Quartz-enhanced photoacoustic spectroscopy

A new approach to detecting a weak photoacoustic signal in a gas medium is described. Instead of a gas-filled resonant acoustic cavity, the sound energy is accumulated in a high-Q crystal element. Feasibility experiments utilizing a quartz-watch tuning fork demonstrate a sensitivity of 1.2×10-7 cm-1 W/Hz. Potential further developments and applications of this technique are discussed.