Efficient infrared emission from patterned thin metal films on a Si photonic crystal

We study the infrared optical response of periodically patterned thin metal films on a Si photonic crystal using Fourier‐transform infrared spectroscopy and full electrodynamic calculations. Thin metallic films on top of Si substrate were patterned using optical lithography; furthermore the Si substrate was etched, using the metal as a mask. The structures have a narrow band absorption spectrum for wavelengths close to the lattice constant of the patterning. Both Al and Au films gave similar infrared response. Our results can be explained by multiple scattering electrodynamic simulations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)