A shape measuring device includes a light source unit, a light splitting unit, a reference mirror, a light receiving unit and a processing unit. The light source unit generates light and can change the wavelength of the light. The light splitting unit splits the light generated from the light source unit into at least a reference light and a measurement light. The light receiving unit receives the reference light which is reflected by the reference mirror so as to form a reference light path, and the measurement light which is reflected by a light-transmitting target object formed on a substrate so as to form a measurement light path. The processing unit calculates the shape of the measurement argent object based on an interference change resulting from a wavelength change of the light between the reference light and the measurement light received by the light receiving unit.

A device for absolute distance measurement includes a first tunable light source for emitting a first wavelength light of a first tunable frequency modulated by a first modulating frequency and a second light source for emitting a second wavelength light of a second frequency modulated by a second modulating frequency. An optical coupler couples the first wavelength light and the second wavelength light into an interferometer cavity. An interferometer detector provides an interference measurement signal based on a detected interference pattern. A demodulator unit generates a first demodulation signal based on the interference measurement signal by demodulation with the first modulating frequency and a second demodulation signal based on the interference measurement signal by demodulation with the second modulating frequency. A computation unit computes an absolute distance by evaluating the first demodulation signal acquired during a sweep of the first tunable frequency and the second demodulation signal.

The present invention discloses a processing method for laser heterodyne interferometric signal based on locking edge with high frequency digital signal. A reference signal and a measurement signal of heterodyne interferometer, after being processed by photodetector, signal amplifier, filtering circuit, voltage comparator and high frequency digital edge locking module, are transferred to pulse counting synchronized latching processing module, to obtain entire cycle interference fringe numbers and filling pulse numbers in one interference fringe cycle, of the reference signal and the measurement signal; the numbers are transferred to a computer to obtain displacement and speed of a measured object; usage of a high frequency digital pulse signal to lock the rising edge of laser heterodyne interferometric signal can improve the gradient of the rising edge of interference signal and eliminate wrong pulse caused by noises, and improve the accuracy and stability of the processing for the following signals.

The invention relates to an optical coherence microscopy system for fast, phase resolved imaging by means of optical coherence microscopy with decoupled illumination and detection apertures, producing a dark-field effect with an enhanced optical contrast. The setup uses a light source with an appropriate temporal coherence, an interferometer and an array detector combined with a spectrometer. The dark-field effect is produced by optical filter means in the illumination and detection paths, positioned in conjugated planes of the sample microscope objective. These optical means comprise for example refractive or diffractive elements, amplitude or phase masks, or programmable spatial light modulators. The object is scanned via a scanning unit allowing a point scan of the object.

A system for providing optical actuation and optical sensing can include an optical coherence tomography (OCT) device that performs optical imaging of a sample based on optical interferometry from an optical sampling beam interacting with an optical sample and an optical reference beam; an OCT light source to provide an OCT imaging beam into the OCT device which splits the OCT imaging beam into the optical sampling beam and the optical reference beam; and a light source that produces an optical actuation beam comprising a plurality of wavelengths that is coupled along with the optical sampling beam to be directed to the sample to actuate particles or structures in the sample so that the optical imaging captures information of the sample under the optical actuation.

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.

An optical sensor includes an optical fiber inscribed with a repeated refraction pattern such that light scattered from a location on the optical fiber is scattered at multiple frequencies in a range of frequencies. The inscribed patterns overlap at every measurement point along at least a portion of the length of the sensor. An optical sensing system including control circuitry coupled to the optical fiber detects measurement scatter data from the optical fiber over the range of frequencies, determines a change in the detected measurement scatter data over the range of frequencies, and extracts a parameter describing a state of the optical fiber from the determined change in the detected measurement scatter data. The sensor may be made by inscribing a first light refracting pattern on the optical fiber at every measurement point along at least a portion of the length of the sensor and inscribing a second light refracting pattern on the optical fiber that overlaps the first inscribed light refracting pattern at every measurement point along at least that portion of the length of the sensor.

An optical distance measurement device includes: a photodetector including PDs for receiving interference light output from an optical interference unit and outputting detection signals of the interference light; and a switch for selecting one of the detection signals output from the PDs, in which a distance calculation unit calculates a distance to a measurement object on the basis of the detection signal selected by the switch.

An optical distance measurement device includes: a photodetector including PDs for receiving interference light output from an optical interference unit and outputting detection signals of the interference light; and a switch for selecting one of the detection signals output from the PDs, in which a distance calculation unit calculates a distance to a measurement object on the basis of the detection signal selected by the switch.

Exemplary apparatus and method are provided. In particular, an electromagnetic radiation can be emitted with, e.g. a light source arrangement. For example, the light source arrangement can include a cavity and a filter, and a spectrum of the electromagnetic radiation can be controlled, e.g., with such cavity and filter, to have a mean frequency that changes (i) at an absolute rate that is greater than about 100 terahertz per millisecond, and (ii) over a range that is greater than about 10 terahertz. Additionally or alternatively, the light source arrangement can include a frequency shifting device which can shift the mean frequency of the electromagnetic radiation.