Abstract
Nonlinear optical devices and their implementation into modern nanophotonic architectures are constrained by their usually moderate nonlinear response. Recently, epsilon-near-zero (ENZ) materials have been found to have a strong optical nonlinearity, which can be enhanced through the use of cavities or nano-structuring. Here, we study the pump dependent properties of the plasmon resonance in the ENZ region in a thin layer of thin indium tin oxide (ITO). Exciting this mode using the Kretschmann-Raether configuration, we study reflection switching properties of a 60nm layer close to the resonant plasmon frequency. We demonstrate the thermal switching mechanism, which results in a shift in the plasmon resonance frequency of 20THz for a TM pump intensity of 75GW/cm2. For degenerate pump and probe frequencies, we highlight an additional coherent contribution, not previously isolated in ENZ nonlinear optics studies, which leads to an overall pump induced change in reflection from 1% to 45%.
Ultrafast all-optical switching enabled by epsilon-near-zero-tailored absorption in metal-insulator nanocavities
