Abstract: Embodiments relate generally to systems and methods for filtering unwanted wavelengths from an IR detector. In some embodiments, it may be desired to remove or reduce the wavelengths absorbed by water, to reduce the effects of water on the detection of the target gas. In some embodiments, a filter glass may be used in the IR detector, wherein the filter glass comprises one or more materials that contain hydroxyls in their molecular structure, and wherein the spectral absorption properties of the filter glass are operable to at least reduce wavelengths of light absorbed by water from the optical, thereby reducing the IR detector's cross sensitivity to water.

Abstract: A non-dispersive photoacoustic gas detector includes an infrared light source, a first closed chamber, a first acoustic sensor in fluid communication with the first closed chamber, a second closed chamber, and a second acoustic sensor in fluid communication with the second closed chamber. The first closed chamber comprises a plurality of windows that are substantially transparent to infrared light from the infrared light source. The second closed chamber comprises at least one window that is substantially transparent to infrared light from the infrared light source, and the first closed chamber is arranged in series with the second closed chamber between the infrared light source and the second closed chamber.

Abstract: A non-dispersive photoacoustic gas detector comprises an infrared light source, a closed chamber, a gas sample disposed within the closed chamber, and an acoustic sensor in fluid communication with the dosed chamber. The dosed chamber comprises at least one window that is substantially transparent to infrared light from the infrared light source, and the gas sample comprises a gas or a mixture of at least two gases.

Abstract: A non-dispersive photoacoustic gas detector includes an infrared light source, a first closed chamber, a first acoustic sensor in fluid communication with the first closed chamber, a second closed chamber, and a second acoustic sensor in fluid communication with the second closed chamber. The first closed chamber comprises a plurality of windows that are substantially transparent to infrared light from the infrared light source. The second closed chamber comprises at least one window that is substantially transparent to infrared light from the infrared light source, and the first closed chamber is arranged in series with the second closed chamber between the infrared light source and the second closed chamber.

Abstract: Embodiments relate generally to systems and methods for filtering unwanted wavelengths from an IR detector. In some embodiments, it may be desired to remove or reduce the wavelengths absorbed by water, to reduce the effects of water on the detection of the target gas. In some embodiments, a filter glass may be used in the IR detector, wherein the filter glass comprises one or more materials that contain hydroxyls in their molecular structure, and wherein the spectral absorption properties of the filter glass are operable to at least reduce wavelengths of light absorbed by water from the optical, thereby reducing the IR detector's cross sensitivity to water.

Abstract: An illustrative cavity ring down gas sensor includes an optical cavity for receiving a gas to be detected and at least two electromagnetic radiation sources. The first electromagnetic radiation source may emit a first beam of light having a wavelength corresponding to an absorption wavelength of the gas to be detected, and the second electromagnetic radiation source may emit a second beam of light having a second wavelength that is off of an absorption wavelength of the gas to be detected. The first beam of light may detect a cavity ring down time decay, which is related to the concentration of the gas to be detected. The second beam of light may be used to detect a baseline cavity ring down time decay, which may be used to help increase the accuracy of the sensor by, for example, helping to compensate the concentration of the gas detected by the first beam of light for sensor variations caused by, for example, sensor age, temperature or pressure changes, and/or other conditions.

Abstract: A cavity ring down gas sensor may include a radiation source emits an input beam of light having a wavelength corresponding to an absorption line of a gas to be detected. The input beam of light is coupled into an optical cavity to amplify an internal beam of light that is reflected about the optical cavity. An optical element is disposed in the optical cavity at an angle close to, but not at, the Brewster's angle to reflect a relatively small portion of the internal beam of light to a detector. When a specified light intensity is reached in the optical cavity, the input beam of light may be prevented from entering the optical cavity, and a cavity ring down time decay may be measured. The cavity ring down time decay may be related to the gas concentration of a gas to be detected in the optical cavity.

Abstract: An illustrative cavity ring down gas sensor includes an optical cavity for receiving a gas to be detected and at least two electromagnetic radiation sources. The first electromagnetic radiation source may emit a first beam of light having a wavelength corresponding to an absorption wavelength of the gas to be detected, and the second electromagnetic radiation source may emit a second beam of light having a second wavelength that is off of an absorption wavelength of the gas to be detected. The first beam of light may detect a cavity ring down time decay, which is related to the concentration of the gas to be detected. The second beam of light may be used to detect a baseline cavity ring down time decay, which may be used to help increase the accuracy of the sensor by, for example, helping to compensate the concentration of the gas detected by the first beam of light for sensor variations caused by, for example, sensor age, temperature or pressure changes, and/or other conditions.

Abstract: A cavity ring down gas sensor is disclosed. In one illustrative embodiment, the cavity ring down gas sensor includes an electromagnetic radiation source (e.g. laser) configured to emit an input beam of light having a wavelength corresponding to an absorption line of a gas to be detected. The input beam of light may be coupled into an optical cavity to amplify an internal beam of light that is reflected about the optical cavity. An optical element may be disposed in the optical cavity at an angled close to, but not at, the Brewster's angle to reflect a relatively small portion of the internal beam of light in the optical cavity to a detector for determining the intensity of the internal beam of light in the optical cavity. When a specified light intensity is reached in the optical cavity, the input beam of light may be shut off or otherwise prevented from entering the optical cavity, and a cavity ring down time decay may be measured.

Abstract: A system having a multiple-mirror ring-down cavity with one mirror where light may be input into the cavity and light from the cavity may be detected. A valve may permit light to enter or not to enter the cavity. An amplifier may be connected to a detector for detecting light from the cavity. The amplifier may be off or set at a low gain when light is entering the cavity and be on at a medium or high gain at a time when light is not entering the cavity.

Abstract: A system having a multiple-mirror ring-down cavity with one mirror where light may be input into the cavity and light from the cavity may be detected. A valve may permit light to enter or not to enter the cavity. An amplifier may be connected to a detector for detecting light from the cavity. The amplifier may be off or set at a low gain when light is entering the cavity and be on at a medium or high gain at a time when light is not entering the cavity.