Multiple jet engine pollutant measurement with tunable diode laser arrays

This SBIR Phase1 project will involve the development of a novel method of simultaneously measuring multiple trace chemical species in jet engine exhaust, based upon an extension of the technology of tunable diode laser (TDL) spectroscopy. We will develop and demonstrate a new means of combining the light from two or more diode lasers into a single analysis beam. This will enable a multiplication of the number of chemical species which are simultaneously measured. The type of beam multiplexing technique which we intend to investigate has not been previously demonstrated in a TDL system. This type of measurement system will serve the needs of quantifying aircraft exhaust in several ways. The simultaneous measurement of minor constituents and either CO2 or H2O allows the determination of an emission index for the minor species. A greater number of simultaneous concentration measurements allows a better understanding of the basic chemistry of the combustion process and will enable development of engine systems with reduced emissions. The proposed technology can enhance existing TDL systems, including two currently used by NASA in combustion emissions studies, and others in use in atmospheric applications.