The present invention provides a laser-based method and apparatus that uses absorption spectroscopy to detect the mole fraction of CO2 in a high temperature gas stream. In a preferred embodiment, a distributed feedback based diode laser sensor operating at a wavelength near 1996.89 nm (5007.787 cm1)...http://www.google.ca/patents/US20020158202?utm_source=gb-gplus-sharePatent US20020158202 - Laser-based sensor for measuring combustion parameters
