In recent years several extensive data sets have been collected to characterize horizontal laser propagation in a maritime
environment. We report on data collected on a 1.35-km range over an arm of San Diego Bay. We analyze various
atmospheric turbulence features of the optical propagation data, and we compare the experimental results with numerical
wave-optics simulations. The goals are (a) to extract atmospheric turbulence strength descriptors for the period of record,
and (b) to assess the ability of wave-optics simulation to reproduce the experimental results. We comment on the degrees
of freedom available when comparing simulation and measurement, due to the lack of completely comprehensive
We report scintillometer measurements for near-infrared propagation over a 51.4-km path, at an average altitude of 760 m over mountainous desert terrain. We present time series and histograms of normalized irradiance variance and path-averaged C2n values. We compare the results with an average vertical C2n profile constructed from past balloon measurements. We also present preliminary results on the temporal power spectra of normalized irradiance.
We report aircraft-based scintillometry measurements for visible light propagation over near-horizontal paths of 50 to 120 km, at altitudes around 40,000 ft. We present time series and histograms of normalized irradiance variance and path-averaged Cn2 values. We also present temporal power spectra and covariance functions of irradiance, and derive turbulence inner scale values from the shape of the normalized covariance functions.
We present the results of a Horizontal Propagation Experiment (HoPE) that was performed at the Phillips Laboratory Starfire Optical Range. In this experiment a laser beam was phase corrected using an adaptive optics system located at the transmitting site and focused toward a target located two miles away. Irradiance patterns of the corrected and uncorrected beam were recorded at the target site. Weather and atmospheric turbulence characteristics along the optical path were recorded at the same time. Strehl ratios calculated from the recorded images show that phase-only correction of a horizontally propagated laser beam can significantly improve the energy collected on-axis even under strongly scintillated conditions. Time- averaged strehl ratios were improved by as much as a factor of 5. Improvements in strehl for varying turbulence conditions and the effect of hardware limitations on the results are discussed.