Abstract: A ScAlMgO4 monocrystalline substrate that is highly cleavable and that does not easily cause cracking in the GaN film id grown on the substrate and a method for manufacturing such a ScAlMgO4 monocrystalline substrate are provided. The ScAlMgO4 monocrystalline substrate has a crystal oxygen concentration of 57 atom % or less as measured by inductively coupled plasma atomic emission spectroscopy analysis.

Abstract: A light emitting device includes a light source and a waveguide structure. The light source emits light having a directionality. The waveguide structure includes an optical waveguide and an exterior part. The optical waveguide has an incident end surface and an emission end surface, converts a wavelength of the light incident from the incident end surface, and emits the light from the emission end surface. The exterior part is optically transparent and covers the optical waveguide such that the incident end surface and the emission end surface are exposed from the exterior part. The optical waveguide is elongated in a length direction. The length direction of the optical waveguide is inclined at a predetermined angle with respect to an optical axis of the light in a predetermined plane including the length direction of the optical waveguide and the optical axis of the light.

Abstract: A RAMO4 substrate that does not easily crack during or after the formation of group III nitride crystal includes a single crystal represented by general formula RAMO4 (wherein R represents one or more trivalent elements selected from the group consisting of Sc, In, Y, and lanthanoid elements, A represents one or more trivalent elements selected from the group consisting of Fe(III), Ga, and Al, and M represents one or more divalent elements selected from the group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). The RAMO4 substrate has a crystal plane with a curvature radius r of 52 m or more, and a square value of correlation coefficient ? of 0.81 or more. The curvature radius r is calculated as an absolute value from X-ray peak position ?i and measurement position Xi after the measurements of X-ray peak positions ?i at a plurality of positions Xi lying on a straight line passing through the center of the RAMO4 substrate.

Abstract: A wavelength conversion device including a cavity that includes an RAMO4 crystal having a single crystal represented by a first general formula of RAMO4, a laser crystal, and a mirror, in which in the first general formula, R represents one or a plurality of trivalent elements selected from the group consisting of Sc, In, Y, and lanthanoid elements, A represents one or a plurality of trivalent elements selected from the group consisting of Fe (III), Ga, and Al, and M represents one or a plurality of divalent elements selected from the group consisting of Mg, Mn, Fe (II), Co, Cu, Zn, and Cd.

Abstract: A RAMO4 substrate includes a single crystal represented by a formula of RAMO4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected from a group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on one surface of the RAMO4 substrate, a satin-finish surface is provided on another surface. The satin-finish surface has surface roughness which is larger than that of the epitaxially-grown surface.

Abstract: A light emitting device includes a light source that emits light having a directivity from a light emitting surface of the light source, a waveguide structure that includes an optical waveguide having an inlet facing the light emitting surface, and a peripheral wall protruding from the inlet toward the light emitting surface, and a lens that is provided between the light emitting surface and the inlet. The peripheral wall has an inner surface surrounding the inlet. The peripheral wall has a first opening closer to the light emitting surface and a second opening closer to the inlet. The first opening is larger than the second opening. The peripheral wall includes a narrow opening portion in which an internal space of the peripheral wall is smaller than the lens when viewed from a direction of an optical axis of the light.

Abstract: Provided herein is a wavelength converter capable of producing shorter wavelengths by wavelength conversion than in related art. A wavelength converter of the present disclosure includes: a first layer formed of a single crystal represented by general formula RAMO4; and a second layer formed of a single crystal represented by the general formula RAMO4 and having a direction of polarization reversed 180° from a direction of polarization of the first layer, wherein, in the general formula, R represents one or more trivalent elements selected from the group consisting of Sc, In, Y, and a lanthanoid element, A represents one or more trivalent elements selected from the group consisting of Fe(III), Ga, and Al, and M represents one or more divalent elements selected from the group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd.

Abstract: Provided herein is a wavelength converter capable of producing shorter wavelengths by wavelength conversion than in related art. A wavelength converter of the present disclosure includes: a first layer formed of a single crystal represented by general formula RAMO4; and a second layer formed of a single crystal represented by the general formula RAMO4 and having a direction of polarization reversed 180° from a direction of polarization of the first layer, wherein, in the general formula, R represents one or more trivalent elements selected from the group consisting of Sc, In, Y, and a lanthanoid element, A represents one or more trivalent elements selected from the group consisting of Fe(III), Ga, and Al, and M represents one or more divalent elements selected from the group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd.

Abstract: A wavelength conversion device including a cavity that includes an RAMO4 crystal having a single crystal represented by a first general formula of RAMO4, a laser crystal, and a mirror, in which in the first general formula, R represents one or a plurality of trivalent elements selected from the group consisting of Sc, In, Y, and lanthanoid elements, A represents one or a plurality of trivalent elements selected from the group consisting of Fe (III), Ga, and Al, and M represents one or a plurality of divalent elements selected from the group consisting of Mg, Mn, Fe (II), Co, Cu, Zn, and Cd.

Abstract: An object is to provide a high-quality ScAlMgO4 single crystal and a device. The ScAlMgO4 single crystal includes Sc, Al, Mg, and O, in which the atomic percentage ratio of Mg to Al, Mg/Al (atom %/atom %), as measured by an inductively coupled plasma emission spectrometric method, is more than 1 and less than 1.1.

Abstract: A ScAlMgO4 single crystal substrate having less collapse of crystal orientation, and a method for producing the single crystal substrate. A ScAlMgO4 single crystal substrate is provided, wherein, when a center of the substrate is designated as coordinates (0,0) and a measurement beam width is set to 1 [mm]×7 [mm] to conduct analysis according to an X-ray diffraction method at respective coordinate positions of (x?m,0) to (xm,0) at an interval of 1 [mm] in an x-axis direction and (0,y?n) to (0,yn) at an interval of 1 mm in a y-axis direction, wherein m and n are each an integer falling within the range so that the measurement beam is not stuck out from the substrate, a worst value of a full width at half maximum of a rocking curve at each of the coordinate positions is less than 20 [sec.].

Abstract: A ScAlMgO4 monocrystalline substrate that is highly cleavable and that does not easily cause cracking in the GaN film id grown on the substrate and a method for manufacturing such a ScAlMgO4 monocrystalline substrate are provided. The ScAlMgO4 monocrystalline substrate has a crystal oxygen concentration of 57 atom % or less as measured by inductively coupled plasma atomic emission spectroscopy analysis.

Abstract: A RAMO4 substrate that does not easily crack during or after the formation of group III nitride crystal includes a single crystal represented by general formula RAMO4 (wherein R represents one or more trivalent elements selected from the group consisting of Sc, In, Y, and lanthanoid elements, A represents one or more trivalent elements selected from the group consisting of Fe(III), Ga, and Al, and M represents one or more divalent elements selected from the group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). The RAMO4 substrate has a crystal plane with a curvature radius r of 52 m or more, and a square value of correlation coefficient ? of 0.81 or more. The curvature radius r is calculated as an absolute value from X-ray peak position ?i and measurement position Xi after the measurements of X-ray peak positions ?i at a plurality of positions Xi lying on a straight line passing through the center of the RAMO4 substrate.

Abstract: An object is to provide a high-quality ScAlMgO4 single crystal and a device. The ScAlMgO4 single crystal includes Sc, Al, Mg, and O, in which the atomic percentage ratio of Mg to Al, Mg/Al (atom %/atom %), as measured by an inductively coupled plasma emission spectrometric method, is more than 1 and less than 1.1.

Abstract: A ScAlMgO4 single crystal substrate having less collapse of crystal orientation, and a method for producing the single crystal substrate. A ScAlMgO4 single crystal substrate is provided, wherein, when a center of the substrate is designated as coordinates (0,0) and a measurement beam width is set to 1 [mm]×7 [mm] to conduct analysis according to an X-ray diffraction method at respective coordinate positions of (x?m,0) to (xm,0) at an interval of 1 [mm] in an x-axis direction and (0,y?n) to (0,yn) at an interval of 1 mm in a y-axis direction, wherein m and n are each an integer falling within the range so that the measurement beam is not stuck out from the substrate, a worst value of a full width at half maximum of a rocking curve at each of the coordinate positions is less than 20 [sec.].

Abstract: A RAMO4 substrate is formed from single crystal represented by a formula of RAMO4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected form a group consisting of Hg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on at least one surface of the RAMO4 substrate. The epitaxially-grown surface includes a plurality of cleavage surfaces which are regularly distributed, and are separated from each other.

Abstract: A RAMO4 substrate includes a single crystal represented by a formula of RAMO4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected from a group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on one surface of the RAMO4 substrate, a satin-finish surface is provided on another surface. The satin-finish surface has surface roughness which is larger than that of the epitaxially-grown surface.

Abstract: A RAMO4 substrate includes a single crystal represented by a formula of RAMO4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected from a group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on at least one surface of the RAMO4 substrate. An unevenness having a height of 500 nm or more is not provided on the epitaxially-grown surface.

Abstract: A RAMO4 substrate is formed from single crystal represented by a formula of RAMO4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected form a group consisting of Hg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on at least one surface of the RAMO4 substrate. The epitaxially-grown surface includes a plurality of cleavage surfaces which are regularly distributed, and are separated from each other.

Abstract: A quartz crucible for growing silicon single crystal comprises a crucible body made of a quartz material and a coating layer of a pure silicon which is formed on an inner wall of the crucible body and has purity equivalent to a silicon material that is to be filled into the crucible body. The pure silicon of the coating layer melts together with a silicon material filled in the quartz crucible.