Additional enhancement of SERS effect by a surface wave in photonic crystal

We propose and demonstrate an enhancement of the Raman signal additional to that provided by the surface‐enhanced Raman spectroscopy (SERS) effect. Such an additional enhancement appears due to a resonance attributed to the existence of a surface wave at a photonic crystal (PC)/vacuum interface. Such a PC is realized as a system of alternating layers deposited on a prism, through which light enters the structure. The SERS‐active layer of aggregates of gold nanoparticles modified by dithionitrobenzoic acid is deposited on the PC/vacuum interface, where the resonant field is located. In the experiment, up to 170‐fold SERS signal enhancement is demonstrated with respect to the same SERS‐active layer deposited at a nonresonant substrate. We propose and demonstrate an enhancement of the Raman signal additional to that provided by the surface‐enhanced Raman spectroscopy (SERS) effect. Enhancement appears due to a resonance attributed to the existence of a surface wave at a photonic crystal/vacuum interface. Up to 170‐fold SERS signal enhancement is demonstrated experimentally with respect to the same SERS‐active layer deposited at a nonresonant substrate.