Evidence for localized surface plasmon polaritons in a liquid crystal containing gold nanoparticles*

We report an observation of the localized surface plasmon polaritons (SPPs) in a nematic liquid crystal containing 14 nm diameter gold nanoparticles (Au NPs). We observe attenuated total reflection (ATR) of p-polarized laser beam incident upon a high-index prism/liquid-crystal-Au-NPs/glass structure used in the Kretschmann configuration.$^{1}$ Unlike the ubiquitous ATR configuration, in which the prism base is coated with a noble metal thin film, our experimental set up does not utilize any such coating. The ATR observed at a specific incident angle and only for p-polarized laser reflects the excitation of localized SPPs at NP/liquid-crystal interface. We discuss possible SPPs related effects, which can significantly change the electro-optical properties of polymer-dispersed liquid crystals.$^{2}$