Efficiency of optical sensing by a plasmonic photonic-crystal slab

A one-dimensional photonic crystal with termination by a noble metal film-a plasmonic photonic-crystal slab-is theoretically analysed for its optical response at the variation of the dielectric permittivity of an analyte. A sharp attenuation peak associated with a 'noble metal-visualized' Bloch surface wave is observed due to plasmon absorption in the metal. We investigate the sensing performance of the slab and show that it is tolerant to the variation of probing conditions and the slab's structural parameters. As a consequence, the considered sensor exhibits an enhanced sensitivity and good robustness in comparison with conventional surface-plasmon and Bloch surface wave sensors.