Scanned wavelength diode-laser sensors for harsh environments

摘要

Diode laser absorption offers the possibility of high-speed, robust, and rugged sensors for a wide variety of practical applications. Pressure broadening complicates absorption measurements of gas temperature and species concentrations in high-pressure, high-temperature practical environments. More agile wavelength scanning can enable measurements of temperature and species concentrations in flames and engines as demonstrated by example measurements using wavelength scanning of a single DFB in laboratory flames or a vertical cavity surface emitting laser (VCSEL) in a pulse detonation engine environment. Although the blending of multiple transitions by pressure broadening complicates the atmospheric pressure spectrum of C_2H_4 fuel, a scanned wavelength strategy enables quantitative measurement of fuel/oxidizer stoichiometry. Wavelength-agile scanning techniques enable high-speed measurements in these harsh environments.