Systems and methods are provided for vibrations detection in a scene. Systems comprise at least one coherent light source configured to illuminate the scene, an optical unit configured to focus scattered light from the scene onto a pixelated detector, the detector configured to provide pixel intensity signals, and a processing unit configured to analyze the pixel intensity signals over the pixels of the detector to derive a vibration spectrum of elements in the scene that correspond to the pixels. The signal modulation at each pixel may be used to indicate the vibrations of the scene element(s) that corresponds to the pixel(s). Vibration information concerning the scene may be used to direct other methods of vibration measurements, such as speckle interferometry, according to derived vibration images of the scene.

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 swept-source OCT imaging system for imaging a region of an object, comprising: a swept light source which generates a beam of varying wavelength; a scanning element which scans the beam across the object; an interferometer which generates interference light by combining light scattered by the object (owing to the scan) with reference light; a photodetector which generates an electrical signal (S) having frequency components spanning a frequency band and caused by interference of the scattered light with the reference light; a band-pass filter module which band-pass filters the electrical signal; and a sample acquisition module which samples the filtered electrical signal. The band-pass filter module extracts at least some of the frequency components spanning the frequency band from the electrical signal. The sample acquisition module band-pass samples the filtered electrical signal.

The present invention relates to an apparatus and a method for measuring a thickness and a refractive index of a multilayer thin film using an angle-resolved spectral interference image according to polarization. More specifically, the present invention relates to an apparatus for measuring a thickness and a refractive index of a multilayer thin film using an angle-resolved spectral interference image according to polarization in an apparatus for measuring a thickness and a refractive index of a measurement object coated with the multilayer thin film, the apparatus including: an illumination optical module having a light source emitting light; a first beam splitter configured to reflect some of the light emitted from the illumination optical module; an objective lens configured to input some of the light reflected from the first beam splitter to the measurement object constituted by the multilayer thin film and reflect the remaining light to a reference plane to form interference light on a back focal plane; a second beam splitter in which interference light where the reflected light incident and reflected to the measurement object interferes with the reflected light reflected from the reference plane is incident, wherein some of the interference light is reflected and the remaining interference light is transmitted; a first angle-resolved spectral image acquiring unit configured to receive interference light reflected from the second beam splitter and first-polarize the interference light located in the back focal plane of the objective lens to acquire a first polarized interference image; and a second angle-resolved spectral image acquiring unit configured to receive interference light transmitted from the second beam splitter and second-polarize the interference light located in the back focal plane of the objective lens to acquire a second polarized interference image.

An ellipsometer includes a first separation unit configured to separate a first reflected light into two reflected lights, a first polarizing optical element configured to separate each of the two reflected lights into two linearly polarized lights, a first interference device configured to form an interference fringe by allowing components of the two linearly polarized lights to interfere with each other, a second separation unit configured to separate a second reflected light into two reflected lights, a second polarizing optical element configured to separate each of the two reflected lights into two linearly polarized lights, and a second interference device configured to form an interference fringe by allowing components of the two linearly polarized lights to interfere with each other.

An optical interferometric range sensor includes a light source that emits light with a changing wavelength, a light splitter that splits the light emitted from the light source into a plurality of beams to be incident on a plurality of spots, an interferometer that generates, for each of the plurality of beams of the split light incident on a corresponding spot of the plurality of spots, interference light based on measurement light and reference light, a light receiver that receives the interference light to convert the interference light to an electric signal, a processor that calculates a distance from a sensor head to a measurement target based on the electric signal, an identifier that identifies the sensor head based on a beat signal generated by the interferometer, and a light adjuster that adjusts an amount of light to be incident on the measurement target based on the sensor head.

An optical interferometric range sensor includes a light source that emits light with a changing wavelength, an interferometer that receives the light emitted from the light source and generates interference light based on measurement light emitted from a sensor head to a measurement target and reflected from the measurement target and reference light traveling on an optical path at least partially different from an optical path of the measurement light, a light receiver that receives the interference light from the interferometer to convert the interference light to an electric signal, a processor that calculates a distance from the sensor head to the measurement target based on the electric signal resulting from conversion performed by the light receiver, an identifier that identifies the sensor head based on a beat signal generated by the interferometer, and a setter that sets a measurement condition corresponding to the sensor head identified by the identifier.

An optical interference range sensor includes: a light source configured to project a light beam while continuously varying a wavelength thereof using a predetermined sweep frequency pattern; a processing unit configured to measure the distance to a measurement target based on an electrical signal converted by a light-receiving unit; and a storage unit configured to store distance information indicating the measured distance. The predetermined sweep frequency pattern includes a first sweep frequency pattern and a second sweep frequency pattern. The processing unit includes an average distance value calculation unit configured to calculate an average distance value based on the measured distance, first distance information indicating a distance based on a light beam projected using the first sweep frequency pattern, and second distance information indicating a distance based on a light beam projected using the second sweep frequency pattern, of past distance information regarding multiple measurements stored in the storage unit.

A measurement apparatus for measuring a thickness of a semiconductor wafer includes: an optical system configured to perpendicularly irradiate a sample wafer and a reference wafer with light, and receive interference signals of the light reflected on front and back surfaces of the respective wafers; a signal processor configured to perform frequency analysis of the interference signals received by the optical system to obtain peak positions of a point spread function of the respective wafers; and a calculator configured to calculate a thickness “tsample” of the sample wafer based on the peak position “x” of the sample wafer and the peak position “y” of the reference wafer obtained by the signal processor, and a thickness “treference” of the reference wafer.

A measurement device, for measuring the shape of an interface to be measured of an optical element having a plurality of interfaces, the device including a measurement apparatus with at least one interferometric sensor illuminated by a low-coherence source, for directing a measurement beam towards the optical element to pass through the plurality of interfaces, and to detect an interference signal resulting from interferences between the measured measurement beam reflected by the interface and a reference beam, a positioning apparatus configured for relative positioning of a coherence area of the interferometric sensor at the level of the interface to be measured, and a digital processor for producing, based on the interference signal, an item of shape information of the interface to be measured according to a field of view.