An interferometer system for measuring the displacement of a location of a test surface includes a reference arm comprising two reflective optical elements with optical power, a measurement arm comprising two reflective optical elements with optical power wherein one of the optical elements of the reference arm is one of the optical elements of the measurement arm. A housing can be provided in which the reflective optical elements are mounted, all such components made from a material having a low CTE. Further, spider support structures can be provided for positioning a reflective optical element within the housing, and/or for positioning a fiber optic device within the system. Light detecting elements can be installed on a side of a spider support structure facing the test surface and used to detect a tilt of the test surface which can be used to improve the accuracy of the displacement measurement.

Component errors prevent linear photonic circuits from being scaled to large sizes. These errors can be compensated by programming the components in an order corresponding to nulling operations on a target matrix X through Givens rotations X.fwdarw.T.sup.X, X.fwdarw.XT.sup.. Nulling is implemented on hardware through measurements with feedback, in a way that builds up the target matrix even in the presence of hardware errors. This programming works with unknown errors and without internal sources or detectors in the circuit. Modifying the photonic circuit architecture can reduce the effect of errors still further, in some cases even rendering the hardware asymptotically perfect in the large-size limit. These modifications include adding a third directional coupler or crossing after each Mach-Zehnder interferometer in the circuit and a photonic implementation of the generalized FFT fractal. The configured photonic circuit can be used for machine learning, quantum photonics, prototyping, optical switching/multicast networks, microwave photonics, or signal processing.

A composite measurement system for measuring nanometer displacement is provided. The system includes: a light source, a polarization beam splitting prism, a first phase change module, a second phase change module, a first right-angle prism, a second right-angle prism, a non-polarization beam splitting prism, a scalar interference light collection module, a vector interference light collection module and a displacement calculation module. In the present disclosure, a photodetector is configured to collect an intensity of scalar interference light of the object to be measured being moved, to obtain a periodic light intensity change curve; a CCD camera is configured to collect images of interference vortex light of the object being moved; and the displacement calculation unit is configured to calculate a displacement of the object according to integer periods of the light intensity change curve and angles of image changes of the interference vortex light.

A measuring arrangement for non-destructive measurement of an object surface by interferometric measuring methods, wherein light strikes the measuring arrangement as a light beam reflected from the surface, including a diaphragm with an aperture; mirror arrangement with two mirrors having mirror surfaces; a camera lens and camera; wherein the incoming light beam passes the diaphragm and diffracts before hitting the mirror arrangement and splits and deflects into two partial beams, which reach and interfere in the camera; wherein the light beam passes the camera lens in front of the camera in beam direction; and wherein one mirror of the mirror arrangement is rotatable relative to the other; and wherein the camera includes a camera chip with a local sampling frequency and the diaphragm diffracts the incoming light beam as it passes through such that its spatial frequency corresponds at most to the maximum camera chip local sampling frequency during detection.

In some embodiments, systems, methods, and media for multiple reference arm spectral domain optical coherence tomography are provided which, in some embodiments, includes: a sample arm coupled to a light source; a first reference arm having a first path length; a second reference arm having a longer second path length; a first optical coupler that combines light from the sample arm and the first reference arm; a second coupler that combines light from the sample arm and the second reference arm; and an optical switch comprising: a first input port coupled to the first optical coupler; a second input coupled to the second coupler via an optical waveguide that induces a delay at least equal to an acquisition time of an image sensor; and an output coupled to the image sensor.

An optical measurement system measuring optical parameters of an object is provided. The object includes at least two light-transmitting layers. The optical measurement system includes a light source module, an image capture module, and a controller. The light source module emits at least two measurement light beams toward the object. The measurement light beams are respectively incident on the object at different angles. The image capture module receives light spots formed on a sensing surface of the image capture module by at least two first light beams after the measurement light beams are reflected by the object and at least two second light beams after the measurement light beams are refracted and reflected between the object. The controller is electrically connected to the image capture module to obtain positions of the light spots. The controller calculates the optical parameters of the object according to the positions of the light spots.

A device and method for measuring a surface of an object, including at least one light source, at least one optical sensor, and an interferometry device having a measurement arm and a reference arm, the former directing light from each light source towards the surface of the object and directing light from the surface towards each optical sensor; the measurement device, in an interferometry configuration, illuminating the reference arm and the measurement arm with each light source and directing the light from the measurement arm and the reference arm towards each optical sensor to form an interference signal; the measurement device, in an imaging configuration illuminating at least the measurement arm and directing the light from the measurement arm towards the optical sensor to form an image of the surface; the measurement device including a digital processor producing, from the interference signal and the image, information on the surface.

A method for measuring bending of extended vertically directed channels. A fibre-optic sensor having a gravity pendulum fixed at the end of a flexible hollow carrier rod is placed inside the extended vertically directed channel. A light signal is supplied via fibre-optic lines connected to the sensor to record light signals. The flexible hollow carrier rod with the fibre-optic sensor is placed along the channel and detects interference in a gas gap with a photoreceiver, said gas gap varying during the passage of the fibre-optic sensor as a result of the angular motion of the gravity pendulum away from the axis of the bowed channel. Profilograms of the variations of the gas gap for each fibre-optic line are recorded; and the magnitude and direction of bending of the channel from the vertical axis are calculated to simplify measurements of bending of a vertically directed channel while maintaining measurement accuracy.

An adjustable beam directing optical system for a focused laser differential interferometer (FLDI) instrument according to various aspects of the present technology may include optical half waveplate to achieve an incident linear polarization orientation with equal components of laser intensity aligned to the vertical and horizontal axis of the optical system, and an optical prism for splitting these components of an incident laser beam into two orthogonally-polarized beams equally about an optical axis of the FLDI instrument. A series of beam realignment devices positioned downstream of the optical prism are configured to selectively direct each beam to a predetermined location.

An adjustable beam directing optical system for a focused laser differential interferometer (FLDI) instrument according to various aspects of the present technology may include optical half waveplate to achieve an incident linear polarization orientation with equal components of laser intensity aligned to the vertical and horizontal axis of the optical system, and an optical prism for splitting these components of an incident laser beam into two orthogonally-polarized beams equally about an optical axis of the FLDI instrument. A series of beam realignment devices positioned downstream of the optical prism are configured to selectively direct each beam to a predetermined location.