WO2022249581A1 - レーザ素子及び電子機器 - Google Patents
レーザ素子及び電子機器 Download PDFInfo
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Classifications
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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
- H01S3/09—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
-
- 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
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
- H01S3/1123—Q-switching
- H01S3/113—Q-switching using intracavity saturable absorbers
-
- 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
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/18—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
- H01S5/183—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
-
- 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
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
- H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
Definitions
- the present disclosure relates to laser elements and electronic devices.
- the peak power of a laser is defined as pulse energy ⁇ pulse width, and it is important to obtain a shorter pulse width in order to obtain higher peak power.
- Q-switched solid-state lasers that output laser pulses are characterized in that the length of their own cavity and the resulting pulse width are proportional, and the minimum cavity length is affected by the length of the solid-state laser medium used.
- the length of the solid-state laser medium installed in the cavity as the gain medium is determined by the amount of absorption of the pumping light. Therefore, the excitation efficiency is remarkably lowered.
- the length of the solid-state laser medium is not preferable to make the length of the solid-state laser medium shorter than the excitation light absorption length, and it is not possible to obtain a shorter pulse.
- the length of the solid-state laser medium is shortened in an attempt to obtain a short pulse width, the amount of pumping light absorbed is reduced and the pumping efficiency is lowered.
- the excitation light or oscillation light that excites the solid-state laser medium may resonate in each resonator and become a standing wave in the solid-state laser medium. In this case, the excitation efficiency and stability of the solid-state laser medium are lowered.
- the present disclosure provides a laser element that can suppress standing waves of excitation light or oscillation light while integrating a plurality of optical elements.
- a laser device includes a laminated semiconductor layer having a first reflective layer for a first wavelength and an active layer that emits surface light of the first wavelength, and the laminated semiconductor layer is arranged on the rear side of the optical axis.
- a laser medium having a second reflective layer for a second wavelength on a first surface facing the laminated semiconductor layer and a third reflective layer for a first wavelength on a second surface opposite to the first surface;
- a first polarization conversion element is provided between the second reflective layer and the laser medium to shift the phases of light beams of two wavelengths in mutually orthogonal vibration directions.
- a second polarization conversion element which is provided between the first reflective layer and the fourth reflective layer and which controls the polarization of the light of the first or second wavelength, is provided between the second polarizing conversion element for changing the phase of the light in the orthogonal vibration direction.
- at least one of first and second polarization control elements, the optical axis of the laminated semiconductor layer, the optical axis of the laser medium, the first and second polarization conversion elements, and the optical axis of the first or second polarization control element are arranged on one axis.
- An anisotropic material, a metasurface structure, or a photonic crystal structure is used for the first and second polarization conversion elements.
- the first and second polarization conversion elements give a phase difference of about 1/4 wavelength to the light of the first and second wavelengths, respectively, in the vibration directions orthogonal to each other.
- a fifth reflective layer provided on the laser medium side of the laminated semiconductor layer is further provided.
- the first polarization control element is provided between the first reflection layer and the first polarization conversion element, and controls the polarization of light of the first wavelength.
- the second polarization control element is provided between the fourth reflective layer and the second polarization conversion element, and controls polarization of light of the second wavelength.
- the first polarization control element has a fine structure on its surface so as to have different transmittances for mutually orthogonally polarized light of the first wavelength.
- the second polarization control element has a fine structure on its surface so as to have different transmittances for mutually orthogonally polarized light of the second wavelength.
- a saturable absorber provided between the third reflective layer and the fourth reflective layer is further provided.
- the first polarization conversion element is arranged between the first polarization control element and the second reflective layer, and the second polarization conversion element is arranged between the laser medium and the third reflective layer.
- the first polarization conversion element is arranged between the second reflective layer and the laser medium
- the second polarization conversion element is arranged between the third reflective layer and the second polarization control element.
- the first polarization conversion element is arranged between the second reflective layer and the laser medium, and the second polarization conversion element is arranged between the laser medium and the third reflective layer.
- the fourth reflective layer has a fine structure on its surface so as to have different transmittances for mutually orthogonally polarized light of the second wavelength.
- the saturable absorber has a fine structure on its surface so as to have different transmittances for mutually orthogonally polarized light of the second wavelength.
- the fourth reflective layer causes the light of the second wavelength to differ in phase with respect to the light of the vibration directions orthogonal to each other.
- the first polarization control element is provided between the second reflection layer and the first polarization conversion element, has different transmittances with respect to polarized light of the first wavelength that are orthogonal to each other, and It has a fine structure on its surface so as to have different transmittances for polarized lights of two wavelengths that are orthogonal to each other.
- the second polarization control element is provided between the third reflection layer and the second polarization conversion element, has different transmittances for mutually orthogonally polarized light of the first wavelength, and It has a fine structure on its surface so as to have different transmittances for polarized lights of two wavelengths that are orthogonal to each other.
- the first polarization conversion element has a fine structure on its surface so as to have different transmittances for mutually orthogonally polarized light of the first wavelength.
- the second polarization conversion element has a fine structure on its surface so as to have different transmittances for mutually orthogonally polarized light of the second wavelength.
- the laminated semiconductor layer, laser medium, fourth reflective layer, first resonator, second resonator, first polarization conversion element, second polarization conversion element, and first or second polarization control element are integrally bonded.
- a transparent member provided at any position between the first reflective layer and the fourth reflective layer is further provided.
- An electronic device is an electronic device comprising a laser element and a control unit that controls emission of light from the laser element, wherein the laser element includes a first reflective layer for a first wavelength, an active layer that emits surface light of a first wavelength; and a second reflective layer for the second wavelength on the first surface facing the laminated semiconductor layer disposed on the rear side of the optical axis of the laminated semiconductor layer.
- a laser medium having a third reflective layer for the first wavelength on a second surface opposite to the first surface; a fourth reflective layer for a second wavelength; a first resonator for resonating light of the first wavelength between the first reflective layer and the third reflective layer; A second resonator that resonates the light of the wavelength, and a first polarization converter that is provided between the first reflective layer and the laser medium and causes the phases of the light of the first wavelength to differ from each other in the vibration directions that are orthogonal to each other.
- a second polarizing conversion element provided between the second reflective layer and the laser medium, the second polarizing conversion element for causing a phase difference between the light beams of the second wavelength in the vibration directions orthogonal to each other; and at least one of a first or a second polarization control element provided between the 4 reflective layers and controlling the polarization of light of the first or second wavelength, the optical axis of the laminated semiconductor layer, the light of the laser medium
- the axis, the first and second polarization conversion elements, and the optical axis of the first or second polarization control element are arranged on one axis.
- FIG. 1 is a diagram showing the basic configuration of a laser device according to the present disclosure
- FIG. FIG. 2 is a cross-sectional view showing a configuration example of the laser device according to the first embodiment
- FIG. 2 is a cross-sectional view showing a configuration example of a laser device including a transparent member
- FIG. 5 is a cross-sectional view showing a configuration example of a laser device according to a second embodiment
- FIG. 5 is a cross-sectional view showing a configuration example of a laser device according to a third embodiment
- FIG. 5 is a cross-sectional view showing a configuration example of a laser device according to a fourth embodiment
- Sectional drawing which shows the structural example of the laser element by 5th Embodiment.
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according to a seventh embodiment
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according to an eighth embodiment
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according to a ninth embodiment
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according to a tenth embodiment
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according to an eleventh embodiment
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according to a seventh embodiment
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according to an eighth embodiment
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according to a ninth embodiment
- FIG. 11 is a cross-sectional view showing a configuration example of a laser device according
- FIG. 21 is a cross-sectional view showing a configuration example of a laser device according to a twelfth embodiment
- FIG. 21 is a cross-sectional view showing a configuration example of a laser device according to a thirteenth embodiment
- FIG. 16 is a block diagram showing an example of the functional configuration of the camera and CCU shown in FIG. 15; The figure which shows an example of a schematic structure of a microsurgery system.
- a laser device has a structure in which a structure using a part of a surface-emitting laser as a light-emitting device and a solid-state laser medium for Q-switching are integrally joined.
- laser elements according to the present disclosure may include laser elements that do not have a Q-switch function, but first, a laser element that has a Q-switch function will be described.
- two resonators share the Q-switching solid-state laser medium. These two resonators have a first resonator resonating at a first wavelength and a second resonator (also called Q-switched solid-state laser resonator) resonating at a second wavelength.
- the laser element according to the present disclosure is an integrated laminated structure that can be manufactured using semiconductor process technology, it is excellent in mass productivity and in laser output stability.
- the light emitting element is one form of a vertical cavity surface emitting laser (VCSEL).
- VCSEL vertical cavity surface emitting laser
- the difference from the VCSEL is that at least one of the mirrors forming the resonator is provided outside the laminated semiconductor layer, which is the main body of the light emitting element.
- a laser device according to the present disclosure has a structure in which a solid-state laser medium is arranged between a laminated semiconductor layer and a mirror arranged outside the laminated semiconductor layer, as will be described later.
- the laser element can generate a laser pulse with a short pulse width by Q-switching.
- the solid-state laser medium is shared by the cavity for the excitation light and the cavity for the oscillation light.
- the excitation light or oscillation light that excites the solid-state laser medium resonates in each resonator and becomes a standing wave in the solid-state laser medium.
- the standing wave of the excitation light does not excite the solid-state laser medium at the node portion thereof, thereby reducing the excitation efficiency.
- the standing wave of the excitation light causes reabsorption of the oscillation light in the solid-state laser medium.
- a standing wave of the oscillating light causes a so-called spatial hole burning phenomenon.
- polarization conversion elements are provided on both sides of the solid-state laser medium to change the phases of the excitation light or oscillation light in the mutually orthogonal vibration directions, and a polarization control element is provided. Assume that the laser is oscillated only with polarized light in one direction. This makes it possible to suppress the generation of standing waves of excitation light or oscillation light without impairing the advantage of the compact integrated structure.
- a laser device has the following three features.
- the first resonator and the second resonator share a solid-state laser medium.
- the first cavity includes a light-emitting element and a solid-state laser medium.
- the second resonator includes a solid-state laser medium and a saturable absorber, and performs Q-switched laser oscillation with excitation light from the first resonator.
- Polarization conversion elements are provided on both sides of the solid-state laser medium, respectively, so that the phases of the excitation light and/or the oscillation light are different from each other in the vibration directions perpendicular to each other. Furthermore, at least one polarization control element for controlling polarization in one direction is provided between the polarization conversion element and the reflecting layer on the opposite side of the solid-state laser medium in the resonator. These polarization conversion element and polarization control element suppress standing waves of excitation light and/or oscillation light in the solid-state laser medium.
- the light-emitting element, solid-state laser medium, and saturable absorber have an integrated structure.
- excitation light generated by injecting current into the light-emitting device is absorbed by the solid-state laser medium within the first cavity.
- the solid-state laser medium constitutes a second cavity together with a saturable absorber placed in the first cavity.
- the solid-state laser medium becomes sufficiently excited, the output of spontaneous emission light increases, and when it exceeds a certain threshold, the light absorption rate in the saturable absorber drops sharply, and the spontaneous emission light generated in the solid-state laser medium is It becomes permeable through the saturable absorber and causes stimulated emission in the solid-state laser medium. This causes Q-switched pulsing.
- FIG. 1 is a diagram showing the basic configuration of a laser device 1 according to the present disclosure.
- a laser device 1 shown in FIG. 1 has a structure in which a light-emitting device 2, a solid-state laser medium 3, and a saturable absorber 4 are integrally joined.
- the light emitting element 2 has a semiconductor layer with a laminated structure (laminated semiconductor layer).
- the light emitting device 2 of FIG. 1 has a structure in which a substrate 5, a fifth reflective layer R5, a clad layer 6, an active layer 7, a clad layer 8, and a first reflective layer R1 are laminated in this order.
- the laser device 1 in FIG. 1 has a bottom emission type configuration in which continuous wave (CW) excitation light is emitted from the substrate 5, the CW excitation light is emitted from the first reflective layer R1 side.
- a top emission type configuration is also possible.
- the substrate 5 is an n-GaAs substrate 5, for example. Since the n-GaAs substrate 5 absorbs light of the first wavelength ⁇ 1, which is the excitation wavelength of the light emitting element 2, at a constant rate, it is desirable to make it as thin as possible. On the other hand, it is desirable to have a thickness sufficient to maintain the mechanical strength during the joining process, which will be described later.
- the active layer 7 performs surface emission of the first wavelength ⁇ 1.
- the clad layers 6 and 8 are, for example, AlGaAs clad layers.
- the first reflective layer R1 reflects light of the first wavelength ⁇ 1.
- the fifth reflective layer R5 has a constant transmittance for light of the first wavelength ⁇ 1.
- an electrically conductive semiconductor distributed reflective layer DBR: Distributed Bragg Reflector
- a current is injected from the outside through the first reflective layer R1 and the fifth reflective layer R5, recombination and light emission occur in the quantum well in the active layer 7, and laser oscillation of the first wavelength ⁇ 1 is performed.
- a part of the surface layer (for example, AlAs layer) 31A on the clad layer side of the first reflective layer R1 is oxidized to become an oxide layer (for example, Al 2 O 3 layer) 32 .
- the fifth reflective layer R ⁇ b>5 is provided on the solid-state laser medium 3 side of the light-emitting element 2 and is provided between the semiconductor layer of the light-emitting element 2 and the solid-state laser medium 3 .
- the fifth reflective layer R5 is arranged on the n-GaAs substrate 5, for example.
- the fifth reflective layer R5 has a multilayer reflective film made of Al z1 Ga 1-z1 As/Al z2 Ga 1-z2 As (0 ⁇ z1 ⁇ z2 ⁇ 1) doped with an n-type dopant (eg, silicon).
- the fifth reflective layer R5 is also called n-DBR. More specifically, an n-contact layer 33 is arranged between the fifth reflective layer R5 and the n-GaAs substrate 5. As shown in FIG.
- the active layer 7 has, for example, a multiple quantum well layer in which an Al x1 In y1 Ga 1-x1-y1 As layer and an Al x3 In y3 Ga 1-x3-y3 As layer are laminated.
- the first reflective layer R1 has, for example, a multiple reflection film made of Al z3 Ga 1-z3 As/Al Z4 Ga 1-z4 As (0 ⁇ z3 ⁇ z4 ⁇ 1) doped with a p-type dopant (eg, carbon). .
- the first reflective layer R1 is also called p-DBR.
- Each of the semiconductor layers R5, 6, 7, 8 and R1 in the light emitting element 2 can be formed using a crystal growth method such as MOCVD (metal organic chemical vapor deposition) and MBE (molecular beam epitaxy). After crystal growth, processes such as mesa etching for element isolation, formation of an insulating film, and vapor deposition of an electrode film enable driving by current injection.
- a crystal growth method such as MOCVD (metal organic chemical vapor deposition) and MBE (molecular beam epitaxy).
- MOCVD metal organic chemical vapor deposition
- MBE molecular beam epitaxy
- a solid-state laser medium 3 is bonded to the end surface of the n-GaAs substrate 5 of the light-emitting element 2 opposite to the fifth reflective layer R5.
- the end surface of the solid-state laser medium 3 on the light emitting element 2 side is called a first surface F1
- the end surface of the solid-state laser medium 3 on the saturable absorber 4 side is called a second surface F2.
- a laser pulse emitting surface of the saturable absorber 4 is called a third surface F3
- an end surface of the light emitting element 2 on the solid-state laser medium 3 side is called a fourth surface F4.
- An end face of the saturable absorber 4 on the solid-state laser medium 3 side is called a fifth face F5.
- the fourth surface F4 of the light-emitting element 2 is joined to the first surface F1 of the solid-state laser medium 3, and the second surface F2 of the solid-state laser medium 3 is connected to the saturable absorber 4. is joined to the fifth surface F5 of the .
- the laser device 1 in FIG. 1 includes a first resonator 11 and a second resonator 12.
- the first resonator 11 resonates light with a first wavelength ⁇ 1 between the first reflective layer R1 in the light emitting element 2 and the third reflective layer R3 in the solid-state laser medium 3 .
- the second resonator 12 resonates light of the second wavelength ⁇ 2 between the second reflective layer R2 in the solid-state laser medium 3 and the fourth reflective layer R4 in the saturable absorber 4 .
- the second resonator 12 is also called a Q-switched solid-state laser resonator 12.
- a third reflective layer R3, which is a highly reflective layer, is provided in the solid-state laser medium 3 so that the first resonator 11 can perform stable resonant operation.
- a normal light emitting device 2 has a partially reflecting mirror for emitting the light of the first wavelength ⁇ 1 to the outside at the position of the third reflecting layer R3 in FIG.
- the third reflective layer R3 is used to confine the power of the pumping light of the first wavelength ⁇ 1 within the first resonator 11. It has a reflective layer.
- first reflective layer R1, fifth reflective layer R5, and third reflective layer R3 are provided inside the first resonator 11 composed of the light emitting element 2 and the solid-state laser medium 3. be done. Therefore, the first resonator 11 has a coupled cavity structure.
- the solid-state laser medium 3 is excited. This causes Q-switched laser pulse oscillation in the second resonator 12 .
- the second resonator 12 resonates light of the second wavelength ⁇ 2 between the second reflective layer R2 in the solid-state laser medium 3 and the fourth reflective layer R4 in the saturable absorber 4 .
- the second reflective layer R2 is a highly reflective layer, while the fourth reflective layer R4 is a partially reflective layer.
- the fourth reflective layer R4 is provided on the end surface of the saturable absorber 4, but the fourth reflective layer R4 may be arranged on the rear side of the optical axis from the laser pulse emission surface of the saturable absorber 4. good.
- the rearward direction of the optical axis is the direction in which light is emitted on the optical axis. That is, the fourth reflective layer R4 does not necessarily have to be provided inside or on the surface of the saturable absorber 4.
- FIG. even if the fourth reflective layer R4 is arranged on the front side of the optical axis relative to the saturable absorber 4, the light of the second wavelength ⁇ 2 is resonated between the second reflective layer R2 and the fourth reflective layer R4. need to let
- the solid-state laser medium 3 includes, for example, Yb (yttrium)-doped YAG (yttrium aluminum garnet) crystal Yb:YAG.
- the first wavelength ⁇ 1 of the first resonator 11 is 940 nm
- the second wavelength ⁇ 2 of the second resonator 12 is 1030 nm.
- the solid-state laser medium 3 is not limited to Yb:YAG. :SFAP, Yb:YVO, Yb:glass, Yb:KYW, Yb:BCBF, Yb:YCOB, Yb:GdCOB, YB:YAB can be used.
- the solid-state laser medium 3 may be a four-level solid-state laser medium 3 or a quasi-three-level solid-state laser medium 3 .
- first wavelength ⁇ 1 the appropriate excitation wavelength
- the saturable absorber 4 includes, for example, Cr (chromium)-doped YAG (Cr:YAG) crystal.
- the saturable absorber 4 is a material whose transmittance increases when the intensity of incident light exceeds a predetermined threshold.
- the excitation light of the first wavelength ⁇ 1 from the first resonator 11 increases the transmittance of the saturable absorber 4 and emits a laser pulse of the second wavelength ⁇ 2. This is called a Q-switch.
- V:YAG can also be used as the material of the saturable absorber 4 .
- other types of saturable absorbers 4 may be used. Moreover, it does not prevent using an active Q switch element as the Q switch.
- the light-emitting element 2, the solid-state laser medium 3, and the saturable absorber 4 are shown separately, but these are laminated structures that are joined together using a joining process.
- bonding processes that can be used include surface activated bonding, atomic diffusion bonding, plasma activated bonding, and the like. Alternatively, other bonding (adhesion) processes can be used.
- the electrodes E1 and E2 for injecting current into the first reflective layer R1 and the fifth reflective layer R5 are preferably arranged so as not to be exposed on the surface of the n-GaAs substrate 5 at least. .
- electrodes E1 and E2 are arranged on the end surface of the light emitting element 2 on the first reflective layer R1 side.
- the electrode E1 is a p-electrode and is electrically connected to the first reflective layer R1.
- the electrode E2 is an n-electrode, and is formed by filling the inner wall of a trench extending from the first reflective layer R1 to the n-contact layer 33 with a conductive material 35 with an insulating film 34 interposed therebetween.
- this end face can be soldered to a support substrate (not shown). Even when a plurality of laser elements are arranged in an array, by arranging the electrodes E1 and E2 on the same end surface, this end surface can be mounted on the support substrate. Note that the shape and location of the electrodes E1 and E2 shown in FIG. 1 are merely examples.
- the arithmetic mean roughness Ra of each surface layer must be about 1 nm or less, preferably 0.5 nm or less. Chemical mechanical polishing (CMP) is used to achieve a surface layer having these arithmetic mean roughnesses.
- CMP Chemical mechanical polishing
- a dielectric multilayer film may be arranged between the layers and the layers may be joined via the dielectric multilayer film.
- the GaAs substrate 5, which is the base substrate of the light emitting element 2 has a refractive index n of 3.2 at a wavelength of 940 nm, which is higher than YAG (n: 1.7) and general dielectric multilayer materials.
- an antireflection film (AR coating film or non-reflection coating film) that does not reflect the light of the first wavelength ⁇ 1 of the first resonator 11 is arranged between the light emitting element 2 and the solid-state laser medium 3. is desirable. It is also desirable to dispose an antireflection film (AR coating film or non-reflection coating film) between the solid-state laser medium 3 and the saturable absorber 4 as well.
- polishing may be difficult.
- a material transparent to the first wavelength ⁇ 1 and the second wavelength ⁇ 2 such as SiO 2
- SiO 2 is deposited as a base layer for bonding, and this SiO 2 layer is processed by arithmetic. It may be polished to an average roughness Ra of about 1 nm (preferably 0.5 nm or less) and used as an interface for bonding.
- materials other than SiO 2 can be used as the underlayer, and the material is not limited here.
- a non-reflective film may be provided between the SiO 2 material of the underlayer and the base layer.
- Dielectric multilayer film includes short wavelength transmission filter film (SWPF: Short Wave Pass Filter), long wavelength transmission filter film (LWPF: Long Wave Pass Filter), band pass filter film (BPF: Band Pass Filter), non-reflection protection There is a film (AR: Anti-Reflection) and the like. It is desirable to arrange different kinds of dielectric multilayer films according to need.
- a PVD (Physical Vapor Deposition) method can be used as a method for forming the dielectric multilayer film, and specifically, a film forming method such as vacuum deposition, ion-assisted deposition, or sputtering can be used. It does not matter which film formation method is applied. Also, the characteristics of the dielectric multilayer film can be arbitrarily selected.
- the second reflective layer R2 may be a short wavelength transmission filter film
- the third reflective layer R3 may be a long wavelength transmission filter film.
- short wavelength transmission means that the light of the first wavelength ⁇ 1 is transmitted and the light of the second wavelength ⁇ 2 is reflected.
- long wavelength transmission means reflecting light of the first wavelength ⁇ 1 and transmitting light of the second wavelength ⁇ 2.
- a polarizer with a photonic crystal structure that separates the ratio of P-polarized light and S-polarized light may be provided inside the second resonator 12 .
- a diffraction grating may be provided inside the second resonator 12 to convert the polarization state of the emitted laser pulse from random polarization to linear polarization.
- the output of the spontaneous emission light increases, and when it exceeds a certain threshold, the saturable absorber The light absorptance at 4 drops abruptly, and the spontaneous emission light generated in the solid-state laser medium 3 becomes able to pass through the saturable absorber 4 .
- the light of the first wavelength ⁇ 1 emitted from the first resonator 11 is emitted from the solid-state laser medium 3, and the light of the second wavelength ⁇ 1 is emitted from the second resonator 12 between the second reflective layer R2 and the fourth reflective layer R4. Resonate the light of ⁇ 2.
- Q-switched laser oscillation occurs, and a Q-switched laser pulse is emitted toward space (the space on the right side in FIG. 1) via the fourth reflective layer R4.
- a nonlinear optical crystal for wavelength conversion can be arranged inside the second cavity 12 .
- the wavelength of the laser pulse after wavelength conversion can be changed.
- wavelength conversion materials include nonlinear optical crystals such as LiNbO 3 , BBO, LBO, CLBO, BiBO, KTP, and SLT. Phase-matching materials similar to these may also be used as the wavelength conversion material. However, any kind of wavelength conversion material is acceptable.
- the wavelength converting material can convert the second wavelength ⁇ 2 to another wavelength.
- FIG. 2A is a cross-sectional view showing a configuration example of the laser device 1 according to the first embodiment.
- the laser device 1 further includes polarization conversion elements 21 and 22 and a polarization control element 31 in addition to the basic configuration of FIG.
- a saturable absorber 4 is arranged between the third reflective layer R3 and the fourth reflective layer R4.
- optical elements constituting the laser element 1 for example, the light emitting element 2, the solid state laser medium 3, the reflective layers R1 to R5, the resonators 11 and 12, the polarization conversion elements 21 and 22, the polarization The control elements 31
- optical elements constituting the laser element 1 for example, the light emitting element 2, the solid state laser medium 3, the reflective layers R1 to R5, the resonators 11 and 12, the polarization conversion elements 21 and 22, the polarization The control elements 31
- the laser element 1 for example, the light emitting element 2, the solid state laser medium 3, the reflective layers R1 to R5, the resonators 11 and 12, the polarization conversion elements 21 and 22, the polar
- the polarization conversion element 21 as the first polarization conversion element is placed at any position between the first reflective layer R1 and the solid-state laser medium 3 in the excitation light resonator 11 and on the optical axis of the excitation light resonator 11. are placed. More specifically, the polarization conversion element 21 is provided between the polarization control element 31 and the second reflective layer R2. The polarization conversion element 21 causes the excitation light of the first wavelength to have different phases with respect to the light in the vibration directions orthogonal to each other.
- the polarization conversion element 22 as the second polarization conversion element is arranged on the opposite side of the solid-state laser medium 3 with respect to the polarization conversion element 21 .
- the polarization conversion element 22 is arranged on the optical axis of the excitation light resonator 11 somewhere between the fourth reflective layer R4 and the solid-state laser medium 3 . More specifically, the polarization conversion element 22 is provided between the third reflective layer R3 and the solid-state laser medium 3.
- the polarization conversion element 22 causes the excitation light of the first wavelength to have different phases with respect to the light in the vibration directions orthogonal to each other.
- the two polarization conversion elements 21 and 22 are arranged on both sides of the solid-state laser medium 3 .
- the polarization conversion elements 21 and 22 give different phase differences to the lights in the vibration directions orthogonal to each other in the excitation light.
- the polarization conversion elements 21 and 22 each give a phase difference of about a quarter wavelength (that is, ⁇ /2) between the TM (Transverse Magnetic) wave and the TE (Transverse Electric) wave of the excitation light.
- the main axes of the polarization conversion elements 21 and 22 are perpendicular to each other and are inclined 45 degrees with respect to the polarization direction defined by the polarization control element 31 .
- the phase difference given to the excitation light by the polarization conversion elements 21 and 22 does not necessarily have to be 1/4 wavelength.
- An anisotropic material, a metasurface structure, a photonic crystal structure, or the like is used for the polarization conversion elements 21 and 22, for example.
- the polarization conversion elements 21 and 22 give different phase differences to the light beams in the mutually orthogonal vibration directions in the excitation light beam, so that the excitation light beam does not become a standing wave in the solid-state laser medium 3, and the efficiency is improved. can excite the solid-state laser medium 3 dynamically.
- the polarization conversion elements 21 and 22 act on the excitation light, but do not act on the oscillation light of the second wavelength ⁇ 2.
- the polarization conversion elements 21 and 22 may act on the oscillation light as described later.
- the polarization control element 31 as the first polarization control element is provided at any position between the first reflection layer R1 and the fourth reflection layer R4 or the polarization conversion element 21.
- FIG. More specifically, the polarization control element 31 is provided between the substrate 5 of the light emitting element 2 and the polarization conversion element 21 and arranged on the optical axis of the excitation light resonator 11 .
- the polarization control element 31 controls the polarization of the excitation light with the first wavelength ⁇ 1.
- dielectrics eg, Al2O3 , SiO2 , Ta2O5 , HfO2
- semiconductors eg, GaN, InN, AlN
- transparent materials are used.
- a grating structure as a fine structure is formed on the surface of the polarization control element 31 .
- the polarization control element 31 has different transmittances for mutually orthogonal polarized light (TM wave, TE wave) of the excitation light of the first wavelength ⁇ 1.
- the grating structure may be, for example, a concavo-convex structure having a period equal to or less than the first wavelength ⁇ 1 of the excitation light and having a depth equal to or less than a quarter of the first wavelength ⁇ 1 of the excitation light.
- the grating structure may be, for example, a one-dimensional surface relief grating structure that utilizes 0th order diffracted light (transmitted light).
- the pattern of the grating structure may be a so-called line-and-space pattern.
- the polarization control element 31 has different transmittances for mutually orthogonal polarized light (TM wave, TE wave) in the 0th order diffracted light (transmitted light) of the excitation light.
- the polarization control element 31 controls the polarization of the excitation light in one direction instead of random polarization, so it is possible to improve the characteristics of the excitation light resonator 11, such as stabilizing the oscillation output and improving the wavelength conversion efficiency. becomes.
- the polarization control element 31 may have different transmittances for mutually orthogonal polarized light (TM wave, TE wave). etc.
- the polarized light having a high transmittance with respect to the polarization control element 31 among the excitation light is oscillated in the solid-state laser medium 3 by the polarization conversion elements 21 and 22 so as not to become standing waves.
- the solid-state laser medium 3 standing waves generated by the excitation light resonating in the first resonator can be suppressed, and the solid-state laser medium 3 can be excited with high efficiency.
- the transparent member HE may be provided at any position between the first reflective layer R1 and the fourth reflective layer R4.
- the transparent member HE functions as a spacer that adjusts the length of the optical resonator 11 or 12 in the optical axis direction.
- the transparent member HE when adjacent to the solid-state laser medium 3, the transparent member HE has both the function of discharging heat from the solid-state laser medium 3 and the function of a spacer.
- FIG. 2B is a cross-sectional view showing a configuration example of the laser element 1 including the transparent member HE.
- the transparent member HE is adjacent to the solid state laser medium 3 via a reflective layer R2.
- the transparent member HE has both the function of adjusting the length of the optical resonator 11 in the optical axis direction and the function of exhausting heat.
- FIG. 3 is a cross-sectional view showing a configuration example of the laser device 1 according to the second embodiment.
- the polarization conversion element 21 is arranged between the second reflective layer R2 and the solid-state laser medium 3 .
- the polarization conversion element 22 is arranged between the third reflective layer R3 and the polarization control element 32 .
- the polarization control element 32 is provided at any position between the fourth reflective layer R4 and the polarization conversion element 22 . More specifically, the polarization control element 32 is provided between the saturable absorber 4 and the polarization conversion element 22 .
- the polarization conversion elements 21 and 22 and the polarization control element 32 are provided on the oscillation optical resonator 12 side to suppress the standing wave of the oscillation light of the second wavelength ⁇ 2.
- the polarization conversion elements 21 and 22 give different phase differences to the light beams in oscillation directions orthogonal to each other in the oscillation light beams.
- the polarization conversion elements 21 and 22 each give a phase difference of about a quarter wavelength (that is, ⁇ /2) between the TM wave and the TE wave of the oscillation light.
- the main axes of the polarization conversion elements 21 and 22 are perpendicular to each other and are inclined 45 degrees with respect to the polarization direction defined by the polarization control element 32 .
- the phase difference given to the oscillation light by the polarization conversion elements 21 and 22 does not necessarily have to be a quarter wavelength.
- An anisotropic material, a metasurface structure, a photonic crystal structure, or the like is used for the polarization conversion elements 21 and 22, for example.
- the polarization conversion elements 21 and 22 give different phase differences to the light beams in the oscillation directions orthogonal to each other in the oscillation light, so that the oscillation light does not become a standing wave in the solid-state laser medium 3, and the efficiency is improved. laser oscillation is realized.
- the polarization conversion elements 21 and 22 act on the oscillation light, but do not act on the excitation light of the first wavelength ⁇ 1. However, there is no problem even if the polarization conversion elements 21 and 22 act on the excitation light as described later.
- a polarization control element 32 as a second polarization control element is provided between the saturable absorber 4 and the polarization conversion element 22 and arranged on the optical axis of the oscillation optical resonator 12 .
- the polarization control element 32 controls the polarization of the oscillation light of the second wavelength ⁇ 2.
- dielectrics eg, Al2O3 , SiO2 , Ta2O5 , HfO2
- semiconductors eg, GaN, InN, AlN
- transparent materials are used.
- a grating structure as a fine structure is formed on the surface of the polarization control element 32 .
- the polarization control element 32 has different transmittances for mutually orthogonal polarized light (TM wave, TE wave) of the oscillation light of the second wavelength ⁇ 2.
- the grating structure may be, for example, a concavo-convex structure having a period equal to or less than the second wavelength ⁇ 2 of the oscillating light and a depth equal to or less than 1/4 of the second wavelength ⁇ 2 of the oscillating light.
- the grating structure may be, for example, a one-dimensional surface relief grating structure that utilizes 0th order diffracted light (transmitted light). That is, the pattern of the grating structure may be a so-called line-and-space pattern.
- the polarization control element 32 has different transmittances for mutually orthogonal polarized light (TM wave, TE wave) in the 0th order diffracted light (transmitted light) of the oscillation light.
- the polarization control element 32 controls the polarization of the oscillating light in one direction instead of random polarization, so it is possible to improve the characteristics of the oscillating optical resonator 12, such as stabilizing the oscillation output and improving the wavelength conversion efficiency. becomes.
- the polarization control element 32 may have different transmittances for mutually orthogonal polarized light (TM wave, TE wave). etc.
- the saturable absorber 4 is provided between the polarization control element 32 and the fourth reflective layer R4. However, the saturable absorber 4 may be placed anywhere between the third reflective layer R3 and the fourth reflective layer R4.
- the oscillation light polarized light having a high transmittance with respect to the polarization control element 32 is oscillated in the solid-state laser medium 3 by the polarization conversion elements 21 and 22 so as not to become standing waves.
- the standing wave generated by the oscillation light resonating in the second cavity is suppressed, and the oscillation light can be stably and highly efficiently output.
- FIG. 4 is a cross-sectional view showing a configuration example of the laser device 1 according to the third embodiment.
- the polarization conversion element 21 is arranged between the second reflective layer R2 and the solid-state laser medium 3.
- the polarization conversion element 22 is arranged between the solid-state laser medium 3 and the third reflective layer R3.
- both polarization control elements 31 and 32 are provided as polarization control elements.
- the polarization control element 31 is provided between the fifth reflective layer R5 and the second reflective layer R2.
- the polarization control element 32 is provided between the saturable absorber 4 and the third reflective layer R3.
- the polarization conversion elements 21 and 22 are shared by both the excitation optical resonator 11 and the oscillation optical resonator 12 .
- a polarization control element 31 is provided on the excitation optical resonator 11 side, and a polarization control element 32 is provided on the oscillation optical resonator 12 side.
- the configurations of the polarization conversion elements 21 and 22 may be the same as those of the first and second embodiments. That is, the polarization conversion elements 21 and 22 give different phase differences to the light beams in the vibration directions orthogonal to each other in both the excitation light beam and the oscillation light beam.
- the polarization conversion elements 21 and 22 give a phase difference of about a quarter wavelength (that is, ⁇ /2) between the oscillation light and the TM wave and TE wave of the oscillation light, respectively.
- the main axes of the polarization conversion elements 21 and 22 are perpendicular to each other and are inclined 45 degrees with respect to the polarization direction defined by the polarization control element 32 .
- the phase difference given to the excitation light and the oscillation light by the polarization conversion elements 21 and 22 does not necessarily have to be 1/4 wavelength.
- the polarization conversion elements 21 and 22 give different phase differences to the excitation light and the oscillation light in the mutually orthogonal vibration directions, so that the excitation light and the oscillation light are stationary in the solid state laser medium 3. Efficient laser oscillation is possible without becoming a wave.
- the polarization control element 31 is provided between the light emitting element 2 and the second reflective layer R2 and arranged on the optical axis of the excitation light resonator 11 .
- the polarization control element 31 controls the polarization of the excitation light with the first wavelength ⁇ 1.
- the polarization control element 32 is provided between the third reflective layer R3 and the saturable absorber 4, and arranged on the optical axis of the oscillation optical resonator 12.
- the polarization control element 32 controls the polarization of the oscillation light of the second wavelength ⁇ 2.
- the configurations of the polarization control elements 31 and 32 may be similar to those of the first and second embodiments.
- polarized light having a high transmittance with respect to the polarization control element 31 is oscillated in the solid-state laser medium 3 by the polarization conversion elements 21 and 22 so as not to become standing waves.
- the standing wave of the excitation light is suppressed in the solid-state laser medium 3, and the solid-state laser medium 3 can be excited with high efficiency.
- polarized light having a high transmittance with respect to the polarization control element 32 is oscillated in the solid-state laser medium 3 by the polarization conversion elements 21 and 22 so as not to become standing waves.
- the standing wave of the oscillation light is suppressed in the solid-state laser medium 3, and the laser oscillation can be stabilized and highly efficient.
- FIG. 5 is a cross-sectional view showing a configuration example of the laser device 1 according to the fourth embodiment.
- the fourth reflective layer R4 of the second embodiment also functions as the polarization control element 32.
- a fine structure similar to that of the polarization control element 32 is formed on the surface of the fourth reflective layer R4 on the saturable absorber 4 side.
- the fourth reflective layer R4 can also function as the polarization control element 32 with respect to the oscillation light.
- the fourth reflective layer R4 has different transmittances with respect to mutually orthogonal polarizations (for example, TM waves and TE waves) of the oscillation light of the second wavelength ⁇ 2.
- the polarization control element 32 and the fourth reflected light R4 are not separated but are integrally formed, so that the laser element 1 according to the fourth embodiment can be further miniaturized.
- FIG. 6 is a cross-sectional view showing a configuration example of the laser device 1 according to the fifth embodiment.
- the fourth reflective layer R4 of the third embodiment has the function of the polarization control element 32 as well. That is, the polarization control element 32 for the oscillation light and the fourth reflected light R4 are integrated. In this case, a fine structure similar to that of the polarization control element 32 is formed on the surface of the fourth reflective layer R4 on the saturable absorber 4 side. Thereby, the fourth reflective layer R4 can also function as the polarization control element 32 with respect to the oscillation light.
- the fourth reflective layer R4 has different transmittances with respect to mutually orthogonal polarizations (for example, TM waves and TE waves) of the oscillation light of the second wavelength ⁇ 2.
- the polarization control element 32 and the fourth reflected light R4 are not separated but are integrally formed, so that the laser element 1 according to the fifth embodiment can be further miniaturized.
- FIG. 7 is a cross-sectional view showing a configuration example of the laser device 1 according to the sixth embodiment.
- the saturable absorber 4 of the second embodiment also functions as the polarization control element 32 . That is, the oscillating light polarization control element 32 and the saturable absorber 4 are integrated. For example, a fine structure similar to the polarization control element 32 is formed on the surface of the saturable absorber 4 . Thereby, the saturable absorber 4 can also have the function of the polarization control element 32 with respect to the oscillation light.
- the saturable absorber 4 has different transmittances for mutually orthogonal polarizations (for example, TM waves and TE waves) of the oscillation light of the second wavelength ⁇ 2.
- the anisotropy of the saturable absorber may be used instead of providing the fine structure.
- the polarization control element 32 and the fourth reflected light R4 are not separated but are integrally formed, so that the laser element 1 according to the sixth embodiment can be further miniaturized.
- FIG. 8 is a cross-sectional view showing a configuration example of the laser device 1 according to the seventh embodiment.
- the saturable absorber 4 of the third embodiment also functions as the polarization control element 32 . That is, the oscillating light polarization control element 32 and the saturable absorber 4 are integrated.
- a fine structure similar to the polarization control element 32 is formed on the surface of the saturable absorber 4 .
- the saturable absorber 4 can also have the function of the polarization control element 32 with respect to the oscillation light.
- the saturable absorber 4 has different transmittances for mutually orthogonal polarizations (for example, TM waves and TE waves) of the oscillation light of the second wavelength ⁇ 2.
- the anisotropy of the saturable absorber may be used instead of providing the fine structure.
- the polarization control element 32 and the saturable absorber 4 are not separated but integrally formed, so that the laser element 1 according to the seventh embodiment can be further miniaturized.
- FIG. 9 is a cross-sectional view showing a configuration example of the laser device 1 according to the eighth embodiment.
- the fourth reflective layer R4 of the second embodiment also functions as the polarization conversion element 22.
- the polarization conversion element 22 and the fourth reflective layer R4 are integrally constructed.
- the saturable absorber 4 is made of, for example, an anisotropic material, a metasurface structure, a photonic crystal structure, or the like, like the polarization conversion element 22 .
- the fourth reflective layer R4 can give different phase differences to the light beams in the vibration directions orthogonal to each other in the oscillation light beam. In this manner, the polarization conversion element 22 and the fourth reflected light R4 are not separated but are integrally formed, so that the laser element 1 according to the eighth embodiment can be further miniaturized.
- the polarization control element 31 is provided between the second reflective layer R2 and the polarization conversion element 21 in the eighth embodiment. That is, the polarization control element 31 is provided on the opposite side of the solid-state laser medium 3 from the fourth reflective layer R4 having a polarization conversion function.
- the polarization control element 31 has different transmittances for mutually orthogonal polarized light in the oscillation light.
- FIG. 10 is a cross-sectional view showing a configuration example of the laser device 1 according to the ninth embodiment.
- the polarization control element 31 of the third embodiment also functions as the polarization control element 32 . That is, the polarization control element 32 for the oscillation light is omitted, and the polarization control element 31 controls the polarization of both the oscillation light and the excitation light.
- the polarization control element 31 is provided between the second reflected light R2 and the polarization conversion element 21 and is shared by the pumping optical resonator 11 and the oscillation optical resonator 12 .
- the surface of the polarization control element 31 is formed with a fine structure that realizes the functions of both the polarization control elements 31 and 32 of the third embodiment.
- the polarization control element 31 can control the polarization of both the excitation light and the oscillation light. That is, the polarization control element 31 has a fine structure on the surface so as to have different transmittances for mutually orthogonal polarized light in excitation light and different transmittances for mutually orthogonal polarized light in oscillation light. . Since the polarization control element 31 also has the function of the polarization control element 32, the laser element 1 according to the ninth embodiment can be further miniaturized.
- FIG. 11 is a cross-sectional view showing a configuration example of the laser device 1 according to the tenth embodiment.
- the polarization control element 32 of the third embodiment also functions as the polarization control element 31 . That is, the excitation light polarization control element 31 is omitted, and the polarization control element 32 controls the polarization of both the oscillation light and the excitation light.
- the polarization control element 32 is provided between the polarization conversion element 22 and the third reflected light R3 and is shared by the pumping optical resonator 11 and the oscillation optical resonator 12 .
- the surface of the polarization control element 32 is formed with a fine structure that realizes the functions of both the polarization control elements 31 and 32 of the third embodiment.
- the polarization control element 32 can control the polarization of both the excitation light and the oscillation light.
- the polarization control element 32 has a fine structure on its surface so that it has different transmittances for mutually orthogonal polarized light in excitation light and different transmittances for mutually orthogonal polarized light in oscillation light. . Since the polarization control element 32 also functions as the polarization control element 31, the laser element 1 according to the tenth embodiment can be further miniaturized.
- FIG. 12 is a cross-sectional view showing a configuration example of the laser device 1 according to the eleventh embodiment.
- the polarization conversion element 21 of the first embodiment also functions as the polarization control element 31 . That is, the excitation light polarization control element 31 is omitted, and the polarization conversion element 21 also has the function of controlling the polarization of the excitation light.
- the polarization conversion element 21 is arranged between the light emitting element 2 and the second reflected light R2 and provided in the excitation light resonator 11 . Thereby, the polarization conversion element 21 can control the polarization of the excitation light.
- the polarization conversion element 21 has different transmittances for mutually orthogonal polarizations (TM waves and TE waves) of the excitation light. Since the polarization conversion element 21 also functions as the polarization control element 31 in this way, the laser element 1 according to the eleventh embodiment can be further miniaturized.
- FIG. 13 is a cross-sectional view showing a configuration example of the laser device 1 according to the twelfth embodiment.
- the polarization conversion element 22 of the second embodiment also functions as the polarization control element 32 . That is, the polarization control element 32 for the oscillation light is omitted, and the polarization conversion element 22 also has the function of controlling the polarization of the oscillation light.
- the polarization conversion element 22 is arranged between the saturable absorber 4 and the third reflected light R3 and provided in the oscillation optical resonator 12 . Thereby, the polarization conversion element 22 can control the polarization of the oscillation light.
- the polarization conversion element 22 has different transmittances for mutually orthogonal polarizations (TM waves and TE waves) of the oscillation light. Since the polarization conversion element 22 also functions as the polarization control element 32 in this manner, the laser element 1 according to the twelfth embodiment can be further miniaturized.
- FIG. 14 is a cross-sectional view showing a configuration example of the laser device 1 according to the thirteenth embodiment.
- the polarization conversion element 21 of the third embodiment also functions as the polarization control element 31, and the polarization conversion element 22 functions as the polarization control element 32 as well. That is, the excitation light polarization control element 31 and the oscillation light polarization control element 32 are omitted.
- the polarization conversion element 21 has a function of controlling the polarization of the excitation light
- the polarization conversion element 22 has a function of controlling the polarization of the oscillation light.
- the polarization conversion element 21 is arranged between the second reflected light R2 and the solid-state laser medium 3 and shared by the pumping optical resonator 11 and the oscillation optical resonator 12 . Thereby, the polarization conversion element 21 can control the polarization of the excitation light.
- the polarization conversion element 22 is arranged between the solid-state laser medium 3 and the third reflected light R3, and is shared by the excitation optical resonator 11 and the oscillation optical resonator 12. Thereby, the polarization conversion element 22 can control the polarization of the oscillation light.
- the laser element 1 according to the thirteenth embodiment can be further miniaturized.
- FIG. 15 is a diagram showing an example of a schematic configuration of an endoscope system 5000 to which technology according to the present disclosure can be applied.
- FIG. 16 is a diagram showing an example of the configuration of an endoscope 5001 and a CCU (Camera Control Unit) 5039.
- FIG. 15 illustrates a state in which an operator (for example, a doctor) 5067 who is a surgical participant is performing surgery on a patient 5071 on a patient bed 5069 using an endoscope system 5000 .
- an operator for example, a doctor
- the endoscope system 5000 supports an endoscope 5001, which is a medical imaging device, a CCU 5039, a light source device 5043, a recording device 5053, an output device 5055, and an endoscope 5001. and a support device 5027 .
- an insertion aid called a trocar 5025 is punctured into a patient 5071. Then, the scope 5003 and surgical instrument 5021 connected to the endoscope 5001 are inserted into the body of the patient 5071 via the trocar 5025 .
- the surgical instrument 5021 is, for example, an energy device such as an electric scalpel, forceps, or the like.
- a surgical image which is a medical image of the inside of the patient's 5071 photographed by the endoscope 5001, is displayed on the display device 5041.
- the operator 5067 uses the surgical instrument 5021 to treat the surgical target while viewing the surgical image displayed on the display device 5041 .
- the medical images are not limited to surgical images, and may be diagnostic images captured during diagnosis.
- the endoscope 5001 is an imaging unit for imaging the inside of the body of a patient 5071.
- a camera 5005 includes a zoom optical system 50052 that enables optical zoom, a focus optical system 50053 that enables focus adjustment by changing the focal length of an imaging unit, and a light receiving element 50054 .
- the endoscope 5001 converges light on the light receiving element 50054 through the connected scope 5003 to generate pixel signals, and outputs the pixel signals to the CCU 5039 through the transmission system.
- the scope 5003 is an insertion portion that has an objective lens at its tip and guides light from the connected light source device 5043 into the body of the patient 5071 .
- the scope 5003 is, for example, a rigid scope for rigid scopes and a flexible scope for flexible scopes.
- the scope 5003 may be a direct scope or a perspective scope.
- the pixel signal may be a signal based on a signal output from a pixel, such as a RAW signal or an image signal.
- a memory may be installed in the transmission system connecting the endoscope 5001 and the CCU 5039, and the parameters relating to the endoscope 5001 and the CCU 5039 may be stored in the memory.
- the memory may be arranged, for example, on the connection part of the transmission system or on the cable.
- the parameters of the endoscope 5001 at the time of shipment and the parameters changed when the power is supplied may be stored in the memory of the transmission system, and the operation of the endoscope may be changed based on the parameters read from the memory.
- an endoscope and a transmission system may be collectively referred to as an endoscope.
- the light receiving element 50054 is a sensor that converts received light into pixel signals, and is, for example, a CMOS (Complementary Metal Oxide Semiconductor) type imaging element.
- the light-receiving element 50054 is preferably an imaging element having a Bayer array and capable of color imaging.
- the light receiving element 50054 is, for example, 4K (horizontal pixel number 3840 ⁇ vertical pixel number 2160), 8K (horizontal pixel number 7680 ⁇ vertical pixel number 4320) or square 4K (horizontal pixel number 3840 or more ⁇ vertical pixel number 3840 or more). It is preferable that the image sensor has a number of pixels corresponding to the resolution.
- the light receiving element 50054 may be a single sensor chip or a plurality of sensor chips.
- a prism may be provided to separate the incident light into predetermined wavelength bands, and each wavelength band may be imaged by a different light-receiving element.
- a plurality of light receiving elements may be provided for stereoscopic viewing.
- the light receiving element 50054 may be a sensor including an arithmetic processing circuit for image processing in a chip structure, or may be a ToF (Time of Flight) sensor.
- the transmission system is, for example, an optical fiber cable or wireless transmission. The wireless transmission is sufficient as long as the pixel signals generated by the endoscope 5001 can be transmitted.
- Mirror 5001 and CCU 5039 may be connected.
- the endoscope 5001 may transmit not only the pixel signal but also information related to the pixel signal (for example, processing priority of the pixel signal, synchronization signal, etc.) at the same time.
- the endoscope may be configured by integrating a scope and a camera, or by providing a light-receiving element at the tip of the scope.
- the CCU 5039 is a control device that comprehensively controls the connected endoscope 5001 and light source device 5043. For example, as shown in FIG. processing equipment. Also, the CCU 5039 may centrally control the connected display device 5041 , recording device 5053 and output device 5055 . For example, the CCU 5039 controls the irradiation timing and irradiation intensity of the light source device 5043 and the type of irradiation light source.
- the CCU 5039 performs image processing such as development processing (for example, demosaicing processing) and correction processing on the pixel signals output from the endoscope 5001, and outputs the processed pixel signals (for example, image processing) to an external device such as the display device 5041. ). Also, the CCU 5039 transmits a control signal to the endoscope 5001 to control driving of the endoscope 5001 .
- the control signal is, for example, information about imaging conditions such as magnification and focal length of the imaging unit.
- the CCU 5039 may have an image down-conversion function, and may be configured to output a high-resolution (eg, 4K) image to the display device 5041 and a low-resolution (eg, HD) image to the recording device 5053 at the same time.
- a high-resolution (eg, 4K) image to the display device 5041
- a low-resolution (eg, HD) image to the recording device 5053 at the same time.
- the CCU 5039 is connected to external devices (eg, recording device, display device, output device, support device) via an IP converter that converts signals into a predetermined communication protocol (eg, IP (Internet Protocol)).
- IP Internet Protocol
- the connection between the IP converter and the external device may be configured by a wired network, or part or all of the network may be configured by a wireless network.
- the IP converter on the CCU5039 side has a wireless communication function, and the received video is sent to an IP switcher or output via a wireless communication network such as the 5th generation mobile communication system (5G) or the 6th generation mobile communication system (6G). It may be sent to the side IP converter.
- 5G 5th generation mobile communication system
- 6G 6th generation mobile communication system
- the light source device 5043 is a device capable of emitting light in a predetermined wavelength band, and includes, for example, a plurality of light sources and a light source optical system that guides light from the plurality of light sources.
- the light source is, for example, a xenon lamp, an LED light source, or an LD light source.
- the light source device 5043 has, for example, LED light sources corresponding to the three primary colors R, G, and B, and emits white light by controlling the output intensity and output timing of each light source. Further, the light source device 5043 may have a light source capable of irradiating special light used for special light observation separately from the light source for irradiating normal light used for normal light observation.
- Special light is light in a predetermined wavelength band different from normal light that is light for normal light observation.
- Normal light is, for example, white light or green light.
- narrow-band light observation which is a type of special light observation, by alternately irradiating blue light and green light, the wavelength dependence of light absorption in body tissues can be used to detect specific tissues such as blood vessels on the surface of the mucous membrane. can be shot with high contrast.
- fluorescence observation which is a type of special light observation, excitation light that excites the drug injected into the body tissue is irradiated, and fluorescence emitted by the body tissue or the drug as a marker is received to obtain a fluorescence image.
- a drug such as indocyanine green (ICG) injected into the body tissue is irradiated with infrared light having an excitation wavelength band, and the fluorescence of the drug is received to detect the body tissue. structure and the affected area can be easily visualized.
- an agent for example, 5-ALA
- the light source device 5043 sets the type of irradiation light under the control of the CCU 5039 .
- the CCU 5039 may have a mode in which normal light observation and special light observation are alternately performed by controlling the light source device 5043 and the endoscope 5001 .
- information based on pixel signals obtained by special light observation is preferably superimposed on pixel signals obtained by normal light observation.
- the special light observation may be infrared light observation in which infrared light is irradiated to look deeper than the surface of the organ, or multispectral observation utilizing hyperspectral spectroscopy. Additionally, photodynamic therapy may be combined.
- a recording device 5053 is a device for recording pixel signals (for example, an image) obtained from the CCU 5039, and is, for example, a recorder.
- a recording device 5053 records the image acquired from the CCU 5039 on an HDD, an SDD, or an optical disc.
- the recording device 5053 may be connected to a hospital network and accessible from equipment outside the operating room. Also, the recording device 5053 may have an image down-conversion function or an image up-conversion function.
- the display device 5041 is a device capable of displaying an image, such as a display monitor.
- a display device 5041 displays a display image based on pixel signals obtained from the CCU 5039 .
- the display device 5041 may function as an input device that enables line-of-sight recognition, voice recognition, and gesture-based instruction input by being equipped with a camera and a microphone.
- the output device 5055 is a device for outputting information acquired from the CCU 5039, such as a printer.
- the output device 5055 prints on paper a print image based on the pixel signals acquired from the CCU 5039, for example.
- the support device 5027 is an articulated arm including a base portion 5029 having an arm control device 5045 , an arm portion 5031 extending from the base portion 5029 , and a holding portion 5032 attached to the tip of the arm portion 5031 .
- the arm control device 5045 is configured by a processor such as a CPU, and operates according to a predetermined program to control driving of the arm section 5031 .
- the support device 5027 controls parameters such as the length of each link 5035 constituting the arm portion 5031 and the rotation angle and torque of each joint 5033 by means of the arm control device 5045 .
- the support device 5027 functions as an endoscope support arm that supports the endoscope 5001 during surgery. Thereby, the support device 5027 can take the place of the scopist who is an assistant holding the endoscope 5001 .
- the support device 5027 may be a device that supports a microscope device 5301, which will be described later, and can also be called a medical support arm.
- the control of the support device 5027 may be an autonomous control method by the arm control device 5045, or may be a control method in which the arm control device 5045 controls based on the user's input.
- control method is a master/slave method in which the support device 5027 as a slave device (replica device), which is a patient cart, is controlled based on the movement of the master device (primary device), which is the operator console at hand of the user. It's okay. Also, the control of the support device 5027 may be remotely controlled from outside the operating room.
- slave device replica device
- master device primary device
- control of the support device 5027 may be remotely controlled from outside the operating room.
- FIG. 17 is a diagram illustrating an example of a schematic configuration of a microsurgery system to which technology according to the present disclosure can be applied;
- the same reference numerals are given to the same configurations as those of the endoscope system 5000, and duplicate descriptions thereof will be omitted.
- FIG. 17 schematically shows an operator 5067 performing an operation on a patient 5071 on a patient bed 5069 using a microsurgery system 5300 .
- FIG. 17 omits illustration of the cart 5037 in the configuration of the microsurgery system 5300 and also shows a simplified microscope device 5301 instead of the endoscope 5001 .
- the microscope device 5301 in this description may refer to the microscope section 5303 provided at the tip of the link 5035 or may refer to the entire configuration including the microscope section 5303 and the support device 5027 .
- an image of a surgical site captured by a microscope device 5301 is enlarged and displayed on a display device 5041 installed in the operating room.
- the display device 5041 is installed at a position facing the operator 5067, and the operator 5067 observes the state of the operation site by the image displayed on the display device 5041, for example, resection of the affected area.
- Various measures are taken against Microsurgery systems are used, for example, in ophthalmic and brain surgery.
- the support device 5027 can support other observation devices or other surgical tools instead of the endoscope 5001 or the microscope section 5303 at its distal end.
- the other observation device for example, forceps, forceps, a pneumoperitoneum tube for pneumoperitoneum, or an energy treatment instrument for incising tissue or sealing a blood vessel by cauterization can be applied.
- the technology according to the present disclosure may be applied to a support device that supports components other than such a microscope section.
- the technology according to the present disclosure can be suitably applied to the surgical instrument 5021 among the configurations described above. Specifically, by irradiating the affected area of the patient with a short laser pulse from the laser device 1 according to the present embodiment, the affected area can be treated more safely and reliably without damaging the area around the affected area. can.
- this technique can take the following structures. (1) a laminated semiconductor layer having a first reflective layer for a first wavelength and an active layer for performing surface emission of the first wavelength; A second reflective layer for a second wavelength on a first surface facing the laminated semiconductor layer disposed on the rear side of the optical axis of the laminated semiconductor layer, and a second reflective layer for the first wavelength on a second surface opposite to the first surface.
- a laser medium having a third reflective layer for a fourth reflective layer for the second wavelength, disposed on the second surface or disposed on the rear side of the optical axis from the second surface; a first resonator that resonates the light of the first wavelength between the first reflective layer and the third reflective layer; a second resonator that resonates the light of the second wavelength between the second reflective layer and the fourth reflective layer; a first polarization conversion element provided between the first reflective layer and the laser medium, the first polarization conversion element for causing a phase difference with respect to the light of the first or second wavelength in vibration directions orthogonal to each other; a second polarization conversion element provided between the second reflective layer and the laser medium, the second polarization conversion element for causing the light of the first or second wavelength to differ in phase with respect to the light of vibration directions orthogonal to each other; at least one of a first or second polarization control element provided between the first reflective layer and the fourth reflective layer for controlling polarization of light of the first or second wavelength;
- a laser device in
- any one of (1) to (5), wherein the second polarization control element is provided between the fourth reflective layer and the second polarization conversion element, and controls polarization of light of the second wavelength. 10.
- Laser device as described.
- the laser device according to any one of (1) to (8), further comprising a saturable absorber provided between the third reflective layer and the fourth reflective layer.
- the first polarization conversion element is arranged between the first polarization control element and the second reflective layer, The laser device according to any one of (1) to (9), wherein the second polarization conversion device is arranged between the laser medium and the third reflective layer.
- the first polarization conversion element is arranged between the second reflection layer and the laser medium, and the second polarization conversion element is arranged between the third reflection layer and the second polarization control element.
- the laser device according to any one of (1) to (10), arranged.
- the first polarization conversion element is arranged between the second reflective layer and the laser medium, and the second polarization conversion element is arranged between the laser medium and the third reflective layer.
- the laser device according to (9), wherein the saturable absorber has a fine structure on its surface so as to have different transmittances for mutually orthogonally polarized light of the second wavelength.
- the laser device according to any one of (1) to (14), wherein the fourth reflective layer causes the light of the second wavelength to have a phase difference with respect to the light of vibration directions orthogonal to each other.
- the first polarization control element is provided between the second reflective layer and the first polarization conversion element, Microstructures on the surface so as to have different transmittances for mutually orthogonally polarized light of the first wavelength and different transmittances for mutually orthogonally polarized light of the second wavelength.
- the laser device according to any one of (1) to (15), having (17) The second polarization control element is provided between the third reflective layer and the second polarization conversion element, Microstructures on the surface so as to have different transmittances for mutually orthogonally polarized light of the first wavelength and different transmittances for mutually orthogonally polarized light of the second wavelength.
- the laser device according to any one of (1) to (16), having (18) The first polarization conversion element according to any one of (1) to (17), wherein the first polarization conversion element has a fine structure on its surface so as to have different transmittances for mutually orthogonally polarized light of the first wavelength.
- Laser device as described.
- Laser device as described.
- An electronic device comprising a laser element and a control section for controlling emission of light from the laser element,
- the laser element is a laminated semiconductor layer having a first reflective layer for a first wavelength and an active layer for performing surface emission of the first wavelength; A second reflective layer for a second wavelength on a first surface facing the laminated semiconductor layer disposed on the rear side of the optical axis of the laminated semiconductor layer, and a second reflective layer for the first wavelength on a second surface opposite to the first surface.
- a laser medium having a third reflective layer for a fourth reflective layer for the second wavelength, disposed on the second surface or disposed on the rear side of the optical axis from the second surface; a first resonator that resonates the light of the first wavelength between the first reflective layer and the third reflective layer; a second resonator that resonates the light of the second wavelength between the second reflective layer and the fourth reflective layer; a first polarization conversion element provided between the first reflective layer and the laser medium, the first polarization conversion element for causing a phase difference with respect to the light of the first wavelength in vibration directions orthogonal to each other; a second polarization conversion element that is provided between the second reflective layer and the laser medium and that causes the light of the second wavelength to have different phases with respect to the light of vibration directions that are orthogonal to each other; at least one of a first or second polarization control element provided between the first reflective layer and the fourth reflective layer for controlling polarization of light of the first or second wavelength;
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Abstract
Description
第2偏光変換素子は、第3反射層と第2偏光制御素子との間に配置されている。
まず、本開示によるレーザ素子の内部構成と動作を説明する前に、本開示によるレーザ素子の技術的特徴を説明する。
(1)第1共振器と第2共振器が、固体レーザ媒質を共有する。第1共振器は、発光素子と固体レーザ媒質とを含む。第2共振器は、固体レーザ媒質と可飽和吸収体を含んでおり、第1共振器からの励起光によってQスイッチレーザ発振を行う。
本開示によるレーザ素子では、発光素子に電流を注入することによって発生される励起光を、第1共振器内の固体レーザ媒質で吸収させる。固体レーザ媒質は、第1共振器内に設置された可飽和吸収体とともに、第2共振器を構成する。固体レーザ媒質が十分な励起状態となり、自然放出光の出力が上がって、ある閾値を超えると可飽和吸収体での光吸収率が急激に低下し、固体レーザ媒質で発生された自然放出光は可飽和吸収体を透過できるようになり、固体レーザ媒質において誘導放出を生じさせる。これによりQスイッチパルス発振が起こる。
以下、本開示によるレーザ素子の具体的な実施形態を説明する。図1は本開示によるレーザ素子1の基本構成を示す図である。図1のレーザ素子1は、発光素子2と、固体レーザ媒質3と、可飽和吸収体4とを一体に接合した構成を備えている。
次に、図1のレーザ素子1の動作を説明する。発光素子2の電極を介して電流を活性層7に注入することで、第1共振器11内で第1波長λ1のレーザ発振が起こり、固体レーザ媒質3が励起される。固体レーザ媒質3には可飽和吸収体4が接合されていることから、第1波長λ1のレーザ発振が起こった最初の段階では、固体レーザ媒質3からの自然放出光は可飽和吸収体4に吸収されてしまい、可飽和吸収体4の出射面側の第4反射層R4による光フィードバックが起こらず、Qスイッチレーザ発振には至らない。
図2Aは、第1実施形態によるレーザ素子1の構成例を示す断面図である。レーザ素子1は、図1の基本構成に対して、偏光変換素子21、22と、偏光制御素子31とをさらに備える。可飽和吸収体4は、第3反射層R3と第4反射層R4との間に配置されている。尚、本明細書の実施形態において、レーザ素子1を構成する光学素子(例えば、発光素子2、固体レーザ媒質3、反射層R1~R5、共振器11、12、偏光変換素子21、22、偏光制御素子31)は一体に接合されている。
図3は、第2実施形態によるレーザ素子1の構成例を示す断面図である。第2実施形態によれば、偏光変換素子21は、第2反射層R2と固体レーザ媒質3との間に配置されている。偏光変換素子22は、第3反射層R3と偏光制御素子32との間に配置されている。また、偏光制御素子32は、第4反射層R4と偏光変換素子22との間のいずれかの位置に設けられている。より詳細には、偏光制御素子32は、可飽和吸収体4と偏光変換素子22との間に設けられている。このように、第2実施形態では、偏光変換素子21、22および偏光制御素子32が発振光共振器12側に設けられており、第2波長λ2の発振光の定在波を抑制する。
図4は、第3実施形態によるレーザ素子1の構成例を示す断面図である。第3実施形態によれば、偏光変換素子21は、第2反射層R2と固体レーザ媒質3との間に配置されている。偏光変換素子22は、固体レーザ媒質3と第3反射層R3との間に配置されている。また、第3実施形態では、偏光制御素子については、偏光制御素子31および32の両方が設けられている。偏光制御素子31は、第5反射層R5と第2反射層R2との間に設けられている。偏光制御素子32は、可飽和吸収体4と第3反射層R3との間に設けられている。このように、第3実施形態では、偏光変換素子21、22が、励起光共振器11および発振光共振器12の両方に共有されている。また、偏光制御素子31が励起光共振器11側に設けられており、偏光制御素子32が発振光共振器12側に設けられている。これにより、第1波長λ1の励起光および第2波長λ2の発振光の両方の定在波を抑制することができる。
図5は、第4実施形態によるレーザ素子1の構成例を示す断面図である。第4実施形態では、第2実施形態の第4反射層R4が偏光制御素子32の機能を兼ね備えている。即ち、発振光の偏光制御素子32と第4反射光R4とが一体として構成されている。この場合、偏光制御素子32と同様の微細構造が可飽和吸収体4側の第4反射層R4の表面に形成されている。これにより、第4反射層R4は、発振光に対して偏光制御素子32の機能を兼ね備えることができる。即ち、第4反射層R4は、第2波長λ2の発振光のうち互いに直交する偏光(例えば、TM波、TE波)に対して異なる透過率を有する。このように、偏光制御素子32と第4反射光R4とが別体となっておらず、一体として構成されているので、第4実施形態によるレーザ素子1は、さらに小型化することができる。
図6は、第5実施形態によるレーザ素子1の構成例を示す断面図である。第5実施形態では、第3実施形態の第4反射層R4が偏光制御素子32の機能を兼ね備えている。即ち、発振光の偏光制御素子32と第4反射光R4とが一体として構成されている。この場合、偏光制御素子32と同様の微細構造が可飽和吸収体4側の第4反射層R4の表面に形成されている。これにより、第4反射層R4は、発振光に対して偏光制御素子32の機能を兼ね備えることができる。即ち、第4反射層R4は、第2波長λ2の発振光のうち互いに直交する偏光(例えば、TM波、TE波)に対して異なる透過率を有する。このように、偏光制御素子32と第4反射光R4とが別体となっておらず、一体として構成されているので、第5実施形態によるレーザ素子1は、さらに小型化することができる。
図7は、第6実施形態によるレーザ素子1の構成例を示す断面図である。第6実施形態では、第2実施形態の可飽和吸収体4が偏光制御素子32の機能を兼ね備えている。即ち、発振光の偏光制御素子32と可飽和吸収体4とが一体として構成されている。例えば、偏光制御素子32と同様の微細構造が可飽和吸収体4の表面に形成されている。これにより、可飽和吸収体4は、発振光に対して偏光制御素子32の機能を兼ね備えることができる。即ち、可飽和吸収体4は、第2波長λ2の発振光のうち互いに直交する偏光(例えば、TM波、TE波)に対して異なる透過率を有する。なお、微細構造を設けるのではなく、可飽和吸収体の異方性を利用してもよい。このように、偏光制御素子32と第4反射光R4とが別体となっておらず、一体として構成されているので、第6実施形態によるレーザ素子1は、さらに小型化することができる。
図8は、第7実施形態によるレーザ素子1の構成例を示す断面図である。第7実施形態では、第3実施形態の可飽和吸収体4が偏光制御素子32の機能を兼ね備えている。即ち、発振光の偏光制御素子32と可飽和吸収体4とが一体として構成されている。例えば、偏光制御素子32と同様の微細構造が可飽和吸収体4の表面に形成されている。これにより、可飽和吸収体4は、発振光に対して偏光制御素子32の機能を兼ね備えることができる。即ち、可飽和吸収体4は、第2波長λ2の発振光のうち互いに直交する偏光(例えば、TM波、TE波)に対して異なる透過率を有する。なお、微細構造を設けるのではなく、可飽和吸収体の異方性を利用してもよい。このように、偏光制御素子32と可飽和吸収体4とが別体となっておらず、一体として構成されているので、第7実施形態によるレーザ素子1は、さらに小型化することができる。
図9は、第8実施形態によるレーザ素子1の構成例を示す断面図である。第8実施形態では、第2実施形態の第4反射層R4が偏光変換素子22の機能を兼ね備えている。即ち、偏光変換素子22と第4反射層R4とが一体として構成されている。この場合、可飽和吸収体4は、偏光変換素子22と同様に、例えば、異方性材料、メタサーフェス構造、フォトニック結晶構造等で構成されている。これにより、第4反射層R4は、発振光において互いに直交する振動方向の光に対して異なる位相差を与えることができる。このように、偏光変換素子22と第4反射光R4とが別体となっておらず、一体として構成されているので、第8実施形態によるレーザ素子1は、さらに小型化することができる。
図10は、第9実施形態によるレーザ素子1の構成例を示す断面図である。第9実施形態では、第3実施形態の偏光制御素子31が、偏光制御素子32の機能を兼ね備えている。即ち、発振光の偏光制御素子32が省略されており、偏光制御素子31が、発振光および励起光の両方の偏光を制御する。偏光制御素子31は、第2反射光R2と偏光変換素子21との間に設けられ、励起光共振器11および発振光共振器12に対して共有化されている。例えば、偏光制御素子31の表面には、第3実施形態の偏光制御素子31および32の両方の機能を実現する微細構造が形成されている。これにより、偏光制御素子31は、励起光および発振光の両方の偏光を制御することができる。即ち、偏光制御素子31は、励起光において互いに直交する偏光に対して異なる透過率を有し、かつ、発振光において互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する。偏光制御素子31が、偏光制御素子32の機能を兼ね備えるので、第9実施形態によるレーザ素子1は、さらに小型化することができる。
図11は、第10実施形態によるレーザ素子1の構成例を示す断面図である。第10実施形態では、第3実施形態の偏光制御素子32が、偏光制御素子31の機能を兼ね備えている。即ち、励起光の偏光制御素子31が省略されており、偏光制御素子32が、発振光および励起光の両方の偏光を制御する。偏光制御素子32は、偏光変換素子22と第3反射光R3との間に設けられ、励起光共振器11および発振光共振器12に対して共有化されている。例えば、偏光制御素子32の表面には、第3実施形態の偏光制御素子31および32の両方の機能を実現する微細構造が形成されている。これにより、偏光制御素子32は、励起光および発振光の両方の偏光を制御することができる。即ち、偏光制御素子32は、励起光において互いに直交する偏光に対して異なる透過率を有し、かつ、発振光において互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する。偏光制御素子32が、偏光制御素子31の機能を兼ね備えるので、第10実施形態によるレーザ素子1は、さらに小型化することができる。
図12は、第11実施形態によるレーザ素子1の構成例を示す断面図である。第11実施形態では、第1実施形態の偏光変換素子21が偏光制御素子31の機能を兼ね備えている。即ち、励起光の偏光制御素子31が省略されており、偏光変換素子21が、励起光の偏光を制御する機能を兼ね備える。偏光変換素子21は、発光素子2と第2反射光R2との間に配置され、励起光共振器11に設けられている。これにより、偏光変換素子21は、励起光の偏光を制御することができる。即ち、偏光変換素子21は、励起光のうち互いに直交する偏光(TM波、TE波)に対して異なる透過率を有する。このように、偏光変換素子21が、偏光制御素子31の機能を兼ね備えるので、第11実施形態によるレーザ素子1は、さらに小型化することができる。
図13は、第12実施形態によるレーザ素子1の構成例を示す断面図である。第12実施形態では、第2実施形態の偏光変換素子22が偏光制御素子32の機能を兼ね備えている。即ち、発振光の偏光制御素子32が省略されており、偏光変換素子22が、発振光の偏光を制御する機能を兼ね備える。偏光変換素子22は、可飽和吸収体4と第3反射光R3との間に配置され、発振光共振器12に設けられている。これにより、偏光変換素子22は、発振光の偏光を制御することができる。即ち、偏光変換素子22は、発振光のうち互いに直交する偏光(TM波、TE波)に対して異なる透過率を有する。このように、偏光変換素子22が、偏光制御素子32の機能を兼ね備えるので、第12実施形態によるレーザ素子1は、さらに小型化することができる。
図14は、第13実施形態によるレーザ素子1の構成例を示す断面図である。第13実施形態では、第3実施形態の偏光変換素子21が偏光制御素子31の機能を兼ね備え、かつ、偏光変換素子22が偏光制御素子32の機能を兼ね備えている。即ち、励起光の偏光制御素子31および発振光の偏光制御素子32が省略されている。偏光変換素子21が、励起光の偏光を制御する機能を兼ね備え、偏光変換素子22が、発振光の偏光を制御する機能を兼ね備える。
内視鏡システムの例を図15、図16を用いて説明する。図15は、本開示に係る技術が適用可能な内視鏡システム5000の概略的な構成の一例を示す図である。図16は、内視鏡5001およびCCU(Camera Control Unit)5039の構成の一例を示す図である。図15では、手術参加者である術者(例えば、医師)5067が、内視鏡システム5000を用いて、患者ベッド5069上の患者5071に手術を行っている様子が図示されている。図15に示すように、内視鏡システム5000は、医療イメージング装置である内視鏡5001と、CCU5039と、光源装置5043と、記録装置5053と、出力装置5055と、内視鏡5001を支持する支持装置5027と、から構成される。
内視鏡5001は、患者5071の体内を撮像する撮像部であり、例えば、図16に示すように、入射した光を集光する集光光学系50051と、撮像部の焦点距離を変更して光学ズームを可能とするズーム光学系50052と、撮像部の焦点距離を変更してフォーカス調整を可能とするフォーカス光学系50053と、受光素子50054と、を含むカメラ5005である。内視鏡5001は、接続されたスコープ5003を介して光を受光素子50054に集光することで画素信号を生成し、CCU5039に伝送系を通じて画素信号を出力する。なお、スコープ5003は、対物レンズを先端に有し、接続された光源装置5043からの光を患者5071の体内に導光する挿入部である。スコープ5003は、例えば硬性鏡では硬性スコープ、軟性鏡では軟性スコープである。スコープ5003は直視鏡や斜視鏡であってもよい。また、画素信号は画素から出力された信号に基づいた信号であればよく、例えば、RAW信号や画像信号である。また、内視鏡5001とCCU5039とを接続する伝送系にメモリを搭載し、メモリに内視鏡5001やCCU5039に関するパラメータを記憶する構成にしてもよい。メモリは、例えば、伝送系の接続部分やケーブル上に配置されてもよい。例えば、内視鏡5001の出荷時のパラメータや通電時に変化したパラメータを伝送系のメモリに記憶し、メモリから読みだしたパラメータに基づいて内視鏡の動作を変更してもよい。また、内視鏡と伝送系をセットにして内視鏡と称してもよい。受光素子50054は、受光した光を画素信号に変換するセンサであり、例えばCMOS(Complementary Metal Oxide Semiconductor)タイプの撮像素子である。受光素子50054は、Bayer配列を有するカラー撮影可能な撮像素子であることが好ましい。また、受光素子50054は、例えば4K(水平画素数3840×垂直画素数2160)、8K(水平画素数7680×垂直画素数4320)または正方形4K(水平画素数3840以上×垂直画素数3840以上)の解像度に対応した画素数を有する撮像素子であることが好ましい。受光素子50054は、1枚のセンサチップであってもよいし、複数のセンサチップでもよい。例えば、入射光を所定の波長帯域ごとに分離するプリズムを設けて、各波長帯域を異なる受光素子で撮像する構成であってもよい。また、立体視のために受光素子を複数設けてもよい。また、受光素子50054は、チップ構造の中に画像処理用の演算処理回路を含んでいるセンサであってもよいし、ToF(Time of Flight)用センサであってもよい。なお、伝送系は例えば光ファイバケーブルや無線伝送である。無線伝送は、内視鏡5001で生成された画素信号が伝送可能であればよく、例えば、内視鏡5001とCCU5039が無線接続されてもよいし、手術室内の基地局を経由して内視鏡5001とCCU5039が接続されてもよい。このとき、内視鏡5001は画素信号だけでなく、画素信号に関連する情報(例えば、画素信号の処理優先度や同期信号等)を同時に送信してもよい。なお、内視鏡はスコープとカメラを一体化してもよく、スコープの先端部に受光素子を設ける構成としてもよい。
CCU5039は、接続された内視鏡5001や光源装置5043を統括的に制御する制御装置であり、例えば、図16に示すように、FPGA50391、CPU50392、RAM50393、ROM50394、GPU50395、I/F50396を有する情報処理装置である。また、CCU5039は、接続された表示装置5041や記録装置5053、出力装置5055を統括的に制御してもよい。例えば、CCU5039は、光源装置5043の照射タイミングや照射強度、照射光源の種類を制御する。また、CCU5039は、内視鏡5001から出力された画素信号に対して現像処理(例えばデモザイク処理)や補正処理といった画像処理を行い、表示装置5041等の外部装置に処理後の画素信号(例えば画像)を出力する。また、CCU5039は、内視鏡5001に対して制御信号を送信し、内視鏡5001の駆動を制御する。制御信号は、例えば、撮像部の倍率や焦点距離などの撮像条件に関する情報である。なお、CCU5039は画像のダウンコンバート機能を有し、表示装置5041に高解像度(例えば4K)の画像を、記録装置5053に低解像度(例えばHD)の画像を同時に出力可能な構成としてもよい。
光源装置5043は、所定の波長帯域の光を照射可能な装置であり、例えば、複数の光源と、複数の光源の光を導光する光源光学系と、を備える。光源は、例えばキセノンランプ、LED光源やLD光源である。光源装置5043は、例えば三原色R、G、Bのそれぞれに対応するLED光源を有し、各光源の出力強度や出力タイミングを制御することで白色光を出射する。また、光源装置5043は、通常光観察に用いられる通常光を照射する光源とは別に、特殊光観察に用いられる特殊光を照射可能な光源を有していてもよい。特殊光は、通常光観察用の光である通常光とは異なる所定の波長帯域の光であり、例えば、近赤外光(波長が760nm以上の光)や赤外光、青色光、紫外光である。通常光は、例えば白色光や緑色光である。特殊光観察の一種である狭帯域光観察では、青色光と緑色光を交互に照射することにより、体組織における光の吸収の波長依存性を利用して、粘膜表層の血管等の所定の組織を高コントラストで撮影することができる。また、特殊光観察の一種である蛍光観察では、体組織に注入された薬剤を励起する励起光を照射し、体組織または標識である薬剤が発する蛍光を受光して蛍光画像を得ることで、通常光では術者が視認しづらい体組織等を、術者が視認しやすくすることができる。例えば、赤外光を用いる蛍光観察では、体組織に注入されたインドシアニングリーン(ICG)等の薬剤に励起波長帯域を有する赤外光を照射し、薬剤の蛍光を受光することで、体組織の構造や患部を視認しやすくすることができる。また、蛍光観察では、青色波長帯域の特殊光で励起され、赤色波長帯域の蛍光を発する薬剤(例えば5-ALA)を用いてもよい。なお、光源装置5043は、CCU5039の制御により照射光の種類を設定される。CCU5039は、光源装置5043と内視鏡5001を制御することにより、通常光観察と特殊光観察が交互に行われるモードを有してもよい。このとき、通常光観察で得られた画素信号に特殊光観察で得られた画素信号に基づく情報を重畳されることが好ましい。また、特殊光観察は、赤外光を照射して臓器表面より奥を見る赤外光観察や、ハイパースペクトル分光を活用したマルチスペクトル観察であってもよい。さらに、光線力学療法を組み合わせてもよい。
記録装置5053は、CCU5039から取得した画素信号(例えば画像)を記録する装置であり、例えばレコーダーである。記録装置5053は、CCU5039から取得した画像をHDDやSDD、光ディスクに記録する。記録装置5053は、病院内のネットワークに接続され、手術室外の機器からアクセス可能にしてもよい。また、記録装置5053は画像のダウンコンバート機能またはアップコンバート機能を有していてもよい。
表示装置5041は、画像を表示可能な装置であり、例えば表示モニタである。表示装置5041は、CCU5039から取得した画素信号に基づく表示画像を表示する。なお、表示装置5041はカメラやマイクを備えることで、視線認識や音声認識、ジェスチャによる指示入力を可能にする入力デバイスとしても機能してよい。
出力装置5055は、CCU5039から取得した情報を出力する装置であり、例えばプリンタである。出力装置5055は、例えば、CCU5039から取得した画素信号に基づく印刷画像を紙に印刷する。
支持装置5027は、アーム制御装置5045を有するベース部5029と、ベース部5029から延伸するアーム部5031と、アーム部5031の先端に取り付けられた保持部5032とを備える多関節アームである。アーム制御装置5045は、CPU等のプロセッサによって構成され、所定のプログラムに従って動作することにより、アーム部5031の駆動を制御する。支持装置5027は、アーム制御装置5045によってアーム部5031を構成する各リンク5035の長さや各関節5033の回転角やトルク等のパラメータを制御することで、例えば保持部5032が保持する内視鏡5001の位置や姿勢を制御する。これにより、内視鏡5001を所望の位置または姿勢に変更し、スコープ5003を患者5071に挿入でき、また、体内での観察領域を変更できる。支持装置5027は、術中に内視鏡5001を支持する内視鏡支持アームとして機能する。これにより、支持装置5027は、内視鏡5001を持つ助手であるスコピストの代わりを担うことができる。また、支持装置5027は、後述する顕微鏡装置5301を支持する装置であってもよく、医療用支持アームと呼ぶこともできる。なお、支持装置5027の制御は、アーム制御装置5045による自律制御方式であってもよいし、ユーザの入力に基づいてアーム制御装置5045が制御する制御方式であってもよい。例えば、制御方式は、ユーザの手元の術者コンソールであるマスター装置(プライマリ装置)の動きに基づいて、患者カートであるスレイブ装置(レプリカ装置)としての支持装置5027が制御されるマスタ・スレイブ方式でもよい。また、支持装置5027の制御は、手術室の外から遠隔制御が可能であってもよい。
図17は、本開示に係る技術が適用され得る顕微鏡手術システムの概略的な構成の一例を示す図である。なお、以下の説明において、内視鏡システム5000と同様の構成については、同一の符号を付し、その重複する説明を省略する。
(1)
第1波長に対する第1反射層と、前記第1波長の面発光を行う活性層と、を有する積層半導体層と、
前記積層半導体層の光軸の後方側に配置され、前記積層半導体層と対向する第1面に第2波長に対する第2反射層および前記第1面と反対側の第2面に前記第1波長に対する第3反射層を有するレーザ媒質と、
前記第2面に配置されるか、又は前記第2面より光軸の後方側に配置される、前記第2波長に対する第4反射層と、
前記第1反射層および前記第3反射層の間で前記第1波長の光を共振させる第1共振器と、
前記第2反射層および前記第4反射層の間で前記第2波長の光を共振させる第2共振器と、
前記第1反射層と前記レーザ媒質との間に設けられ、前記第1または第2波長の光において互いに直交する振動方向の光に対して位相を相違させる第1偏光変換素子と、
前記第2反射層と前記レーザ媒質との間に設けられ、前記第1または第2波長の光において互いに直交する振動方向の光に対して位相を相違させる第2偏光変換素子と、
前記第1反射層と前記第4反射層との間に設けられ、前記第1または第2波長の光において偏光を制御する第1または第2偏光制御素子のうち少なくとも一つとを備え、
前記積層半導体層の光軸、前記レーザ媒質の光軸、前記第1および第2偏光変換素子、並びに、前記第1または第2偏光制御素子の光軸は、一軸上に配置されるレーザ素子。
(2)
前記第1および第2偏光変換素子には、異方性材料、メタサーフェス構造、または、フォトニック結晶構造が用いられる、(1)に記載のレーザ素子。
(3)
前記第1および第2偏光変換素子は、それぞれ前記第1または第2波長の光において互いに直交する振動方向の光に対して約4分の1波長の位相差を与える、(1)または(2)に記載のレーザ素子。
(4)
前記積層半導体層の前記レーザ媒質側に設けられた第5反射層をさらに備える、(1)から(3)のいずれか一項に記載のレーザ素子。
(5)
前記第1偏光制御素子は、前記第1反射層と前記第1偏光変換素子との間に設けられ、前記第1波長の光の偏光を制御する、(1)から(4)のいずれか一項に記載のレーザ素子。
(6)
前記第2偏光制御素子は、前記第4反射層と前記第2偏光変換素子との間に設けられ、前記第2波長の光の偏光を制御する、(1)から(5)のいずれか一項に記載のレーザ素子。
(7)
前記第1偏光制御素子は、前記第1波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、(1)から(6)のいずれか一項に記載のレーザ素子。
(8)
前記第2偏光制御素子は、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、(1)から(7)のいずれか一項に記載のレーザ素子。
(9)
前記第3反射層と前記第4反射層との間に設けられた可飽和吸収体をさらに備える、(1)から(8)のいずれか一項に記載のレーザ素子。
(10)
前記第1偏光変換素子は、前記第1偏光制御素子と前記第2反射層との間に配置されており、
前記第2偏光変換素子は、前記レーザ媒質と前記第3反射層との間に配置されている、(1)から(9)のいずれか一項に記載のレーザ素子。
(11)
前記第1偏光変換素子は、前記第2反射層と前記レーザ媒質との間に配置されており、 前記第2偏光変換素子は、前記第3反射層と前記第2偏光制御素子との間に配置されている、(1)から(10)のいずれか一項に記載のレーザ素子。
(12)
前記第1偏光変換素子は、前記第2反射層と前記レーザ媒質との間に配置されており、 前記第2偏光変換素子は、前記レーザ媒質と前記第3反射層との間に配置されている、(1)から(11)のいずれか一項に記載のレーザ素子。
(13)
前記第4反射層は、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、(1)から(12)のいずれか一項に記載のレーザ素子。
(14)
前記可飽和吸収体は、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、(9)に記載のレーザ素子。
(15)
前記第4反射層は、前記第2波長の光において互いに直交する振動方向の光に対して位相を相違させる、(1)から(14)のいずれか一項に記載のレーザ素子。
(16)
前記第1偏光制御素子は、前記第2反射層と前記第1偏光変換素子との間に設けられており、
前記第1波長の光のうち互いに直交する偏光に対して異なる透過率を有し、かつ、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、(1)から(15)のいずれか一項に記載のレーザ素子。
(17)
前記第2偏光制御素子は、前記第3反射層と前記第2偏光変換素子との間に設けられており、
前記第1波長の光のうち互いに直交する偏光に対して異なる透過率を有し、かつ、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、(1)から(16)のいずれか一項に記載のレーザ素子。
(18)
前記第1偏光変換素子は、前記第1波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、(1)から(17)のいずれか一項に記載のレーザ素子。
(19)
前記第2偏光変換素子は、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、(1)から(18)のいずれか一項に記載のレーザ素子。
(20)
前記積層半導体層、前記レーザ媒質、前記第4反射層、前記第1共振器、前記第2共振器、前記第1偏光変換素子、前記第2偏光変換素子および前記第1または第2偏光制御素子は一体に接合されている、(1)から(19)のいずれか一項に記載のレーザ素子。
(21)
前記第1反射層と前記第4反射層との間のいずれかの位置に設けられた透明部材をさらに備える、(1)から(20)のいずれか一項に記載のレーザ素子。
(22)
レーザ素子と、前記レーザ素子から光を放出する制御を行う制御部と、を備える電子機器であって、
前記レーザ素子は、
第1波長に対する第1反射層と、前記第1波長の面発光を行う活性層と、を有する積層半導体層と、
前記積層半導体層の光軸の後方側に配置され、前記積層半導体層と対向する第1面に第2波長に対する第2反射層および前記第1面と反対側の第2面に前記第1波長に対する第3反射層を有するレーザ媒質と、
前記第2面に配置されるか、又は前記第2面より光軸の後方側に配置される、前記第2波長に対する第4反射層と、
前記第1反射層および前記第3反射層の間で前記第1波長の光を共振させる第1共振器と、
前記第2反射層および前記第4反射層の間で前記第2波長の光を共振させる第2共振器と、
前記第1反射層と前記レーザ媒質との間に設けられ、前記第1波長の光において互いに直交する振動方向の光に対して位相を相違させる第1偏光変換素子と、
前記第2反射層と前記レーザ媒質との間に設けられ、前記第2波長の光において互いに直交する振動方向の光に対して位相を相違させる第2偏光変換素子と、
前記第1反射層と前記第4反射層との間に設けられ、前記第1または第2波長の光において偏光を制御する第1または第2偏光制御素子のうち少なくとも一つとを備え、
前記積層半導体層の光軸、前記レーザ媒質の光軸、前記第1および第2偏光変換素子、並びに、前記第1または第2偏光制御素子の光軸は、一軸上に配置される、電子機器。
Claims (22)
- 第1波長に対する第1反射層と、前記第1波長の面発光を行う活性層と、を有する積層半導体層と、
前記積層半導体層の光軸の後方側に配置され、前記積層半導体層と対向する第1面に第2波長に対する第2反射層および前記第1面と反対側の第2面に前記第1波長に対する第3反射層を有するレーザ媒質と、
前記第2面に配置されるか、又は前記第2面より光軸の後方側に配置される、前記第2波長に対する第4反射層と、
前記第1反射層および前記第3反射層の間で前記第1波長の光を共振させる第1共振器と、
前記第2反射層および前記第4反射層の間で前記第2波長の光を共振させる第2共振器と、
前記第1反射層と前記レーザ媒質との間に設けられ、前記第1または第2波長の光において互いに直交する振動方向の光に対して位相を相違させる第1偏光変換素子と、
前記第4反射層と前記レーザ媒質との間に設けられ、前記第1または第2波長の光において互いに直交する振動方向の光に対して位相を相違させる第2偏光変換素子と、
前記第1反射層と前記第4反射層との間に設けられ、前記第1または第2波長の光において偏光を制御する第1または第2偏光制御素子のうち少なくとも一つとを備え、
前記積層半導体層の光軸、前記レーザ媒質の光軸、前記第1および第2偏光変換素子、並びに、前記第1または第2偏光制御素子の光軸は、一軸上に配置される、レーザ素子。 - 前記第1および第2偏光変換素子には、異方性材料、メタサーフェス構造、または、フォトニック結晶構造が用いられる、請求項1に記載のレーザ素子。
- 前記第1および第2偏光変換素子は、それぞれ前記第1または第2波長の光において互いに直交する振動方向の光に対して約4分の1波長の位相差を与える、請求項1に記載のレーザ素子。
- 前記積層半導体層の前記レーザ媒質側に設けられた第5反射層をさらに備える、請求項1に記載のレーザ素子。
- 前記第1偏光制御素子は、前記第1反射層と前記第1偏光変換素子との間に設けられ、前記第1波長の光の偏光を制御する、請求項1に記載のレーザ素子。
- 前記第2偏光制御素子は、前記第4反射層と前記第2偏光変換素子との間に設けられ、前記第2波長の光の偏光を制御する、請求項1に記載のレーザ素子。
- 前記第1偏光制御素子は、前記第1波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、請求項1に記載のレーザ素子。
- 前記第2偏光制御素子は、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、請求項1に記載のレーザ素子。
- 前記第3反射層と前記第4反射層との間に設けられた可飽和吸収体をさらに備える、請求項1に記載のレーザ素子。
- 前記第1偏光変換素子は、前記第1偏光制御素子と前記第2反射層との間に配置されており、
前記第2偏光変換素子は、前記レーザ媒質と前記第3反射層との間に配置されている、請求項1に記載のレーザ素子。 - 前記第1偏光変換素子は、前記第2反射層と前記レーザ媒質との間に配置されており、 前記第2偏光変換素子は、前記第3反射層と前記第2偏光制御素子との間に配置されている、請求項1に記載のレーザ素子。
- 前記第1偏光変換素子は、前記第2反射層と前記レーザ媒質との間に配置されており、 前記第2偏光変換素子は、前記レーザ媒質と前記第3反射層との間に配置されている、請求項1に記載のレーザ素子。
- 前記第4反射層は、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、請求項1に記載のレーザ素子。
- 前記可飽和吸収体は、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、請求項9に記載のレーザ素子。
- 前記第4反射層は、前記第2波長の光において互いに直交する振動方向の光に対して位相を相違させる、請求項1に記載のレーザ素子。
- 前記第1偏光制御素子は、前記第2反射層と前記第1偏光変換素子との間に設けられており、
前記第1波長の光のうち互いに直交する偏光に対して異なる透過率を有し、かつ、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、請求項1に記載のレーザ素子。 - 前記第2偏光制御素子は、前記第3反射層と前記第2偏光変換素子との間に設けられており、
前記第1波長の光のうち互いに直交する偏光に対して異なる透過率を有し、かつ、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、請求項1に記載のレーザ素子。 - 前記第1偏光変換素子は、前記第1波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、請求項1に記載のレーザ素子。
- 前記第2偏光変換素子は、前記第2波長の光のうち互いに直交する偏光に対して異なる透過率を有するように表面に微細構造を有する、請求項1に記載のレーザ素子。
- 前記積層半導体層、前記レーザ媒質、前記第4反射層、前記第1共振器、前記第2共振器、前記第1偏光変換素子、前記第2偏光変換素子および前記第1または第2偏光制御素子は一体に接合されている、請求項1に記載のレーザ素子。
- 前記第1反射層と前記第4反射層との間のいずれかの位置に設けられた透明部材をさらに備える、請求項1に記載のレーザ素子。
- レーザ素子と、前記レーザ素子から光を放出する制御を行う制御部と、を備える電子機器であって、
前記レーザ素子は、
第1波長に対する第1反射層と、前記第1波長の面発光を行う活性層と、を有する積層半導体層と、
前記積層半導体層の光軸の後方側に配置され、前記積層半導体層と対向する第1面に第2波長に対する第2反射層および前記第1面と反対側の第2面に前記第1波長に対する第3反射層を有するレーザ媒質と、
前記第2面に配置されるか、又は前記第2面より光軸の後方側に配置される、前記第2波長に対する第4反射層と、
前記第1反射層および前記第3反射層の間で前記第1波長の光を共振させる第1共振器と、
前記第2反射層および前記第4反射層の間で前記第2波長の光を共振させる第2共振器と、
前記第1反射層と前記レーザ媒質との間に設けられ、前記第1波長の光において互いに直交する振動方向の光に対して位相を相違させる第1偏光変換素子と、
前記第4反射層と前記レーザ媒質との間に設けられ、前記第2波長の光において互いに直交する振動方向の光に対して位相を相違させる第2偏光変換素子と、
前記第1反射層と前記第4反射層との間に設けられ、前記第1または第2波長の光において偏光を制御する第1または第2偏光制御素子のうち少なくとも一つとを備え、
前記積層半導体層の光軸、前記レーザ媒質の光軸、前記第1および第2偏光変換素子、並びに、前記第1または第2偏光制御素子の光軸は、一軸上に配置される、電子機器。
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JPH1084169A (ja) * | 1996-07-26 | 1998-03-31 | Commiss Energ Atom | 直軸キャビティ半導体レーザーによる光学的ポンピングを備えた固体マイクロレーザー |
US20030039274A1 (en) * | 2000-06-08 | 2003-02-27 | Joseph Neev | Method and apparatus for tissue treatment and modification |
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JP2007316158A (ja) * | 2006-05-23 | 2007-12-06 | Hamamatsu Photonics Kk | 偏光制御素子及びそれを用いたレーザシステム |
JP2010199288A (ja) * | 2009-02-25 | 2010-09-09 | Hamamatsu Photonics Kk | パルスレーザ装置 |
WO2018221083A1 (ja) * | 2017-05-29 | 2018-12-06 | ソニー株式会社 | 受動qスイッチパルスレーザー装置、加工装置および医療装置 |
WO2020137136A1 (ja) * | 2018-12-25 | 2020-07-02 | ソニー株式会社 | レーザ装置 |
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JPH07302946A (ja) * | 1993-11-30 | 1995-11-14 | Fuji Photo Film Co Ltd | 固体レーザー |
JPH1084169A (ja) * | 1996-07-26 | 1998-03-31 | Commiss Energ Atom | 直軸キャビティ半導体レーザーによる光学的ポンピングを備えた固体マイクロレーザー |
US20030039274A1 (en) * | 2000-06-08 | 2003-02-27 | Joseph Neev | Method and apparatus for tissue treatment and modification |
US20060159132A1 (en) * | 2005-01-19 | 2006-07-20 | Young York E | System and method for a passively Q-switched, resonantly pumped, erbium-doped crystalline laser |
JP2007316158A (ja) * | 2006-05-23 | 2007-12-06 | Hamamatsu Photonics Kk | 偏光制御素子及びそれを用いたレーザシステム |
JP2010199288A (ja) * | 2009-02-25 | 2010-09-09 | Hamamatsu Photonics Kk | パルスレーザ装置 |
WO2018221083A1 (ja) * | 2017-05-29 | 2018-12-06 | ソニー株式会社 | 受動qスイッチパルスレーザー装置、加工装置および医療装置 |
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