An optical speckle receiver for receiving a speckle signal from a sample, the optical speckle receiver comprising an optical detector and an aperture and/or lens array. The aperture and array respectively comprise a plurality of apertures or lenses and is located between the sample and the optical detector such that the received speckle pattern is obtained from multiple discrete sample locations.

This application discloses a measurement apparatus that does not use a femtosecond laser light source and a delay stage. The measurement apparatus mixes a first laser light from a first CW laser light source and a second laser light from a second CW laser light source to generate an interference light having a beat in a range from GHz to THz and demultiplexes the interference light into a pump light and a probe light. A generating photoconductive antenna is irradiated with the pump light, and a detecting photoconductive antenna is irradiated with the probe light. A current value of an electromagnetic wave propagating through a waveguide connecting the generating photoconductive antenna and the detecting photoconductive antenna is measured using a current system connected to the detecting photoconductive antenna.

The invention discloses a four-quadrant interferometry system based on an integrated array wave plate. PBS splits an output laser light into two paths, the reflected light and the transmitted light are respectively transformed into reference light and measuring light, the reference light and the measuring light are converged in PBS, the converging light enters a signal receiving unit and is split into four beams, and the four beams irradiate on a four-quadrant interference signal detector with an integrated array wave plate. The invention solves the problems that the existing signal detection system occupies a large space, is not conducive to array integration, and cannot be used in scenes with high space and size requirements.

A system for compensating for phase noise, with particular application in lidar, includes a compensation interferometer that receives a signal from a source, and splits it into a first and second path, with a path length difference Δτ between them. Typically the path length is significantly less than that of the return distance to a target. The output of the compensation interferometer, which consists of phase noise generated in time Δτ is vectorially summed during a time similar to a signal flight time to a target, and the result used to reduce phase noise present on measurements of a target. It further includes means for selecting Δτ such that competing noise elements are reduced or optimised.

A truncated non-linear interferometer-based sensor system includes an input port that receives an optical beam and a non-linear amplifier that amplifies the optical beam with a pump beam and renders a probe beam and a conjugate beam. The system’s local oscillators have a relationship with the respective beams. The system includes a sensor that transduces an input with the probe beam and the conjugate beam or their respective local oscillators. It includes one or more phase-sensitive detectors that detect a phase modulation between the respective local oscillators and the probe beam and the conjugate beam. Output from the phase-sensitive-detectors is based on the detected phase modulation. The phase-sensor-detectors include measurement circuitry that measure the phase signals. The measurement is the sum or difference of the phase signals in which the measured combination exhibit a quantum noise reduction in an intensity difference or a phase sum or an amplitude difference quadrature.

A simultaneous phase-shift point diffraction interferometer and method for detecting wave aberration. The interferometer comprises an ideal spherical wave generation module, an optical system to be measured, an image plane mask, a polarization phase shift module, a two-dimensional polarization imaging photodetector and a data processing unit. Single photodetector is adopted to realize simultaneous detection of more than three phase shift interference patterns, and has the advantages that environmental interference suppression, a flexible optical path, high measurement accuracy, and calibration of system errors of the interferometer may be realized.

A polarization-separated, phase-shifted interferometer can generate interferograms without moving parts. It uses a phase shifter, such as an electro-optic phase modulator, to modulate the relative phase between sample and reference beams. These beams are transformed into orthogonal polarization states (e.g., horizontally and vertically polarized states) and coupled via a common path (e.g., polarization-maintaining fiber) to a polarizing beam splitter (PBS), which sends them into separate sample and reference arms. Quarter-wave plates in the sample and reference arms rotate the polarization states of the sample and reference beams so they are coupled out of the PBS to a detector via a 45° linear polarizer. The polarizer projects the aligned polarization components of the sample and reference beams onto the detector, where they interfere with known relative phase to produce an output that can be used to map surface topography of the test object.

A device is provided for determining an orientation of an optical device of a coherence tomograph. The device has an optical reference geometry, a deflection optics configured to direct an optical measuring beam reflected by the optical device onto the optical reference geometry, and an evaluation unit configured to determine a distance between a first reference plane and at least one second reference plane of the optical reference geometry in order to determine the orientation of the optical device.

A system for optimizing optics is provided. The system is configured to calibrate a position of a reference arm of an interferometric imaging system such that an image of a sample is visible when the sample is positioned at a working distance of an objective lens to provide an initial calibrated position. An image is obtained using the initial calibrated position. Image quality of the obtained image is assessed to determine if the obtained image is a valid image. A path length of the reference arm is adjusted if it is determined that the obtained image is not a valid image. A difference between the calibrated position of the reference arm and the adjusted position of the reference arm is calculated. System elements are adjusted based on the calculated difference such that the ample is visible when the sample is positioned at the working distance at the adjusted position.

A system and method are provided for optical homodyne detection in an optical fiber interferometer. A detection signal is obtained by interfering an optical data signal with a phase-modulated optical reference signal. The modulator for the optical reference signal is phase-locked to an oscillatory modulation waveform. In embodiments, the modulator includes a piezoelectric element. In more specific embodiments, the modulator is a piezoelectric optical fiber-stretcher.