Giant light absorption by plasmons in a nanoporous metal film

✍ Scribed by Teperik, T. V. ;Popov, V. V. ;García de Abajo, F. J.

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 132 KB
• Volume: 202
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200460349

✦ Synopsis

Abstract

We have calculated the light absorption spectra of a metal film containing a hexagonal two‐dimensional lattice of spherical nano‐voids. It is shown that giant resonant absorption of light occurs at the plasma resonance of the void lattice in the visible when the void‐to‐surface distance and the inter‐void spacing are thinner than the skin depth. The maximum absorbance, at plasma resonance, is shown to be 50%. This phenomenon occurs when the void‐to‐surface distance has a specific value, which ensures optimal coupling of plasmons in the voids to the external light. We have found a physical criterion for the optimal coupling, which reads that the radiative broadening of the plasma resonance must be equal to its dissipative broadening in order to produce maximum light absorption at the resonance. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)