Multispectral plasmonic supercells

By excitation of surface plasmon-polariton modes upon a multi-periodic metallic surface, we presented a new class of semiconductor-based multiband plasmonic supercell with potential application in trapping the light over a wide range of wavelengths and angles of incidence. The concept for three encoded periods corresponding to different spatial frequencies of surface modulation function at a silver:germanium interface shows a plasmon-enhanced absorption probability of 18.13% in a wide wavelength band of 400–1200 nm. This translates to an enhanced absorption factor of 7.5% in the Ge photoactive layer for a multiband structure compared to that of a single-band. (paper)