Abstract: An optical coherence tomographic device may include: a light source; a measurement light generator that generates measurement light and generates reflected light from a target region in a scattering sample by irradiating the target region with the measurement light; a reference light generator that generates reference light; an interference light generator that generates interference light by combining the reflected light and the reference light; an interference light detector that detects the interference light and generates interference signals by converting the interference light; and a processor. The processor may cause the OCT device to execute: acquiring tomographic images for a same cross section in the target region in time series from the interference signals; calculating an entropy of the generated interference signals based on the tomographic images; and specifying a dynamic part in the tomographic images based on the calculated entropy.

Abstract: A method for determining a retardance of a layer of a sample. The method includes: transmitting a first portion of a polarized light to a sample arm of an optical system and a second portion of the polarized light to a reference arm of the optical system; combining first return light returned from the sample arm and second return light from the reference arm; detecting, using a detector, the combined light along a first polarization state and a second polarization state to produce polarization data, the second polarization state being different from the first polarization state; determining, using a processor coupled to the detector, polarization states of light returning from upper and lower surfaces of a layer of the sample based on detecting the combined light; and determining, using the processor, a retardance of the layer of the sample based on the determined polarization states.

Abstract: An acousto-optic modulator (AOM) laser frequency shifter system includes a laser configured to generate an incident beam, a first optical splitter optically coupled to the laser and configured to split the incident beam into at least one portion of the incident beam, at least one phase-shift channel optically coupled to the first optical splitter and configured to generate at least one frequency-shifted beam with an acousto-optic modulator (AOM) from the at least one portion of the incident beam received from the first optical splitter, and a second optical splitter configured to receive the at least one frequency-shifted beam from the at least one phase-shift channel and configured to direct the at least one frequency-shifted beam to an interferometer configured to acquire an interferogram of a sample with the at least one frequency-shifted beam.

Abstract: A position encoder for monitoring relative movement between a first object and a second object includes a grating that is coupled to the first object, and an image sensor assembly that is coupled to the second object. The image sensor includes a first image sensor; a second image sensor that is spaced apart from the first image sensor; an optical element that includes a first optical surface and a second optical surface that is spaced apart from the first optical surface; and an illumination system.

Abstract: A system and method is provided for imaging and/or spectroscopy involving generation of a first signal field and a first idler field, illumination of the object with the first idler field, generation of second signal field and a second idler field, combination of the first and second idler fields, such that the two fields are indistinguishable, combination of the first and second signal fields, such that the two fields interfere, first measurement of the interfered signal field by a detection means, one or more additional measurements of the interfered signal field, wherein for each additional measurement a different phase shift is generated in the setup, and wherein all measurements are carried out within the stability time of the setup, and calculation of a phase function.

Abstract: Source light having a range of optical wavelengths is generated. The source light is split into sample light and reference light. The sample light is delivered into a sample, such that the sample light is scattered by the sample, resulting in signal light that exits the sample. The signal light and the reference light are combined into an interference light pattern having optical modes, each having a direct current (DC) component and at least one alternating current (AC) component. Different subsets of the optical modes of the interference light pattern are respectively detected, and analog signals representative of the optical modes of the interference light pattern are output. Pair of the analog signals are subtracted from each other, and differential analog signals are output. The sample is analyzed based on the differential analog signals.

Abstract: A method, apparatus, and system are provided to monitor and characterize the dynamics of a phase change region (PCR) created during laser welding, specifically keyhole welding, and other material modification processes, using low-coherence interferometry. By directing a measurement beam to multiple locations within and overlapping with the PCR, the system, apparatus, and method are used to determine, in real time, spatial and temporal characteristics of the weld such as keyhole depth, length, width, shape and whether the keyhole is unstable, closes or collapses. This information is important in determining the quality and material properties of a completed finished weld. It can also be used with feedback to modify the material modification process in real time.

Abstract: Disclosed herein are a method for diagnosing a disease of a body tissue by using LIBS (Laser-Induced Breakdown Spectroscopy) comprising: preparing a laser device including: a laser projection module, outputting the laser to a suspicious region of the body tissue, a light receiving module, receiving a plurality of light, a spectrum measurement module, and a guide unit; and projecting the laser to generate plasma by inducing tissue ablation in the suspicious region; wherein the laser projected to the suspicious region has a target area, and wherein the target area has smaller size than the suspicious region such that the target area is located inside the suspicious region.

Abstract: The invention relates to a method for creating a two-dimensional interferogram with a Michelson-type free-beam interferometer, comprising an extended, partially spatially coherent light source and a two-dimensional light detector, wherein light from the light source is split by a beam splitter with a semitransparent beam splitter mirror into a sample light beam and a reference light beam and taken to a sample arm and a reference arm, wherein the sample light beam returning from a sample is directed by the beam splitter mirror onto the light detector, wherein the reference light beam emerging from the reference arm makes a predetermined angle greater than zero with the sample light beam on the light detector, and wherein the length of the reference arm is variable, where the reference light beam is directed by means of an odd number of reflections in each reflection plane in at least one reference arm section so that it is displaced laterally to itself and travels antiparallel through a light-deflecting elemen

Abstract: The present invention relates to a method for the non-invasive optical characterization of a heterogeneous medium, comprising: a step of illuminating, by means of a series of incident light waves, a given field of view of the heterogeneous medium, positioned in a focal plane of a microscope objective (30); a step of determining a first distortion matrix (Dur, Drr) in an observation basis defined between a conjugate plane of the focal plane (FP) and an observation plane, said first distortion matrix corresponding, in a correction basis defined between a conjugate plane of the focal plane and an aberration correction plane, to the term-by-term matrix product of a first reflection matrix (Rur) of the field of view, determined in the correction basis, with the phase conjugate matrix of a reference reflection matrix, defined for a model medium, in said correction basis; and a step of determining, from the first distortion matrix, at least one mapping of a physical parameter of the heterogeneous medium.

Abstract: In an observation method, measurement values of an object of measurement at a plurality of different positions in a plane that intersects a depth direction are acquired from an optical coherence tomography instrument (S100). In the observation method, the measurement values at a same depth position at each of the plurality of positions are averaged (S104). In the observation method, the average values at each of the depth positions are integrated in the depth direction (S105). In the observation method, a shrinkage parameter of the object of measurement is calculated on the basis of the integrated value (S106).

Abstract: OCT measuring device in the present exemplary embodiment includes: wavelength sweep light source that emits light of which a wavelength is swept; optical interferometer that divides the light into measurement light and reference light, emits measurement light toward measurement surface of measuring target object, and generates an optical interference intensity signal indicating an intensity of interference between measurement light reflected from measurement surface and reference light; electro-optic element which is a phase modulator arranged in a light path of optical interferometer; measurement processor which is a signal generator that derives a position of measurement surface and generates a phase amount indicator signal that indicates a phase amount of phase modulator based on the optical interference intensity signal; and electro-optic element controller which is a phase amount controller that controls the phase amount given to the light that is transmitted through phase modulator.

Abstract: Proposed are a three-dimensional (3D) optical tomography method and apparatus using a partially coherent light and a multi-illumination pattern. The 3D optical diffraction tomography method based on low coherence light and a multi-illumination pattern using a 3D optical diffraction tomography apparatus may include making light incident on a sample using a plurality of patterns, measuring, by an image measurement unit, different locations at different depth locations of the sample and measuring two-dimensional (2D) images of the sample, and reconstructing 3D refractive index information of the sample based on the different patterns and the 2D images obtained at the different depth locations.

Abstract: In an observation method, measurement values of an object of measurement at a plurality of different positions in a plane that intersects a depth direction are acquired from an optical coherence tomography instrument (S100). In the observation method, measurement values are integrated in the depth direction at each of the plurality of positions (S104). In the observation method, a shrinkage parameter of the object of measurement is calculated on the basis of the integrated values at each of the plurality of positions (S105).

Abstract: Systems and methods for reducing fluorescence and systematic noise in time-gated spectroscopy are disclosed. Exemplary methods include: a method for reducing fluorescence and systematic noise in time-gated spectroscopy may comprise: providing first light using an excitation light source; receiving, by a detector, first scattered light from a material responsive to the first light during a first time window; detecting a peak intensity of the first scattered light; receiving, by the detector, second scattered light from the material responsive to the first light during a second time window; detecting a peak intensity of the second scattered light; recovering a spectrum of the material by taking a ratio of the peak intensity of the first scattered light and the peak intensity of the second scattered light; and identifying at least one molecule of the material using the recovered spectrum and a database of identified spectra.

Abstract: A digitizer and processor device for a swept-source optical coherence tomography (SS-OCT) imaging system, comprising: an input configured to receive an OCT signal; a control input configured to receive a k-clock signal; a combiner unit (130) receiving the OCT signal and the k-clock signal configured to output a composite signal; a digitizing unit (60) arranged to convert the composite signal into a digital composite signal (69); a data processing unit (70) arranged to determine a profile of optical density in a sample that generated the OCT signal based on the digital composite signal (69).

Abstract: An ultra-sensitive speckle-analyzing system is disclosed which includes an image capture device configured to receive a scattered field having a speckle configuration and thereby capture i) a reference speckle image, and ii) a subsequent speckle image, each of the reference and the subsequent speckle images having a plurality of speckles on a background; and a processor configured to generate a cross-correlation between the plurality of speckles of the reference and the subsequent speckle images, to thereby represent a change in the speckle configuration.

Abstract: The invention relates to an OCT system, comprising: an OCT light source for emitting OCT light into an object beam path and a reference beam path; and a detector for capturing an interference signal produced from the object beam path and the reference beam path. A wavelength-dependent beamsplitter is arranged in the OCT beam path such that a first spectral partial beam is guided along a longer path and a second spectral partial beam is guided along a shorter path. The invention further relates to a corresponding OCT method. Two measurement regions separated from each other can be sensed by means of the OCT system according to the invention.

Abstract: An exemplary aspect is a method of processing data acquired by applying an optical coherence tomography (OCT) scan to a sample. The method includes preparing a three dimensional data set acquired from a sample, creating a two dimensional map based on representative intensity values of a plurality of pieces of A-scan data included in the three dimensional data set, placing the three dimensional data set based on the two dimensional map, and executing a process based on at least a partial data set of the three dimensional data set on which placement based on the two dimensional map has been performed.

Abstract: An ophthalmic apparatus may include: a wavelength sweeping light source; a reference optical system; a calibration optical system; a light receiving element configured to receive calibration interference light which is a combination of calibration light and reference light; and a signal processor configured to sample a calibration interference signal outputted from the light receiving element when it receives the calibration interference light. The signal processor may sample the calibration interference light in at least first and second frequency bands, which are different and used for measuring a specific region of a subject eye. The ophthalmic apparatus calculates a difference between first and second waveforms, the first waveform being a waveform of the calibration interference signal that is sampled in the first frequency band and Fourier transformed, the second waveform being a waveform of the calibration interference signal that is sampled in the second frequency band and Fourier transformed.