Abstract

Lord Rayleigh demonstrated that the normalized central irradiance in the image of an infinitesimal object is a sensitive measure of aberration. He utilized this criteria in the study of symmetric and asymmetric aberrations in spectroscopes ¹. Rayleigh's technique was applied by Strehl to the analysis of atmosphere induced wavefront distortions on telescope images ². The normalized central irradiance of the point spread function (PSF) has become known as the Strehl Ratio (SR). SR is now widely used as a figure of merit in optical design. SR is often determined indirectly from interferometric measurements by applying Marechai's relation ³ to the measured wavefront aberration.

© 1990 Optical Society of America