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: Light-emitting device (1) includes waveguide structure (5) and exterior part (4). Waveguide structure (5) includes light receiving surface (51) including incident end surface (31) and first surface (41), and radiation surface (52) including emission end surface (32) and second surface (42). A position of waveguide structure (5) with respect to light source (2) is determined to cause light (L1) to be incident on light receiving surface (51). Incident range (R) on which light (L1) is incident on light receiving surface (51) includes at least a part of incident end surface (31) and at least a part of first surface (41) such that a part of light (L1) is incident on incident end surface (31) and another part of light (L1) is incident on first surface (41), passes through exterior part (4), and is emitted from second surface (42).

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 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: 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: 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.].