SBIR-STTR Award

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.Advanced Diagnostics,Aerosol Evolution,Long-Wave Infrared Spectroscopy,Chemical Agent Defeat,combustion

We propose developing new instrumentation based on swept-wavelength external cavity quantum cascade lasers (swept-ECQCLs), to acquire physical/chemical data on chemical weapon agent (CWA) and simulant properties in laboratory-scale explosive testing, and to improve/validate computational fluid dynamics (CFD) codes. In Phase I, we demonstrated laboratory measurements of CWA simulant combustion using a swept-ECQCL to measure broadband infrared transmission/absorption spectra through explosive fireballs at a 400 Hz rate and determine fireball temperature and species concentrations versus time. Aerosolized CWA simulants DIMP and TEP were measured and identified unambiguously based on their absorption spectra, and decomposition products ethene and propene were quantified for different explosive test configurations. For Phase II, Opticslah LLC proposes developing the swept-ECQCL instrumentation and analysis algorithms into a hardened prototype, performing extensive laboratory-scale high-explosive testing of the system, and comparing measurements with CFD simulation outputs. The swept-ECQCL instrumentation will provide a versatile diagnostic for high-speed in-situ sensing of CWA simulants in explosive fireballs for immediate applications in CWA-defeat and validation of CFD codes, and future standoff detection with larger-scale explosive testing. The technology will be viable for high-speed chemical sensing applications in additional defense/commercial markets to detect toxic chemicals, perform combustion/engine diagnostics, monitor industrial processes, and more.