title: Algorithm study of Collins formula and inverse Collins formula.
abstract: In the study of a diffraction field of a light wave passing through a symmetrical paraxial optical system, the Collins formula and its inverse are convenient for calculation. The algorithm study of the Collins formula demonstrates that both a single fast Fourier transform algorithm and a double fast Fourier transform algorithm can be used in diffraction calculation. But, whichever algorithm is adopted, only by meeting some specific conditions can the amplitude and phase distributions of a diffracted wave be calculated correctly. Based on the Nyquist sampling theorem, the indispensable conditions to calculate a diffraction field accurately are presented.
authors.affiliation: Kunming University of Science and Technology, 68 Wenchang Road, 1.21 Street, Kunming 650093, Yunnan, China.
authors.forename: Junchang
authors.initials: J
authors.lastname: Li
authors.forename: Chongguang
authors.initials: C
authors.lastname: Li