ANALYSIS OF MEASURED PHOTON RETURNS FROM SODIUM BEACONS

We describe an approach to the computation of photon returns from meso spheric sodium beacons excited by laser pulse trains and discuss as sp ecific examples the required numbers of photons for adaptive-optical c ompensation of atmospheric turbulence. Computed photon return signals are compared with reported measurements for pulses that are long, shor t, or comparable to the D-2 radiative lifetime (16 ns). Analytical app roximations in good agreement with the numerical computations are deri ved. The results are consistent with experimental data for the differe nt pulse durations. (C) 1998 Optical Society of America.