Abstract: An optical apparatus includes a light source, an optical waveguide element, a light detector, and an optical system. The light source emits a light beam. The optical waveguide element includes first and second gratings. The first grating causes part of the light beam to propagate in the optical waveguide element as a guided light beam. The second grating causes part of the guided light beam to exit from the optical waveguide element. The optical system causes the light beam to enter the first grating and causes a reflected light beam from an object to enter the second grating. Part of the reflected light beam entering the second grating propagates in the optical waveguide element and exits from the first grating as an optical feedback beam. The optical system causes part of the optical feedback beam to enter the light detector as separated light beams separated depending on wavelength.

Abstract: An optical device includes: a light source that emits laser light; an optical waveguide element positioned on the optical path of the laser light; a first member positioned on the optical path, and has a bottom surface that faces the optical waveguide element, and a side surface that is rotationally symmetric about the optical path; and a control circuit. The optical waveguide element includes: a first grating that includes a plurality of portions arranged in the radial direction and having mutually different refractive indices, and that causes a portion of the laser light that is incident to be propagated in the radial direction within the optical waveguide element; and a second grating that includes a plurality of portions arranged outside the first grating, arranged in the radial direction, and having mutually different refractive indices, and that causes light to be emitted from the optical waveguide element.

Abstract: A structural body includes a first dielectric layer and a second dielectric layer which is in contact with the first dielectric layer and which has a refractive index different from that of the first dielectric layer. The second dielectric layer includes at least two dielectric films different in hydrogen concentration from each other. The interface between the first dielectric layer and the second dielectric layer has periodic first irregularities.

Abstract: A light-guide sheet according to the present disclosure is a light-guide sheet that takes in incident light and waveguides light in a direction intersecting with an incident direction of the incident light inside the light-guide sheet. The light-guide sheet includes: a lower refractive index layer; a light-transmissive layer that is continuously stacked with the lower refractive index layer and has a refractive index that is higher than a refractive index of the lower refractive index layer; and a diffraction grating that is disposed on the light-transmissive layer and changes a travelling direction of the incident light. A pattern of the diffraction grating is divided into a plurality of partial patterns on the light-transmissive layer, and each of the plurality of partial patterns has a concentric circular shape or a concentric polygonal shape.

Abstract: An optical apparatus includes a light source, an optical waveguide element, a light detector, and an optical system. The light source emits a light beam. The optical waveguide element includes first and second gratings. The first grating causes part of the light beam to propagate in the optical waveguide element as a guided light beam. The second grating causes part of the guided light beam to exit from the optical waveguide element. The optical system causes the light beam to enter the first grating and causes a reflected light beam from an object to enter the second grating. Part of the reflected light beam entering the second grating propagates in the optical waveguide element and exits from the first grating as an optical feedback beam. The optical system causes part of the optical feedback beam to enter the light detector as separated light beams separated depending on wavelength.

Abstract: A photo-detection system includes: a photo-detection apparatus including a light-shielding film, an optically-coupled layer, and a photodetector including first and second photo-detection cells; and an arithmetic circuit that generates, based on first signals and second signals, third signals each representing coherence of light having entered a position of each of the first and second photo-detection cells and generates at least one selected from the group consisting of an average value of the third signals, a standard deviation of the third signals, a ratio between the standard deviation and the average value, and a ratio between an average value of a first portion of the third signals based on light having entered the positions of the first photo-detection cells and an average value of a second portion of the third signals based on light having entered the positions of the second photo-detection cells.

Abstract: An optical device includes: a light source that emits laser light; an optical waveguide element positioned on the optical path of the laser light; a first transparent member positioned on the optical path, and has a bottom surface that faces the optical waveguide element, and a side surface that is rotationally symmetric about the optical path; and a control circuit. The optical waveguide element includes: a first grating that includes a plurality of portions arranged in the radial direction and having mutually different refractive indices, and that causes a portion of the laser light that is incident to be propagated in the radial direction within the optical waveguide element; and a second grating that includes a plurality of portions arranged outside the first grating, arranged in the radial direction, and having mutually different refractive indices, and that causes light to be emitted from the optical waveguide element.

Abstract: A structural body includes a first dielectric layer and a second dielectric layer which is in contact with the first dielectric layer and which has a refractive index different from that of the first dielectric layer. The second dielectric layer includes at least two dielectric films different in hydrogen concentration from each other. The interface between the first dielectric layer and the second dielectric layer has periodic first irregularities.

Abstract: A light-guide sheet according to the present disclosure is a light-guide sheet that takes in incident light and waveguides light in a direction intersecting with an incident direction of the incident light inside the light-guide sheet. The light-guide sheet includes: a lower refractive index layer; a light-transmissive layer that is continuously stacked with the lower refractive index layer and has a refractive index that is higher than a refractive index of the lower refractive index layer; and a diffraction grating that is disposed on the light-transmissive layer and changes a travelling direction of the incident light. A pattern of the diffraction grating is divided into a plurality of partial patterns on the light-transmissive layer, and each of the plurality of partial patterns has a concentric circular shape or a concentric polygonal shape.

Abstract: A measurement apparatus includes a light source, an imaging device, a signal processing circuit, and a controller. The controller causes the light source to irradiate a first portion of the scatterer, causes the element to obtain an image signal from a first target area, causes the light source to irradiate a second portion of the scatterer, and causes the element to obtain an image signal from a second target area. The circuit uses the image signals to generate data regarding the position of a target object inside the scatterer. A first distance between the first portion and a center of the first target area is equal to a second distance between the second portion and a center of the second target area, or a difference between the first and second distances is smaller than 10% of a smaller one of the first and second distances.

Abstract: A photo-detection apparatus includes a light-shielding film, an optically-coupled layer, a photodetector, and an optical system. In the light-shielding film, light-transmitting regions and light-shielding regions are alternately arranged in at least a first direction within a plane. The optically-coupled layer faces the light-shielding film and includes a grating that propagates light in the first direction. The photodetector includes first photo-detection cells and second photo-detection cells arranged on an imaging area. The optical system is disposed between the optically-coupled layer and the photodetector. An image of light transmitted by parts of the optically-coupled layer that face each of the light-transmitting regions and light-shielding regions is enlarged or reduced by the optical system and formed on a corresponding one of the first and second photo-detection cells.

Abstract: A waveguide sheet captures incident light and waveguides the incident light in a direction intersecting with an incident direction. The waveguide sheet includes a diffraction grating layer that changes a traveling direction of the incident light and a plurality of first light-transmissive pairs. Each of the first light-transmissive pairs includes a first light-transmissive layer having a shape with first concave streaks and first convex streaks being repeatedly arranged in a first direction that is a direction intersecting with the incident direction, and a second light-transmissive layer laminated on the first light-transmissive layer.

Abstract: A waveguide sheet captures incident light and waveguides the incident light in a direction intersecting with an incident direction. The waveguide sheet includes a diffraction grating layer that changes a traveling direction of the incident light and a plurality of first light-transmissive pairs. Each of the first light-transmissive pairs includes a first light-transmissive layer having a shape with first concave streaks and first convex streaks being repeatedly arranged in a first direction that is a direction intersecting with the incident direction, and a second light-transmissive layer laminated on the first light-transmissive layer.

Abstract: An imaging apparatus includes an image sensor, an optical system, a control circuit, and a signal processing circuit. The image sensor includes a light-shielding film in which light-transmitting regions and light-shielding regions are alternately arranged in at least a first direction within a plane, a photodetector disposed opposite the light-shielding film, and an optically-coupled layer disposed between the light-shielding film and the photodetector. The optically-coupled layer includes a grating which generates a propagating light that propagates in the first direction and a transmitting light that transmits the optically-coupled layer when light of a predetermined wavelength enters the light-transmitting regions. The signal processing circuit extracts two different frames from frames included in a moving image acquired by the image sensor.

Abstract: A photodetection device including an image sensor that includes first pixels and second pixels; an interference element that includes incident regions; and illumination that emits light in a first wavelength band and a second wavelength band. The interference element causes first interference of light in the first wavelength band incident on two incident regions, and guides resultant light of the first interference to any of the first pixels and guides another part of the light in the first wavelength band to any of the second pixels, and causes second interference of part of the light in the second wavelength band incident on the two incident regions, and guides resultant light of the second interference to any of the first pixels and guides another part of the light in the second wavelength band incident on the two incident regions to any of the second pixels.

Abstract: A photodetection device including an image sensor that includes fifth pixels and sixth pixels; an interference element that includes fifth incident regions; and illumination that emits light in a first wavelength band and a second wavelength band. The interference element causes first interference of light in the first wavelength band incident on two fifth incident regions, and guides resultant light of the first interference to any of the fifth pixels and guides another part of the light in the first wavelength band to any of the sixth pixels, and causes second interference of part of the light in the second wavelength band incident on the two fifth incident regions, and guides resultant light of the second interference to any of the fifth pixels and guides another part of the light in the second wavelength band incident on the two fifth incident regions to any of the sixth pixels.

Abstract: A light detection device according to one aspect of the present disclosure includes: a light detector having a main surface and including at least one first detector and at least one second detector disposed along the main surface; a light coupling layer disposed on or apart from the light detector and including a first low-refractive-index layer, a first high-refractive-index layer disposed on the first low-refractive-index layer and including a first grating, and a second low-refractive-index layer disposed on the first high-refractive-index layer, the first high-refractive-index layer having a higher refractive index than the first and second low-refractive-index layers; and a light shielding film disposed on the light coupling layer and including at least one light transmitting region and at least one light shielding region adjacent to the at least one light transmitting region.

Abstract: A light detection device includes a light detector including first detectors and second detectors both disposed along a main surface; a light coupling layer disposed on or above the light detector; and a light shielding film disposed on the light coupling layer. The light coupling layer includes a first low-refractive-index layer, a first high-refractive-index layer that is disposed on the first low-refractive-index layer and includes a first grating, and a second low-refractive-index layer that is disposed on the first high-refractive-index layer. The light shielding film includes a light transmitting region and a light shielding region adjacent to the light transmitting region. The light transmitting region faces two or more first detectors included in the first detectors, and the light shielding region faces two or more second detectors included in the second detectors.

Abstract: A light detection device includes a light detector including a first detector and a second detector; a light coupling layer disposed on or above the light detector; and a polarizer array that is disposed on the light coupling layer. The light coupling layer includes a first low-refractive-index layer, a first high-refractive-index layer including a first grating and a second grating adjacent to the first grating, and a second low-refractive-index layer in this order. The polarizer array includes a first polarizer that transmits light polarized in one direction and a second polarizer that is adjacent to the first polarizer and blocks the light polarized in the one direction. The first grating and the first polarizer face the first detector, and the second grating and the second polarizer face the second detector.

Abstract: A photodetection device comprises: an image sensor that includes first pixels, second pixels, third pixels, and fourth pixels; an interference element that includes first incident regions and second incident regions; and an optical system that causes light in a first wavelength band to be incident on the first incident regions and causes light in a second wavelength band different from the first wavelength band to be incident on the second incident regions. The interference element causes first interference of part of the light in the first wavelength band incident on two first incident regions that are included in the first incident regions. The interference element also causes second interference of part of the light in the second wavelength band incident on two second incident regions.