Abstract: A gas sensor system is provided, comprising: a gas cell operable so as to receive a sample gas; a vacuum system fluidically coupled to the gas cell operable to maintain the sample gas within the gas cell at a sub-ambient pressure; a pressure sensor operable to sense a pressure of the sample gas; a thermally insulated enclosure having the gas cell therein; a heat source or heat exchanger operable to influence an interior temperature of the thermally insulated enclosure; a light source within the thermally insulated enclosure operable to provide a mid-infrared (mid-IR) light into and through the gas cell; a photodetector within the thermally insulated enclosure operable to receive the attenuated mid-IR; and a control system electronically coupled to the vacuum system and to the pressure sensor operable to maintain the sample gas within the gas cell at the predetermined pressure to within one torr (1 Torr).

Abstract: A gas sensor system is provided, comprising: a gas cell operable so as to receive a sample gas; a vacuum system fluidically coupled to the gas cell operable to maintain the sample gas within the gas cell at a sub-ambient pressure; a pressure sensor operable to sense a pressure of the sample gas; a thermally insulated enclosure having the gas cell therein; a heat source or heat exchanger operable to influence an interior temperature of the thermally insulated enclosure; a light source within the thermally insulated enclosure operable to provide a mid-infrared (mid-IR) light into and through the gas cell; a photodetector within the thermally insulated enclosure operable to receive the attenuated mid-IR; and a control system electronically coupled to the vacuum system and to the pressure sensor operable to maintain the sample gas within the gas cell at the predetermined pressure to within one ton (1 Torr).

Abstract: A gas sensor system is provided, comprising: a gas cell operable so as to receive a sample gas; a vacuum system fluidically coupled to the gas cell operable to maintain the sample gas within the gas cell at a sub-ambient pressure; a pressure sensor operable to sense a pressure of the sample gas; a thermally insulated enclosure having the gas cell therein; a heat source or heat exchanger operable to influence an interior temperature of the thermally insulated enclosure; a light source within the thermally insulated enclosure operable to provide a mid-infrared (mid-IR) light into and through the gas cell; a photodetector within the thermally insulated enclosure operable to receive the attenuated mid-IR; and a control system electronically coupled to the vacuum system and to the pressure sensor operable to maintain the sample gas within the gas cell at the predetermined pressure to within one torr (1 Torr).

Abstract: A gas sensor system is provided, comprising: a gas cell operable so as to receive a sample gas; a vacuum system fluidically coupled to the gas cell operable to maintain the sample gas within the gas cell at a sub-ambient pressure; a pressure sensor operable to sense a pressure of the sample gas; a thermally insulated enclosure having the gas cell therein; a heat source or heat exchanger operable to influence an interior temperature of the thermally insulated enclosure; a light source within the thermally insulated enclosure operable to provide a mid-infrared (mid-IR) light into and through the gas cell; a photodetector within the thermally insulated enclosure operable to receive the attenuated mid-IR; and a control system electronically coupled to the vacuum system and to the pressure sensor operable to maintain the sample gas within the gas cell at the predetermined pressure to within one torr (1 Torr).

Abstract: A gas sensor system is provided, comprising: a gas cell operable so as to receive a sample gas; a vacuum system fluidically coupled to the gas cell operable to maintain the sample gas within the gas cell at a sub-ambient pressure; a pressure sensor operable to sense a pressure of the sample gas; a thermally insulated enclosure having the gas cell therein; a heat source or heat exchanger operable to influence an interior temperature of the thermally insulated enclosure; a light source within the thermally insulated enclosure operable to provide a mid-infrared (mid-IR) light into and through the gas cell; a photodetector within the thermally insulated enclosure operable to receive the attenuated mid-IR; and a control system electronically coupled to the vacuum system and to the pressure sensor operable to maintain the sample gas within the gas cell at the predetermined pressure to within one torr (1 Torr).

Abstract: A gas sensor system includes a laser module, optical chamber module, and a gas sensor cell. The laser chamber module includes two laser light sources producing laser light emissions at wavelengths ?1 and ?2, respectively. Each beam path optionally includes an optical isolator. The beam paths enter the housing of the optical chamber module where they are combined into a third wavelength, ?. The housing of the optical chamber module includes an inlet and an outlet for passing a selected target gas. The gas sensor cell mates to the inlet of the housing. The target gas passes through the adjacent gas cell and into the optical chamber module through the inlet. The target gas exits the optical chamber module through the outlet. Within the optical chamber module, a nonlinear crystal receives the laser light emissions at wavelengths ?1 and ?2 and generates the third wavelength, ?3. The wavelength ?3 is selected to be at the mid-IR spectral absorption feature of the target gas, i.e.

Abstract: A gas sensor system includes a laser module, optical chamber module, and a gas sensor cell. The laser chamber module includes two laser light sources producing laser light emissions at wavelengths ?1 and ?2, respectively. Each beam path optionally includes an optical isolator. The beam paths enter the housing of the optical chamber module where they are combined into a third wavelength, ?. The housing of the optical chamber module includes an inlet and an outlet for passing a selected target gas. The gas sensor cell mates to the inlet of the housing. The target gas passes through the adjacent gas cell and into the optical chamber module through the inlet. The target gas exits the optical chamber module through the outlet. Within the optical chamber module, a nonlinear crystal receives the laser light emissions at wavelengths ?1 and ?2 and generates the third wavelength, ?3. The wavelength ?3 is selected to be at the mid-IR spectral absorption feature of the target gas, i.e.

Abstract: A gas sensor system is provided, comprising: a gas cell operable so as to receive a sample gas; a vacuum system fluidically coupled to the gas cell operable to maintain the sample gas within the gas cell at a sub-ambient pressure; a pressure sensor operable to sense a pressure of the sample gas; a thermally insulated enclosure having the gas cell therein; a heat source or heat exchanger operable to influence an interior temperature of the thermally insulated enclosure; a light source within the thermally insulated enclosure operable to provide a mid-infrared (mid-IR) light into and through the gas cell; a photodetector within the thermally insulated enclosure operable to receive the attenuated mid-IR; and a control system electronically coupled to the vacuum system and to the pressure sensor operable to maintain the sample gas within the gas cell at the predetermined pressure to within one torr (1 Torr).

Abstract: This patent describes a new method and apparatus which allows optical cavities to be used simply and effectively as absorption cells for the purpose of performing sensitive absorption spectroscopy. This method introduces a continuous-wave light beam into the cavity using an off-axis cavity alignment geometry to systematically eliminate the resonances commonly associated with optical cavities, while preserving the absorption signal amplifying properties of such cavities. This reduces the complexity of the apparatus considerably compared with other optical cavity-based absorption methods when applied in conjunction with either cavity ringdown spectroscopy or integrated cavity output spectroscopy. This method can also be used to characterize other optical loss processes occurring within the cavity such as scattering or total extinction coefficients, and to determine the losses due to the cavity mirrors themselves (reflectometry).

Abstract: Chemically specific fiber and waveguide sensors are formed in a fiber optic or optical waveguide material in which injected light is trapped within a Bragg grating optical cavity. The Bragg cavity effectively traps the light for long times, corresponding to effective path lengths equal to hundreds or thousands of meters in the fiber or waveguide medium. The Bragg grating optical cavity is surrounded by a cladding of chemically sensitive material whose optical properties change when exposed to specific chemicals or classes of chemicals. The change in the optical properties of the cladding results in a change in the light trapping characteristics of the fiber or waveguide. Changes in optical transmission of the fiber optic or waveguide sensor can then be related to the concentration of specific chemicals or classes of chemicals in the environment surrounding the sensor.