Second-harmonic generation in one-dimensional metal gratings with dual extraordinary transmissions

We investigate the enhanced second-harmonic generation (SHG) in nonlinear metal gratings with simultaneously extraordinary optical transmissions (EOTs) for the fundamental and the second-harmonic wavelengths, i.e., dual EOTs. We show that the strongly temporal and spatial dispersions at Wood's anomalies, the asymmetry in the grating structure and the intrinsic dispersion of the media are of great importance in achieving dual-EOT SHG. Metal gratings with dual EOTs are present and the maximum enhancement on SHG is around 20. Weak points of dual-EOT SHG, potential improvement and future applications are discussed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3327215]