Design and realization of plasmonic nanostructures with large third-order optical nonlinearity

Abstract

We designed an optical structure comprising plasmonic and dielectric materials that exhibits large third-order optical susceptibility and low-power consumption. Finite-difference time-domain simulation results were used to select tightly-packed gold nanosphere (AuNS) film, indium tin oxide (ITO) films, and gold (Au) thin film to construct AuNS/ITO/Au sandwiched nanostructures. Local-field enhancement factors up to 425 and large third-order optical susceptibility (χ(3)) with an amplitude order of 4.4 × 10−2 esu were achieved under an excitation power of 0.1 mW. These χ(3) results are exceptionally high, thereby rendering AuNS/ITO/Au a promising material for future applications in optical switches and related nonlinear optical devices.