Abstract: An FM-NMOR magnetometer and concomitant magnetometry method comprising providing a linearly-polarized pump beam generator, employing a center wavelength approximately equal to a center wavelength of hyperfine peaks, and employing a modulation amplitude in the range HFS-3×LW to HFS.

Abstract: A method for evaluating the condition of a ceramic coating deposited on a substrate comprising illuminating the ceramic coating with light, measuring the intensity of light returned from the ceramic coating as function of depth in the coating and transverse position on the coating, and analyzing the measured light intensities to obtain one or more of intensity of the light returned from the exposed coating surface relative to the intensity of light returned from the coating/substrate interface, intensity of the light returned from the coating/substrate interface relative to the intensity of light returned from the bulk of the ceramic coating, determination of roughness at the exposed surface of the ceramic coating, and determination of roughness of the interface between the ceramic coating and underlying bond coat or substrate.

Abstract: A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

Abstract: An apparatus and method for monitoring gas velocity, temperature, and pressure in combustion systems and flow devices, in particular at inlets and isolators of scramjet engines. The invention employs wavelength modulation spectroscopy with first harmonic detection and without the need to scan the full absorption spectra.

Abstract: A magnetometer and concomitant magnetometry method comprising emitting light from a light source, via a pulse generator pulsing light from the light source, directing the pulsed light to an atomic chamber, employing a field sensor in the atomic chamber, and via a signal processing module receiving a signal from the field sensor.

Abstract: An apparatus and method (and related kit) for determination of the isotopic ratio of 13C to 12C in a gas sample containing carbon dioxide comprising introducing gas into a gas sample chamber, directing light into the sample chamber from a laser light source, the laser light source being capable of accessing one or more of the wavelength pairs 2054.37 and 2052.42; 2054.96 and 2051.67; or 2760.53 and 2760.08 nanometers, and with a detector detecting the laser light energy after passage through the sample chamber.

Abstract: An optical cell and a method of operating an optical cell comprising employing a first mirror comprising a first hole therein at approximately a center of the first mirror and through which laser light enters the cell, employing a second mirror comprising a second hole therein at approximately a center of the second mirror and through which laser light exits the cell, and forming a Lissajous pattern of spots on the mirrors by repeated reflection of laser light entering the cell.

Abstract: An apparatus and method for quantifying ketone or alydehyde concentrations of gas. The invention includes passing a gas sample through a reactor and an optical cell and determining a concentration of a gaseous reaction product. Using the concentration of the gaseous reaction product and a predetermined reaction conversion efficiency, a ketone or aldehyde concentration is calculated. This invention can be used for diabetes screening, diabetes maintenance, identification and quantification of ketosis, explosives detection and formaldehyde detection.

Abstract: The present invention is a portable gas leak detector preferably comprising a portable optical spectroscopy apparatus for measurement of gas concentration.

Abstract: An optical spectroscopy apparatus and method for measurement of species concentration, number density, or column density comprising emitting light from a laser light source, receiving light via a fixed length optical path from the source and containing a species to be detected, receiving light via a detector at an end of the path, determining one or more of species concentration, number density, and column density via signal processing electronics connected to the detector, and switching between a plurality of operational modes measuring a same absorption feature of the species depending on measured absorbance.

Abstract: A multiple pass optical cell and method comprising providing a pair of opposed cylindrical mirrors having curved axes with substantially equal focal lengths, positioning an entrance hole for introducing light into the cell and an exit hole for extracting light from the cell, wherein the entrance hole and exit hole are coextensive or non-coextensive, introducing light into the cell through the entrance hole, and extracting light from the cell through the exit hole.

Abstract: An apparatus and method for differential spectral interferometry comprising providing an interferometer comprising a light source; employing an element to provide a dithered relative phase shift between target and reference arms of the interferometer, detecting output from the interferometer, demodulating signals received from the detector at different multiples of the dither frequencies, generating more than one real-valued interferograms from demodulated signals, and using the real-valued interferograms to obtain the complex spectral interferogram.

Abstract: An apparatus and method for monitoring oxygen concentrations in fuel tank ullage comprising providing a sensor head comprising an optical cavity, exposing the optical cavity to an ambient gaseous environment of a fuel tank or air separation module, via a laser light source emitting wavelength modulated light through the cavity, and receiving the wavelength modulated light with a detector.

Abstract: A multiple pass optical cell and method comprising providing a pair of opposed mirrors, one cylindrical and one spherical, introducing light into the cell via an entrance mechanism, and extracting light from the cell via an exit mechanism, wherein the entrance mechanism and exit mechanism are coextensive or non-coextensive.

Abstract: An external cavity laser and a method of generating laser light via an external cavity laser comprising emitting laser light from a source, collimating light output by the source, receiving collimated light with a diffraction grating, reflecting light received from the diffraction grating back to the diffraction grating with a cavity feedback mirror, wherein at least a portion of the mirror is curved, and tuning the external cavity laser to a set of wavelengths.

Abstract: A spectrometer and spectrometry method comprising modulating a light source with a carrier waveform multiplied by an envelope function, directing light from the light source through a sample region and to a photodetector, and demodulating current from the photodetector at a reference frequency. Also a method for computing a modulation waveform comprising specifying a target detection efficiency in a Fourier space, computing a response of a waveform that comprises a carrier wave multiplied by an envelope function, and modifying the envelope function using nonlinear optimization means to minimize a difference between the computed response and a predetermined target detection efficiency.

Abstract: An apparatus and method for differential spectral interferometry comprising providing an interferometer comprising a light source; employing an element to provide a dithered relative phase shift between target and reference arms of the interferometer, detecting output from the interferometer, demodulating signals received from the detector at different multiples of the dither frequencies, generating more than one real-valued interferograms from demodulated signals, and using the real-valued interferograms to obtain the complex spectral interferogram.

Abstract: An apparatus for and method of detecting fires comprising detecting (with one or more detectors) levels of carbon monoxide, carbon dioxide, and smoke in an ambient environment, computing (using a processor) over time rates of increase of each of the levels, and generating an alarm if one or more of the rates of increase exceed predetermined threshold rates of increase.

Abstract: An absorption spectroscopy method comprising providing a sample in a container, rotating the container, while rotating the container, directing a beam of electromagnetic radiation through the container, the beam comprising one or more wavelengths selected from the group consisting of visible wavelengths, infrared wavelengths, and ultraviolet wavelengths, and measuring characteristics of the beam after it passes through the container. Also an absorption spectroscopy apparatus comprising a container holder, a drive rotating the container holder, means for, while rotating the container, directing a beam of electromagnetic radiation through the container, the beam comprising one or more wavelengths selected from visible wavelengths, infrared wavelengths, and ultraviolet wavelengths, and means for receiving the beam after passage through the container.

Abstract: A multiple pass optical cell and method comprising providing a pair of opposed cylindrical mirrors having curved axes with substantially equal focal lengths, positioning an entrance hole for introducing light into the cell and an exit hole for extracting light from the cell, wherein the entrance hole and exit hole are coextensive or non-coextensive, introducing light into the cell through the entrance hole, and extracting light from the cell through the exit hole.