Propagation equation of Gaussian beams through apertured focusing systems and parametric study of focal shift

摘要

Diffraction of a Gaussian beam passing through a circular aperture subsequently focused by a lens is investigated. An expression is derived for the amplitude distribution beyond the lens. With the aid of the axial intensity and encircled energy, the effect of the aperture-lens separation on the focal shift is obtained, and the quantitative influence of the truncation parameter and Fresnel number on the focal shift is also presented. (c) 2019 Optical Society of America.