A differential absorption lidar has been built to measure CO<sub>2</sub> concentration in the atmosphere. The transmitter is a pulsed single-frequency Ho:Tm:YLF laser at a 2.05-μm wavelength. A coherent heterodyne receiver was used to achieve sensitive detection, with the additional capability for wind profiling by a Doppler technique. Signal processing includes an algorithm for power measurement of a heterodyne signal. Results show a precision of the CO<sub>2</sub> concentration measurement of 1%–2% 1ς standard deviation over column lengths ranging from 1.2 to 2.8 km by an average of 1000 pulse pairs. A preliminary assessment of instrument sensitivity was made with an 8-h-long measurement set, along with correlative measurements with an <i>in situ</i> sensor, to determine that a CO<sub>2</sub> trend could be detected.
© 2004 Optical Society of America
(140.0140) Lasers and laser optics : Lasers and laser optics
(140.3580) Lasers and laser optics : Lasers, solid-state
(280.0280) Remote sensing and sensors : Remote sensing and sensors
(280.1910) Remote sensing and sensors : DIAL, differential absorption lidar
Grady J. Koch, Bruce W. Barnes, Mulugeta Petros, Jeffrey Y. Beyon, Farzin Amzajerdian, Jirong Yu, Richard E. Davis, Syed Ismail, Stephanie Vay, Michael J. Kavaya, and Upendra N. Singh, "Coherent Differential Absorption Lidar Measurements of CO2," Appl. Opt. 43, 5092-5099 (2004)