Nonlocality-Broaden Optical Bistability in a Nonlinear Plasmonic Core-Shell Cylinder

With the self-consistent mean-field method in the framework of full-wave nonlocal scattering theory, we theoretically investigate the optical bistability in a nonlocal metallic nanocylinder coated with Kerr-type nonlinear shell. A nonlocality enhanced Fano profile is found for this coated cylinder in the linear limit. We illustrate the relation between the linear plasmonic resonant wavelength and the viable parameters for optical bistability in parameter space. It is found that nonlocality will lead to impressive blue shift of the resonant wavelength, and hence dramatically increase the bistable region in the parameter space of incident wavelength and geometrical factor. We demonstrate the input field-controllable and input-wavelength-controllable scatterings in the nonlinear case, respectively. It indicates that nonlocal effects show opposite influences on these two nonlinear scattering processes, and the bistability in the scattering spectrum is weaken by nonlocality. Our study reveals that these self-tunable optical resonant scatters can be used as all-optical switches and might provide flexible possibilities in the design of optical bitable devices.