Metallic rugate structures are theoretically investigated for achieving near-perfect absorption in the visible and near-infrared regions. Our model builds on nanoporous metal films whose porosity (volume fraction of voids) follows a sinewave along the film thickness. By setting the initial phase of porosity at the top surface as 0, near-perfect absorption is obtained. The impacts of various structural parameters on the characteristic absorption behaviors are studied. Furthermore, multiple peaks or bands with high absorption can be achieved by integrating several periodicities in one structure. The rugate absorbers show near-perfect absorption for TE and TM polarizations and large incident angles.
© 2012 Optical Society of America
Optics at Surfaces
Original Manuscript: May 4, 2012
Revised Manuscript: June 20, 2012
Manuscript Accepted: July 6, 2012
Published: August 16, 2012
Shiwei Shu and Yang Yang Li, "Metallic rugate structures for near-perfect absorbers in visible and near-infrared regions," Opt. Lett. 37, 3495-3497 (2012)