Observation of Doubly Scattered Coherent Waves Through Ground Induced Turbulence

Abstract

Building upon the work of Phillips, et al. (1990) and Eric Jakeman (1987), a simple experimental apparatus has been developed and consists of various lasers, a 60 cm beam expander/director designated T1, and a 1220 m target board outfitted with reflectors at the Malabar Test Facility, Phillips Lab OL-AG. Retroreflectors were used to ensure an exact path reversal through the intervening turbulence due solely to temperature differentials at the ground- air interface. This apparatus produces a doubly forward scattered coherent wave. Observation along the twice travelled beam path using a beam splitter and a simple refracting telescope, laser line filter, and video camera produced a basic gaussian profile with a 3db enhancement peak due to stong turbulence.