Laser microphotoacoustic sensor of ammonia traces in the atmosphere

A microphotoacoustic highly selective sensor of ammonia is built. Main attention is paid to the operation mechanism of the acoustic sensor based on a quartz tuning fork. The optimal dimensions and configuration of the acoustic resonator are determined, which made it possible to increase the sensor sensitivity by two—three times compared to the sensitivity of the existing devices. The detector sensitivity for ammonia was 60ppb (0.05 mg m^-3) for the measurement time of 10s and a 25-mW, 1.53-μm laser beam in the acoustic resonator.