Optical device and light-emitting device

An optical device comprising:

• an upconversion layer containing an upconversion material configured to receive excitation light in a first wavelength range and output light in a second wavelength range shorter than the first wavelength range;
• a first light confinement layer having a light reflection characteristic of reflecting at least a part of light in the second wavelength range;
• a second light confinement layer having a light reflection characteristic of reflecting a part of light in the second wavelength range and transmitting the remainder, the second light confinement layer being disposed such that the upconversion layer is located between the first light confinement layer and the second light confinement layer;
• and
• a resonance mode forming layer provided between the upconversion layer and the first light confinement layer or between the upconversion layer and the second light confinement layer, the resonance mode forming layer including a base layer and a plurality of modified refractive index regions having a refractive index different from a refractive index of the base layer and two-dimensionally distributed on a reference surface perpendicular to a thickness direction of the resonance mode forming layer, and configured to form a resonance mode of the light in the second wavelength range along the reference surface.

An optical device comprising:

• an upconversion layer containing an upconversion material configured to receive excitation light in a first wavelength range and output light in a second wavelength range shorter than the first wavelength range;
• a first light confinement layer having a light reflection characteristic of reflecting at least a part of light in the second wavelength range;
• a second light confinement layer having a light reflection characteristic of reflecting a part of light in the second wavelength range and transmitting the remainder, the second light confinement layer being disposed such that the upconversion layer is located between the first light confinement layer and the second light confinement layer, and having a single-layer structure in which a resonance mode of the light in the second wavelength range is formed;
• and
• a resonance mode forming layer configured to form the resonance mode of the light in the second wavelength range, the resonance mode forming layer being provided on a side on which a layer surface of the second light confinement layer facing the upconversion layer is located, the resonance mode forming layer including a base layer constituting a part of the second light confinement layer, and a plurality of modified refractive index regions defined by a plurality of recesses two-dimensionally distributed on the layer surface of the second light confinement layer as a reference surface perpendicular to a thickness direction of the resonance mode forming layer, the plurality of recesses having a refractive index different from a refractive index of the base layer.