WO2016140154A1 - Solid-state laser medium and solid-state laser beam amplifier - Google Patents

Solid-state laser medium and solid-state laser beam amplifier Download PDF

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Publication number
WO2016140154A1
WO2016140154A1 PCT/JP2016/055747 JP2016055747W WO2016140154A1 WO 2016140154 A1 WO2016140154 A1 WO 2016140154A1 JP 2016055747 W JP2016055747 W JP 2016055747W WO 2016140154 A1 WO2016140154 A1 WO 2016140154A1
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Prior art keywords
solid
active region
state laser
laser medium
region
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PCT/JP2016/055747
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French (fr)
Japanese (ja)
Inventor
太田　猛史
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カナレ電気株式会社
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Priority to JP2016520106A priority Critical patent/JPWO2016140154A1/en
Publication of WO2016140154A1 publication Critical patent/WO2016140154A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/04—Arrangements for thermal management
    • H01S3/042—Arrangements for thermal management for solid state lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/0941—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a laser diode

Definitions

  • the present invention relates to a solid-state laser medium.
  • the present invention also relates to a solid-state laser optical amplifier, and more particularly to a solid-state laser optical amplifier provided with a disk-shaped solid laser medium.
  • Patent Document 1 discloses a solid-state laser medium in which an active region is formed by doping a laser-active species into a part of a disk-shaped (thin-film) transparent mother crystal by ion implantation.
  • Patent Document 2 discloses a solid-state laser using a solid-state laser medium in which a transparent window region is provided around a thin-film active region.
  • Patent Document 3 discloses a solid-state laser in which a solid-state laser medium and a semiconductor laser are provided on a common heat sink.
  • Patent Document 4 discloses a structure in which excitation light from a semiconductor laser is directly introduced into a solid-state laser medium in which an active region and a transparent region are stacked.
  • Patent Document 5 discloses a structure in which excitation light is introduced through a slab optical waveguide into a solid-state laser medium in which an active region and a transparent region are laminated.
  • Patent Document 6 discloses a method of forming a solid laser medium having an active region and a transparent region by diffusion bonding or adhesion.
  • Patent Document 7 discloses a method of forming a solid laser medium having an active region and a transparent region by a sintering method.
  • Patent Document 8 discloses a method of forming a solid laser medium having a transparent region at the periphery of an active region by a sintering method.
  • Patent Document 9 discloses a solid-state laser medium in which a side surface of a transparent region provided at a peripheral portion of an active region is inclined and an antireflection coating is applied.
  • Patent Document 10 discloses a solid-state laser in which an active region and a transparent region are stacked and the active region is directly cooled by a liquid.
  • Non-Patent Document 1 discloses a solid-state laser in which excitation light from a semiconductor laser is directly introduced into a solid-state laser medium in which a transparent region is provided at the periphery of an active region.
  • the thickness of the transparent region of the excitation light introducing portion is larger than the thickness of the active region. For this reason, introduction of excitation light is easy.
  • the solid laser medium is formed by the ion implantation method, the productivity is low, and it is difficult to dope the laser active species at a high concentration.
  • An object of the present invention is to provide a solid-state laser medium that is easy to manufacture, can be highly doped with laser active species, and can be easily introduced with excitation light.
  • the solid-state laser medium of the present invention comprises a flat active region and a flat transparent region, and the outer shape of the transparent region is larger than the outer shape of the active region, and one surface of the active region is high.
  • the reflective layer is provided, the surface of the active region on which the high reflectance layer is provided is cooled by contacting the heat sink, and the active region is arranged so that the outer shape does not protrude from the transparent region, and the excitation light is transparent. It is introduced from the side surface of the region, and excitation light reaches the active region through the transparent region and excites the active region.
  • the thickness of the transparent region can be made larger than that of the active region, the introduction of excitation light can be facilitated. Since the active region and the transparent region are formed by bonding, manufacturing is easy, and the active region can be highly doped with laser active species.
  • FIG. 1 shows the configuration of a solid-state laser medium 10 according to the first embodiment of the present invention.
  • FIG. 1 shows a configuration of a solid-state laser laser oscillator 20 configured using the solid-state laser medium 10 .
  • FIG. 1A is a view of the solid-state laser light medium 10 as viewed from the upper surface side.
  • FIG. 1B is a cross-sectional view of the solid-state laser medium 10 taken along the line XX ′.
  • FIG. 1C is a side view showing another configuration of the active region of the solid-state laser laser emitting medium 10 .
  • FIG. 1D is a side view showing the configuration of a solid-state laser laser oscillator 20 configured using the solid-state laser medium 10 .
  • the solid laser medium 10 is a solid laser medium composed of an active region 1 and a transparent region 2.
  • the active region 1 is, for example, a YAG single crystal, a base material such as ceramics doped with a laser active species such as Nd or Yb.
  • the transparent region 2 is, for example, a YAG single crystal not doped with a laser active species, ceramics, or the like.
  • a high reflectivity layer 8 is provided on one surface 4 of the active region 1.
  • An antireflective coating layer 9 is provided on one surface 3 of the transparent region 2. Another surface 11 of the active region 1 and another surface 5 of the transparent region 2 are joined.
  • the active region 1 is flat and circular.
  • the transparent region 2 is flat and circular.
  • the outer shape of the active region 1 is smaller than the outer shape of the transparent region 2, and the active region 1 is joined so as not to protrude the outer shape of the transparent region 2.
  • the shapes of the active region 1 and the transparent region 2 of the solid-state laser medium 10 are circular, but other shapes may be used.
  • the solid-state laser medium 10 can be manufactured using the methods described in Patent Documents 6, 7, and 8. That is, the solid-state laser medium 1 can be manufactured by a technique such as diffusion bonding, bonding with an adhesive, or bonding using sintering.
  • the active region 1 and the transparent region 2 are formed by joining, manufacturing is easy. Further, the active region can be doped with laser active species at a high concentration.
  • Excitation light 12 is introduced into the side surface 6 of the transparent region 2, reaches the active region 1 through the excitation light 12 transparent region 2, and excites the active region 1. For this reason, the active region 1 expresses the function of light amplification. Since the high reflectivity layer 8 is provided on the surface 4 of the active region 1, the solid-state laser medium 10 functions as an optical amplifier having a reflecting mirror function. Such an optical amplifier is called an active mirror.
  • FIG. 1D shows a configuration of a solid-state laser laser oscillator 20 configured using the solid-state laser medium 10 and the output reflecting mirror 22.
  • the high reflectivity layer 8 and the output reflecting mirror 22 form a Fabry-Perot resonator, and laser oscillation 21 occurs.
  • the surface 4 of the active region 1 is bonded to a heat sink (not shown).
  • the side surface 7 of the active region 1 is a rough surface. This is to prevent the parasitic oscillation 13 shown in FIG. This parasitic oscillation 13 occurs because an unintended Fabry-Perot resonator (parasitic Fabry-Perot resonator) is formed by the side surface 7 of the active region 1.
  • the reflectance may be reduced by applying a non-reflective coating to the side surface 7 of the active region 1. If the reflectance of the side surface 7 is reduced, the parasitic oscillation 13 can be prevented.
  • the configuration in which the side surface 7 of the active region 1 is rough also has an effect of suppressing parasitic oscillation caused by the whispering gallery mode that occurs when the active region 1 is circular.
  • the whispering gallery mode is a mode that propagates along the circumference of a circular waveguide. This is a mode as indicated by reference numeral 38 in FIG.
  • an inclined side surface 15 may be provided instead of the side surface 7.
  • the inclined side surface 15 may be further roughened.
  • a non-reflective coating may be further applied to the inclined side surface 15.
  • the side surface 7 of the active region 1 is not involved in the introduction of excitation light and can be roughened. Further, the side surface 7 can be provided with an independent inclination. For this reason, occurrence of parasitic oscillation can be prevented.
  • the active region 1 and the transparent region 2 are individually formed in the solid laser medium 10 , the active region 1 is sufficiently thinned to increase the cooling efficiency of the active region 1, and at the same time, the transparent region 2 is thickened to be excited. Introduction of the light 2 can be facilitated. Further, even when the active region 1 has a large diameter, the active region 1 can be uniformly excited by controlling the thickness of the transparent region 2.
  • FIG. 2 shows a solid-state laser medium 30 according to the second embodiment of the present invention.
  • FIG. 2A is a top view showing the solid-state laser medium 30 .
  • FIG. 2B is a side view showing a method for exciting the solid-state laser medium 30 .
  • FIG. 2C shows the evanescent coupling.
  • FIG. 2D shows the shape of the active region 1 for suppressing parasitic oscillation.
  • the solid-state laser medium 30 has a structure in which the transparent region 2 and the active region 1 are individually formed and physically contacted.
  • the transparent region 2 and the active region 1 are evanescently coupled through a thin gas layer (vacuum layer) 33.
  • the surface 4 of the active region 1 is bonded to the heat sink 31.
  • the surface 5 of the transparent region 2 is in physical contact with the surface 11 of the active region 1 by pressure 32.
  • the excitation light 12 is introduced into the side surface 6 of the transparent region 2.
  • FIG. 2 (c) In the configuration of FIG. 2 (b), evanescent coupling as shown in FIG. 2 (c) occurs.
  • a thin gas layer (vacuum layer) 33 is formed between the active region 1 and the transparent region 2.
  • the excitation light 12 generates evanescent light 34 at the interface between the transparent region 2 and the gas layer (vacuum layer) 33, and this evanescent light 34 is transmitted light at the interface between the gas layer (vacuum layer) 33 and the active region 1. 35.
  • Reflected light 36 is also generated and propagates through the transparent region 42. The transmitted light 35 is absorbed by the active region 1 and excites the active region 1.
  • FIG. 2D shows the shape of the active region 1 for suppressing parasitic oscillation.
  • the side surface 37 of the active region 1 is intentionally formed to have irregularities, thereby causing parasitic oscillation due to the parasitic Fabry-Perot resonator and parasitic oscillation caused by the whispering gallery mode 38. Can be suppressed.
  • the transparent region 2 and the active region 1 are individually formed and physically contacted. In this configuration, since it is not necessary to join the transparent region 2 and the active region 1, the solid-state laser medium 30 can be easily manufactured.
  • the material selection is limited because the thermal expansion coefficients of the transparent region 2 and the active region 1 must be close to each other. On the other hand, there is no such restriction in the configuration of the present embodiment.
  • FIG. 3 shows the configuration of the solid-state laser medium 40 according to the third embodiment of the present invention.
  • the solid-state laser medium 40 includes a pentagonal transparent region 42.
  • a circular active region 41 is also provided.
  • FIG. 3B shows a cross-sectional structure similar to that of the solid-state laser medium 10 shown in FIG.
  • FIG. 3C shows a cross-sectional structure similar to that of the solid-state laser medium disclosed in Patent Document 1.
  • FIG. 3D shows a cross-sectional structure similar to that of the solid-state laser medium disclosed in Patent Document 2.
  • the generation of parasitic oscillation can be suppressed by adopting a shape in which there is no combination of sides parallel to the sides of the transparent region 42.
  • Parasitic oscillation due to the parasitic Fabry-Perot resonator is more likely to occur as the optical coupling between the transparent region and the active region is stronger, and this parasitic oscillation is particularly likely to occur in the configuration of FIG. Next, this parasitic oscillation is likely to occur in FIG. 3C, and then to the configuration of FIG. 3B.
  • the parasitic oscillation caused by the whispering gallery mode is unlikely to occur in the configurations of FIGS. 3 (c) and 3 (d). This is because if the refractive index difference between the active region 41 and the transparent region 42 is small, a whispering gallery mode is hardly formed at the interface between the active region 41 and the transparent region 42.
  • the parasitic oscillation by the parasitic Fabry-Perot resonator is also the parasitic oscillation by the whispering gallery mode. It is difficult to occur.
  • parasitic oscillation due to the whispering gallery mode in the active region 41 may occur.
  • the side surface of the active region 41 is roughened, or the side surface shape shown in FIG. Oscillation can be suppressed.
  • the transparent region 42 having an outer shape of a regular polygon having an odd number of vertices is used as in the present embodiment, there is no combination of sides parallel to the sides of the transparent region 42, so that the parasitic Fabry-Perot resonator is used. The resulting parasitic oscillation can be reduced.
  • the outer shape of the active layer 41 may be a polygonal system having an odd number of vertices. As a result, generation of a parasitic Fabry-Perot resonator in the active layer 41 can be prevented.
  • FIG. 4 shows the configuration of a solid-state laser optical amplifier 50 according to the fourth embodiment of the present invention.
  • FIG. 4 shows a configuration of a solid-state laser laser oscillator 60 configured using the solid-state laser optical amplifier 50 .
  • FIG. 4A is a view of the solid-state laser optical amplifier 50 as viewed from the upper surface side.
  • FIG. 4B is a YY ′ cross-sectional view of the solid-state laser optical amplifier 50 .
  • FIG. 4C is a side view of the solid state laser oscillator 60 .
  • the solid laser medium 51 is a flat thin film, and the outer shape is circular.
  • the transparent region 52 is provided above the active region 53 and is provided so as to surround the peripheral portion of the active region 53. For this reason, the thickness of the solid-state laser medium 1 is larger than the thickness of the active region 53. Further, the outer shape of the solid-state laser medium 51 is larger than the outer shape of the active region 53.
  • a high reflectivity layer 58 is provided on one surface of the solid-state laser medium 51.
  • the high reflectivity layer 58 has a high reflectivity with respect to the wavelength of light amplified by the solid-state laser optical amplifier 50 .
  • the surface of the solid laser medium 51 on which the high reflectance layer 58 is provided is bonded to the heat sink 56.
  • the outer shape of the heat sink 56 is larger than the outer shape of the solid-state laser medium 51.
  • a non-reflective coating layer 59 is provided on the surface of the solid laser medium 51 opposite to the surface on which the high reflectivity layer 58 is provided.
  • the active region 53 of the solid-state laser medium 51 is provided on the surface side where the high reflectivity layer 58 is provided.
  • a semiconductor laser 54 for excitation is provided on a heat sink 56 via a submount 55.
  • the semiconductor laser 54 is mounted on the submount 55 in a junction-down manner.
  • the submount 55 is bonded on the heat sink 56.
  • the submount 55 Since the semiconductor laser 54 is mounted on the submount 55 in a junction-down manner, the laser beam emission point of the semiconductor laser 54 is almost at the height of the submount 55 from the heat sink 56. Therefore, the submount 55 also functions as an optical alignment member.
  • the pumping semiconductor laser 54 is provided close to the solid-state laser medium 51, and the pumping light 57 from the semiconductor laser 54 is directly introduced into the solid-state laser medium 51 without passing through an optical system.
  • FIG. 4C shows a solid-state laser laser oscillator 60 configured using a solid-state laser optical amplifier 50 .
  • the solid-state laser laser oscillator 60 includes a solid-state laser optical amplifier 50 and an output reflecting mirror 61.
  • the high reflectivity layer 58 and the output reflecting mirror 61 form a Fabry-Perot resonator, whereby the laser oscillation light 62 is generated. A part of the laser oscillation light 62 is taken out as output light 63.
  • the solid-state laser optical amplifier 50 can be reduced in size and the structure can be simplified.
  • the thickness of the solid-state laser medium 51 is larger than the thickness of the active region 53, it is easy to introduce the excitation light 57 from the semiconductor laser 54 into the solid-state laser medium 51.
  • the transparent region 52 is also provided at the peripheral portion of the active region 53, the outer shape of the solid laser medium 51 is larger than the outer shape of the active region 53. For this reason, the active region 53 can be excited by a larger number of semiconductor lasers 54.
  • the transparent region 52 is also provided at the peripheral portion of the active region 53, parasitic oscillation due to the whispering gallery mode can be prevented.
  • the excitation light 57 passes through the transparent region 52 above the active region 53, the active region 53 can be uniformly excited even when the active region 53 has a large diameter.
  • the solid medium 10 shown in FIG. 1 can be used instead of the solid laser medium 51.
  • the solid-state laser medium 30 shown in FIG. 2 can be used instead of the solid-state laser medium 51.
  • the solid laser medium 40 shown in FIG. 3 can be used instead of the solid laser medium 51.
  • FIG. 5 shows the configuration of the fifth embodiment of the present invention.
  • the solid-state laser optical amplifier 70 has a configuration in which the heat sink 56 of the solid-state laser optical amplifier 50 is replaced with a heat sink 71 and the excitation light source is replaced with the semiconductor laser stack 72 from the semiconductor laser 54.
  • the semiconductor laser stack 72 has a structure in which a plurality of semiconductor laser chips are stacked.
  • a cylindrical lens 73 is provided corresponding to each semiconductor laser chip of the semiconductor laser stack 72.
  • the heat sink 71 is larger than the active region 53 but smaller than the transparent region 52.
  • the active region 53 of the solid-state laser medium 51 is bonded to the heat sink 71 via a submount 77.
  • the heat sink 71 is made of inexpensive copper.
  • the submount 77 is formed of a copper-tungsten alloy or the like having an appropriate composition ratio, and the thermal expansion coefficient is substantially the same as the material (YAG) forming the active region 53. With this configuration, thermal strain applied to the active region 53 is suppressed.
  • the transparent region 52 of the solid laser medium 51 protrudes from the heat sink 71. For this reason, the excitation light 75 from the semiconductor laser stack 72 is introduced into the side surface 76 of the solid-state laser medium 51 without being scattered by the heat sink 71.
  • the excitation light 75 from the semiconductor laser stack 72 is converted into parallel light by the cylindrical lens 73 and then introduced into the side surface 76 of the solid-state laser medium 51 by the common cylindrical lens 74.
  • the entire thickness of the solid-state laser medium 75 can be adjusted by increasing the thickness of the transparent region 52. Therefore, even if the semiconductor laser stack 72 having a large number of stacks is used, the excitation light 75 can be efficiently introduced into the solid-state laser medium 51 by making the thickness of the solid-state laser medium 51 appropriate. If the number of stacks is increased, the output of the pumping light can be increased, so that the output of the solid-state laser optical amplifier 70 can be increased.
  • the transparent region 52 is also provided in the peripheral portion of the active region 53, the active region 53 can be excited by a larger number of semiconductor laser stacks 72. Further, parasitic oscillation due to the whispering gallery mode can be suppressed.
  • the solid laser medium 10 shown in FIG. 1 can be used instead of the solid laser medium 51.
  • the solid-state laser medium 30 shown in FIG. 2 can be used instead of the solid-state laser medium 51.
  • the solid-state laser medium 40 shown in FIG. 3 can be used instead of the solid-state laser medium 51.
  • FIG. 6A shows the configuration of a solid-state laser optical amplifier 80 according to the sixth embodiment of the present invention.
  • the solid-state laser optical amplifier 80 has a configuration in which the heat sink 71 of the solid-state laser optical amplifier 70 is replaced with a heat sink 81.
  • the heat sink 81 includes a cooling tank 84 filled with a liquid 82.
  • the solid laser medium 51 is directly cooled by the liquid 82.
  • the solid-state laser medium 51 is attached to the heat sink 81 via an O-ring 83 and an attachment mechanism (not shown).
  • the O-ring 83 prevents the liquid 82 from leaking.
  • the solid-state laser medium 51 includes the transparent region 52, it is possible to give a physically high intensity by making the transparent region 52 sufficiently thick. For this reason, the solid laser medium 51 can be prevented from being damaged by the pressure of the liquid 82.
  • Patent Document 10 discloses a structure that directly cools the active region side of a solid-state laser medium in which an active region and a transparent region are stacked, but does not disclose a structure that excites the solid-state laser medium from the side surface. Moreover, the structure which provides a transparent area
  • the active region and the transparent region are stacked, and the solid laser medium provided with the transparent region at the periphery of the active region is excited from the side.
  • the solid-state laser laser medium 51 can be excited by introducing the excitation light 75 from the side surface of the solid-state laser laser medium 51.
  • 6A can be modified into a configuration according to FIG.
  • FIG. 6B shows a modification of the solid-state laser optical amplifier 80 .
  • the solid-state laser laser medium 51 is characterized in that a heat radiation fin 85 is bonded.
  • the radiating fin 85 is made of a copper tungsten alloy or a copper molybdenum alloy having an appropriate composition ratio and has a value close to the thermal expansion coefficient of YAG, which is the laser crystal material of the solid-state laser laser medium 51.
  • the radiating fins 85 are provided with irregularities (not shown) so that the contact area with the liquid 82 is increased. Thereby, cooling efficiency improves.
  • the heat sink 81 can be constructed of an inexpensive material such as copper. For this reason, when making the active region 53 large-diameter, high cost efficiency can be obtained.
  • the solid medium 10 shown in FIG. 1 can be used instead of the solid laser medium 51. Further, the shape of the side surface 37 shown in FIG. 2D can be adopted as the active region 1 of the solid-state laser medium 10 .
  • SYMBOLS 1 Active region, 2 ... Transparent region, 3 ... One surface of transparent region 2, 4 ... One surface of active region 1, 5 ... Another surface of transparent region 2, 6 ... Side surface of transparent region 2, 7 ... Side surface of active region 1, 8 ... high reflectance layer, 9 ... non-reflective coating layer, 10 ... solid laser medium, 11 ... another surface of active region 1, 12 ... excitation light, 13 ... parasitic oscillation, 15 ... active region 1 inclined side surface, 16 ... input light, 17 ... output light, 20 ... solid laser oscillator, 21 ... laser oscillation, 22 ... output reflector, 30 solid laser medium, 31 ... heat sink, 32 ... pressure, 33 ...
  • Heat sink 72 ... Semiconductor laser Stack 73 ... Cylindrical lens, 74 ... Common cylindrical lens, 75 ... Excitation light, 76 ... Side surface of solid laser medium 51, 77 ... Submount, 80 ... Solid laser optical amplifier, 81 ... Heat sink, 82 ... Liquid, 83 ... O Ring, 84 ... cooling tank, 85 ... radiating fin.

Abstract

[Problem] To provide a solid-state laser medium, which can be manufactured easily and doped with laser activate species at a high concentration, and into which excitation light can be easily introduced. [Solution] A solid-state laser medium 10 is a solid-state laser medium configured from an active region 1 and a transparent region 2. A high reflectance layer 8 is provided on one surface 4 of the active region 1. A no-reflectance coat layer 9 is provided on one surface 3 of the transparent region 2. Another surface 11 of the active region 1 and another surface 5 of the transparent region 2 are bonded to each other. The solid-state laser medium 10 amplifies input light 16, and outputs output light 17. A solid-state laser oscillator 20 is configured using the solid-state laser medium 10 and an output reflecting mirror 22, the high-reflectance layer 8 and the output reflecting mirror 22 form a Fabry-Perot resonator, and laser oscillation 21 is generated.

Description

固体レーザ媒質及び固体レーザ光増幅器Solid state laser medium and solid state laser optical amplifier
　本発明は固体レーザ媒質に関する。また、固体レーザ光増幅器に関し、特にディスク状の固体レーザ媒質を備えた固体レーザ光増幅器に関する。 The present invention relates to a solid-state laser medium. The present invention also relates to a solid-state laser optical amplifier, and more particularly to a solid-state laser optical amplifier provided with a disk-shaped solid laser medium.
　特許文献１には、ディスク状（薄膜状）の透明な母結晶の一部にレーザ活性種をイオン注入によってドープして活性領域を形成した固体レーザ媒質が開示されている。 Patent Document 1 discloses a solid-state laser medium in which an active region is formed by doping a laser-active species into a part of a disk-shaped (thin-film) transparent mother crystal by ion implantation.
　特許文献２には、薄膜状の活性領域の周辺に透明なウインドー領域を設けた固体レーザ媒質を用いた固体レーザが開示されている。 Patent Document 2 discloses a solid-state laser using a solid-state laser medium in which a transparent window region is provided around a thin-film active region.
　特許文献３には、固体レーザ媒質と半導体レーザを共通のヒートシンク上に設けた固体レーザが開示されている。 Patent Document 3 discloses a solid-state laser in which a solid-state laser medium and a semiconductor laser are provided on a common heat sink.
　特許文献４には、活性領域と透明領域を積層した固体レーザ媒質に、半導体レーザからの励起光を直接導入する構造が開示されている。 Patent Document 4 discloses a structure in which excitation light from a semiconductor laser is directly introduced into a solid-state laser medium in which an active region and a transparent region are stacked.
　特許文献５には、また、活性領域と透明領域を積層した固体レーザ媒質に、スラブ光導波路を介して励起光を導入する構造が開示されている。 Patent Document 5 discloses a structure in which excitation light is introduced through a slab optical waveguide into a solid-state laser medium in which an active region and a transparent region are laminated.
　特許文献６には、活性領域と透明領域を有する固体レーザ媒質を拡散接合もしくは接着によって形成する手法が開示されている。 Patent Document 6 discloses a method of forming a solid laser medium having an active region and a transparent region by diffusion bonding or adhesion.
　特許文献７には、活性領域と透明領域を有する固体レーザ媒質を焼結法によって形成する手法が開示されている。 Patent Document 7 discloses a method of forming a solid laser medium having an active region and a transparent region by a sintering method.
　特許文献８には、活性領域の周縁部に透明領域を有する固体レーザ媒質を焼結法によって形成する手法が開示されている。 Patent Document 8 discloses a method of forming a solid laser medium having a transparent region at the periphery of an active region by a sintering method.
　特許文献９には、活性領域の周縁部に設けられた透明領域の側面が傾斜し、反射防止コーティングが施されている固体レーザ媒質が開示されている。 Patent Document 9 discloses a solid-state laser medium in which a side surface of a transparent region provided at a peripheral portion of an active region is inclined and an antireflection coating is applied.
　特許文献１０には、活性領域と透明領域を積層し、活性領域を液体によって直接冷却する固体レーザが開示されている。 Patent Document 10 discloses a solid-state laser in which an active region and a transparent region are stacked and the active region is directly cooled by a liquid.
　非特許文献１には活性領域の周縁部に透明領域を設けた固体レーザ媒質に半導体レーザからの励起光を直接導入した固体レーザが開示されている。 Non-Patent Document 1 discloses a solid-state laser in which excitation light from a semiconductor laser is directly introduced into a solid-state laser medium in which a transparent region is provided at the periphery of an active region.
特許第３５０３５８８号公報Japanese Patent No. 3503588 特許第５０７０５１９号公報Japanese Patent No. 5070519 特開２００３－１８８４４２公報JP 2003-188442 A ＷＯ２００４／１１４４７６パンフレットWO2004 / 114476 brochure 特開２００７－１１００３９公報JP 2007-110039 A 特開平１１－２６１１３７号公報JP-A-11-261137 特開２００３－０２０２８８公報JP 2003-020288 A 特開２００３－２５８３５０公報JP 2003-258350 A 特開２００７－３１１５０４公報JP 2007-31504 A 特許第３８３９７１７号公報Japanese Patent No. 3839717
　特許文献１に開示されている固体レーザ媒質は活性領域の厚さに比べて、励起光導入部の透明領域の厚さが大きい。このため、励起光の導入が容易である。しかし、イオン注入法によって固体レーザ媒質を形成しているので生産性が低く、また、レーザ活性種の高濃度ドープが難しい。 In the solid-state laser medium disclosed in Patent Document 1, the thickness of the transparent region of the excitation light introducing portion is larger than the thickness of the active region. For this reason, introduction of excitation light is easy. However, since the solid laser medium is formed by the ion implantation method, the productivity is low, and it is difficult to dope the laser active species at a high concentration.
　本発明は、製造が容易で、レーザ活性種の高濃度ドープが可能で、励起光導入が容易な固体レーザ媒質を提供することを目的とする。 An object of the present invention is to provide a solid-state laser medium that is easy to manufacture, can be highly doped with laser active species, and can be easily introduced with excitation light.
　上記課題を解決するために本発明の固体レーザ媒質は、平板状の活性領域と平板状の透明領域を備え、透明領域の外形は活性領域の外形より大きく、活性領域の一つの面には高反射率層が設けられ、活性領域の高反射率層が設けられた面はヒートシンクに接触して冷却され、活性領域の外形が透明領域の外形をはみ出さないように配置され、励起光が透明領域の側面から導入され、励起光が透明領域を経て活性領域に至り、活性領域を励起することを特徴とする。 In order to solve the above problems, the solid-state laser medium of the present invention comprises a flat active region and a flat transparent region, and the outer shape of the transparent region is larger than the outer shape of the active region, and one surface of the active region is high. The reflective layer is provided, the surface of the active region on which the high reflectance layer is provided is cooled by contacting the heat sink, and the active region is arranged so that the outer shape does not protrude from the transparent region, and the excitation light is transparent. It is introduced from the side surface of the region, and excitation light reaches the active region through the transparent region and excites the active region.
　本発明によれば、透明領域の厚さを活性領域よりも厚くできるため、励起光の導入を容易にすることができる。活性領域と透明領域を接合して形成するので、製造が容易であり、活性領域にレーザ活性種を高濃度ドープできる。 According to the present invention, since the thickness of the transparent region can be made larger than that of the active region, the introduction of excitation light can be facilitated. Since the active region and the transparent region are formed by bonding, manufacturing is easy, and the active region can be highly doped with laser active species.
本発明の第一実施例の固体レーザ媒質１０の構成を示す概略図である。It is the schematic which shows the structure of the solid-state laser medium 10 of the 1st Example of this invention. 本発明の第二実施例の固体レーザ媒質３０の構成を示す概略図である。It is the schematic which shows the structure of the solid-state laser medium 30 of the 2nd Example of this invention. 本発明の第三実施例の固体レーザ媒質４０の構成を示す概略図である。It is the schematic which shows the structure of the solid-state laser medium 40 of the 3rd Example of this invention. 本発明の第四実施例の固体レーザ光増幅器５０の構成を示す概略図である。It is the schematic which shows the structure of the solid-state laser optical amplifier 50 of 4th Example of this invention. 本発明の第五実施例の固体レーザ光増幅器７０の構成を示す概略図である。It is the schematic which shows the structure of the solid-state laser optical amplifier 70 of 5th Example of this invention. 本発明の第六実施例の固体レーザ光増幅器８０の構成を示す概略図である。It is the schematic which shows the structure of the solid state laser optical amplifier 80 of the 6th Example of this invention.
　以下に、図面を参照して本発明に係わる固体レーザ発振器の実施の形態を詳細に説明する。この実施の形態により本発明が限定されるものではない。なお、各図面において、同一の構成要素には同一の符号を付与している。 Embodiments of a solid-state laser oscillator according to the present invention will be described in detail below with reference to the drawings. The present invention is not limited to the embodiments. In the drawings, the same reference numerals are assigned to the same components.
［第一実施例］
　図１に本発明の第一実施例の固体レーザ媒質１０の構成を示す。また、図１にこの固体レーザ媒質１０を用いて構成した固体レーザレーザ発振器２０の構成を示す。 [First embodiment]
FIG. 1 shows the configuration of a solid-state laser medium 10 according to the first embodiment of the present invention. FIG. 1 shows a configuration of a solid-state laser laser oscillator 20 configured using the solid-state laser medium 10 .
　図１（ａ）は固体レーザ光媒質１０を上面側から見た図である。図１（ｂ）は固体レーザ媒質１０のＸ－Ｘ'断面図である。図１（ｃ）は固体レーザレーザ発媒質１０の活性領域の別の構成を示す側面図である。図１（ｄ）は固体レーザ媒質１０を用いて構成した固体レーザレーザ発振器２０の構成を示す側面図である。 FIG. 1A is a view of the solid-state laser light medium 10 as viewed from the upper surface side. FIG. 1B is a cross-sectional view of the solid-state laser medium 10 taken along the line XX ′. FIG. 1C is a side view showing another configuration of the active region of the solid-state laser laser emitting medium 10 . FIG. 1D is a side view showing the configuration of a solid-state laser laser oscillator 20 configured using the solid-state laser medium 10 .
　固体レーザ媒質１０は活性領域１と透明領域２からなる固体レーザ媒質である。活性領域１は、例えば、ＹＡＧの単結晶、セラミクスなどの母材にＮｄやＹｂなどのレーザ活性種をドープしたものである。透明領域２は、例えば、レーザ活性種がドープされていないＹＡＧの単結晶、セラミクスなどである。 The solid laser medium 10 is a solid laser medium composed of an active region 1 and a transparent region 2. The active region 1 is, for example, a YAG single crystal, a base material such as ceramics doped with a laser active species such as Nd or Yb. The transparent region 2 is, for example, a YAG single crystal not doped with a laser active species, ceramics, or the like.
　活性領域１の一つの面４には高反射率層８が設けられている。透明領域２の一つの面３には無反射率コート層９が設けられている。活性領域１の別の面１１と透明領域２の別の面５が接合されている。 A high reflectivity layer 8 is provided on one surface 4 of the active region 1. An antireflective coating layer 9 is provided on one surface 3 of the transparent region 2. Another surface 11 of the active region 1 and another surface 5 of the transparent region 2 are joined.
　活性領域１は平板状で円形状である。透明領域２は平板状で円形状である。活性領域１の外形は透明領域２の外形より小さく、活性領域１は透明領域２の外形をはみ出さないように接合されている。 The active region 1 is flat and circular. The transparent region 2 is flat and circular. The outer shape of the active region 1 is smaller than the outer shape of the transparent region 2, and the active region 1 is joined so as not to protrude the outer shape of the transparent region 2.
　図１においては、固体レーザ媒質１０の活性領域１と透明領域２の形状を円形としたが、他の形状を用いてもよい。 In FIG. 1, the shapes of the active region 1 and the transparent region 2 of the solid-state laser medium 10 are circular, but other shapes may be used.
　固体レーザ媒質１０は、特許文献６、７、及び、８に記載されている手法を用いて製造することができる。すなわち、固体レーザ媒質１は拡散接合、接着剤による接着、あるいは、焼結を用いた接合などの手法で製造することができる。 The solid-state laser medium 10 can be manufactured using the methods described in Patent Documents 6, 7, and 8. That is, the solid-state laser medium 1 can be manufactured by a technique such as diffusion bonding, bonding with an adhesive, or bonding using sintering.
　本実施例では、活性領域１と透明領域２を接合して形成するので製造が容易である。また、活性領域にレーザ活性種を高い濃度でドープすることができる。 In this embodiment, since the active region 1 and the transparent region 2 are formed by joining, manufacturing is easy. Further, the active region can be doped with laser active species at a high concentration.
　透明領域２の側面６に励起光１２が導入され、励起光１２透明領域２を経て活性領域１に至り、活性領域１を励起する。このため、活性領域１は光増幅の機能を発現する。活性領域１の面４には高反射率層８が設けられているので、固体レーザ媒質１０は、反射鏡機能を備えた光増幅器として機能する。このような光増幅器はアクティブミラーの別名で呼ばれる。 Excitation light 12 is introduced into the side surface 6 of the transparent region 2, reaches the active region 1 through the excitation light 12 transparent region 2, and excites the active region 1. For this reason, the active region 1 expresses the function of light amplification. Since the high reflectivity layer 8 is provided on the surface 4 of the active region 1, the solid-state laser medium 10 functions as an optical amplifier having a reflecting mirror function. Such an optical amplifier is called an active mirror.
　固体レーザ媒質１０は、入力光１６を増幅して出力光１７を出射する。図１（ｄ）に固体レーザ媒質１０と出力反射鏡２２を用いて構成した固体レーザレーザ発振器２０の構成を示す。高反射率層８と出力反射鏡２２がファブリーペロー共振器を形成し、レーザ発振２１が生じる。なお、活性領域１の面４は図示しないヒートシンクに接合されている。 The solid-state laser medium 10 amplifies the input light 16 and emits output light 17. FIG. 1D shows a configuration of a solid-state laser laser oscillator 20 configured using the solid-state laser medium 10 and the output reflecting mirror 22. The high reflectivity layer 8 and the output reflecting mirror 22 form a Fabry-Perot resonator, and laser oscillation 21 occurs. The surface 4 of the active region 1 is bonded to a heat sink (not shown).
　活性領域１の側面７は粗面となっている。これは、図１（ｂ）に示す寄生発振１３が生じるのを防ぐためである。この寄生発振１３は活性領域１の側面７によって、意図しないファブリーペロー共振器（寄生ファブリーペロー共振器）が形成されるために生じる。 The side surface 7 of the active region 1 is a rough surface. This is to prevent the parasitic oscillation 13 shown in FIG. This parasitic oscillation 13 occurs because an unintended Fabry-Perot resonator (parasitic Fabry-Perot resonator) is formed by the side surface 7 of the active region 1.
　寄生発振１３を抑制する別の方法としては、活性領域１の側面７に無反射コートを施して反射率を低減してもよい。側面７の反射率を低減させれば寄生発振１３を防ぐことができる。 As another method of suppressing the parasitic oscillation 13, the reflectance may be reduced by applying a non-reflective coating to the side surface 7 of the active region 1. If the reflectance of the side surface 7 is reduced, the parasitic oscillation 13 can be prevented.
　また、活性領域１の側面７は粗面とした構成は、活性領域１を円形とした場合に生じるささやき回廊モードによって生じる寄生発振を抑制する効果もある。なお、ささやき回廊モードとは、円形の導波路の周に沿って伝播するモードのことである。後述の図２（ｄ）に参照番号３８として示すようなモードのことである。 Further, the configuration in which the side surface 7 of the active region 1 is rough also has an effect of suppressing parasitic oscillation caused by the whispering gallery mode that occurs when the active region 1 is circular. The whispering gallery mode is a mode that propagates along the circumference of a circular waveguide. This is a mode as indicated by reference numeral 38 in FIG.
　また、図１（ｃ）に示すように側面７に代えて、傾斜した側面１５を設けてもよい。活性領域１の面４に対して側面１５を直角以外の角度とすることによって、活性領域１の側面によって寄生ファブリーペロー共振器が形成されることを防ぐことができる。傾斜した側面１５をさらに粗面化してもよい。傾斜した側面１５にさらに無反射コートを施してもよい。 Further, as shown in FIG. 1C, an inclined side surface 15 may be provided instead of the side surface 7. By making the side surface 15 have an angle other than a right angle with respect to the surface 4 of the active region 1, it is possible to prevent a parasitic Fabry-Perot resonator from being formed by the side surface of the active region 1. The inclined side surface 15 may be further roughened. A non-reflective coating may be further applied to the inclined side surface 15.
　固体レーザ媒質１０では活性領域１の側面７は励起光の導入に関与していないため、粗面化することができる。また、側面７に独立した傾斜を設けることができる。このため、寄生発振の発生を防止することができる。 In the solid-state laser medium 10 , the side surface 7 of the active region 1 is not involved in the introduction of excitation light and can be roughened. Further, the side surface 7 can be provided with an independent inclination. For this reason, occurrence of parasitic oscillation can be prevented.
　固体レーザ媒質１０は活性領域１と透明領域２が個別に形成されているので、活性領域１を十分に薄くして活性領域１の冷却効率を上げ、同時に、透明領域２を厚くして、励起光２の導入を容易にすることができる。また、活性領域１を大口径化した場合も透明領域２の厚さを制御することによって、活性領域１を均一に励起することができる。 Since the active region 1 and the transparent region 2 are individually formed in the solid laser medium 10 , the active region 1 is sufficiently thinned to increase the cooling efficiency of the active region 1, and at the same time, the transparent region 2 is thickened to be excited. Introduction of the light 2 can be facilitated. Further, even when the active region 1 has a large diameter, the active region 1 can be uniformly excited by controlling the thickness of the transparent region 2.
［第二実施例］
　図２に本発明の第二実施例の固体レーザ媒質３０を示す。図２（ａ）は固体レーザ媒質３０を示す上面図である。図２（ｂ）は固体レーザ媒質３０の励起方法を示す側面図である。図２（ｃ）はエバネッセント結合について示す図である。図２（ｄ）は寄生発振を抑制するための活性領域１の形状である。 [Second Example]
FIG. 2 shows a solid-state laser medium 30 according to the second embodiment of the present invention. FIG. 2A is a top view showing the solid-state laser medium 30 . FIG. 2B is a side view showing a method for exciting the solid-state laser medium 30 . FIG. 2C shows the evanescent coupling. FIG. 2D shows the shape of the active region 1 for suppressing parasitic oscillation.
　固体レーザ媒質３０は透明領域２と活性領域１を個別に形成して、物理的に接触させた構造を有している。透明領域２と活性領域１は薄い気体層（真空層）３３を介してエバネッセント結合している。 The solid-state laser medium 30 has a structure in which the transparent region 2 and the active region 1 are individually formed and physically contacted. The transparent region 2 and the active region 1 are evanescently coupled through a thin gas layer (vacuum layer) 33.
　図２（ａ）に示すように、活性領域１の面４はヒートシンク３１に接着されている。透明領域２の面５が活性領域１の面１１に圧力３２によって物理的に接触している。図２（ｂ）に示すように励起光１２は透明領域２の側面６に導入される。 As shown in FIG. 2A, the surface 4 of the active region 1 is bonded to the heat sink 31. The surface 5 of the transparent region 2 is in physical contact with the surface 11 of the active region 1 by pressure 32. As shown in FIG. 2B, the excitation light 12 is introduced into the side surface 6 of the transparent region 2.
　図２（ｂ）の構成では図２（ｃ）に示すようなエバネッセント結合が生じる。活性領域１と透明領域２の間には薄い気体層（真空層）３３が形成される。このような構造では励起光１２は透明領域２と気体層（真空層）３３の界面でエバネッセント光３４が生じ、このエバネッセント光３４は気体層（真空層）３３と活性領域１の界面で透過光３５に変換される。また、反射光３６も生じて透明領域４２中を伝播する。透過光３５は活性領域１に吸収されて活性領域１を励起する。 In the configuration of FIG. 2 (b), evanescent coupling as shown in FIG. 2 (c) occurs. A thin gas layer (vacuum layer) 33 is formed between the active region 1 and the transparent region 2. In such a structure, the excitation light 12 generates evanescent light 34 at the interface between the transparent region 2 and the gas layer (vacuum layer) 33, and this evanescent light 34 is transmitted light at the interface between the gas layer (vacuum layer) 33 and the active region 1. 35. Reflected light 36 is also generated and propagates through the transparent region 42. The transmitted light 35 is absorbed by the active region 1 and excites the active region 1.
　図２（ｄ）に寄生発振を抑制するための活性領域１の形状を示す。図２（ｄ）に示すように、活性領域１の側面３７を、意図的に凹凸を含む形状とすることにより、寄生ファブリーペロー共振器による寄生発振、及び、ささやき回廊モード３８に起因する寄生発振を抑制することができる。 FIG. 2D shows the shape of the active region 1 for suppressing parasitic oscillation. As shown in FIG. 2 (d), the side surface 37 of the active region 1 is intentionally formed to have irregularities, thereby causing parasitic oscillation due to the parasitic Fabry-Perot resonator and parasitic oscillation caused by the whispering gallery mode 38. Can be suppressed.
　本実施例では、透明領域２と活性領域１を個別に形成して物理的に接触させている。この構成では、透明領域２と活性領域１を接合させる必要が無いので、固体レーザ媒質３０の製造が容易である。 In this embodiment, the transparent region 2 and the active region 1 are individually formed and physically contacted. In this configuration, since it is not necessary to join the transparent region 2 and the active region 1, the solid-state laser medium 30 can be easily manufactured.
　透明領域２と活性領域１を接合させる場合は、透明領域２と活性領域１の熱膨張係数が近い値である必要があるので、材料選択に制限があった。これに対して、本実施例の構成ではこのような制限がない。 When joining the transparent region 2 and the active region 1, the material selection is limited because the thermal expansion coefficients of the transparent region 2 and the active region 1 must be close to each other. On the other hand, there is no such restriction in the configuration of the present embodiment.
［第三実施例］
　図３に本発明の第三実施例の固体レーザ媒質４０の構成を示す。図３（ａ）に示すように、固体レーザ媒質４０は五角形状の透明領域４２を備えている。また、円形の活性領域４１を備えている。 [Third embodiment]
FIG. 3 shows the configuration of the solid-state laser medium 40 according to the third embodiment of the present invention. As shown in FIG. 3A, the solid-state laser medium 40 includes a pentagonal transparent region 42. A circular active region 41 is also provided.
　特許文献２に開示されているように、活性領域を透明領域が取り囲む固体レーザ媒質では、透明領域の端面同士が共振器（寄生ファブリーペロー共振器）を形成してしまうことがある。これに対して、本実施例の固体レーザ媒質４０では、透明領域４２の複数の辺４４において互いに平行な辺の組み合わせが無いために、寄生ファブリーペロー共振器が形成されず、寄生発振４３の生成が抑制される。 As disclosed in Patent Document 2, in a solid laser medium in which an active region is surrounded by a transparent region, end surfaces of the transparent region may form a resonator (parasitic Fabry-Perot resonator). On the other hand, in the solid-state laser medium 40 of the present embodiment, there is no combination of sides parallel to each other in the plurality of sides 44 of the transparent region 42, so a parasitic Fabry-Perot resonator is not formed, and generation of the parasitic oscillation 43 Is suppressed.
　図３（ｂ）は図１に示した固体レーザ媒質１０と同様の断面構造を示す。図３（ｃ）は特許文献１に開示されている固体レーザ媒質と同様の断面構造を示す。図３（ｄ）は特許文献２に開示されている固体レーザ媒質と同様の断面構造を示す。 FIG. 3B shows a cross-sectional structure similar to that of the solid-state laser medium 10 shown in FIG. FIG. 3C shows a cross-sectional structure similar to that of the solid-state laser medium disclosed in Patent Document 1. FIG. 3D shows a cross-sectional structure similar to that of the solid-state laser medium disclosed in Patent Document 2.
　これらのいずれの構造においても、透明領域４２の辺に互いに平行な辺の組み合わせが無い形状を採用することによって、寄生発振の生成を抑制することができる。 In any of these structures, the generation of parasitic oscillation can be suppressed by adopting a shape in which there is no combination of sides parallel to the sides of the transparent region 42.
　寄生ファブリーペロー共振器に起因する寄生発振は、透明領域と活性領域の光学的結合が強いほど起こりやすいので、この寄生発振は特に図３（ｄ）の構成で起こり易い。次いでこの寄生発振は図３（ｃ）で起こり易く、その次に図３（ｂ）の構成で起こり易い。 Parasitic oscillation due to the parasitic Fabry-Perot resonator is more likely to occur as the optical coupling between the transparent region and the active region is stronger, and this parasitic oscillation is particularly likely to occur in the configuration of FIG. Next, this parasitic oscillation is likely to occur in FIG. 3C, and then to the configuration of FIG. 3B.
　一方、ささやき回廊モードに起因する寄生発振は、図３（ｃ）と図３（ｄ）の構成では起こり難い。活性領域４１と透明領域４２の屈折率差が小さいと、活性領域４１と透明領域４２の界面ではささやき回廊モードが形成されにくいからである。 On the other hand, the parasitic oscillation caused by the whispering gallery mode is unlikely to occur in the configurations of FIGS. 3 (c) and 3 (d). This is because if the refractive index difference between the active region 41 and the transparent region 42 is small, a whispering gallery mode is hardly formed at the interface between the active region 41 and the transparent region 42.
　透明領域４２の外周部は空気と界面を形成するので、この領域にはささやき回廊モードが形成されるが、この領域には利得がないため、寄生発振が起こり難い。 Since the outer peripheral portion of the transparent region 42 forms an interface with air, a whispering gallery mode is formed in this region, but since there is no gain in this region, parasitic oscillation hardly occurs.
　以上から、図３（ａ）の平面構造を有して図３（ｃ）と図３（ｄ）の断面構造を有する場合は、寄生ファブリーペロー共振器による寄生発振も、ささやき回廊モードによる寄生発振も生じ難いこととなる。 From the above, in the case of having the planar structure of FIG. 3A and the cross-sectional structures of FIG. 3C and FIG. 3D, the parasitic oscillation by the parasitic Fabry-Perot resonator is also the parasitic oscillation by the whispering gallery mode. It is difficult to occur.
　図３（ａ）の平面構造を有して図３（ｂ）の断面構造を有する場合は、活性領域４１内でのささやき回廊モードに起因する寄生発振は生じ得る。この場合は、前述の通り、活性領域４１の側面を粗面化する、あるいは図２（ｄ）にしめすような側面形状を採用することにより、活性領域４１内でのささやき回廊モードに起因する寄生発振を抑制できる。 In the case of having the planar structure of FIG. 3A and the cross-sectional structure of FIG. 3B, parasitic oscillation due to the whispering gallery mode in the active region 41 may occur. In this case, as described above, the side surface of the active region 41 is roughened, or the side surface shape shown in FIG. Oscillation can be suppressed.
　本実施例のように、奇数の頂点を有する正多角形を外形形状とする透明領域４２を用いると、透明領域４２の辺に互いに平行な辺の組み合わせが無いために、寄生ファブリーペロー共振器に起因する寄生発振を低減できる。 When the transparent region 42 having an outer shape of a regular polygon having an odd number of vertices is used as in the present embodiment, there is no combination of sides parallel to the sides of the transparent region 42, so that the parasitic Fabry-Perot resonator is used. The resulting parasitic oscillation can be reduced.
　なお、活性層４１の外形形状を奇数の頂点を有する多角系とすることもできる。これによって、活性層４１内の寄生ファブリーペロー共振器の発生を防ぐことができる。 It should be noted that the outer shape of the active layer 41 may be a polygonal system having an odd number of vertices. As a result, generation of a parasitic Fabry-Perot resonator in the active layer 41 can be prevented.
［第四実施例］
　図４に本発明の第四実施例の固体レーザ光増幅器５０の構成を示す。また、図４にこの固体レーザ光増幅器５０を用いて構成した固体レーザレーザ発振器６０の構成を示す。図４（ａ）は固体レーザ光増幅器５０を上面側から見た図である。図４（ｂ）は固体レーザ光増幅器５０のＹ－Ｙ'断面図である。図４（ｃ）は固体レーザレーザ発振器６０の側面図である。 [Fourth embodiment]
FIG. 4 shows the configuration of a solid-state laser optical amplifier 50 according to the fourth embodiment of the present invention. FIG. 4 shows a configuration of a solid-state laser laser oscillator 60 configured using the solid-state laser optical amplifier 50 . FIG. 4A is a view of the solid-state laser optical amplifier 50 as viewed from the upper surface side. FIG. 4B is a YY ′ cross-sectional view of the solid-state laser optical amplifier 50 . FIG. 4C is a side view of the solid state laser oscillator 60 .
　固体レーザ媒質５１は平板状の薄膜であり、外形は円形状である。外形が円形状の透明領域５２と、外形が円形状の活性領域５３とから成る。透明領域５２は活性領域５３の上方に設けられると共に、活性領域５３の周縁部を取り囲むように設けられている。このため、固体レーザ媒質１の厚さは活性領域５３の厚さより大きくなっている。また、固体レーザ媒質５１の外形は活性領域５３の外形より大きくなっている。 The solid laser medium 51 is a flat thin film, and the outer shape is circular. A transparent region 52 having a circular outer shape and an active region 53 having a circular outer shape. The transparent region 52 is provided above the active region 53 and is provided so as to surround the peripheral portion of the active region 53. For this reason, the thickness of the solid-state laser medium 1 is larger than the thickness of the active region 53. Further, the outer shape of the solid-state laser medium 51 is larger than the outer shape of the active region 53.
　固体レーザ媒質５１の一つの面には高反射率層５８が設けられている。この高反射率層５８は固体レーザ光増幅器５０が増幅する光の波長に対して高い反射率を有している。固体レーザ媒質５１の高反射率層５８が設けられた面がヒートシンク５６に接着されている。ヒートシンク５６の外形は固体レーザ媒質５１の外形より大きい。 A high reflectivity layer 58 is provided on one surface of the solid-state laser medium 51. The high reflectivity layer 58 has a high reflectivity with respect to the wavelength of light amplified by the solid-state laser optical amplifier 50 . The surface of the solid laser medium 51 on which the high reflectance layer 58 is provided is bonded to the heat sink 56. The outer shape of the heat sink 56 is larger than the outer shape of the solid-state laser medium 51.
　固体レーザ媒質５１の高反射率層５８が設けられた面とは反対側の面には無反射コート層５９が設けられている。固体レーザ媒質５１の活性領域５３は高反射率層５８が設けられる面側に設けられている。 A non-reflective coating layer 59 is provided on the surface of the solid laser medium 51 opposite to the surface on which the high reflectivity layer 58 is provided. The active region 53 of the solid-state laser medium 51 is provided on the surface side where the high reflectivity layer 58 is provided.
　励起用の半導体レーザ５４が、サブマウント５５を介してヒートシンク５６上に設けられている。半導体レーザ５４はサブマウント５５にジャンクションダウンで実装されている。また、サブマウント５５はヒートシンク５６上に接着されている。 A semiconductor laser 54 for excitation is provided on a heat sink 56 via a submount 55. The semiconductor laser 54 is mounted on the submount 55 in a junction-down manner. The submount 55 is bonded on the heat sink 56.
　半導体レーザ５４はサブマウント５５にジャンクションダウンで実装されているので、半導体レーザ５４のレーザ光出射点はヒートシンク５６から、ほぼ、サブマウント５５の高さの位置となる。したがって、サブマウント５５は光学的アライメント部材としても機能する。 Since the semiconductor laser 54 is mounted on the submount 55 in a junction-down manner, the laser beam emission point of the semiconductor laser 54 is almost at the height of the submount 55 from the heat sink 56. Therefore, the submount 55 also functions as an optical alignment member.
　励起用の半導体レーザ５４は固体レーザ媒質５１に近接して設けられており、光学系を介すことなく、半導体レーザ５４からの励起光５７は、直接、固体レーザ媒質５１に導入されている。 The pumping semiconductor laser 54 is provided close to the solid-state laser medium 51, and the pumping light 57 from the semiconductor laser 54 is directly introduced into the solid-state laser medium 51 without passing through an optical system.
　図４（ｃ）に固体レーザ光増幅器５０を用いて構成した固体レーザレーザ発振器６０を示す。固体レーザレーザ発振器６０は、固体レーザ光増幅器５０と出力反射鏡６１を備えている。 FIG. 4C shows a solid-state laser laser oscillator 60 configured using a solid-state laser optical amplifier 50 . The solid-state laser laser oscillator 60 includes a solid-state laser optical amplifier 50 and an output reflecting mirror 61.
　高反射率層５８と出力反射鏡６１とがファブリーペロー共振器を形成することにより、レーザ発振光６２が生成される。レーザ発振光６２の一部が出力光６３として外部に取りだされる。 The high reflectivity layer 58 and the output reflecting mirror 61 form a Fabry-Perot resonator, whereby the laser oscillation light 62 is generated. A part of the laser oscillation light 62 is taken out as output light 63.
　本実施例では、半導体レーザ５４からの励起光５７を、直接、固体レーザ媒質５１に導入しているので、固体レーザ光増幅器５０を小型化でき、かつ、構造を簡易化できる。 In this embodiment, since the excitation light 57 from the semiconductor laser 54 is directly introduced into the solid-state laser medium 51, the solid-state laser optical amplifier 50 can be reduced in size and the structure can be simplified.
　本実施例では、活性領域５３の厚さよりも固体レーザ媒質５１の厚さが大きいので、半導体レーザ５４からの励起光５７を固体レーザ媒質５１に導入することが容易である。 In this embodiment, since the thickness of the solid-state laser medium 51 is larger than the thickness of the active region 53, it is easy to introduce the excitation light 57 from the semiconductor laser 54 into the solid-state laser medium 51.
　本実施例では、活性領域５３の周縁部にも透明領域５２が設けられているので、固体レーザ媒質５１の外形は活性領域５３の外形より大きい。このため、より多数の半導体レーザ５４によって活性領域５３を励起することができる。 In the present embodiment, since the transparent region 52 is also provided at the peripheral portion of the active region 53, the outer shape of the solid laser medium 51 is larger than the outer shape of the active region 53. For this reason, the active region 53 can be excited by a larger number of semiconductor lasers 54.
　本実施例では、活性領域５３の周縁部にも透明領域５２が設けられているので、ささやき回廊モードによる寄生発振を防ぐことができる。 In this embodiment, since the transparent region 52 is also provided at the peripheral portion of the active region 53, parasitic oscillation due to the whispering gallery mode can be prevented.
　本実施例では、活性領域５３の上方の透明領域５２を励起光５７が通過するので、活性領域５３が大口径化した場合も、活性領域５３を均一に励起することができる。 In this embodiment, since the excitation light 57 passes through the transparent region 52 above the active region 53, the active region 53 can be uniformly excited even when the active region 53 has a large diameter.
　図４の構成において、固体レーザ媒質５１に代えて、図１に示した固体媒質１０を用いることができる。図４の構成において、固体レーザ媒質５１に代えて、図２に示した固体レーザ媒質３０を用いることができる。図４の構成において、固体レーザ媒質５１に代えて、図３に示した固体レーザ媒質４０を用いることができる。 In the configuration of FIG. 4, the solid medium 10 shown in FIG. 1 can be used instead of the solid laser medium 51. In the configuration of FIG. 4, the solid-state laser medium 30 shown in FIG. 2 can be used instead of the solid-state laser medium 51. In the configuration of FIG. 4, the solid laser medium 40 shown in FIG. 3 can be used instead of the solid laser medium 51.
［第五実施例］
　図５に本発明の第五実施例の構成を示す。固体レーザ光増幅器７０は、固体レーザ光増幅器５０のヒートシンク５６をヒートシンク７１に代え、励起光源を半導体レーザ５４から半導体レーザスタック７２に代えた構成となっている。 [Fifth Example]
FIG. 5 shows the configuration of the fifth embodiment of the present invention. The solid-state laser optical amplifier 70 has a configuration in which the heat sink 56 of the solid-state laser optical amplifier 50 is replaced with a heat sink 71 and the excitation light source is replaced with the semiconductor laser stack 72 from the semiconductor laser 54.
　半導体レーザスタック７２は複数の半導体レーザチップを積層させた構造を有している。半導体レーザスタック７２の各半導体レーザチップに対応してシリンドリカルレンズ７３が設けられている。 The semiconductor laser stack 72 has a structure in which a plurality of semiconductor laser chips are stacked. A cylindrical lens 73 is provided corresponding to each semiconductor laser chip of the semiconductor laser stack 72.
　ヒートシンク７１は活性領域５３より大きいが、透明領域５２よりは小さな外形とされている。固体レーザ媒質５１の活性領域５３はサブマウント７７を介してヒートシンク７１に接着されている。 The heat sink 71 is larger than the active region 53 but smaller than the transparent region 52. The active region 53 of the solid-state laser medium 51 is bonded to the heat sink 71 via a submount 77.
　ヒートシンク７１は安価な銅によって形成されている。サブマウント７７は適切な組成比の銅タングステン合金などによって形成され、活性領域５３を形成する材料（ＹＡＧ）と熱膨張率が略一致している。この構成によって活性領域５３に加えられる熱歪を抑制している。 The heat sink 71 is made of inexpensive copper. The submount 77 is formed of a copper-tungsten alloy or the like having an appropriate composition ratio, and the thermal expansion coefficient is substantially the same as the material (YAG) forming the active region 53. With this configuration, thermal strain applied to the active region 53 is suppressed.
　固体レーザ媒質５１の透明領域５２はヒートシンク７１より張り出している。このため、半導体レーザスタック７２からの励起光７５は、ヒートシンク７１によってけられることなく、固体レーザ媒質５１の側面７６に導入される。 The transparent region 52 of the solid laser medium 51 protrudes from the heat sink 71. For this reason, the excitation light 75 from the semiconductor laser stack 72 is introduced into the side surface 76 of the solid-state laser medium 51 without being scattered by the heat sink 71.
　半導体レーザスタック７２からの励起光７５はシリンドリカルレンズ７３によって平行光に変換されてから、共通シリンドリカルレンズ７４によって固体レーザ媒質５１の側面７６に導入される。 The excitation light 75 from the semiconductor laser stack 72 is converted into parallel light by the cylindrical lens 73 and then introduced into the side surface 76 of the solid-state laser medium 51 by the common cylindrical lens 74.
　一般的に、図５に示したような励起光学系では、半導体レーザスタック６２のスタック数を増やすと、共通シリンドリカルレンズ７４の収差によって集光されたレーザ光の径が大きくなるという問題がある。このため、固体レーザ媒質７１が薄いと励起光を効率よく導入することができない。 Generally, in the excitation optical system as shown in FIG. 5, when the number of the semiconductor laser stacks 62 is increased, there is a problem that the diameter of the laser beam condensed due to the aberration of the common cylindrical lens 74 increases. For this reason, if the solid-state laser medium 71 is thin, excitation light cannot be efficiently introduced.
　これに対して、本実施例では固体レーザ媒質７５の全体の厚さは透明領域５２の厚さを厚くすることによって調整することができる。したがって、スタック数の多い半導体レーザスタック７２を用いても、固体レーザ媒質５１の厚さを適切にすることにより、励起光７５を効率よく固体レーザ媒質５１に導入することができる。スタック数を増やせば、励起光を大出力化できるので、固体レーザ光増幅器７０の大出力化を実現することができる。 In contrast, in the present embodiment, the entire thickness of the solid-state laser medium 75 can be adjusted by increasing the thickness of the transparent region 52. Therefore, even if the semiconductor laser stack 72 having a large number of stacks is used, the excitation light 75 can be efficiently introduced into the solid-state laser medium 51 by making the thickness of the solid-state laser medium 51 appropriate. If the number of stacks is increased, the output of the pumping light can be increased, so that the output of the solid-state laser optical amplifier 70 can be increased.
　本実施例では、活性領域５３の周縁部にも透明領域５２が設けられているので、より多数の半導体レーザスタック７２によって活性領域５３を励起することができる。また、ささやき回廊モードによる寄生発振を抑制できる。 In this embodiment, since the transparent region 52 is also provided in the peripheral portion of the active region 53, the active region 53 can be excited by a larger number of semiconductor laser stacks 72. Further, parasitic oscillation due to the whispering gallery mode can be suppressed.
　図５の構成において、固体レーザ媒質５１に代えて、図１に示した固体レーザ媒質１０を用いることができる。図５の構成において、固体レーザ媒質５１に代えて、図２に示した固体レーザ媒質３０を用いることができる。図５の構成において、固体レーザ媒質５１に代えて、図３に示した固体レーザ媒質４０を用いることができる。 In the configuration of FIG. 5, the solid laser medium 10 shown in FIG. 1 can be used instead of the solid laser medium 51. In the configuration of FIG. 5, the solid-state laser medium 30 shown in FIG. 2 can be used instead of the solid-state laser medium 51. In the configuration of FIG. 5, the solid-state laser medium 40 shown in FIG. 3 can be used instead of the solid-state laser medium 51.
［第六実施例］
　図６（ａ）に本発明の第六実施例の固体レーザ光増幅器８０の構成を示す。固体レーザ光増幅器８０は、固体レーザ光増幅器７０のヒートシンク７１をヒートシンク８１に代えた構成となっている。 [Sixth embodiment]
FIG. 6A shows the configuration of a solid-state laser optical amplifier 80 according to the sixth embodiment of the present invention. The solid-state laser optical amplifier 80 has a configuration in which the heat sink 71 of the solid-state laser optical amplifier 70 is replaced with a heat sink 81.
　ヒートシンク８１は液体８２で満たされた冷却槽８４を備えている。固体レーザ媒質５１は液体８２によって直接冷却される構成となっている。固体レーザ媒質５１はＯリング８３と図示しない取り付け機構を介してヒートシンク８１に取り付けられている。Ｏリング８３は液体８２が漏えいすることを防いでいる。 The heat sink 81 includes a cooling tank 84 filled with a liquid 82. The solid laser medium 51 is directly cooled by the liquid 82. The solid-state laser medium 51 is attached to the heat sink 81 via an O-ring 83 and an attachment mechanism (not shown). The O-ring 83 prevents the liquid 82 from leaking.
　固体レーザ媒質５１は透明領域５２を備えているので、透明領域５２を十分に厚くすることによって物理的に高い強度を持たせることができる。このため、液体８２の圧力によって固体レーザ媒質５１が破損することが防げる。 Since the solid-state laser medium 51 includes the transparent region 52, it is possible to give a physically high intensity by making the transparent region 52 sufficiently thick. For this reason, the solid laser medium 51 can be prevented from being damaged by the pressure of the liquid 82.
　本実施例によれば、固体レーザ媒質５１を破損させずに、液体８２を用いて、直接冷却するので高い冷却効率が得られる。 According to this embodiment, since the solid laser medium 51 is directly damaged using the liquid 82 without damaging it, high cooling efficiency can be obtained.
　特許文献１０には、活性領域と透明領域を積層した固体レーザ媒質の活性領域側を直接冷却する構造が開示されているが、固体レーザ媒質を側面から励起する構造は開示されていない。また、活性領域の周縁部に透明領域を設ける構造は開示されていない。 Patent Document 10 discloses a structure that directly cools the active region side of a solid-state laser medium in which an active region and a transparent region are stacked, but does not disclose a structure that excites the solid-state laser medium from the side surface. Moreover, the structure which provides a transparent area | region in the peripheral part of an active area | region is not disclosed.
　これに対して、本実施例では活性領域と透明領域を積層し、かつ、活性領域の周縁部に透明領域を設けた固体レーザ媒質を側面から励起する構成とした。このため、固体レーザレーザ媒質５１の側面から励起光７５を導入して固体レーザレーザ媒質５１を励起することができる。 On the other hand, in this embodiment, the active region and the transparent region are stacked, and the solid laser medium provided with the transparent region at the periphery of the active region is excited from the side. For this reason, the solid-state laser laser medium 51 can be excited by introducing the excitation light 75 from the side surface of the solid-state laser laser medium 51.
　また、本実施例では活性領域の周縁部に透明領域を設けた固体レーザ媒質を用いているので、ささやき回廊モードに起因する寄生発振が抑制される。 Further, in this embodiment, since a solid-state laser medium provided with a transparent region at the periphery of the active region is used, parasitic oscillation due to the whispering gallery mode is suppressed.
　図６（ａ）の構成を図４に準じた構成に変形することもできる。 6A can be modified into a configuration according to FIG.
　図６（ｂ）に固体レーザ光増幅器８０の変形例を示す。固体レーザレーザ媒質５１に放熱フィン８５を接着した構成としたことが特徴である。放熱フィン８５は適当な組成比の銅タングステン合金や銅モリブテン合金を用いて固体レーザレーザ媒質５１のレーザ結晶材料であるＹＡＧの熱膨張係数に近い値としている。この放熱フィン８５には図示しない凹凸が設けられ、液体８２との接触面積が増加するように構成されている。これにより、冷却効率が向上する。 FIG. 6B shows a modification of the solid-state laser optical amplifier 80 . The solid-state laser laser medium 51 is characterized in that a heat radiation fin 85 is bonded. The radiating fin 85 is made of a copper tungsten alloy or a copper molybdenum alloy having an appropriate composition ratio and has a value close to the thermal expansion coefficient of YAG, which is the laser crystal material of the solid-state laser laser medium 51. The radiating fins 85 are provided with irregularities (not shown) so that the contact area with the liquid 82 is increased. Thereby, cooling efficiency improves.
　図６（ｂ）の構成によれば、固体レーザレーザ媒質５１と放熱フィン８５の熱膨張係数を略一致させたので、固体レーザレーザ媒質５１に熱歪が加わることを抑制できる。 6B, since the thermal expansion coefficients of the solid-state laser laser medium 51 and the radiating fins 85 are substantially matched, it is possible to suppress thermal strain from being applied to the solid-state laser laser medium 51.
　図６（ｂ）の構成によれば、ヒートシンク８１を銅などの安価な材料で構築することができる。このため、活性領域５３を大口径化する場合に高いコスト効率を得ることができる。 6B, the heat sink 81 can be constructed of an inexpensive material such as copper. For this reason, when making the active region 53 large-diameter, high cost efficiency can be obtained.
　図６の構成において、固体レーザ媒質５１に代えて、図１に示した固体媒質１０を用いることができる。また、固体レーザ媒質１０の活性領域１として図２（ｄ）に示した側面３７の形状を採用することができる。 In the configuration of FIG. 6, the solid medium 10 shown in FIG. 1 can be used instead of the solid laser medium 51. Further, the shape of the side surface 37 shown in FIG. 2D can be adopted as the active region 1 of the solid-state laser medium 10 .
１…活性領域、２…透明領域、３…透明領域２の一つの面、４…活性領域１の一つの面、５…透明領域２の別の面、６…透明領域２の側面、７…活性領域１の側面、８…高反射率層、９…無反射コート層、１０…固体レーザ媒質、１１…活性領域１の別の面、１２…励起光、１３…寄生発振、１５…活性領域１の傾斜した側面、１６…入力光、１７…出力光、２０…固体レーザレーザ発振器、２１…レーザ発振、２２…出力反射鏡、３０固体レーザ媒質、３１…ヒートシンク、３２…圧力、３３…薄い気体層（真空層）、３４…エバネッセント光、３５…透過光、３６…反射光、３７…活性領域１の凹凸を含む形状の側面、３８…ささやき回廊モード、４０…固体レーザ媒質、４１…活性領域、４２…透明領域、４３…寄生発振、４４…透明領域４２の辺、５０…固体レーザ光増幅器、５１…固体レーザ媒質、５２…透明領域、５３…活性領域、５４半導体レーザ、５５…サブマウント、５６…ヒートシンク、５７…励起光、５８…高反射率層、５９…無反射コート層、６０…固体レーザレーザ発振器、６１…出力反射鏡、６２…レーザ発振光、６３…出力光、７０…固体レーザ光増幅器、７１…ヒートシンク、７２…半導体レーザスタック、７３…シリンドリカルレンズ、７４…共通シリンドリカルレンズ、７５…励起光、７６…固体レーザ媒質５１の側面、７７…サブマウント、８０…固体レーザ光増幅器、８１…ヒートシンク、８２…液体、８３…Ｏリング、８４…冷却槽、８５…放熱フィン。 DESCRIPTION OF SYMBOLS 1 ... Active region, 2 ... Transparent region, 3 ... One surface of transparent region 2, 4 ... One surface of active region 1, 5 ... Another surface of transparent region 2, 6 ... Side surface of transparent region 2, 7 ... Side surface of active region 1, 8 ... high reflectance layer, 9 ... non-reflective coating layer, 10 ... solid laser medium, 11 ... another surface of active region 1, 12 ... excitation light, 13 ... parasitic oscillation, 15 ... active region 1 inclined side surface, 16 ... input light, 17 ... output light, 20 ... solid laser oscillator, 21 ... laser oscillation, 22 ... output reflector, 30 solid laser medium, 31 ... heat sink, 32 ... pressure, 33 ... thin Gas layer (vacuum layer), 34 ... evanescent light, 35 ... transmitted light, 36 ... reflected light, 37 ... side surface including irregularities of active region 1, 38 ... whispering gallery mode, 40 ... solid laser medium, 41 ... active Area 42 ... Transparent area 43 ... Parasitic oscillation 44 ... Side of the transparent region 42 50 Solid-state laser optical amplifier 51 Solid-state laser medium 52 Transparent region 53 Active region 54 Semiconductor laser 55 Submount 56 Heat sink 57 Excitation light 58 High Reflectance layer, 59 ... Non-reflective coating layer, 60 ... Solid laser laser oscillator, 61 ... Output reflecting mirror, 62 ... Laser oscillation light, 63 ... Output light, 70 ... Solid laser optical amplifier, 71 ... Heat sink, 72 ... Semiconductor laser Stack 73 ... Cylindrical lens, 74 ... Common cylindrical lens, 75 ... Excitation light, 76 ... Side surface of solid laser medium 51, 77 ... Submount, 80 ... Solid laser optical amplifier, 81 ... Heat sink, 82 ... Liquid, 83 ... O Ring, 84 ... cooling tank, 85 ... radiating fin.

Claims (9)

  1. 　活性領域と透明領域を備えた固体レーザ媒質において、
    　活性領域は平板状であり、
    　透明領域は平板状であり、
    　活性領域の一つの面には高反射率層が設けられ、
    　活性領域の高反射率層が設けられた面はヒートシンクに接触して冷却され、
    　透明領域の外形は活性領域の外形より大きく、
    　活性領域の外形が透明領域の外形をはみ出さないように配置され、
    　励起光が透明領域の側面から導入され、
    　励起光が透明領域を経て活性領域に至り、活性領域を励起することを特徴とする固体レーザ媒質。     In a solid-state laser medium having an active region and a transparent region,
    The active region is flat,
    The transparent area is flat,
    A high reflectivity layer is provided on one surface of the active region,
    The surface provided with the high reflectivity layer in the active region is cooled in contact with the heat sink,
    The outline of the transparent area is larger than the outline of the active area,
    Arranged so that the outer shape of the active region does not protrude from the outer shape of the transparent region,
    Excitation light is introduced from the side of the transparent region,
    A solid-state laser medium characterized in that excitation light reaches an active region through a transparent region and excites the active region.
  2. 　請求項１の固体レーザ媒質において、前記活性領域の外形形状が微細な凹凸を含むことを特徴とする固体レーザ媒質。 2. The solid-state laser medium according to claim 1, wherein an outer shape of the active region includes fine irregularities.
  3. 　請求項１の固体レーザ媒質において、前記活性領域の側面が、活性領域の高反射率層が設けられた面に対して垂直でないことを特徴とする固体レーザ媒質。 2. The solid-state laser medium according to claim 1, wherein a side surface of the active region is not perpendicular to a surface of the active region provided with the high reflectance layer.
  4. 　請求項１の固体レーザ媒質において、
    　活性領域と透明領域は気体層もしくは真空層を介して接触していることを特徴とする固体レーザ媒質。     The solid-state laser medium of claim 1,
    An active region and a transparent region are in contact with each other through a gas layer or a vacuum layer.
  5. 　活性領域と活性領域の周縁部を取り囲む透明領域を備えた固体レーザ媒質において、透明領域の外形形状が互いに平行な辺の組み合わせが無い形状としたことを特徴とする固体レーザ媒質。 A solid-state laser medium comprising a transparent region surrounding an active region and a peripheral portion of the active region, wherein the outer shape of the transparent region is a shape having no combination of sides parallel to each other.
  6. 　固体レーザ媒質、ヒートシンク、及び、複数の半導体レーザを備えた固体レーザ光増幅器において、
    　固体レーザ媒質は透明領域と活性領域を有し、活性領域に接して固体レーザ光増幅器の増幅光波長に対して高い反射率を有する高反射率層が設けられ、
    　活性領域の高反射率層が設けられた面と反対側に透明領域が設けられ、
    　高反射率層と平行な面内において活性領域の周縁部を取り囲むように透明領域が設けられ、
    　ヒートシンク上に、固体レーザ活性領域に設けられた高反射率側が接するように固体レーザ薄膜媒質が設けられ、
    　複数の半導体レーザがヒートシンク上に固体レーザ媒質の側面に近接して設けられ、
    　光学系を介さずに、複数の半導体レーザからの励起光が、直接、固体レーザ媒質の側面に導入されることを特徴とする固体レーザ光増幅器。     In a solid-state laser optical amplifier including a solid-state laser medium, a heat sink, and a plurality of semiconductor lasers,
    The solid laser medium has a transparent region and an active region, and is provided with a high reflectivity layer having a high reflectivity with respect to the amplified light wavelength of the solid laser optical amplifier in contact with the active region,
    A transparent region is provided on the side opposite to the surface provided with the high reflectance layer of the active region,
    A transparent region is provided so as to surround the periphery of the active region in a plane parallel to the high reflectivity layer,
    A solid laser thin film medium is provided on the heat sink so that the high reflectance side provided in the solid laser active region is in contact with the heat sink,
    A plurality of semiconductor lasers are provided on the heat sink adjacent to the side surface of the solid-state laser medium,
    A solid-state laser optical amplifier, wherein excitation light from a plurality of semiconductor lasers is directly introduced into a side surface of a solid-state laser medium without passing through an optical system.
  7. 　固体レーザ媒質、ヒートシンク、複数の半導体レーザスタック、及び、各半導体レーザスタックに対応した結合光学系を備えた固体レーザ光増幅器において、
    　固体レーザ媒質は透明領域と活性領域を有し、活性領域に接して固体レーザ光増幅器の増幅光波長に対して高い反射率を有する高反射率層が設けられ、
    　活性領域の高反射率層が設けられた面と反対側に透明領域が設けられ、
    　高反射率層と平行な面内において活性領域の周縁部を取り囲むように透明領域が設けられ、
    　ヒートシンク上に、固体レーザ活性領域に設けられた高反射率側が接するように固体レーザ薄膜媒質が設けられ、
    　ヒートシンクは活性領域全面と接触し、
    　固体レーザ媒質の外形はヒートシンクの外形より大きく、
    　固体レーザ媒質はヒートシンクより張り出してヒートシンクに設けられ、
    　各半導体レーザスタックからの励起光は結合光学系を介して固体レーザ媒質の側面に導入されることを特徴とする固体レーザ光増幅器。     In a solid-state laser optical amplifier having a solid-state laser medium, a heat sink, a plurality of semiconductor laser stacks, and a coupling optical system corresponding to each semiconductor laser stack,
    The solid laser medium has a transparent region and an active region, and is provided with a high reflectivity layer having a high reflectivity with respect to the amplified light wavelength of the solid laser optical amplifier in contact with the active region,
    A transparent region is provided on the side opposite to the surface provided with the high reflectance layer of the active region,
    A transparent region is provided so as to surround the periphery of the active region in a plane parallel to the high reflectivity layer,
    A solid laser thin film medium is provided on the heat sink so that the high reflectance side provided in the solid laser active region is in contact with the heat sink,
    The heat sink is in contact with the entire active area,
    The external shape of the solid laser medium is larger than the external shape of the heat sink,
    The solid laser medium projects from the heat sink and is provided on the heat sink.
    A solid-state laser optical amplifier, wherein excitation light from each semiconductor laser stack is introduced to a side surface of a solid-state laser medium through a coupling optical system.
  8. 　固体レーザ媒質、ヒートシンク、を備えた固体レーザ光増幅器において、
    　固体レーザ媒質は透明領域と活性領域を有し、活性領域に接して固体レーザ光増幅器の増幅光波長に対して高い反射率を有する高反射率層が設けられ、
    　活性領域の高反射率層が設けられた面と反対側に透明領域が設けられ、
    　高反射率層と平行な面内において活性領域の周縁部を取り囲むように透明領域が設けられ、
    　ヒートシンクには液体を備えた冷却槽が設けられ、
    　この冷却槽中の液体と固体レーザ活性領域に設けられた高反射率側が接するように固体レーザ薄膜媒質が設けられ、
    　透明領域の側面から励起光が導入されたことを特徴とする固体レーザ光増幅器。     In a solid-state laser optical amplifier including a solid-state laser medium and a heat sink,
    The solid laser medium has a transparent region and an active region, and is provided with a high reflectivity layer having a high reflectivity with respect to the amplified light wavelength of the solid laser optical amplifier in contact with the active region,
    A transparent region is provided on the side opposite to the surface provided with the high reflectance layer of the active region,
    A transparent region is provided so as to surround the periphery of the active region in a plane parallel to the high reflectivity layer,
    The heat sink is provided with a cooling tank with liquid,
    The solid laser thin film medium is provided so that the liquid in the cooling tank is in contact with the high reflectance side provided in the solid laser active region,
    A solid-state laser optical amplifier, wherein excitation light is introduced from a side surface of a transparent region.
  9. 　活性領域と透明領域を備えた固体レーザ媒質において、
    　活性領域は平板状であり、
    　透明領域は平板状であり、
    　活性領域の一つの面には高反射率層が設けられ、
    　活性領域と透明領域は積層され、
    　活性領域の高反射率層が設けられた面には放熱フィンが接着されたことを特徴とする固体レーザ媒質。     In a solid-state laser medium having an active region and a transparent region,
    The active region is flat,
    The transparent area is flat,
    A high reflectivity layer is provided on one surface of the active region,
    The active area and the transparent area are laminated,
    A solid-state laser medium, wherein a radiation fin is adhered to a surface of the active region on which a high reflectivity layer is provided.
PCT/JP2016/055747 2015-03-03 2016-02-26 Solid-state laser medium and solid-state laser beam amplifier WO2016140154A1 (en)

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