We analyze the focusing properties of Fresnel zone plates fabricated over steel tapes using laser ablation. Our intention is to implement the use of micro-optical elements when the use of conventional chrome–glass elements is not indicated. Because of the manufacture process, the surface presents a certain anisotropic roughness, which reduces the focusing properties. First, we develop numerical simulations by means of the Rayleigh–Sommerfeld approach, showing how roughness in both levels of the Fresnel zone plate affects the focalization of the lens. We also manufacture Fresnel zone plates over steel tape, and perform experimental verification that corroborates the numerical results.
© 2010 Optical Society of America
Optics at Surfaces
Original Manuscript: October 29, 2009
Revised Manuscript: February 4, 2010
Manuscript Accepted: March 8, 2010
Published: March 24, 2010
Francisco Javier Salgado-Remacha, Luis Miguel Sanchez-Brea, Francisco Javier Alvarez-Rios, and Eusebio Bernabeu, "Rough Fresnel zone plates over metallic surfaces," Appl. Opt. 49, 1750-1756 (2010)