Tunable local surface plasmon resonance in liquid-crystal-coated Ag nanoparticles

• We investigate a model based on the casuistic theory.
• Varying metallic material of core can tune the resonant wavelength.
• Varying anisotropy extent can tune and modulate resonant wavelength.
• Varying the thickness can tune and modulate resonant wavelength.
• Enhancement with anisotropy and isotropy shell is comparative.

The far-field and near-field properties of a spherical nematic liquid crystal (NLC) coated metal nanoparticle (NPs) have been investigated in an external field, basing on the quasistatic theory. The resonant wavelength is tunable by varying metallic material of core, anisotropy extent and thickness of liquid crystals (LCs). The field enhancement is along the incident polarization near the outer surface of the shell. The direction of field is reverse in the inner surface comparing with the one if outer shell. In contrast to isotropy shell, the surface plasmon resonance (SPR) shows an obvious red shift and field enhancement near outer surface of the shell always is stronger.