The invention concerns a method for measuring the concentration of a substance or mixture of substances and/or determining the level in a fluid with intrinsic fluorescence, preferably fuel systems. The invention also refers to the optical device suitable for implementing the method, which comprises a unit which generates light for excitation of the sample; a unit of detection of the signal emitted by the sample and a unit of signal processing. The device and method by which it is implemented also allow the determination of the spatial distribution of the substance or mixture of liquid substances and/or the fluid level in a container. One of the main applications is the measurement of the concentration of oxygen in the fuel tank of aircrafts, based on the measurement of the intrinsic fluorescence of the fuel.

A digital speckle pattern interferometer (DSPI) is provided for long-range measurement of displacement of materials within a hazardous environments. A test arm of a portion of coherent beam from a laser is aimed at a selected angle to traverse a distance to a test surface. An input collimator has a lens wide enough to receive a reflected beam from the test surface and is focused at a corresponding distance. The reflected beam is combined with a reference beam split from the coherent radiation onto a camera for measuring displacement of the test surface based on an electronic speckle pattern interferometer (ESPI).

The invention relates to a method for measuring a multilayered substrate (1, 1′, 1″), particularly with at least one structure (7, 7′, 7″, 7′″, 7.sup.IV, 7.sup.V) with critical dimensions, particularly with a surface structure (7, 7′, 7″, 7′″, 7.sup.IV, 7.sup.V) with critical dimensions, characterized in that the method has at least the following steps, particularly the following procedure:

producing (110) the substrate (1, 1′, 1″) with a plurality of layers (2, 3, 4, 5, 6, 6′, 6″), particularly with a structure (7, 7′, 7″, 7′″, 7.sup.IV, 7.sup.V), particularly with a structure (7, 7′, 7″, 7″′, 7.sup.IV, 7.sup.V) on a surface (6o, 6′o, 6″o) of an uppermost layer (6, 6′, 6″), wherein the dimensions of the layers and in particular the structures are known,

measuring (120) the substrate (1, 1′, 1″), and in particular the structure (7, 7′, 7″, 7′″, 71.sup.IV, 7.sup.V)) using at least one measuring technology,

creating (130) a simulation of the substrate using the measurement results from the measurement of the substrate (1, 1′, 1″),

comparing (140) the measurement results with simulation results from the simulation of the substrate (1, 1′, 1″),

optimizing the simulation (130) and renewed creation (130) of a simulation of the substrate using the measurement results from the measurement of the substrate (1, 1′, 1″), in the event that there is a deviation of the measurement results from the simulation results, or calculating (150) parameters of further substrates, in the event that the measurement results correspond to the simulation results.

A Raman multi-gas detection system including an enhancement unit coupled between a light source and a detector. The enhancement unit includes a nanongrid having a plurality of nanogaps. A gas is coupled to the enhancement unit and is configured to flow through the plurality of nanogaps of the nanogrid. The nanogrid comprises one or more plasmon-active materials. The light source is configured to generate plasmon-enhanced electric fields in the plurality of nanogaps of the nanogrid to induce enhanced Raman scattering of the constituent molecules in the gas within the plurality of nanogaps such that a plurality of different constituent molecules in the gas can be detected. In one embodiment, a molecule in the gas is configured to scatter the light from the light source at a rate more than 1000 times greater than in the free space in the enhancement unit.

The present disclosure relates to methods and systems for assessing the quality of a meat product. In certain embodiments, the present disclosure provides a method of assessing quality of a meat product, the method comprising receiving data representative of light emitted from the meat product upon application of incident light to the meat product, analysing the data to determine one or more parameters indicative of quality of the meat product, and assessing the quality of the meat product on the basis of the one or more parameters.

Systems and methods for detecting photothermal effect in a sample are described herein. In these systems and methods, a pump source is configured to generate a pump pulse train, a probe source is configured to generate a probe pulse train and is synchronized with the pump pulse train, and a camera collects the resulting data. The camera is configured to collect a first signal corresponding to a hot frame, wherein the hot frame includes visible probe beam as modified by a pump beam and a second signal corresponding to a cold frame, wherein the cold frame includes visible probe beam that has not been modified by a pump beam. A processor can subtract the second signal from the first signal to detect the photothermal effect.

An optical system configured to measure a raised or receded surface feature on a surface of a sample may comprise a broadband light source; a tunable filter configured to filter broadband light emitted from the broadband light source and to generate a first light beam at a selected wavelength; a linewidth control element configured to receive the first light beam and to generate a second light beam having a predefined linewidth and a predetermined coherence length; collimating optics optically coupled to the second light beam and configured to collimate the second light beam; collinearizing optics optically coupled to the collimating optics and configured to align the collimated second light beam onto the raised or receded surface feature of the sample, and a processor system and at least one digital imager configured to measure a height of the raised surface or depth of the receded surface from light reflected at least from those surfaces.

The present invention comprises methods and apparatus utilizing multiple detectors to measure properties related to light scattered by particles. Characteristics of particles are determined from the measured properties.

A method and apparatus for detecting a pulsed THz beam includes emitting, by THz emitter, pulsed THz radiation of outgoing pulse shape for interacting with target body; detecting, by THz detector, incoming THz radiation comprising THz pulses, and outputting, by THz detector, a raw detector data of pulse shapes of incoming THz pulses; and determining, by pulse shape reconstruction module, a reconstructed incoming pulse shape based on the raw detector data, measuring, by sensor, a time-of-flight quantity (d) affecting the time of flight of the THz radiation; and adjusting operation of at least one of THz emitter, THz detector and pulse shape reconstruction module using the time-of-flight quantity (d), for correcting for variations in time of flight of the THz radiation.

An inspection system for an additive manufacturing machine can include a housing configured to be mounted to an internal construction of the additive manufacturing machine, wherein the housing defines a laser inlet configured to allow a laser beam from a laser of the additive manufacturing machine to enter into the housing, wherein the housing defines a laser outlet configured to allow the laser beam to exit from the housing and to allow reflected light to enter into the housing. One or more detectors is disposed within the housing and configured to receive the reflected light. The system includes one or more optical elements configured to allow the laser beam to pass through the housing from the laser inlet to the laser outlet toward a build area of the additive manufacturing machine and to direct reflected light from the laser outlet to the one or more detectors within the housing.