Aerosol elastic scatter signatures in the near- and mid-wave IR spectral regions

Abstract

An essential milestone in the development of lidar for biological aerosol detection is accurate characterization of agent, simulant, and interferent scattering signatures. MIT Lincoln Laboratory has developed the Standoff Aerosol Active Signature Testbed (SAAST) to further this task, with particular emphasis on the near- and mid-wave infrared. Spectrally versatile and polarimetrically comprehensive, the SAAST can measure an aerosol sample's full Mueller Matrix across multiple elastic scattering angles for comparison to model predictions. A single tunable source covers the 1.35-5 µm spectral range, and waveband-specific optics and photoreceivers can generate and analyze all six classic polarization states. The SAAST is highly automated for efficient and consistent measurements, and can accommodate a wide angular scatter range, including oblique angles for sample characterization and very near backscatter for lidar performance evaluation. This paper presents design details and selected results from recent measurements.