Enhanced deep ultraviolet inverse polarization transmission through hybrid Al-SiO2 gratings

We report on the enhancement of inverse polarization transmission of deep ultraviolet light, with the TE transmittance eta(TE) largely exceeding the TM transmittance eta(TM), through a hybrid Al-SiO2 grating: The grating slits are conformally filled with SiO2. Strong coupling of the incident wave to surface plasmon polaritons greatly reduces the TM transmittance, whereas the coupling to the low-loss TE mode, with its effective refractive index approaching that of the substrate, leads to the enhanced TE transmittance. At resonance, a pronounced inverse polarization extinction ratio of 35 dB was obtained in our experiment, much higher than any previously reported values. (C) 2013 AIP Publishing LLC.