In one aspect, a method of detecting a trace gas is disclosed. The method includes containing the trace gas in an optical cavity. The method further includes injecting a first laser light from a first laser into the optical cavity causing the trace gas to transition from an energy state lower that a first excited energy state to the first excited energy state, and injecting a second laser light from a second laser into the optical cavity causing the trace gas to transition from the first excited energy state to a second excited energy state. The method includes measuring, by a detector, a first cavity ringdown intensity as a function of time after turning off the second laser with the first laser on, and a second cavity ringdown intensity as a function of time after turning off the second laser with the first laser off.

The invention relates to a method for compensation for different sensitivities at different wavelengths in a spectrometric measuring system, including steps of calibrating the measuring system in a wavelength range with respect to one or more known reference standards, creating a wavelength-dependent compensation algorithm for linearization, and adjusting the measuring system using the compensation algorithm. The invention further discloses a corresponding measuring system.

The invention relates to a method for compensation for different sensitivities at different wavelengths in a spectrometric measuring system, including steps of calibrating the measuring system in a wavelength range with respect to one or more known reference standards, creating a wavelength-dependent compensation algorithm for linearization, and adjusting the measuring system using the compensation algorithm. The invention further discloses a corresponding measuring system.

Modulation-encoded light, using different spectral bin coded light components, can illuminate a stationary or moving (relative) target object or scene. Response signal processing can use information about the respective different time-varying modulation functions, to decode to recover information about a respective response parameter affected by the target object or scene. Electrical or optical modulation encoding can be used. LED-based spectroscopic analysis of a composition of a target (e.g., SpO2, glucose, etc.) can be performed; such can optionally include decoding of encoded optical modulation functions. Baffles or apertures or optics can be used, such as to constrain light provided by particular LEDs. Coded light illumination can be used with a focal plane array light imager receiving response light for inspecting a moving semiconductor or other target. Encoding can use orthogonal functions, such as an RGB illumination sequence, or a sequence of combinations of spectrally contiguous or non-contiguous colors.

System for performing chemical spectroscopy on samples from the scale of nanometers to millimeters or more with a multifunctional platform combining analytical and imaging techniques including dual beam photo-thermal spectroscopy with confocal microscopy, Raman spectroscopy, fluorescence detection, various vacuum analytical techniques and/or mass spectrometry. In embodiments described herein, the light beams of a dual-beam system are used for heating and sensing.

System for performing chemical spectroscopy on samples from the scale of nanometers to millimeters or more with a multifunctional platform combining analytical and imaging techniques including dual beam photo-thermal spectroscopy with confocal microscopy, Raman spectroscopy, fluorescence detection, various vacuum analytical techniques and/or mass spectrometry. In embodiments described herein, the light beams of a dual-beam system are used for heating and sensing.

A light radiating portion radiates light with wavelength λ1 having predetermined absorptivity for an object and light with wavelength λ2 having smaller absorptivity for the object than the wavelength λ1, to a target, so as to scan in 2-dimensional directions. A light receiving portion receives scattered lights reflected by the target based on light with wavelength λ1 and light with wavelength λ2. A measuring portion generates information used for detection of the object at the target, based on difference between the two scattered lights with wavelength λ1 and wavelength λ2 received by the light receiving portion. An output portion outputs whether or not the object is present at the target, by 2-dimensional area information, based on scanning by the light radiating portion and information generated by the measuring portion.

A light radiating portion radiates light with wavelength λ1 having predetermined absorptivity for an object and light with wavelength λ2 having smaller absorptivity for the object than the wavelength λ1, to a target, so as to scan in 2-dimensional directions. A light receiving portion receives scattered lights reflected by the target based on light with wavelength λ1 and light with wavelength λ2. A measuring portion generates information used for detection of the object at the target, based on difference between the two scattered lights with wavelength λ1 and wavelength λ2 received by the light receiving portion. An output portion outputs whether or not the object is present at the target, by 2-dimensional area information, based on scanning by the light radiating portion and information generated by the measuring portion.

A system, wearable device, and method include a light emitter configured to emit light at a first wavelength of between approximately 900 and 1000 nanometers and at a second wavelength of approximately 1350 nanometers, a first light detector spaced at a first distance from the light emitter, and a second light detector spaced at a second distance from the light emitter, the second distance approximately twice the first distance. At least one of hydration and glycogen of muscle tissue is determinable based on a relationship between backscatter light from the muscle tissue as detected by the second light detector and backscatter light from non-muscle tissue as detected by the first light detector.

A temperature measurement system configured to measure a temperature of a target object having a first main surface and a second main surface includes a light source unit configured to emit output light penetrating the target object and including a first wavelength range and a second wavelength range; a measurement unit configured to measure a spectrum of reflected light; an optical path length ratio calculator configured to calculate an optical path length ratio between the output light of the first wavelength range and the output light of the second wavelength range; and a temperature calculator configured to calculate the temperature of the target object based on the optical path length ratio and a previously investigated relationship between the temperature of the target object and a refractive index ratio between the output light of the first wavelength range and the output light of the second wavelength range.