A metrology system including a heterodyne light source is provided. The heterodyne light source includes a first light source, an acousto-optic modulator and a source optical arrangement. The acousto-optic modulator receives at least one wavelength laser beam from the first light source and generates at least one corresponding frequency shifted laser beam (e.g., with orthogonal polarization). The source optical arrangement includes a receiving optical element portion and a birefringent optical element portion. The receiving optical element portion receives the wavelength laser beam(s) and the corresponding frequency shifted laser beam(s) and directs the beams along an optical path toward the birefringent optical element portion. The birefringent optical element portion combines the beams to output a combined beam (e.g., which may be utilized as part of a measurement process to determine at least one measurement distance to at least one surface point on a workpiece, etc.).

An optical interrogation system, e.g., an OFDR-based system, measures local changes, of index of refraction of a sensing light guide subjected to a time-varying disturbance. Interferometric measurement signals detected for a length of the sensing light guide are transformed into the spectral domain. A time varying signal is determined from the transformed interferometric measurement data set. A compensating signal is determined from the time varying signal which is used to compensate the interferometric measurement data set for the time-varying disturbance. Further robustness is achieved using averaging and strain compensation. The compensation technique may be applied along the length of the light guide.

A method for capturing a tomographic image of an eye includes: obtaining a plurality of tomographic images of an examinee's eye by an optical scanning; obtaining a displacement distribution that is a distribution of a displacement for each A-scan among the plurality of tomographic images; and correcting a displacement among the tomographic images based on the displacement distribution.

Interferometric measurement signals are detected by a single optical interferometric interrogator for a length of a sensing light guide and an interferometric measurement data set corresponding to the interferometric measurement signals is generated. The interferometric measurement data set is transformed into a spectral domain to produce a transformed interferometric measurement data set. The transformed interferometric measurement data set is compared to a baseline interferometric data set to identify a time-varying signal corresponding to a time-varying disturbance. The baseline interferometric data set is representative of the sensing light guide not being subjected to the time-varying disturbance. A compensating signal is determined from the time-varying signal and used to compensate at least a portion of the interferometric measurement data set for the time-varying disturbance as part of producing a measurement of the parameter.

A dental optical coherence tomography system for scanning a sample has a swept source laser configured to generate output light having a range of wavelengths. Two or more optical channels each provide a reference and sample path for the output light, wherein each optical channel has a corresponding detector to provide an output signal according to combined light from the sample and reference, wherein the detector output signal characterizes back-reflected or back-scattered light from the sample path over a range of depths below a surface. A scanning reflector simultaneously directs sample path output light from each of the two or more channels toward the sample surface and directs returned light from the sample to the corresponding sample path and detector. A processor is in signal communication with the detector for each optical channel and that is configured to record and store results from the output signals received from each detector.

A method for measuring a surface shape of an optical element, wherein the optical element has a main body with a substrate and a reflective surface, and wherein at least one cooling channel for receiving a coolant is formed in the substrate, comprising: a) recording a cooling channel pressure, b) recording a measurement environment pressure, c) determining a pressure difference based on the cooling channel pressure and the measurement environment pressure, d) comparing the pressure difference with a predetermined target pressure difference, e) monitoring for a deviation between the pressure difference and the target pressure difference, wherein, if a deviation greater than a predetermined limit value is detected, the cooling channel pressure is adapted in such a way that the deviation becomes less than or equal to the predetermined limit value, and f) measuring the surface shape if the deviation is less than or equal to the predetermined limit value.

The invention relates to an interferometric measurement device and to an interferometric method for determining the surface topography of a measurement object (1). The essence of the invention is that the light intensities I.sup.q(z.sub.i) of at least one other detector element q of the multi-element detector (6) are also used besides the light intensities I.sup.p(z.sub.i) of this detector element to determine the value z.sup.p associated with a detector element p (6b) of the measurement device.

Disclosed is a technology for stabilizing a phase using a modulator bias controller and a laser that emits a beam with a frequency fixed.

A system and method for metrology and profilometry using a light field generator are disclosed. For this purpose, a system such as an optical analysis system scans a sample using light, and detects light reflected off a sample in various ways. The system operates different operational modes including a backscatter intensity, a triangulation, and an interferometric mode. For this purpose, the optical analysis system includes one or more optical angle modulation systems, such as surface acoustic wave (SAW) modulators, that emit light, a sample holder, and a scanning system that scans the one or more SAW modulators relative to the sample holder. The system performs tomographic reconstructions of information generated by the scans to create 3D maps/volume datasets of the sample.

A fiber-coupled phased-array includes a first photonic integrated circuit (PIC) and a second PIC. The first PIC includes a first set of lenslets and waveguides. The second PIC includes a second set of lenslets and waveguides and is placed at a distance from the first PIC. The optical fibers couple the first PIC to the second PIC and form an interferometric imager that can sample spatial frequencies of a target. Optical delay errors induced by a relative placement of the first PIC and the second PIC are compensated for.