A homodyne encoder system has adaptive matching of path lengths. Primary apertures receive light from a target. An optical spreader spreads apart the light passing through the primary apertures by at least a factor of two times a baseline separation of the primary apertures. The optical spreader includes a plurality of actuators for modifying the path lengths within the homodyne encoder system through the primary apertures to a detector. A focusing optic focuses the light from the optical spreader at the detector. The detector detects an image of the target with the light from the focusing optic.

A homodyne encoder system has adaptive matching of path lengths. Primary apertures receive light from a target. An optical spreader spreads apart the light passing through the primary apertures by at least a factor of two times a baseline separation of the primary apertures. The optical spreader includes a plurality of actuators for modifying the path lengths within the homodyne encoder system through the primary apertures to a detector. A focusing optic focuses the light from the optical spreader at the detector. The detector detects an image of the target with the light from the focusing optic.

A high backscattering optical fiber comprising a perturbed segment in which the perturbed segment reflects a relative power such that the optical fiber has an effective index of n.sub.eff, a numerical aperture of NA, a scatter of R.sub.p.fwdarw.r.sup.(fiber) that varies axially along the optical fiber, a total transmission loss of α.sub.fiber, an in-band range greater than one nanometer (1 nm), and a figure of merit (FOM) in the in-band range. The FOM being defined as: $\mathrm{FOM}=\frac{R_{p.fwdarw.r}^{\left(\mathrm{fiber}\right)}}{{{\alpha }_{\mathrm{fiber}}\left(\frac{\mathrm{NA}}{2n_{\mathrm{eff}}}\right)}^2}.$

A white light interferometric fiber-optic gyroscope based on a rhombic optical path difference bias structure includes a laser, a rhombic optical path difference bias structure, a fiber coil and a photodetector. The white light interferometric fiber-optic gyroscope adopts an all-fiber structure to simplify the complexity of a gyroscope system and reduce the overall cost. A white light interferometric demodulation algorithm is used to realize linear output of rotation rate signals.

A white light interferometric fiber-optic gyroscope based on a rhombic optical path difference bias structure includes a laser, a rhombic optical path difference bias structure, a fiber coil and a photodetector. The white light interferometric fiber-optic gyroscope adopts an all-fiber structure to simplify the complexity of a gyroscope system and reduce the overall cost. A white light interferometric demodulation algorithm is used to realize linear output of rotation rate signals.

A method for determining local position of an optical element associated with an optical path for transporting a laser beam in a working head of a machine for laser processing a material, includes generating a measurement beam of low coherence optical radiation traveling a measurement optical path, leading the measurement beam towards the optical element and the reflected or diffused measurement beam towards an optical interferometric sensor arrangement, generating a reference beam of low coherence optical radiation traveling a reference optical path and leading the reference beam towards the interferometric optical sensor arrangement, superimposing the measurement and reference beams on a common region of incidence, detecting a position of a pattern of interference fringes between the measurement and reference beams, and determining a difference in optical length between the measurement and reference optical paths as a function of the position of the interference pattern along an illumination axis, or of the frequency of the interference pattern in the frequency domain.

A method for determining local position of an optical element associated with an optical path for transporting a laser beam in a working head of a machine for laser processing a material, includes generating a measurement beam of low coherence optical radiation traveling a measurement optical path, leading the measurement beam towards the optical element and the reflected or diffused measurement beam towards an optical interferometric sensor arrangement, generating a reference beam of low coherence optical radiation traveling a reference optical path and leading the reference beam towards the interferometric optical sensor arrangement, superimposing the measurement and reference beams on a common region of incidence, detecting a position of a pattern of interference fringes between the measurement and reference beams, and determining a difference in optical length between the measurement and reference optical paths as a function of the position of the interference pattern along an illumination axis, or of the frequency of the interference pattern in the frequency domain.

A method and a device for label-free all-optical neural regulation and imaging are provided. The method stimulates a neural activity through an infrared laser pulse, and acquires an optical scattered signal caused by the neural activity by optical coherence tomography (OCT) to realize label-free all-optical neural regulation and imaging. The method specifically includes: aiming an infrared laser at a target brain region, injecting a certain time series of laser pulses, synchronously scanning and imaging the target brain region by OCT, analyzing a relative change of an OCT scattered signal before and after laser stimulation, and acquiring a brain function signal based on OCT to realize synchronous neural regulation and imaging. The method and the device enable synchronous neural regulation and imaging without causing crosstalk between the regulation and imaging channels, and without the need for injection of a contrast agent or viral transfection.

A method and a device for label-free all-optical neural regulation and imaging are provided. The method stimulates a neural activity through an infrared laser pulse, and acquires an optical scattered signal caused by the neural activity by optical coherence tomography (OCT) to realize label-free all-optical neural regulation and imaging. The method specifically includes: aiming an infrared laser at a target brain region, injecting a certain time series of laser pulses, synchronously scanning and imaging the target brain region by OCT, analyzing a relative change of an OCT scattered signal before and after laser stimulation, and acquiring a brain function signal based on OCT to realize synchronous neural regulation and imaging. The method and the device enable synchronous neural regulation and imaging without causing crosstalk between the regulation and imaging channels, and without the need for injection of a contrast agent or viral transfection.

A device and method for measuring a surface of an object, including at least one light source, at least one optical sensor, and an interferometry device having a measurement arm and a reference arm, the former directing light from each light source towards the surface of the object and directing light from the surface towards each optical sensor; the measurement device, in an interferometry configuration, illuminating the reference arm and the measurement arm with each light source and directing the light from the measurement arm and the reference arm towards each optical sensor to form an interference signal; the measurement device, in an imaging configuration illuminating at least the measurement arm and directing the light from the measurement arm towards the optical sensor to form an image of the surface; the measurement device including a digital processor producing, from the interference signal and the image, information on the surface.