A laser-based photoacoustic sensor performs trace detection and differentiation of atmospheric NO and NO.sub.2 in order to obtain respective concentrations for NO and NO.sub.2 using photoacoustic spectroscopy. The device of the invention employs a single, pulsed laser having two outputs near 454 nm and...http://www.google.ca/patents/US6160255?utm_source=gb-gplus-sharePatent US6160255 - Laser-based photoacoustic sensor and method for trace detection and differentiantion of atmospheric NO and NO.sub.2
