Objective: The localized surface plasmon resonance (LSPR) and field enhancement of
multilayered nanostructure over single and dimer configuration is studied using finite difference
time domain (FDTD) method.
Experimental: In multilayered nanostructure, there exist concentric nanoshells and metallic core
which are separated by a dielectric layer. Strong couplings between the core and nanoshell plasmon
resonance modes show a shift in LSPR and enhancement in field around nanostructure. The
calculation of the electric field enhancement shows a sharp increase in the electric field on the surface
of inner core i.e., inside the dielectric layer of Metal-Dielectric-Metal (MDM) structure
whereas smaller enhancement on the outer layer of MDM structure is observed.
Results: The Au-Air-Au mono MDM nanostructure shows strong near-field enhancement as compared
to bare nanosphere in the infrared region, which have potential applications in surfaceenhanced
spectroscopy, whereas Al-Air-Al and Ag-Air-Ag shows potential towards lower wavelength
region. On coupling the MDM nanostructure forming a dimer configuration the field enhancement
factor increases to 10^8.
Conclusion: As compared to other nanostructures, MDM nanostructure provides both strong field
enhancement and wide wavelength tunability therefore promising for surface enhanced Raman
spectroscopy (SERS) applications.