An OCT imaging technique capable of suppressing image noise due to reflection on a wall surface of a carrier for carrying an imaging object by a simple configuration is provided. A light regulating member 28 having a transmission pattern where the high transmission parts P1 and the low transmission parts P2 are alternately arranged is placed on a side opposite to the spheroid Sp (imaging object) across the objective lens 27. The transmission pattern is rotationally symmetric with respect to an optical axis AX of the objective lens 27 and a point located at a position point-symmetric with an arbitrary point in the high transmission part with respect to a point where the optical axis of the objective lens intersects with the light regulating surface is included in the low transmission part.

Disclosed are apparatuses and methods for measuring a thickness. The apparatus for measuring a thickness including a light source that emits a femto-second laser, an optical coupler through which a portion of the femto-second laser is incident onto a target and other portion of the femto-second laser is incident onto a reference mirror, a detector configured to receive a reflection signal reflected on the reference mirror and a sample signal generated from the target and configured to measure a thickness of the target based on an interference signal between the reflection signal and the sample signal, and a plurality of optical fiber lines configured to connect the light source, the optical coupler, and the detector to each other may be provided.

An interferometric displacement measurement system and method based on phase modulation of polarized light of micro probe are provided. An electro-optic phase modulator is used to perform sinusoidal phase modulation on a light beam emitted by a semiconductor laser to obtain an adjusted light beam. The adjusted light beam is divided by a polarization beam splitter to generate a reference light beam and a measurement light beam. The two light beams are respectively reflected by a built-in reflection surface of a micro probe and a target mirror, and transmitted to a polarization-maintaining fiber circulator. The reference light beam interferes with the measurement light beam at a fiber optic polarization element to generate an interference light signal. A photodetector converts the interference light signal into an interference electrical signal, and the interference electrical signal is demodulated by a signal demodulator to obtain a displacement value of the target mirror.

An interferometric displacement measurement system and method based on phase modulation of polarized light of micro probe are provided. An electro-optic phase modulator is used to perform sinusoidal phase modulation on a light beam emitted by a semiconductor laser to obtain an adjusted light beam. The adjusted light beam is divided by a polarization beam splitter to generate a reference light beam and a measurement light beam. The two light beams are respectively reflected by a built-in reflection surface of a micro probe and a target mirror, and transmitted to a polarization-maintaining fiber circulator. The reference light beam interferes with the measurement light beam at a fiber optic polarization element to generate an interference light signal. A photodetector converts the interference light signal into an interference electrical signal, and the interference electrical signal is demodulated by a signal demodulator to obtain a displacement value of the target mirror.

An interferometer apparatus comprises an adjustable birefringent device configured to receive an input radiation and produce corresponding replicas having reciprocally orthogonal polarizations and delayed from each other by an adjustable time delay. The birefringent device also introduces an additional time delay between the replicas. The interferometer apparatus also comprises a compensation optical device optically coupled to the adjustable birefringent device and configured to have a respective structural thickness and respective ordinary and extraordinary refractive indexes to introduce a compensation time delay between the replicas having a sign opposite to a sign of the additional time delay.

A detector that detects relative positions of a first object and a second object in directions different from each other on a predetermined plane, includes an illumination optical system configured to illuminate a first mark provided on the first object and a second mark provided on the second object, and a detection optical system configured to detect interference light of diffracted lights from the first mark and the second mark illuminated by the illumination optical system. A light intensity distribution is formed, on a pupil plane of the illumination optical system, to illuminate the first mark and the second mark from a direction tilted with respect to a normal of the predetermined plane. A pupil plane of the detection optical system allows the interference light to pass through and block at least a part light other than the interference light.

An interferometric displacement measurement apparatus (100) includes at least one measurement interferometer (103) for measuring a change in optical path difference between a measurement beam (150) and a reference beam. A light source module (118) is arranged to generate a modulated light beam, having a particular optical spectrum, from which the measurement beam and reference beam are derived. A data acquisition and analysis module (105) can determine a measure representative of the displacement using interference intensity data received from a photodetector (111) which detects the interference of the measurement beam with the reference beam.

Methods and systems of eliminating corrupting influences caused by the propagation medium and the data capture devices themselves from useful image features or characteristics such as the degree of symmetry are disclosed. The method includes the steps of obtaining image-plane data using a plurality of data capture devices, wherein the image-plane data is a combined visibility from each of the data capture devices, measuring the closure phase geometrically in the image-plane directly from the image-plane, removing the corruptions from the image features based on the measured closure phase to remove the non-ideal nature of the measurement process, and outputting the uncorrupted morphological features of the target object in the image.

A method of providing optical coherence tomography (OCT) imaging may comprise using an on-chip frequency comb source interfaced with an OCT system by a circulator as an imaging source and reconstructing OCT images from resulting spectral data from target tissue illuminated by the imaging source.

An eye accommodation distance determining device is provided. The eye accommodation distance determining device includes an interferometer configured to generate a plurality of frequency modulated laser beams in different directions and to generate a plurality of interferometric signals using laser beams reflected from eye reflecting surfaces, a signal processer configured to generate a signal spectrum using each of said plurality of interferometric signals, a distance determiner configured to determine distances to the eye reflecting surfaces for each of said plurality of frequency modulated laser beams, a point coordinates determiner configured to determine coordinates of points on each of the eye reflecting surfaces for each of the laser beams, a reconstructor configured to generate an eye inner structure model based on the determined coordinates of points, and an eye accommodation distance determiner configured to determine, based on said eye inner structure model, an eye accommodation distance.