Abstract: The present invention provides a system for measuring concentrations of trace gases in gas mixtures using the absorption spectroscopy method. The system comprising an optical cell containing a gas mixture, a continuous-wave stepwise tunable external cavity laser, a detector system for measuring an absorption of laser light by the gas in the optical cell, and a processor to conduct an absorption spectroscopy analysis of the gas mixture based on light intensity measured by the detector system at one or more laser frequencies.

Abstract: The present invention provides a system for measuring concentrations of trace gases in gas mixtures using an absorption spectroscopy method. The system comprising: a resonant optical cavity containing a gas mixture, a continuous-wave external cavity laser, a detector system for measuring an absorption of laser light by the gas in the resonant optical cavity, wherein the ratio of the round-trip length of the external cavity laser to the round-trip length of the resonant optical cavity or its inverse value is between N?0.2 and N+0.2, where N is a positive integer number.

Abstract: Systems and methods for detecting trace gases utilize a resonance optical cavity and one, two or more coherent light sources coupled to the cavity through one or more cavity coupling mirrors, whereby two or more optical cavities may share the same gas volume.

Abstract: The present invention provides a system for measuring concentrations of trace gases in gas mixtures using the absorption spectroscopy method. The system comprising an optical cell containing a gas mixture, a continuous-wave stepwise tunable external cavity laser, a detector system for measuring an absorption of laser light by the gas in the optical cell, and a processor to conduct an absorption spectroscopy analysis of the gas mixture based on light intensity measured by the detector system at one or more laser frequencies.

Abstract: The present invention provides a system for measuring concentrations of trace gases in gas mixtures using an absorption spectroscopy method. The system comprising: a resonant optical cavity containing a gas mixture, a continuous-wave external cavity laser, a detector system for measuring an absorption of laser light by the gas in the resonant optical cavity, wherein the ratio of the round-trip length of the external cavity laser to the round-trip length of the resonant optical cavity or its inverse value is between N?0.2 and N+0.2, where N is a positive integer number.

Abstract: The present invention provides a system for measuring concentrations of trace gases in gas mixtures using the absorption spectroscopy method. The system comprising: a resonant optical cavity, a continuous-wave stepwise tunable external cavity laser having a DFB laser as a gain media; a detector system for measuring an absorption of laser light by the gas in the resonant optical cavity, wherein the roundtrip optical cavity length of the external cavity laser are the roundtrip optical cavity length of the resonant cavity are close.

Abstract: The present invention provides systems and methods for measuring the isotope ratios of one or more trace gases based on optical absorption spectroscopy methods. The system includes an optical cavity containing a gas. The system also includes a laser optically coupled with the optical cavity, and a detector system for measuring absorption of laser light by the gas in the cavity.

Abstract: The present invention provides a system for measuring concentrations of trace gases in gas mixtures using the absorption spectroscopy method.

Abstract: The present invention provides systems and methods for measuring the isotope ratios of one or more trace gases based on optical absorption spectroscopy methods. The system includes an optical cavity containing a gas. The system also includes a laser optically coupled with the optical cavity, and a detector system for measuring absorption of laser light by the gas in the cavity.

Abstract: Method of measuring a ratio of concentrations of two isotopologues of a chemical species in a first gas mixture using an optical absorption spectroscopy based gas analyzer; the method includes measuring the line intensity of a rotational-vibrational line of one isotopologue and the line intensity of another rotational-vibrational line of another isotopologue. The method also includes determining the ratio of two line intensities and comparing it with another ratio measured using another gas analyzer for a gas mixture with known concentration of isotopologues. The second ratio can be measured for the same pair of lines or for different pair of lines. The second ratio can be measured at the same gas temperature or at different gas temperature. The method includes determining a ratio of concentrations of two isotopologues based on two ratios of line intensities and two temperatures.

Abstract: Method of measuring a ratio of concentrations of two isotopologues of a chemical species in a first gas mixture using an optical absorption spectroscopy based gas analyzer; the method includes measuring the line intensity of a rotational-vibrational line of one isotopologue and the line intensity of another rotational-vibrational line of another isotopologue. The method also includes determining the ratio of two line intensities and comparing it with another ratio measured using another gas analyzer for a gas mixture with known concentration of isotopologues. The second ratio can be measured for the same pair of lines or for different pair of lines. The second ratio can be measured at the same gas temperature or at different gas temperature. The method includes determining a ratio of concentrations of two isotopologues based on two ratios of line intensities and two temperatures.

Abstract: Systems and methods for measuring the isotope ratio of one or more gaseous oxides produced during combustion of drugs, pharmaceuticals, or medicines aiming to detect counterfeit drugs, pharmaceuticals, or medicines based on comparison of the isotopic composition of the tested drugs, pharmaceuticals, or medicines with the isotopic composition of the authentic products.

Abstract: The present invention provides systems and methods for measuring the isotope ratios of one or more trace gases based on optical absorption spectroscopy methods. The system includes an optical cavity containing a gas. The system also includes a laser optically coupled with the optical cavity, and a detector system for measuring absorption of laser light by the gas in the cavity.

Abstract: The present invention provides a system for measuring concentrations of trace gases in gas mixtures using the absorption spectroscopy method.

Abstract: Systems and methods for detecting trace gases utilize a resonance optical cavity and one, two or more coherent light sources coupled to the cavity through one or more cavity coupling mirrors, whereby two or more optical cavities may share the same gas volume.

Abstract: Systems and methods for detecting trace gases utilize a resonance optical cavity and a coherent light source coupled to the cavity through a cavity coupling mirror. The cavity is constructed of a material having the same or a similar coefficient of thermal expansion as the mirror elements defining the cavity. The main (bulk) cavity material may be the same as the main (bulk) material that forms the mirror elements, or it may be different. Such resonant cavity configurations provide improved accuracy and stability as compared to existing cavity configurations based upon similar principles.

Abstract: Systems and methods for measuring the isotope ratio of one or more trace gases and/or components of gas mixtures such as different gas species present in a gas mixture. The system includes a resonant optical cavity having two or more mirrors and containing a gas, the cavity having a free spectral range that equals the difference between frequencies of two measured absorption lines of different gas species in the gas, or of two different isotopes, divided onto an integer number. The system also includes a continuous-wave tunable laser optically coupled with the resonant optical cavity, and a detector system for measuring an absorption of laser light by the gas in the cavity. The detector system includes one of a photo-detector configured to measure an intensity of the intra-cavity light or both a photo-acoustic sensor configured to measure photo-acoustic waves generated in the cavity and a photo-detector configured to measure an intensity of the intra-cavity light.

Abstract: Laser-based spectroscopy systems and methods including a laser source that emits a beam of radiation, an optical resonant cavity having at least two cavity mirrors, and at least one beam filtering element positioned along a path of the beam external to the cavity and having a front surface, wherein the front surface is oriented such that an intersection of the beam and the surface is at an angle, such as the Brewster's angle or a pseudo-Brewster's, that reduces or eliminates reflection of a predominant polarization component of the beam by the filtering element.

Abstract: Systems and methods for measuring the isotope ratio of one or more trace gases and/or components of gas mixtures such as different gas species present in a gas mixture. The system includes a resonant optical cavity having two or more mirrors and containing a gas, the cavity having a free spectral range that equals the difference between frequencies of two measured absorption lines of different gas species in the gas, or of two different isotopes, divided onto an integer number. The system also includes a continuous-wave tunable laser optically coupled with the resonant optical cavity, and a detector system for measuring an absorption of laser light by the gas in the cavity. The detector system includes one of a photo-detector configured to measure an intensity of the intra-cavity light or both a photo-acoustic sensor configured to measure photo-acoustic waves generated in the cavity and a photo-detector configured to measure an intensity of the intra-cavity light.

Abstract: Systems and methods for controlling the optical path length between a feedback enabled laser and a cavity, and hence the optical feedback phase. A phasor element, positioned along an optical path between the laser and the cavity coupling mirror, includes a gas medium within a volume defined by the phasor element. The phasor element is configured to adjust or control an optical path length of the laser light between the laser and the cavity coupling mirror by adjusting or controlling a density of the gas medium within the phasor volume.