The diffraction of a Gaussian beam normally incident on a circular aperture is investigated by using the boundary-diffraction-wave theory. With the help of the steepest-descent method, an asymptotic representation of the boundary diffraction wave is obtained. The diffracted field, which is the sum of the geometrical-optics component and the diffraction component, is shown to be continuous at the shadow boundary. The diffraction coefficient is compared with that used in Keller’s geometrical theory of diffraction for a plane wave. The error of the asymptotic approximation is also estimated.
© 1980 Optical Society of America
Takashi Takenaka, Masao Kakeya, and Otozo Fukumitsu, "Asymptotic representation of the boundary diffraction wave for a Gaussian beam incident on a circular aperture," J. Opt. Soc. Am. 70, 1323-1328 (1980)