A quantum device includes a non-reciprocal transmission structure, wherein the transmission structure is designed such that for first waves traversing the transmission structure in a forward direction the phases of the first waves are at least partially conserved, and for second waves traversing the transmission structure in a backward direction, the phases of the second waves are at least partially replaced by random ones, such that the phase conservation is more pronounced in the forward direction than in the backward direction.

A crack measuring apparatus includes distance-measuring units, an image pickup unit having pixels the positions of which are identified on an imaging device, an infrared image pickup unit having pixels the positions of which are identified on an imaging device and having sensitivity to infrared rays, driving units, angle-measuring units, and an arithmetic control unit, the arithmetic control unit searches for a cracked portion from a temperature difference in an infrared image by turning the infrared image pickup unit, captures an image of the cracked portion by the image pickup unit and identifies a position of the cracked portion from a density difference in the captured image, measures the position of the cracked portion by the distance-measuring units and the angle-measuring units, and acquires three-dimensional absolute coordinates of the cracked portion.

A 3-D imaging system including a computer determining a plurality of coherence factors measuring an intensity contrast between a first intensity of a first region of an interference comprising constructive interference between a sample wavefront and a reference wavefront, and a second intensity of a second region of the interference comprising destructive interference between the sample wavefront and the reference wavefront, wherein the interference between a reference wavefront and a reflection from different locations on a surface of an object. From the coherence factors, the computer determines height data comprising heights of the surface with respect to an x-y plane perpendicular to the heights and as a function of the locations in the x-y plane. The height data is useful for generating a three dimensional topological image of the surface.

Techniques are described for monitoring the degradation of electrochemical cells. A battery monitoring system monitors, for each of one or more cells of a plurality of cells in a battery, an amount of mechanical deformation using one or more measuring devices. The battery monitoring system determines a number of cells of the plurality of one or more monitored cells for which the monitored amount of mechanical deformation exceeds a deformation threshold. The battery monitoring system determines whether the determined number of cells exceeds a threshold number of cells with an amount of mechanical deformation exceeding the deformation threshold. Responsive to determining the determined number of cells exceeds the threshold number of cells, the battery monitoring system sends a notification that the battery is degraded beyond an acceptable limit.

Techniques are described for monitoring the degradation of electrochemical cells. A battery monitoring system monitors, for each of one or more cells of a plurality of cells in a battery, an amount of mechanical deformation using one or more measuring devices. The battery monitoring system determines a number of cells of the plurality of one or more monitored cells for which the monitored amount of mechanical deformation exceeds a deformation threshold. The battery monitoring system determines whether the determined number of cells exceeds a threshold number of cells with an amount of mechanical deformation exceeding the deformation threshold. Responsive to determining the determined number of cells exceeds the threshold number of cells, the battery monitoring system sends a notification that the battery is degraded beyond an acceptable limit.

Sensor data is captured with a sensor. The sensor data includes a lens-position of a prescription lens relative to a reference point of an optical coherence tomography (OCT) system. A mirror of a reference arm of the OCT system is positioned at an optical pathlength between an eye region of the prescription lens based at least in part on the sensor data. An OCT signal is generated while the mirror is positioned at the optical pathlength. At least one depth profile is generated that includes the prescription lens and the eye region.

Example embodiments include an optical assembly for an optical interrogation system having a single core or a multicore sensing fiber, a measurement fiber to couple light into the sensing fiber, and a reference fiber arranged with the measurement fiber as part of an optical interferometer. A beam splitter combines light from the sensing fiber and with light from the reference fiber. A polarization beam splitting prism separates the combined light into first polarized light and second polarized light that is orthogonal to the first polarized light. The optical assembly can substantially reduce the size, complexity, or cost associated with the traditional optical components in an optical interrogation system that it replaces. Other example optical assemblies are described. Embodiments describe optical interrogation systems using the example optical assemblies.

The invention refers to a frequency shifter for heterodyne interferometry measurements, comprising a chip, an input waveguide configured to guide a light beam, at least four phase modulators, each being arranged to receive the light beam from the input waveguide and configured to modulate a phase of the light beam, an output combiner being arranged to let the light beams modulated by each phase modulator interfere, a first output waveguide coupled to the output combiner and configured to receive the modulated light beams constructively interfering at the output combiner, a second output waveguide coupled to the output combiner and configured to receive the modulated light beams destructively interfering at the output combiner, wherein the input waveguide, the phase modulators, the output combiner, the first output waveguide and the second output waveguide are arranged on the chip.

A measurement device, for measuring the shape of an interface to be measured of an optical element having a plurality of interfaces, the device including: measurement apparatus with at least one interferometric sensor illuminated by a low-coherence source, for directing a measurement beam towards the optical element to pass through the plurality of interfaces, and to detect an interference signal resulting from interferences between the measured measurement beam reflected by the interface and a reference beam; positioning apparatus configured for relative positioning of a coherence area of the interferometric sensor at the level of the interface to be measured; digital processor for producing, based on the interference signal, an item of shape information of the interface to be measured according to a field of view.

A measurement method, for measuring the shape of an interface of an optical element having a plurality of interfaces is also provided.

Translations of an object in a plurality of different spatial directions are measured using a plurality of interferometers to detect interference with light that has been reflected from a diffusively reflective surface, preferably using diffuse reflection from the same planar surface to measure in each of the different spatial directions. At least the interferometers that measure translation in directions that are not perpendicular to the surface each comprises a single mode fiber and a collimator configured to transmit the outgoing light to the object successively through the single mode fiber and the collimator, and to collect reflection into the single mode fiber with the collimator both along a same beam direction. It has been found that, when reflection of a beam with a beam direction at an oblique angle to a diffusively reflective surface is used, the interference resulting from translation of the object is due substantially only to translation in the beam direction.