Cavity enhanced photo acoustic gas sensor
First Claim
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1. A gas sensor comprising:
- an electromagnetic radiation source configured to emit a beam of light;
an optical cavity defined by three or more optical segments separating at least two mirrors, the at least two mirrors being configured to reflect the beam of light through the three or more optical segments, wherein one of the at least two mirrors is an entrance mirror configured to couple at least a portion of the beam of light from the electromagnetic radiation source into the optical cavity;
a photo acoustic cell provided at least partially in one or more of the optical segments of the optical cavity, the photo acoustic cell configured to receive a gas and contain the gas so as to prevent the at least two mirrors from being exposed to the gas; and
a detector acoustically coupled to the photo acoustic cell, the detector configured to detect an acoustic signal that is related to the absorption of the beam of light by the gas in the photo acoustic cell.
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Abstract
Devices and method for photo acoustically detecting a gas are disclosed. In one illustrative embodiment, a gas sensor includes an optical cavity defined by one or more optical segments separating at least two mirrors. A photo acoustic cell, configured to receive a gas from the surrounding environment, is provided at least partially within one or more of the optical segments of the optical cavity. One of the at least two mirrors is configured to couple electromagnetic radiation into the optical cavity and to interact with the gas. A detector is acoustically coupled to the photo acoustic cell to detect absorption of the electromagnetic radiation by the gas.
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Citations
20 Claims
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1. A gas sensor comprising:
- an electromagnetic radiation source configured to emit a beam of light;
an optical cavity defined by three or more optical segments separating at least two mirrors, the at least two mirrors being configured to reflect the beam of light through the three or more optical segments, wherein one of the at least two mirrors is an entrance mirror configured to couple at least a portion of the beam of light from the electromagnetic radiation source into the optical cavity; a photo acoustic cell provided at least partially in one or more of the optical segments of the optical cavity, the photo acoustic cell configured to receive a gas and contain the gas so as to prevent the at least two mirrors from being exposed to the gas; and a detector acoustically coupled to the photo acoustic cell, the detector configured to detect an acoustic signal that is related to the absorption of the beam of light by the gas in the photo acoustic cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 19)
- an electromagnetic radiation source configured to emit a beam of light;
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10. A photo acoustic gas sensor comprising:
- a laser configured to emit a beam of light having a wavelength corresponding to an absorption wavelength of a gas to be detected;
an optical cavity including at least two mirrors separated by three or more optical segments, wherein one of the at least two mirrors couples the beam of light from the laser into the optical cavity, wherein one of the at least two mirrors is electrically tunable to move the optical cavity in and out of a resonance condition, wherein the one of the at least two mirrors that is electrically tunable is configured to deform the mirror around at least one node position according to an applied electrical signal; a photo acoustic cell disposed at least partially within one or more of the optical segments of the optical cavity, the photo acoustic cell configured to receive the gas to be detected; and an acoustical detector acoustically coupled to the photo acoustic cell to detect the interaction of the beam of light and the gas. - View Dependent Claims (11, 12, 13, 14, 18, 20)
- a laser configured to emit a beam of light having a wavelength corresponding to an absorption wavelength of a gas to be detected;
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15. A method of photo acoustically detecting a gas, the method comprising:
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activating a laser to provide a light beam having a wavelength corresponding to an absorption line of a gas; transmitting the light beam into an optical cavity via one of at least two mirrors, wherein the optical cavity includes the at least two mirrors separated by three or more optical segments, wherein one of the at least two mirrors is electrically deformable according to an applied electrical signal; providing a gas in a photo acoustic cell, wherein the photo acoustic cell intersects one or more of the optical segments; and detecting an absorption of the laser beam by the gas in the photo acoustic cell with an acoustical detector. - View Dependent Claims (16, 17)
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Specification