The disclosure provides a microphone chip, a microphone, and a terminal device. The microphone chip includes a substrate and a diaphragm that are disposed oppositely, a reflector located on a side that is of the diaphragm and that is close to the substrate, a grating group located between the substrate and the diaphragm, and an optical emitter and an optical detector that are located between the substrate and the grating group. The grating group includes a plurality of gratings, and distances between at least two gratings in the plurality of gratings and the reflector are different.

A laser interference device includes a measurement laser that outputs a laser beam, a beam splitter that divides the laser beam into a measurement laser beam and a frequency monitor laser beam, a reference laser that outputs a reference laser beam, a frequency detector that detects a beat frequency resulting from interference between the reference laser beam and the frequency monitor laser beam, a wavelength calculator that calculates a wavelength of the frequency monitor laser beam (a wavelength measurement value) on the basis of the beat frequency, a light detector that detects an interference light of the measurement light and the reference light of the measurement laser beam and outputs a light detection signal, and a displacement calculator that calculates a displacement of the measurement mirror by performing an arithmetic process based on the wavelength measurement value and the light detection signal.

A single-beam three-degree-of-freedom homodyne laser interferometer based on an array detector. A single-frequency laser beam is input to a Michelson interference structure, the measurement beam and the reference beam perform non-coaxial interference and form a single-beam homodyne interference signal by setting the angle of a reference plane mirror, the array detector is selected to effectively receive the single-beam homodyne interference signal, and finally, three-degree-of-freedom signal linear decoupling on the single-beam homodyne interference signal is achieved through a three-degree-of-freedom decoupling method based on Lissajous ellipse fitting. The laser interferometer does is free of angle decoupling nonlinearity, the period nonlinear error is remarkably reduced, compared with other existing three-degree-of-freedom laser interferometers, the laser interferometer has the advantages of being simple in structure, large in angle measurement range and easy to integrate, and the high-precision requirement of the three-degree-of-freedom laser interferometer for displacement and angle measurement is met.

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 digital measuring device implemented on a photonic integrated circuit, the digital measuring device including a tunable laser source implemented on the photonic integrated circuit configured to sweep over a frequency range to provide multi-wavelength light, a first waveguide structure implemented on the photonic integrated circuit configured to direct a first portion of light from the laser source at a moving object and receive light reflected from the moving object, a second waveguide structure implemented on the photonic integrated circuit configured to combine a second portion of light from the laser source with the light reflected from the moving object to produce a measurement beam, and a first detector implemented on the photonic integrated circuit configured to detect intensity values of the measurement beam to measure a distance between the digital measuring device and the moving object.

A three-dimensional measurement device includes: a light emitter; an optical system that splits an incident light, irradiates a measurement object with an object light and irradiates a reference plane with a reference light, and recombines the object and reference lights and emits a combined light; an imaging device that takes an image of a light emitted from the optical system; a storage device that stores transmission axis absolute angle data each obtained by a previous actual measurement of an absolute angle of a transmission axis of each polarizer; and a control device that calculates a phase difference between the reference and object lights based on luminance data of each pixel in luminance image data and the transmission axis absolute angle data of each polarizer corresponding to the pixel, and measures a height of the measurement object at the measurement position.

A two-degree-of-freedom heterodyne grating interferometry measurement system, comprising: a single-frequency laser device for emitting a single-frequency laser, and the single-frequency laser can be split into a beam of reference light and a beam of measurement light; an interferometer mirror group and a measurement grating for forming a reference interference signal and a measurement interference signal from the reference light and the measurement light; and a receiving optical fiber for receiving the reference interference signal and the measurement interference signal, wherein a core diameter of the receiving optical fiber is smaller than a width of an interference fringe of the reference interference signal and the measurement interference signal, so that the receiving optical fiber receives a part of the reference interference signal and the measurement interference signal. The measurement system has advantages of insensitivity to grating rotation angle error, small volume, light weight, and a facilitating arrangement.

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.

Optical coherent receiver arrays are described. The optical coherent receiver arrays include an integrated array of photodetectors separated by integrated mirrors which may cause interference of received free space optical and local oscillator signals. The mirrors may serve as splitters, helping to align the received signal and local oscillator to cause interference. The photodetectors of the optical coherent receiver array may be electrically coupled in various manners to read out the signals. The optical coherent receiver array may be implemented in an optical coherence tomography (OCT) imaging system in some embodiments.

A digital measuring device implemented on a photonic integrated circuit, the digital measuring device including a laser source configured to provide light, a first ring resonator configured to produce a first frequency comb of light from the laser source, wherein at least a portion of the first frequency comb of light is directed at a moving object, a local oscillator configured to provide a reference beam, at least one waveguide structure configured to combine the reference beam with light reflected from the moving object to produce a measurement beam, a first multiplexer configured to split the measurement beam into a plurality of channels spaced in frequency, and a plurality of detectors configured to detect an intensity value of each channel of the plurality of channels to measure a distance between the digital measuring device and the moving object.