An eye-tracking device includes an optical device that includes a light source with an optical cavity and a light sensor. The light source is positioned to output coherent light toward an eye of a user and receive at least a portion of the coherent light back from the eye of the user as feedback light. The feedback light enters the optical cavity and causes modulation of an intensity of the coherent light. The light sensor is optically coupled with the light source for detecting the modulated intensity of the coherent light and generating one or more signals based on the detected intensity of the coherent light. The eye-tracking device also includes one or more processors that are coupled to the optical device for determining, from the one or more signals, movement information of the eye. A method of detecting movement of an eye using the eye-tracking device is also disclosed.

A method for full-field measurement using Doppler imaging, comprising the following steps: turning on a laser and adjusting the laser; adjusting a spatial filter to obtain circular laser spots having uniform intensity distribution; adjusting a quarter-wave plate and a whole polarizer in a system, and requiring two beams in a reference object and a measured object having different frequencies and perpendicular polarization directions; applying slight pressure to the measured object, setting a charge coupled device (CCD) camera into a continuous acquisition mode, observing interference fringes, and adjusting a light path so that the fringes are clear and visible; setting the sampling frequency, sampling time, captured image format and resolution size of the CCD camera; turning on a lithium niobate crystal drive power switch to produce a heterodyne carrier frequency; applying continuous equal pushing force to the measured object by means of piezoelectric ceramics (PZT) so as to make the measured object produce continuous bending deformation; controlling the CCD camera to sample using a computer, and collecting a set of time series light interference images along with the continuous deformation of the measured object; and processing the time series light intensity interference image to obtain a three-dimensional data module comprising continuous deformation of the measured objects distributed in time and space.

Provided are systems and methods for using laser interferometry to measure moving objects. Systems provided include laser interferometry systems comprising: a laser emitter configured to emit a laser beam; a beam splitter configured to split the emitted laser beam into a first split beam directed towards a deflector and a second split beam, wherein the first split beam comprises a first beam diameter and a second beam diameter, the first beam diameter being greater than the second beam diameter, and the second split beam comprises a third beam diameter and a fourth beam diameter, the third split beam diameter being greater than the fourth beam diameter; and a deflector configured to deflect the first split beam to intersect with the first split beam, wherein the first beam diameter and the third beam diameter are parallel.

A simple, compact and low-cost passive optical transceiver device with four terminals may be used in an optical transmission system with polarization-diversity coherent detection scheme. The transceiver is composed of a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. The device simultaneously operates as a transmitter and a receiver with optical signals propagating along opposite directions wherein non-reciprocal polarization rotation leads to distinct effects. The received optical signal is thus split into two orthogonal polarization components directed towards two separate ports.

A laser interferometer that includes a light source configured to emit laser light, an optical divider configured to divide the laser light into a first optical path and a second optical path, an optical modulator being provided on the first optical path or the second optical path, including an oscillator that oscillates when a current is applied, and being configured to modulate the laser light by using the oscillator, a photoreceptor configured to receive the laser light and output a photoreception signal, the laser light being reflected by an object to be measured that is provided on the first optical path or the second optical path, and a demodulation circuit configured to demodulate, from the photoreception signal, a Doppler signal derived from the object to be measured, based on a reference signal and a modulation signal derived from the optical modulator, wherein Iq/f≤1×10.sup.−7 is satisfied, where an amplitude value of the current applied to the oscillator that is oscillating is Iq [A] and an oscillation frequency of the oscillator is f [Hz].

System and methods for Light Detecting and Ranging (LIDAR) are disclosed. The LIDAR system includes a light source that is configured project a beam at various wavelengths toward a wavelength dispersive element. The wavelength dispersive element is configured to receive the beam and direct at least a portion of the beam into a field of view (FOV) at an angle dependent on frequency. The system also includes a detector that is positioned to receive portions of the beam reflected from an object within the FOV and a processor that is configured to control the light source and determine a velocity of the object.

A laser interferometer includes a laser light source configured to emit first laser light; an optical modulator that includes a resonator element and is configured to generate second laser light including a modulation signal; a light receiving element configured to receive the second laser light and third laser light including a sample signal; and a calculation unit configured to calculate a displacement of an object to be measured from a light reception signal based on a reference signal, in which the calculation unit includes a preprocessing unit configured to execute a preprocessing of extracting a frequency modulation component from the light reception signal and output a preprocessing signal, a demodulation processing unit configured to mix the preprocessing signal with orthogonal signals to obtain a mixed signal and then execute a demodulation processing of extracting the sample signal from the mixed signal, and an orthogonal signal generation unit configured to generate the orthogonal signals based on a phase of the reference signal and an amplitude of the preprocessing signal.

A LiDAR process executed by a signal processing component of a LiDAR apparatus, including: receiving LiDAR signal data representing a signal received at an optical receiver of a LiDAR apparatus and including a scattered and/or reflected portion of an optical signal transmitted by an optical transmitter of the LiDAR apparatus and encoded with a known digital signal, the scattered and/or reflected portion of the transmitted optical signal having been scattered and/or reflected from an object spaced from the LiDAR apparatus by a distance, and having a Doppler shifted angular frequency due to radial motion of the object relative to the LiDAR apparatus; processing the LiDAR signal data to generate corresponding frequency compensated signal data representing a frequency compensated signal corresponding to the received signal, but in which the Doppler shifted angular frequency has been removed and the known digital signal is encoded into the amplitude of the frequency compensated signal; and correlating the frequency compensated signal with a template of the known digital signal to generate a corresponding measurement of the distance of the object from the LiDAR apparatus.

A frequency shift light modulator includes a resonator and a diffraction grating including a plurality of grooves arranged in parallel in a displacement direction of the resonator, and the diffraction grating is provided on the resonator. By providing the diffraction grating on the resonator, it is easy to realize miniaturization and increase in accuracy of the frequency shift light modulator. Further, it is easy to realize application to a high frequency region in a MHz band, that is, high frequency modulation. It is possible to efficiently obtain an effect based on a combination of the resonator and the diffraction grating.

A laser interferometer includes: a laser light source; a collimator configured to generate collimated light; an optical modulator configured to modulate the collimated light into reference light having a different frequency; and a light receiving element configured to receive object light and the reference light and output a light receiving signal, in which when an optical axis of the collimated light is a first optical axis, when return light is generated, an optical axis of the return light is a second optical axis, a position at which the collimated light is generated is a reference position, the following equation (A) is satisfied:

[00001]$\begin{array}{cc}\frac{K}{2}+\frac{1}{2}\left(R+\frac{2L}{R}\lambda \right)\leqq \Delta y& \left(A\right)\end{array}$

in which Δy is a shift width between the first optical axis and the second optical axis at the reference position, κ is an effective diameter of the collimator, R is a light diameter of the collimated light, L is a distance between the reference position and the optical modulator, and Λ is a wavelength of the collimated light.