A polarization measuring device is operated by passing light having a predetermined input polarization state to a sample for a potentially polarization changing interaction and from the sample through a polarization selective analyzer and to an intensity detector. The method proceeds by varying an angle between the output polarization state of the light emanating from the sample and the analyzer. The wavelength of the light reaching the intensity detector is varied, and a plurality of intensity measurements are performed successively at different constellations of polarization. Spectral modulation states and corresponding intensity values are stored together with polarization and spectral values representing the corresponding constellation. The polarization modulation and the spectral modulation are performed simultaneously and continuously, and during a single, monotonic variation of the polarization modulation state, the spectral modulation state is varied plural times and during each spectral modulation period (?.sub.?) plural successive intensity measurements are performed.

An embodiment of a gas analyzer is described that comprises a light source configured to produce a substantially collimated first beam with a diverging angle of less than about 15 degrees; a gas cell comprising an inlet configured to introduce a gas into the gas cell, an outlet configured to remove the gas from the gas cell, and a plurality of mirrors configured to reflect the substantially collimated first beam within the gas cell; and a detector configured to generate a signal in response to the substantially collimated first beam.

An embodiment of the disclosure provides a system for determining information on one or more constituents in a medium. The system includes N light emitters L.sub.1 . . . L.sub.N, wherein each light emitter L.sub.x provides an amplitude modulated (AM) light at modulation frequency f.sub.x into a flow path of the medium from one side of a containment vessel for the medium. The system further includes a photodetector, for receiving the AM light from each light emitter after it passes through the flow path of the medium, and converting the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency f.sub.x. The system further includes one or more measuring circuits providing information about a concentration of one or more constituents in the medium determined from log ratios of a pair of amplitudes of f.sub.y and f.sub.z frequency components in the electrical signal.

An illuminator/collector assembly can deliver incident light to a sample and collect return light returning from the sample. A sensor can measure ray intensities as a function of ray position and ray angle for the collected return light. A ray selector can select a first subset of rays from the collected return light at the sensor that meet a first selection criterion. In some examples, the ray selector can aggregate ray intensities into bins, each bin corresponding to rays in the collected return light that traverse within the sample an estimated optical path length within a respective range of optical path lengths. A characterizer can determine a physical property of the sample, such as absorptivity, based on the ray intensities, ray positions, and ray angles for the first subset of rays. Accounting for variations in optical path length traversed within the sample can improve accuracy.

The invention relates to a radiation source which comprises: a support (400) provided with a wall (410); a membrane (200) comprising two faces, the membrane (200) being adapted to emit an infrared radiation according to one and the other of its faces, and maintained in suspension with respect to the support (400), the rear face (220) in line with and at a distance D from the wall (410); electrostatic actuating means (300) adapted to vary the distance D; the membrane (200) and the means (300) being laid out such that, for each wavelength, the infrared radiation emitted by the rear face (220) is reflected by the wall (410), passes through the membrane (200) and interferes with the infrared radiation emitted by the front face (210).

An analyser 10 for identifying or verifying or otherwise characterising a liquid based drug sample 16 comprising: an electromagnetic radiation source 11 for emitting electromagnetic radiation 14a in at least one beam at a sample 16, the electromagnetic radiation comprising at least two different wavelengths, a sample detector 17 that detects affected electromagnetic radiation resulting from the emitted electromagnetic radiation affected by the sample, and a processor 18 for identifying or verifying the sample from the detected affected electromagnetic radiation, wherein each wavelength or at least two of the wavelengths is between substantially 1300 nm and 2000 nm, and each wavelength or at least two of the wavelengths is in the vicinity of the wavelength(s) of (or within a region spanning) a spectral characteristic in the liquid spectrum between substantially 1300 nm and 2000 nm.

Implementations disclosed describe, among other things, a system and a method of using a wafer inspection system that includes a plurality of inspection heads configured to concurrently inspect a separate region of a plurality of regions of a wafer. Each inspection head includes an illumination subsystem to illuminate a corresponding region of the wafer, a collection subsystem to collect a portion of light reflected/scattered from the corresponding region of the wafer. Each inspection head further includes a light detection subsystem to detect the collected light and generate one or more signals representative of a state of the corresponding region of the wafer. The wafer inspection system further includes a processing device configured to determine, using the one or more signals received from each of the inspection heads, the quality of the wafer.

A detection method and detection system for a trace gas, the detection method comprising: providing a resonant cavity, a gas to be measured being filled inside of a cavity body of the resonant cavity; providing detection light rays having different frequencies, the detection light rays being incident to the inside of the resonant cavity from one end of the resonant cavity in the extending direction and exiting from the other end of the resonant cavity in the extending direction so as to obtain detection light rays carrying information of a trace gas to be measured, and the cavity body of the resonant cavity having a degree of freedom of expansion and retraction in the extending direction so that the longitudinal mode frequency of the resonant cavity matches the frequencies of the incident detection light rays; and according to the detection light rays that have different frequencies and that carry information of said trace gas, acquiring the molecular saturation absorption spectrum of said trace gas, and calculating the concentration of said trace gas. The detection system comprises: a laser generating device, the resonant cavity, a photoelectric detection device, a feedback control device and a scanning control device. At room temperature, detection light rays provided by a conventional laser are used to detect the concentration of a trace gas.

A light source section configured to couple a plurality of laser beams having different wavelengths and emit measuring light; an illuminating section configured to illuminate a measurement target at a predetermined angle; a light receiving section configured to receive reflected measuring light from the measurement target; and a controlling section configured to compute a reflectance at each of the wavelengths, based on a light receiving result. The light source section includes: a first and a second light source configured to emit each laser beams having different wavelengths; and a dichroic mirror disposed in optical axes of the laser beams intersected, configured to combine the laser beams. The light receiving section includes: a first, a second and a third light receiving unit configured to receive the reflected measuring light from different distance. The controlling section is configured to select which of results from each light receiving unit to use.

A light source may illuminate a scene with pulsed light that is pulsed non-periodically. The scene may include fluorescent material that fluoresces in response to the pulsed light. The pulsed light signal may comprise a maximum length sequence or Gold sequence. A lock-in time-of-flight sensor may take measurements of light returning from the scene. A computer may, for each pixel in the sensor, perform a Discrete Fourier Transform on measurements taken by the pixel, in order to calculate a vector of complex numbers for the pixel. Each complex number in the vector may encode phase and amplitude of incident light at the pixel and may correspond to measurements taken at a given time interval during the pulsed light signal. A computer may, based on phase of the complex numbers for a pixel, calculate fluorescence lifetime and scene depth of a scene point that corresponds to the pixel.