Disclosed are methods and an assembly for robust one-shot interferometry, in particular for optical coherence tomography according to the spatial domain approach (SD-OCT) and/or according to the light-field approach. In one embodiment, the method and the assembly may be used for measurements on material and living tissue, for distance measurement, for 2D or 3D measurement with a finely structured light source imaged onto the object in a diffraction-limited way, or with spots thereof. The assembly may comprise an interferometer having object and reference arms and a detector for electromagnetic radiation. In other embodiments, during a detection process, a plurality of spatial interferograms may be formed by making an inclined and/or curved reference wavefront interfere with an object wavefront for each measurement point. The resulting spatial interferograms may be detected in a single detector frame and may be further evaluated via a computer program.

A multiple beam path laser optical system using a multiple beam reflector. The multiple beam path laser optical system includes a light source part to generate a laser beam to be irradiated to a specimen, the multiple beam reflector to split a laser beam incident thereto from the light source part and to provide a plurality of optical paths, a main beam splitter to irradiate the laser beam split by the multiple beam reflector to the specimen, a transducer to excite the specimen for signal detection of the laser beam irradiated to the specimen, and a control part to analyze an interference pattern of a laser beam reflected from the specimen and recombined in the main beam splitter.

The present application in some embodiments relates to methods for reducing noise and/or clutter when measuring a spectrum, particularly but not only for OCT imaging. In some embodiments a light source is synchronized with a detector. For example a narrow band light source is synchronized with a narrow band detector. For example, the light source may scan over multiple frequency bands and/or the detector may be tuned to a frequency band synergetic to the band of the light source. For example the light source and detector may be tuned to overlapping narrow bands. Optionally the detector has a sensor set for each frequency band. Optionally some sensor sets are individually resettable. For example each set may have a reset circuit. For example, a sensor set for a band not currently being measured is deactivated.

Some embodiments are directed to a technique having an off-axis interferometric geometry that is capable of spatially multiplexing at least six complex wavefronts, while using the same number of camera pixels typically needed for a single off-axis hologram encoding a single complex wavefront. Each of the at least six parallel complex wavefronts is encoded into an off-axis hologram with a different fringe orientation, and all complex wavefronts can be fully reconstructed. This technique is especially useful for highly dynamic samples, as it allows the acquisition of at least six complex wavefronts simultaneously, optimizing the amount of information that can be acquired in a single camera exposure. The off-axis multiplexing holographic system of some embodiments provide an off-axis holography modality that is more camera spatial bandwidth efficient than on-axis holography. Moreover, the off-axis interferometric system allows simple simultaneous acquisition of at least six holographic channels, making it attractive for imaging dynamics.

An overlay metrology system may include, an illumination sub-system, a collection sub-system and a controller. The illumination sub-system may include one or more illumination optics configured to direct an illumination beam to an overlay target on a sample as the sample is scanned along a stage-scan direction by a translation stage, where the overlay target includes one or more cells having a grating-over-grating structure with periodicity along the stage-scan direction. The collection sub-system may include an objective lens, a first photodetector located in a pupil plane at a location of overlap between 0-order diffraction and +1-order diffraction, and a second photodetector located in a pupil plane at a location of overlap between 0-order diffraction and −1-order diffraction. The controller may receive time-varying interference signals from the first and second photodetectors and determine an overlay error between the first and second layers of the sample along the stage-scan direction.

A sensor device is coupled to a mechanical machine. The sensor device detects vibrations of the mechanical machine and transmits the vibration data to a remote processing device. The vibration data may be compressed prior to transmission. The remote processing device receives the data and generates a reconstructed version of the vibration data. The remote processing device includes a machine learning model trained to examine vibration data and to identify a motion pattern associated with an error condition. The machine learning model is applied to the reconstructed vibration data and detects an occurrence of an error condition in the mechanical machine. An alert indicating that an error condition has been detected is transmitted to a human operator. The human operator verifies the status of the mechanical machine and confirms that an error condition has occurred. In response to receipt of the confirmation, the machine learning model is further trained on training data updated to include the vibration data generated by the mechanical machine.

An optical device for sensing a surface profile of an object surface of an object by means of interferometric distance measurement, including a beam splitter for splitting a light beam of a light source into first and second sub-beams, a beam divider for dividing each sub-beam into a reference and a measuring beam, a mirror for reflecting the two reference beams, wherein each measuring beam is directed onto a measuring area on the object surface for reflection and after reflection is directed as object beam to the beam divider, each reference beam reflected by the mirror and directed as mirror beam to the beam divider, the object and mirror beams each interfere and are each fed as an evaluation beam to a detector unit for evaluation. Further include a light source for generating a monochromatic light beam, a detector unit, a signal evaluation unit and for determining the surface profile.

An optical frequency domain reflectometer according to the invention includes: a swept light source that outputs wavelength-swept light; an auxiliary interferometer that has a the auxiliary interference signal generating delay fiber and outputs an auxiliary interference signal from the wavelength-swept light; a measurement interferometer that has a measurement target optical fiber and outputs a measurement interference signal from the wavelength-swept light; a plurality of linearization units that have different delay times, compensate non-linearity in a wavelength sweep of the swept light source for the measurement interference signal, using the auxiliary interference signal, and output compensated signals as output signals; and a weighted addition and Fourier transform unit that outputs a frequency domain signal as a result of addition and Fourier transformation of weighted signals which are multiplying the output signals from the plurality of linearization units by different weights.

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.

Optical Coherence Tomography (OCT) system and apparatus of this instant application is very useful for diagnosis and management of ophthalmic diseases such as retinal diseases and glaucoma etc. Instant innovative OCT diagnostic system leverages advancements in cross technological platforms. The Michelson interferometric system presented in this application could be used for the OCT imaging, which includes biological OCT imaging, medical OCT imaging, ophthalmic OCT imaging, corneal OCT imaging, retinal OCT imaging, and the like. A tunable filter is placed in front of the detector to make the interferometer more sensitive and accurate for examining various samples for diagnosis.