Abstract
Holmes and Rao Gudimetla [J. Opt. Soc. Am. 73, 1119–1122 (1983)] analyze the performance of an adaptive optical system in which the optical path differences caused by atmospheric turbulence are measured at one wavelength and used to compensate an outgoing laser beam of a different wavelength. The wavelength dependence of diffraction is shown to lead to imperfect correction. Earlier work [E. P. Wallner, Proc. Soc. Photo-Opt. Instrum. Eng. 75, 119–125 (1976); J. Opt. Soc. Am. 67, 407–409 (1977)] shows that the wavelength dependence of the index of refraction of air also leads to imperfect correction for beams not directed vertically. In this Communication I compare the refractive and diffractive effects and show that either may be more important, depending on the geometry of the case and the wavelengths used.