Fast optical vapour sensing by Bloch surface waves on porous silicon membranes

The coupling of optical Bloch surface waves at the truncated end of one dimensional porous silicon photonic crystals is exploited for fast vapour sensing. Self-standing multilayered membranes bound to transparent substrates were fabricated by electrochemical etching and used in an attenuated total reflection configuration to resonantly excite the surface waves and perform real-time sensing.