Abstract

A method of Bessel series expansion of the Gaussian light beam—simpler than any of the other methods recently suggested in the literature—is presented, and its effectiveness for a circularly symmetric wave field is studied. In this method, the convergent speed is much faster than that of the Fourier series, and the precision is fine enough. The distribution of energy concentration of the Gaussian beam in successive Fourier-Bessel transform planes is also calculated. When the ratio between a halfwidth Gaussian beam and the diaphragm radius is 2:3, the energy concentration is optimum at the first transform plane; when the sizes of the aperture of the first transform plane and the entrance diaphragm are the same, the ratio 1:2 is optimum at the second transform plane.

© 1987 Optical Society of America