US Patent 7782462 Sono-photonic gas sensor

Sensing a gas includes introducing a gas into a chamber, forming a standing acoustic wave in the chamber, and irradiating the chamber with electromagnetic radiation. Some of the electromagnetic radiation passes into the chamber, through the standing acoustic wave in the chamber, and out of the chamber. An amount of electromagnetic radiation that passes out of the chamber, or is transmitted through the chamber, is detected. A concentration of the gas in the chamber can be assessed.