Liquid–crystal tunable waveguides for integrated plasmonic components

A broad range of liquid–crystal tunable plasmonic waveguides, based on long-range, dielectric-loaded, and channel surface plasmon polaritons, are theoretically designed and investigated. Liquid–crystal switching is rigorously modeled by solving for the coupled elastic/electrostatic problem, whereas the optical studies are conducted via the finite-element method. Extensive tunability of key optical properties, such as modal index, propagation losses, and modal confinement is demonstrated for waveguides of different optical confinement scale. These highly functional waveguiding structures are proposed as building blocks for the design of functional components, e.g. optical attenuators, directional couplers and switches, in integrated plasmonic chips.

► Highly tunable liquid–crystal plasmonic waveguides are designed and theoretically investigated. ► The proposed structures comprise three major plasmonic waveguide types, namely long-range, dielectric-loaded, and channel surface plasmon polariton waveguides. ► The LC reorientation profile is rigorously modeled by solving for the coupled elastic/electrostatic problem. ► By controlling the applied voltage, extensive control of modal index, propagation losses and modal area is demonstrated. ► Tunable properties are shown in three different modal confinement scales: 0.1 μm2, 1 μm2, and 100 μm2.