Abstract

It is shown for the first time we believe, that when a spherical wave illuminates a certain type of diffracting screen, in addition to the expected focal-shift effect, depending on the value of the Fresnel number of the focusing system, a focal switch effect can appear, i.e., an increase in the height of the lateral lobe of the axial-intensity distribution over that of the central lobe.

© 1996 Optical Society of America

Effective Fresnel-number concept for evaluating the relative focal shift in focused beams

Manuel Martı́nez-Corral, Carlos J. Zapata-Rodrı́guez, Pedro Andrés, and Enrique Silvestre
J. Opt. Soc. Am. A 15(2) 449-455 (1998)

Gaussian imaging transformation for the paraxial Debye formulation of the focal region in a low-Fresnel-number optical system

Carlos J. Zapata-Rodrı́guez, Pedro Andrés, Manuel Martı́nez-Corral, and Laura Muñoz-Escrivá
J. Opt. Soc. Am. A 17(7) 1185-1191 (2000)

Design considerations for low-light level low-Fresnel number optical systems

Christoph Baranec
Appl. Opt. 48(32) 6259-6263 (2009)

Focal shift and concept of effective Fresnel number for a Gaussian laser beam

William H. Carter
Appl. Opt. 21(11) 1989-1994 (1982)

Focal shift in small-Fresnel-number focusing systems of different relative aperture

Yajun Li
J. Opt. Soc. Am. A 20(2) 234-239 (2003)