The invention is related to a laser diode based multiple beam laser spot imaging system for characterization of vehicle dynamics. A laser diode based, preferably VCSEL based laser imaging system is utilized to characterize the vehicle dynamics. One or more laser beams are directed to the road surface. A compact imaging system including an imaging matrix sensor such as a CCD or CMOS camera measures locations or separations of individual laser spots. Loading status of vehicles and vehicles' pitch and roll angle can be characterized by analyzing the change of laser spot locations or separations.

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 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].

A device for determining at least one of a speed and a length of a product. The device includes a laser for irradiating a surface of the product, a detector apparatus to detect laser radiation backscattered from the surface, a first sensor with a first transmission grid arranged in front of the first sensor and a second sensor. A first beam splitter splits laser radiation backscattered from the product into laser radiation conducted to at least one of the first sensor and to the second sensor. An evaluation apparatus determines at least one of: (i) the speed; and (ii) the length of the product. A third sensor is provided as is a second beam splitter that splits laser radiation coming from the first beam splitter to at least one of the sensors. The evaluation apparatus eliminates a direct component of the measurement signal received by the first sensor.

Disclosed herein are electronic devices having touch input surfaces. A user's touch input or press on the touch input surface is detected using a set of lasers, such as vertical-cavity surface-emitting lasers (VCSELs) that emit beams of light toward the touch input surface. The user's touch causes changes in the self-mixing interference within the VCSEL of the emitted light with reflected light, such as from the touch input surface. Deflection and movement (e.g., drag motion) of the user's touch is determined from detected changes in the VCSELs' operation due to the self-mixing interference.

An apparatus for measuring fluid speed by using the refraction of light is disclosed. The apparatus includes: a channel in which a passage is formed to allow the flow of a fluid; a first and a second light source that are located in any one region of an upper part and a lower part of the channel; a sensor installed in an opposite region of the region where the first and second light sources are located with respect to the channel, to receive the light emitted from the first and second light sources; a speed calculation unit configured to calculate a speed of the fluid by using the intensity of the light received at the sensor.

A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and a signal generator that outputs the reference signal input to the demodulation circuit and outputs a drive signal input to the optical modulator, in which Vd/Vr<10, where Vr is a voltage of the reference signal and Vd is a voltage of the drive signal.

A method for detecting a gaze direction of an eye includes the steps of irradiating at least one wavelength-modulated laser beam onto an eye, detecting an optical path length of the emitted laser beam based on laser feedback interferometry of the emitted laser radiation with a backscattered radiation from the eye, detecting a Doppler shift of the emitted radiation and the backscattered radiation based on the laser feedback interferometry, detecting an eye velocity based on the Doppler shift, and detecting an eye movement of the eye based on the optical path length and the eye velocity.

A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and an oscillation circuit that outputs the reference signal to the demodulation circuit, and the vibrator is a signal source of the oscillation circuit.

Disclosed herein are electronic devices having touch input surfaces. A user's touch input or press on the touch input surface is detected using a set of lasers, such as vertical-cavity surface-emitting lasers (VCSELs) that emit beams of light toward the touch input surface. The user's touch causes changes in the self-mixing interference within the VCSEL of the emitted light with reflected light, such as from the touch input surface. Deflection and movement (e.g., drag motion) of the user's touch is determined from detected changes in the VCSELs' operation due to the self-mixing interference.