Broadened region for robust optical bistability in a nonlocal core and Kerr shell nanoparticle.

With the self-consistent mean field approximation in the framework of full-wave nonlocal scattering theory, we carry out a theoretical study on the optical bistability in a nonlocal nanoparticle coated with a Kerr-type nonlinear shell. A nonlocality-enhanced Fano profile is found in its scattering spectrum. We demonstrate the nonlocality-broadened bistable region in the geometrical parameter space. We perform the investigation of the nonlinear dependences of the near-field intensity and far-field scattering on the incident wavelength and find the input-wavelength-controllable as well as the input-field-intensity-controllable scattering. We check the stability of the nonlinear steady states and perform its temporal dynamical evolutions.