The present disclosure relates generally to a single photon avalanche diode (SPAD) having a rib waveguide with a doping profile having a multiplication junction, a top cladding layer disposed on a top surface of the rib waveguide, a bottom cladding layer disposed on a bottom surface of the rib waveguide. The SPAD has an anode, a cathode and two field plates. The anode, cathode and the two field plates are configured to suppress the electric field over the multiplication junction relative to a SPAD without the at least two field plates, and the two field plates and/or cathode are positioned adjacent to the intersection of the multiplication junction and the top cladding layer.

Structures for a photodetector or light absorber and methods of forming a structure for a photodetector or light absorber. The structure includes a pad, a waveguide core adjoined to the pad, and a light-absorbing layer on the pad. The waveguide core includes a first longitudinal axis, and the light-absorbing layer includes a second longitudinal axis and an end surface intersected by the second longitudinal axis. The end surface of the light-absorbing layer is positioned adjacent to the waveguide core. The first longitudinal axis of the first waveguide core is inclined relative to the second longitudinal axis of the light-absorbing layer and/or the end surface slanted relative to the second longitudinal axis.

An electronic device can include a housing defining an aperture, and an electromagnetic radiation emitter and an electromagnetic radiation detector disposed in the housing. An optical component can be disposed in the aperture and can include a first region of a first material having a first index of refraction, the first region aligned with the electromagnetic radiation emitter, a second region of the first material, the second region aligned with the electromagnetic radiation detector, and a bulk region surrounding a periphery of the first region and a periphery of the second region, the bulk region including a second material having a second index of refraction that is lower than the first index of refraction.

An optical sensor including a planar nano-photonic microlens array and an electronic apparatus including the same are provided. The optical sensor may include: a sensor substrate including a plurality of photosensitive cells for sensing light; a filter layer provided on the sensor substrate; and a planar nano-photonic microlens array provided on the filter layer, and including a plurality of planar nano-photonic microlenses, wherein the plurality of planar nano-photonic microlenses are two-dimensionally arranged in a first direction and a second direction that is perpendicular to the first direction, and each of the planar nano-photonic microlenses include nano-structures arranged such that the light transmitting through each of the planar nano-photonic microlenses has a phase profile in which a phase change curve is convex in the first direction and the second direction.

Provided is a photodetector element having a photoelectric conversion element, an optical filter provided on a light incident side of the photoelectric conversion element, and an interlayer provided between the photoelectric conversion element and the optical filter, in which the photoelectric conversion element has a quantum dot layer, a first electrode, and a second electrode, the optical filter has predetermined spectral characteristics, and the interlayer includes at least one kind of atom selected from the group consisting of Si, Al, Zr, Sn, Zn, Ce, and Hf, or includes a paraxylene polymer, or has a water vapor permeability as determined by a method in accordance with JIS K 7129 of 110.sup.4 g/m.sup.2/day or less. Provided also are an image sensor and a method for manufacturing a photodetector element.

Provided is a photodetector element having a photoelectric conversion element, an optical filter provided on a light incident side of the photoelectric conversion element, a dielectric multi-layer film provided on a light incident side of the optical filter, and an interlayer provided between the photoelectric conversion element and the optical filter, in which the photoelectric conversion element has a quantum dot layer, a first electrode, and a second electrode, the optical filter is a laminated film including a first filter layer including a coloring material and a second filter layer including a coloring material, and the interlayer includes at least one kind of atom selected from the group consisting of Si, Al, Zr, Sn, Zn, Ce, and Hf, or includes a paraxylene polymer, or has a water vapor permeability as determined by a method in accordance with JIS K 7129 of 110.sup.4 g/m.sup.2/day or less. Provided also are an image sensor and a method for manufacturing a photodetector element.

An optical device includes a nanostructure body which induces surface plasmon resonance when irradiated with light, an alloy layer which is in contact with the nanostructure body and which has a lower work function than the nanostructure body, and an n-type semiconductor which is in Schottky contact with the alloy layer. The nanostructure body is composed of one selected from the group consisting of elemental metals, alloys, metal nitrides, and conductive oxides. The alloy layer is composed of at least two metals.

An optical device includes a nanostructure body which induces surface plasmon resonance when irradiated with light, an alloy layer which is in contact with the nanostructure body and which has a lower work function than the nanostructure body, and an n-type semiconductor which is in Schottky contact with the alloy layer. The nanostructure body is composed of one selected from the group consisting of elemental metals, alloys, metal nitrides, and conductive oxides. The alloy layer is composed of at least two metals.

A multispectral filter for electromagnetic radiation, the filter including at least two-colour filters, each colour filter including: a metal grating including metal patterns repeated according to a given period, each metal pattern being spaced apart from an adjacent metal pattern by a given non-zero spacing; a continuous reflective layer; a pattern of dielectric material of Fabry-Perot cavity between the metal grating and the continuous reflective layer; the thickness of the patterns of dielectric material of the two-colour filters being different.

A fabrication method of a solar cell, the method includes doping a silicon substrate having a first conductive type impurity with a second conductive type impurity, the second conductive type impurity being opposite to the first conductive type impurity, and thereby forming an emitter layer at a front surface part of the silicon substrate, forming an antireflection film on the emitter layer, forming a front electrode on the antireflection film, forming a rear electrode on a rear surface of the silicon substrate, and forming a back surface field layer at a rear surface part of the silicon substrate, the back surface field layer having a concentration of the first conductive type impurity that is higher than that of the silicon substrate, the back surface field layer having a different concentration of the second conductive type impurity from that of the emitter layer.