Far-field disentanglement of modes in hybrid plasmonic-photonic crystals by fluorescence nano-reporters

In this paper, the resonance modes exhibited by a hybrid nanostructure have been disentangled in the far-field owing to narrow-band fluorescence nano-reporters. Hybrid plasmonic-photonic crystals were fabricated using large (457 nm) monodisperse polystyrene spheres self-assembled into 2D photonic crystals and subsequently coated by a 30 nm thick silver layer. Such structures exhibit a complex resonance pattern, which has been elucidated owing to numerical simulations and electric near-field patterns obtained with a scattering type scanning near-field optical microscope (s-SNOM). For the sake of disentangling the resonance modes of the hybrid structure in the far-field, different types of semiconductor quantum dots (QDs), acting as nano-reporters of the local interactions, were dispersed on top of distinct structures. Depending on the relative overlap of the emission spectrum of a particular type of QDs with the resonance features of the hybrid structure, we affect their emission rate in a unique way, as a consequence of the complex interaction occurring between the plasmo-photonic modes and the excitons. Such plasmonic structures appear to be particularly relevant for fluorescence-based sensing devices.