Bloch Surface Waves on dielectric photonic crystals for sensing applications

In this contribution, we consider Bloch surface waves (BSWs) sustained by truncated one dimensional dielectric photonic crystals (1DPC) aimed to sensing applications. Due to their non-radiative nature, BSWs must be excited by evanescent coupling or high-index prisms, as in the case of surface plasmon polaritons on metal films. The strong confinement of the BSWs is connected to an enhancement of the field amplitude close to the air/dielectric interface of the 1DPC. Confinement appears as narrow resonances with large Q-factors, thus making BSWs particularly interesting for sensing. We shall report on computational and experimental results obtained for 1DPCs samples fabricated by two different technologies: amorphous SixNy 1DPC grown by PECVD and electrochemically etched porous Silicon 1DPC. While the former is used as a suitable platform for fundamental studies on BSWs (attenuated total reflection, spectroscopic and near-field characterization) due to the high flatness of the multilayer interfaces and proposed for biosensing applications, the latter is exploited for gas sensing applications.