A Compact and Fast Long-Wave Infrared (LWIR) Spectroscopy System for Aerosol Combustion

To fully understand the combustion dynamics when chemical warfare agents are detonated, fast time-scale diagnostics are needed. While computational modeling may provide insight into the different processes, experimental measurements are needed to verify and validate these models. Since the detonation or combustion of chemical agents can result in optically thick fireballs, innovative techniques must be used to analyze the turbulent mixing of chemicals with oxygen and detonation products, and to characterize their evolution both spatially and temporally. To meet these needs, we propose the development of a broadly tunable frequency-swept long-wave infrared (LWIR) external cavity quantum cascade laser (ECQCL). Preliminary experiments performed for the measurement of trace chemical warfare agent simulant in our lab show that our proposed ECQCL system can operate at 1 kHz or faster, allowing temporal resolution better than 1 ms. Another benefit of our ECQCL system is that by using long wave IR, it can probe deeper into the optically thick fireballs. Our proposed system will be an ideal candidate to perform lab scale experiments at high temperature and high pressures, and can be hardened for outdoor field tests.