An apparatus for oral imaging has a light source energizable to generate a light frequency signal ranging from a minimum to a maximum frequency. An image acquisition apparatus scans the generated light frequency signal to successive positions on a sample surface and to combine a returned signal from each successive position with the generated light frequency signal. The image acquisition apparatus has a detector that obtains a beat frequency signal from the combined returned signal and the generated light frequency signal. A processor that is in signal communication with the detector generates a processed beat signal from the combined signals, wherein the processed beat signal is indicative of the distance from the tunable laser source to the sample surface at the corresponding position. A display is in signal communication with the processor and is energizable to display distance data according to the processed beat signal for each scanned position.

A laser interferometer that includes a laser light source configured to emit emission light, a light splitter configured to split the emission light into first split light, and second split light incident on an object to be measured, a light modulator disposed on an optical path on which the first split light advances, and configured to modulate the first split light into a reference light having a different frequency from a frequency of the first split light, an optical path length change unit provided between the light splitter and the light modulator, and configured to change a first optical path length, the first optical path length being an optical path length between the light splitter and the light modulator, a photoreceptor configured to receive an interference light of the reference light and an object light generated by reflecting the emission light at the object to be measured, and to output a light reception signal, and a controller configured to control operation of the optical path length change unit in accordance with a second optical path length, the second optical path length being an optical path length between the light splitter and the object to be measured.

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.

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 measurement apparatus, including: a laser apparatus that outputs a frequency-modulated laser beam with a plurality of modes; a branching part that branches the frequency-modulated laser beam into a reference light and a measurement light; a beat signal generation part that generates a plurality of beat signals by mixing the reference light and a reflected light that is reflected by radiating the measurement light onto an object to be measured; a conversion part that converts the plurality of beat signals into digital signals by sampling the beat signals at a frequency greater than or equal to four times a resonator frequency of the laser resonator; and a calculation part that calculates a distance from the measurement apparatus to the object to be measured on the basis of the digital signals is provided.

A measurement apparatus, including: a laser apparatus that outputs a frequency-modulated laser beam with a plurality of modes; a branching part that branches the frequency-modulated laser beam into a reference light and a measurement light; a beat signal generation part that generates a plurality of beat signals by mixing the reference light and a reflected light that is reflected by radiating the measurement light onto an object to be measured; a conversion part that converts the plurality of beat signals into digital signals by sampling the beat signals at a frequency greater than or equal to four times a resonator frequency of the laser resonator; and a calculation part that calculates a distance from the measurement apparatus to the object to be measured on the basis of the digital signals is provided.

A light detection and ranging (LIDAR) system includes a LIDAR measurement unit, a reference measurement unit, and a phase cancellation unit. The LIDAR measurement unit estimates a time for which a laser beam travels. The reference measurement unit determines a phase of a laser source. The phase cancellation unit identifies phase noise and cancels the phase noise from the laser beam, at least partially based on the phase of the laser source and the time for which the laser beam travels. The denoised signal is used to determine the range between a laser source and a target.

The present disclosure provides a device that accurately measures vibration at a designated position of a sensing fiber without using digital signal processing to compensate for distance fluctuation. Digital signal processing for correcting fluctuation of a measurement distance due to a frequency offset of a beat signal due to vibration, which is a measurement target, is simplified. In the present disclosure, vibration at a designated position of the sensing fiber is accurately measured without using the digital signal processing to compensate for the distance fluctuation. A spectrum analysis length of an electrical field E(τn) of backscattered light is set to be larger than a delay deviation N.sub.d due to frequency modulation caused by dynamic strain. An index of tolerance of vibration distribution measurement to the delay deviation N.sub.d is also clarified.

A metrology system including a heterodyne light source is provided. The heterodyne light source includes a first light source, an acousto-optic modulator and a source optical arrangement. The acousto-optic modulator receives at least one wavelength laser beam from the first light source and generates at least one corresponding frequency shifted laser beam (e.g., with orthogonal polarization). The source optical arrangement includes a receiving optical element portion and a birefringent optical element portion. The receiving optical element portion receives the wavelength laser beam(s) and the corresponding frequency shifted laser beam(s) and directs the beams along an optical path toward the birefringent optical element portion. The birefringent optical element portion combines the beams to output a combined beam (e.g., which may be utilized as part of a measurement process to determine at least one measurement distance to at least one surface point on a workpiece, etc.).

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.