaxial with the excitation light in a direction different from the optical path of the excitation light. , Laser amplifier. A laser device according to any one of claims 1 to 5,
An optical resonator in which a laser medium body included in the laser device is arranged on a resonant optical path.

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