A laser interferometer includes: a laser light source configured to emit laser light; a light shielding element having an opening through which the laser light passes; an optical modulator configured to modulate the laser light into reference light having a different frequency; and a light receiving element configured to receive object light generated by reflecting the laser light by an object to be measured and the reference light and output a light receiving signal. 0.10≤φ.sub.pin≤10.0, in which φ.sub.pin [mm] is a diameter of the opening.

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.

An interferometer for use in remote sensing systems includes a beam splitter that separates an input wave into a reflected wave, which travels along a first optical path within an upper interferometer arm, and a transmitted wave, which travels along a second optical path within a lower interferometer arm. The reflected and transmitted waves are subsequently recombined by the beam splitter for imaging onto a sensor. A highly dispersive element is incorporated into at least one of the pair of interferometer arms. Due to anomalous dispersion, a frequency shift in a wave transmitted through a dispersive element changes the optical path length within its corresponding arm. As a result, the recombined wave produces an interference pattern with a measurable phase change that can be utilized to calculate the original frequency shift in the input wave with great precision and potential sub-Hertz sensitivity.

A portable electronic device is operable in a particulate matter concentration mode where the portable electronic device uses a self-mixing interferometry sensor to emit a beam of coherent light from an optical resonant cavity, receive a reflection or backscatter of the beam into the optical resonant cavity, produce a self-mixing signal resulting from a reflection or backscatter of the beam of coherent light, and determine a particle velocity and/or particulate matter concentration using the self-mixing signal. The portable electronic device is also operable in an absolute distance mode where the portable electronic device determines whether or not an absolute distance determined using the self-mixing signal is outside or within a particulate sensing volume associated with the beam of coherent light. If not, the portable electronic device may determine a contamination and/or obstruction is present that may result in inaccurate particle velocity and/or particulate matter concentration determination.

Optical coherence tomography (OCT) apparatuses and methods include a first electro-magnetic radiation (EMR) source providing EMR to a first optical path associated with a sample and a second optical path associated with a reference. A multi-beam generator unit (MBGU) generates first and second EMR beams having different wavelength contents. A scanning system illuminates the sample with the first and second EMR beams, at a first and second time, at a first and second location. An interference module generates interference signals based on received EMR returning from the reference and the first and second EMR beams returning from the sample. A detector generates detection signals based on received interference signals and a processor generates OCT data based on the processed detection signals. In some embodiments, three EMR beams having different wavelength contents with linearly independent vectors illuminate at least one same location of the sample.

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 system (1) for generating a signal from a surface (22) having a speed V in a direction U, comprising: a light source (2) emitting a Gaussian light beam along a first optical path (11); a sensor (3) able to evaluate the effects of the electromagnetic interference of the first beam; a means (2′, 4) for generating a second Gaussian light beam along a second optical path (12); a second sensor (3′) able to evaluate the effects of electromagnetic interference of the second beam; a focusing lens (5, 6) located on the first and/or the second optical path (11, 12), focusing the light beam at a distance f and defining an upstream optical path (11′, 12′); and a means (4′, 7) for routing the second beam able to redirect the second path (12′) in the direction of the first path (11′).

A method for obtaining the profile of the outer surface (22) of a medium (21) having a median plane (23) comprising the following steps: obtaining two time signals A and B (1002), for, at each instant, a same geometrical target on a readout line of the outer surface (22); determining at least one Doppler frequency (2001) associated with each time signal A and B; sampling each time signal A and B (2002) at a frequency greater than 2 times the Doppler frequency to obtain a payload signal; determining an envelope (2004) of the payload signal of each signal A and B; performing a relative combination between the envelopes of each signal A and B (3001) to obtain a monotonic and bijective function F; and determining the profile of the outer surface (3002) using a calibration of the function F.

An atomic interferometric accelerometer comprises a laser that emits a pulsed beam at a first frequency, an electro-optic modulator that receives the beam, and a vacuum cell in communication with the electro-optic modulator. The electro-optic modulator outputs a first optical signal corresponding to the beam at the first frequency and a second optical signal having a second frequency different from the first frequency. The vacuum cell has a chamber for laser cooled atoms. The vacuum cell receives the optical signals such that they propagate in a direction that passes through the atoms. A piezo mirror retro-reflects the optical signals back through the vacuum cell in a counter-propagating direction. The piezo mirror is driven with substantially constant velocity during a beam pulse, thereby imparting a Doppler shift to the retro-reflected optical signals to create two non-symmetric counter-propagating lightwave pairs. One of the lightwave pairs supports interferometry while the other is non-resonant.

A computer-implemented method of imaging an object, and an optical coherent tomography (OCT) imaging system implementing same. The method comprises acquiring a three-dimensional optical coherence tomography (OCT) data set representing an object, wherein the OCT data set includes at least a first and a second three-dimensional data subsets, each element of the OCT data set having a respective sampling period, wherein at least a first element of the first data subset represents a point in space that is not represented by any element of the second subset, and at least one element of the second subset has a sampling period different from the sampling period of the first element of the first subset; processing at least the first and the second data subsets according to at least one imaging modality, thereby generating at least a first and a second processed data subsets, each processed data subset representing the object; and generating a composite image representing the object based on at least the first and the second processed data subsets.