Development of a High Precision, Quantum Cascade Laser-Based Detector for Carbon Dioxide and Carbon Monoxide

70814 Measurements of atmospheric concentrations of CO2 and CO from aircraft and remote sites play a central role in strategies for quantifying the sources and sinks of carbon and for controlling global warming from greenhouse gas emissions. A highly sensitive, automated, and robust sensor for CO2 and CO is needed for this purpose. This project will develop an instrument to measure CO2 and CO using newly available ¿quantum cascade¿ lasers that operate in the mid-infrared spectral region without cryogenic cooling. Novel optical designs and judicious selection of the infrared absorption line for CO2 will result in an extremely stable and compact instrument with negligible dependence on ambient operating temperature and pressure. Phase I will investigate the feasibility of using pulsed quantum cascade lasers for high precision absorbance measurements and will demonstrate that the precision requirements for mixing ratios of CO2 (¿100 ppb) and CO (¿2 ppb) can be achieved in the laboratory. Preliminary designs for a field instrument for signal processing, optical-mechanical layout, and calibration protocol will be developed. In Phase II, the instrument will be built and deployed from a light aircraft or a remote surface site. Commercial Applications and Other Benefits as described by the awardee: A improved instrument for CO2 measurements would be widely applicable to environmental and ecological research in addition to the measurement of atmospheric trace gasses. A sensitive, cryogen-free, mid-infrared absorption spectrometer also would have commercial applications in medical diagnostics and industrial process monitoring for detecting a wide variety of gas phase molecules.