Shipboard Atmospheric Propagation Measurements

Aculight proposes to develop a compact, fieldable instrument which can make direct measurements of aerosol absorption at the wavelengths 1.04, 1.6 and 2.1 microns. The instrument will be capable of measurement of absorption levels as low as 10-9 cm-1. The device will be based upon the use of fiber lasers and a novel photo acoustic detection technique which is immune to background acoustic noise. The sensing technique does not require precise optical misalignment, and the use of fiber lasers will make the optical excitation source highly rugged. Since the sensor will provide a direct measurement of aerosol absorption rather than a difference between extinction and scattering, the measurement will provide data which enhances understanding of thermal blooming which affects high power laser propagation in a maritime atmosphere.