CHARACTERIZATION OF ATMOSPHERIC-TURBULENCE PHASE STATISTICS USING WAVE-FRONT SLOPE MEASUREMENTS

Turbulence has long been recognized as one of the most significant fac tors limiting the performance of optical systems operating in the pres ence of atmosphere. Atmospheric turbulence over vertical paths has bee n well characterized, both theoretically and experimentally. Much less is known about turbulence over long, horizontal paths. Perturbations of the wave-front phase can be measured with a Hartmann wave-front sen sor (H-WFS). One can use these measurements to characterize atmospheri c turbulence directly. Theoretical expressions for the slope structure function of the H-WFS measurements are derived and evaluated with the use of numerical quadrature. By concentrating on the slope structure function, we avoid the phase reconstruction step and use the slope mea surements in a more direct fashion. The theoretical slope structure fu nction is compared with estimated slope structure functions computed f rom H-WFS measurements collected in a series of experiments conducted by researchers at the U.S. Air Force's Phillips Laboratory. These expe riments involved H-WFS measurements over high-altitude (airborne) hori zontal paths 20-200 km in length. (C) 1996 Optical Society of America.