Standoff detection of ozone in an open environment using photoacoustic spectroscopy technique

The current work reports a practical photoacoustic spectroscopy (PAS) technique that can be applied for the standoff detection of ozone in an open environment. The developed PAS detection system consists of a laser, a parabolic acoustic reflector, and an acoustic resonator that acts as a lock-in amplifier to extract only the signals resonating with the laser chopping frequency. The design of the acoustic resonator is described, and a detection capability of 700ppb ozone at 2m distance in the ambient air is demonstrated. The system would have broad applications for open-air detection of chemicals in various forms.