Greatly enhanced Kerr nonlinearity in hyperbolic slot waveguides

Waveguides made of hyperbolic metamaterials have unique properties such as extremely high field enhancement. Here we show that hyperbolic slot waveguides, i.e., nanoscale plasmonic slot waveguides cladded by hyperbolic metamaterials can have greatly enhanced Kerr nonlinear effects at even shorter device lengths and lower pump power compared with the conventional metallic slot waveguides. This result points to novel nanoscale waveguide designs for achieving low-driving-power and compact nonlinear nanophotonic devices that are used in diverse applications at both classical and quantum levels.