Highly Chiral Light Emission Using Plasmonic Helicoid Nanoparticles

Materials generating circularly polarized luminescence (CPL) have received increasing interest due to their potential applications in bioimaging, sensing, anticounterfeiting, and display technologies. The possibility of efficient CPL generation is explored for organic molecules, inorganic materials, and their hybrid systems. A chiral plasmonic nanostructure is one candidate for generating strong and highly dissymmetric CPL by coupling with the surrounding luminescent material. Here, the inherent luminescence of gold nanoparticles can produce CPL without using any secondary material is suggested. In this study, the generation of circularly polarized two-photon-induced photoluminescence (TPI-PL) from chiral gold nanostructures is demonstrated. Measurements of TPI-PL show that it has a strong dissymmetry factor of approximate to 0.7 for a single chiral Au nanoparticle. A theoretical simulation study showed that a local chiral electromagnetic field confined to the chiral gap structures contributes to the high degree of circular polarization in TPI-PL. It is believed that this work provides a new route for novel CPL-generating materials with strong dissymmetry and holds promise for various applications using CPL technology. Chemically synthesized chiral gold nanoparticles produce highly circularly polarized luminescence via two-photon excitation. The localized chiral plasmonic field in the chiral gap structure is coupled with the intrinsic photoluminescence of gold and produces visible light emission with a high degree of luminescence dissymmetry (glum approximate to 0.7) at the single nanoparticle level. image