Tunable intrinsic optical bistability of Au-Ag alloy nanoparticle: Effects of spatial position and Au composition

摘要

The intrinsic optical bistability (IOB) of an Au-Ag alloy nanosphere is theoretically investigated. Calculation results based on quasi-static theory and Kerr nonlinearity show that the optical bistable behavior for both spatial average response and local field at the hot location only exists when the local electric field is enhanced and exceed the threshold intensity, which is dependent on the spatial position and gold composition. Our theoretic investigation also presents a physical picture of how the local field enhancement affects the IOB characters of the alloy nanoparticles.