Using an optical tomography method of splitting low coherent light into sample light and reference-light, emitting the sample light to a measurement-target in a line shape, generating interference light by superimposing reflected light from the measurement-target due to emission of the sample light and the reference-light on each other, and acquiring a two-dimensional spectroscopic tomographic-image of the measurement-target by spectroscopically detecting the interference light and performing frequency analysis, an arbitrary wavelength region in an ultraviolet region is cut out from low coherent light including a wavelength region from an ultraviolet region to a visible region and the arbitrary wavelength region is shaped into a spectrum having an arbitrary wavelength width, the two-dimensional spectroscopic tomographic-image is acquired as using the low coherent light, and the penetration depth of the sample light for the measurement-target is evaluated based on the two-dimensional spectroscopic tomographic-image.

An interferometer has a first input configured to provide a first measurement beam at a first frequency, and a second measurement signal at the first frequency. The interferometer has a second input configured to provide a reference beam at a second frequency that is different than the first frequency; an optical element comprising a first portion comprising a polarization beam splitter; and a diffraction grating disposed over the optical element configured to diffract the first measurement beam and the second measurement beam

A fiber optic sensing system for determining the position of an object requires a light source, an optical fiber, a fiber optic splitter, a fiber tip lens, an optical detector and signal processing circuitry. Light emitted by the light source is conveyed via optical fiber and the splitter to the lens and onto an object, such that at least a portion of the light is reflected by the object and conveyed via fiber and the splitter to the detector. Signal processing circuitry coupled to the detector determines the position of the object with respect to the lens based on a characteristic of the reflected light. The system is suitably employed with a hydraulic accumulator having a piston, the position of which varies with the volume of fluid in the accumulator, with the system arranged to determine the position of the piston, from which the volume can be calculated.

Disclosed is an optical probe system that is capable of high speed, high precision, and high resolution 3D digitalization of engineered objects. The 3D dimensional data of the engineered object is measured using a swept source optical coherence tomography system with improved speed, spatial resolutions, and depth range. Also disclosed is a type of coordinate measurement machine (CMM) that is capable of performing high speed, high resolution, and non-contact measurement of engineered objects. The mechanic stylus in the touch-trigger probe of a conventional CMM is replaced with an optical stylus with reconfigurable diameter and length. The distance from the center of the optical stylus to the measurement probe is optically adjusted to match the height of the object to be measured quickly, which eliminates one dimensional movement of the probe and greatly improves the productivity.

The present invention provides a sample inspection and quantitative imaging system and method for performing off-axis interferometric imaging while enabling to record off-axis holograms in an extended field of view (FOV) than possible using a given camera and imaging setup, and thus to enlarge (e.g. double, triple, or even more than this) the interferometric FOV, without changing the imaging parameters, such as the magnification and the resolution.

Multichannel optical coherence systems are disclosed in which optical coherence tomography (OCT) subsystems are operably and respectively connected to optical fibers of a multichannel optical probe, such that each optical fiber forms at least a distal portion of a sample beam path of a respective OCT subsystem. The optical fibers are in optical communication with distal optical elements such that external beam paths associated therewith are directed towards a common spatial region external to the housing. Image processing computer hardware is employed to process OCT signals obtained from the plurality of OCT subsystems to generate an OCT image dataset comprising a plurality of OCT A-scans and process the OCT image dataset to generate volumetric image data based on known positions and orientations of the external beam paths associated with the OCT subsystems.

Translations of an object in a plurality of different spatial directions are measured using a plurality of interferometers to detect interference with light that has been reflected from a diffusively reflective surface, preferably using diffuse reflection from the same planar surface to measure in each of the different spatial directions. At least the interferometers that measure translation in directions that are not perpendicular to the surface each comprises a single mode fiber and a collimator configured to transmit the outgoing light to the object successively through the single mode fiber and the collimator, and to collect reflection into the single mode fiber with the collimator both along a same beam direction. It has been found that, when reflection of a beam with a beam direction at an oblique angle to a diffusively reflective surface is used, the interference resulting from translation of the object is due substantially only to translation in the beam direction.

Apparatus and methods are presented for enhancing the acquisition speed or performance of Fourier domain optical coherence tomography. In preferred embodiments a plurality of wavelength combs containing interleaved selections of wavelengths from a multi-wavelength optical source are generated and projected onto a sample. In certain embodiments the wavelength combs are projected simultaneously onto a plurality of regions of the sample, while in other embodiments the wavelength combs are projected sequentially onto the sample. Light in the wavelength combs reflected or scattered from the sample is detected in a single frame of a sensor array, and the detected light processed to obtain a tomographic profile of the sample. In preferred embodiments the wavelength comb generator comprises a wavelength interleaver in the form of a retro-reflective prism array for imparting different displacements to different selections of wavelengths from the optical source.

A digital speckle pattern interferometer (DSPI) is provided for long-range measurement of displacement of materials within a hazardous environments. A test arm of a portion of coherent beam from a laser is aimed at a selected angle to traverse a distance to a test surface. An input collimator has a lens wide enough to receive a reflected beam from the test surface and is focused at a corresponding distance. The reflected beam is combined with a reference beam split from the coherent radiation onto a camera for measuring displacement of the test surface based on an electronic speckle pattern interferometer (ESPI).

A high-resolution phase detection method and system based on a plane grating laser interferometer. The method uses a dual-frequency interferometer to measure the displacement, and the measurement signal processing comprises an integral part and a decimal portion, a phase equation set of a displacement measurement signal is constructed according to a measurement optical path principle of a heterodyne plane grating laser interferometer; a non-linear equation set for which the unknowns are instantaneous phase, interval phase and signal amplitude is established; and the equation sets above are solved by using the least squares method, so as to realize phase discrimination, thereby realizing precise displacement measurement. The method can solve the problems in the traditional time measurement-based phase detection technology, such as low measurement accuracy, and failing to satisfy small measuring range measurement. The measurement method can be applied to systems such as precision manufacturing equipment and lithography machine.