Abstract

A multi-gas sensing technique based upon two-tone, frequency modulation spectroscopy (TT-FMS) intended for use on a variety of airborne platforms is demonstrated. TT-FMS enables sensitivity comparable to cavity-enhanced methods but with significant advantages in robustness, reliability, power consumption, cost and weight. Multiplexing of TT-FMS provides simultaneous, real-time measurement of carbon dioxide and methane using a single optical path and detector. With standard telecommunication laser diodes used as light sources, the measurement precision of 1–2 × 10⁻⁶ Hz^−1/2 is demonstrated.

© 2015 Optical Society of America