Abstract: An optical system includes: a difference-frequency-light generator that multiplexes output lights from a signal-light light source and an excitation-light light source and inputs the output lights to a nonlinear optical material to generate and output a difference-frequency light having a wavenumber that corresponds to a wavenumber difference between light from the signal-light and from the excitation-light light source, where one of the signal-light source or the excitation-light source is a wavelength-sweeping light source; a splitter that splits a portion of light output from the wavelength-sweeping light source into a first and a second reference light; and an equal-wavenumber-signal generator that receives the first reference light, via an interferometer, to generate and output an equal-wavenumber signal that fluctuates in equal wavenumber intervals according to wavelength sweeping of the wavelength-sweeping light source.

Abstract: Methods and devices for accurate noninvasive measurement of blood analyte concentrations are disclosed. In an example process, optical properties of a blood vessel proximate to the surface of an exposed body part, for example, the sclera or the backside of the eyelid, is measured. Analyte concentrations are determined based on the measured optical properties.

Abstract: A tunable filter includes: a first transparent substrate including a first reflective surface; a second transparent substrate including a second reflective surface that opposes the first reflective surface; and a supporting member, connected to the first transparent substrate, that supports the second transparent substrate on the first transparent substrate so that the second reflective surface is disposed at a position separated from the first reflective surface in a normal direction of the first reflective surface. A cavity between the first reflective surface and the second reflective surface forms an etalon. A relative position of the second transparent substrate with respect to the first transparent substrate changes due to thermal expansion of the supporting member, and a length of the cavity changes in the normal direction.

Abstract: An integrated optical device includes: a housing; a liquid-crystal optical power attenuator, an optical splitter, and an optical power monitor housed inside the housing; and first and second optical fibers housed inside the housing. The first optical fibers input an optical signal from outside the housing to the optical power attenuator. In a polarized state, the optical power attenuator attenuates the optical signal from the first optical fibers. The second optical fibers output the attenuated optical signal from the optical power attenuator to outside the housing. The optical splitter generates a split signal by splitting at least one of: the optical signal input to the optical power attenuator from the first optical fibers, and the attenuated optical signal propagated from the optical power attenuator to the second optical fibers. The optical power monitor receives the split signal and detects a power of the split signal.

Abstract: An optical system includes a light source, an interferometer, and a detector. The interferometer includes a scanner and a lens system disposed downstream of the scanner. The scanner is configured to direct a portion of the optical beam along one of a plurality of different directions within a scanning range. The lens system is configured to project the portion of optical beam to an imaging area defined by a field of view of the optical system, the lens system comprising a first lens, wherein an aspect of the first lens is adjustable so as to render the field of view adjustable without adjusting the scanning range of the scanner. The detector is configured to receive a reflected portion of the optical beam that reflects from an object placed within the imaging area.

Abstract: An optical power attenuator includes: a MEMS package storing a MEMS element that can control a reflection angle of light by a mirror; a capillary member provided to one end of a two-core optical fiber that transmits the light and that has an end surface on a side that inputs/outputs the light to the two-core optical fiber tilted at a predetermined angle relative to an optical axis of the two-core optical fiber; and a lens that causes a light emitted from one of the optical fibers of the two-core optical fiber to become incident on the MEMS element via the capillary member and guides the reflected light reflected by the mirror of the MEMS element to the other optical fiber of the two-core optical fiber.

Abstract: A detection device is provided with a light-receiving module configured to output an electrical signal according to a power of an input light received at a light-receiving surface, an optical lens configured to collimate and guide to the light-receiving surface the input light from the outside, and at least one condensing unit that is provided in a path of the input light between the optical lens and the light-receiving surface and configured to decrease a beam diameter of the input light at the light-receiving surface.

Abstract: An optical coherence tomography (OCT) system combining multiple wavelengths is generally described. In an example, the OCT system includes a first light source configured to emit a first beam having a first wavelength. The OCT system further includes a second light source configured to emit a second beam having a second wavelength. The OCT system further includes an interferometer. The first beam and the second beam are configured to be directed into the interferometer. The interferometer includes a reference path and an interferometer sample path. The OCT system further includes a first beam splitter configured to divide, from an output of the interferometer sample path the first beam into a first sample path, and the second beam into a second sample path. The OCT system further includes a second beam splitter configured to combine the first beam and the second beam into a common axis.

Abstract: A method for imaging includes scanning a B scan of a sample N times at a first slice of a sample. N is greater than or equal to 2. The B scan includes a plurality of A scans. A pixel of the first slice has an M number of A scans within the pixel. Each of the A scans have a spectrum range less than a full spectrum range of the light source. A number of pixels per B scan is an approximate B scan length divided by a lateral resolution size of the pixel. The method further includes determine a flow image of the sample using an optical coherence tomography (OCT) signal reflected back from the sample.

Abstract: An OCT system includes a light source configured to generate an optical beam, a Fizeau-type interferometer configured to receive the optical beam and produce an interference pattern, a detector configured to receive the interference pattern and produce an image signal, and a processing circuit including a processor and a memory, the memory being structured to store instructions that are executable by the processor to cause the processor to receive the image signal from the detector and generate an OCT image based on the image signal. The Fizeau-type interferometer includes a scanning element configured to receive the optical beam and direct the optical beam in a plurality of directions towards a sample and a reflective element configured to divide the directed optical beam into a reference beam and a sample beam that reflects off of a surface of a sample.

Abstract: A detection device for detecting a power of an input light is provided with a light-receiving module that outputs an electrical signal according to a power of an input light received at a light-receiving surface and an optical system that collimates and guides to the light-receiving surface the input light from the outside. Moreover, this detection device is provided with a structure that decreases an incidence angle of the input light at an interface between the optical system and the light-receiving surface.

Abstract: A detection device for detecting a power of an input light is provided with a light-receiving module that outputs an electrical signal according to a power of an input light received at a light-receiving surface and an optical system that collimates and guides to the light-receiving surface the input light from the outside. Moreover, this detection device is provided with a structure that decreases an incidence angle of the input light at an interface between the optical system and the light-receiving surface.

Abstract: An optical coherence tomography (OCT) system combining multiple wavelengths is generally described. In an example, the OCT system includes multiple wavelength swept light sources. The system further includes an interferometer into which light from the light sources is directed and a detector configured to produce an imaging sample signal based on light received from the interferometer. The system also includes a splitter configured to split light from at least one of light sources before the light reaches the interferometer. The system also includes a wavelength reference filter having an equal interval frequency comb and a signal processing circuit. The wavelength reference filter is configured to produce a sequential clock waveform from light received from the splitter, and the signal processing circuit is configured to resample the imaging sample signal based on the sequential clock waveform.

Abstract: A detection device for detecting a power of an input light is provided with a light-receiving module that outputs an electrical signal according to a power of an input light received at a light-receiving surface and an optical system that collimates and guides to the light-receiving surface the input light from the outside. Moreover, this detection device is provided with a structure that decreases an incidence angle of the input light at an interface between the optical system and the light-receiving surface.

Abstract: A system includes a spatial light modulator and a controller. The spatial light modulator is configured to perform phase modulation of a light that passes through a liquid crystal by applying individual voltages to the liquid crystal from each of a plurality of electrodes. The controller is configured to control the voltages applied to the liquid crystal from each of the plurality of electrodes based on phase image data. The phase image data represents values of each pixel corresponding to each of the plurality of electrodes by predetermined gradations. The controller converts gradation values, which are the values of each pixel, into voltages input to the electrodes corresponding to each pixel. The controller is configured to change a fluctuation width from a minimum value to a maximum value of the input voltages corresponding to a fluctuation width from a minimum value to a maximum value of the gradation values.

Abstract: A detection device is provided with a holding body that holds a light-receiving module, an optical fiber pigtail, and a lens. The light-receiving module is provided with a light-receiving element and a stem that supports the light-receiving element. The lens collimates an input light from one end of an input fiber and guides a portion of the input light to the light-receiving element. The lens separates the input light into a transmitted light and a reflected light, guiding the transmitted light to the light-receiving element and guiding the reflected light to an output fiber. The light-receiving element has a center of a light-receiving surface thereof disposed in a position away from an axis of the stem.

Abstract: An optical power attenuator includes: a MEMS package storing a MEMS element that can control a reflection angle of light by a mirror; a capillary member provided to one end of a two-core optical fiber that transmits the light and that has an end surface on a side that inputs/outputs the light to the two-core optical fiber tilted at a predetermined angle relative to an optical axis of the two-core optical fiber; and a lens that causes a light emitted from one of the optical fibers of the two-core optical fiber to become incident on the MEMS element via the capillary member and guides the reflected light reflected by the mirror of the MEMS element to the other optical fiber of the two-core optical fiber.

Abstract: A light control system is provided with a spatial light modulator of a liquid-crystal type, an input unit, and a controller. The input unit is configured to input a light to the spatial light modulator. The controller is configured to cause the spatial light modulator to function as a diffraction grating by electrically controlling the spatial light modulator. The controller is configured to change a path of a diffracted light from the spatial light modulator corresponding to the light input from the input unit by changing a shape of the diffraction grating.

Abstract: An optical coherence tomography (OCT) system combining multiple wavelengths is generally described. In an example, the OCT system includes a first light source configured to emit a first beam having a first wavelength. The OCT system further includes a second light source configured to emit a second beam having a second wavelength. The OCT system further includes an interferometer. The first beam and the second beam are configured to be directed into the interferometer. The interferometer includes a reference path and an interferometer sample path. The OCT system further includes a first beam splitter configured to divide, from an output of the interferometer sample path the first beam into a first sample path, and the second beam into a second sample path. The OCT system further includes a second beam splitter configured to combine the first beam and the second beam into a common axis.

Abstract: An integrated optical device is mounted with two optical fibers that transmit a light and, as functional components in a space of a housing forming an optical path from one of the optical fibers to the other light, is provided with an optical power attenuator that attenuates, using vignetting, a light incident from the one optical fiber or a light emitted from the other optical fiber and a tunable filter that selects a light of a predetermined wavelength from among the light incident from the one optical fiber and emits this selected light from the other optical fiber.