Spectral tuning of localised surface plasmon-polariton resonance in metallic nano-crescents.

The utilisation of plasmonic effects in metallic nanostructures is gaining importance for applications in molecular sensing. Of special interest is the local field enhancement effect, which enables surface-enhanced Raman scattering and significantly boosts the sensitivity of the Raman technique. For in vivo biological research, the ability to excite the resonance of localised surface plasmon-polaritons within the biological window is often desired. A new nanostructure called the nano-crescent is introduced and exhibits strong plasmonic activities within the biological window using a novel intra-particle plasmonic coupling scheme.