Theoretical Investigation of Coupling of Surface Plasmons in One-dimensional Periodic Structure of SiO2 and TiO2 with Defect of Nanocomposite of Liquid Crystals and Core–Shell Nanoparticles

In this work, we theoretically investigate the coupling of localized surface plasmon resonance (LSPR) of nanocomposite layer through the near field enhancement in the host matrix which tunes the optical properties of one-dimensional photonic crystal (1DPC). The surface plasmons appear on the interface of nanocomposite (NC), and dielectric layer gets affected by the variation of dielectric permittivity of NC through the changes in the core radii and shell thickness as well as filling fraction (f). To design the NC, we have considered core–shell nanoparticles of silver (Ag) core and silicon (Si) shell embedded in E7 liquid crystal as host. The coupling of LSPRs through the near field enhancement exhibits tunable resonant peaks and band edges of PBG in the transmission spectra and such characteristics have been discussed using transfer matrix method (TMM) in this study. Also, the filling fractions of Ag@Si nanoparticles and the incident angles of the electromagnetic wave affect the transmission properties of designed configuration as (TiO2|SiO2)5|NC|(TiO2|SiO2)5. The study of proposed structure reveals the effect of metallic core and dielectric shell on the reflection and absorption properties of 1DPC as well as on the near-field coupling. The increment of core radii or shell thickness shows the enhanced metallic property or dielectric property of NC layer. The designed 1DPC can be used in the various devices as energy efficient optical filters, sensors, solar cells, photo-detectors and all-optical switching devices.