摘要 |
A photoacoustic sensing device includes a laser tuned to emit light to cause optical absorption by a gas to be detected, a resonant acoustic sensor positioned to receive pressure waves from the gas, wherein the laser is modulated to match a resonant frequency of the resonant acoustic sensor, and a first mirror positioned to receive light from the laser after the light has passed through the gas and to reflect the received light back through the gas to cause additional optical absorption.
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