Abstract
Optical bistability at nanoscale is a promising way to realize optical switching, a key component of integrated nanophotonic devices. In this work we present an analytical model for optical bistability in a metal nano-antenna involving Kerr nonlinear medium based on detailed analysis of the correlation between the incident and extinction light intensity under surface plasmon resonance (SPR). The model allows one to construct a clear picture on how the threshold, contrast, and other characteristics of optical bistability are influenced by the nonlinear coefficient, incident light intensity, local field enhancement factor, SPR peak width, and other physical parameters of the nano-antenna. It shows that the key towards low threshold power and high contrast optical bistability in the nanosystem is to reduce the SPR peak width. This can be achieved by reducing the absorption of metal materials or introducing gain media into nanosystems.
Highlights
It has been commonly acknowledged that all-optical devices at the micrometer and nanometer scales is a promising way towards realization of next-generation ultrafast communication and signal processing systems beyond today’s microelectronics devices, which have gradually encountered limitation in bandwidth and speed
Optical bistability has been predicted by theory or demonstrated by experimental studies to exist in waveguide-ring resonators [5], photonic crystal cavities [6,7,8], plasmonic crystals [9], subwavelength metallic gratings [10], metal gap waveguide nanocavities [11], and nanoantenna with amorphous silicon filled in the gap [12]
We propose to investigate the optical bistability of an optical nano-antenna [13,14,15] because this structure can provide very strong field enhancement in the center gap due to surface plasmon resonance (SPR) and the SPR peak is very sensitive to the refractive index change of the Kerr material used to fill the gap
Summary
It has been commonly acknowledged that all-optical devices at the micrometer and nanometer scales is a promising way towards realization of next-generation ultrafast communication and signal processing systems beyond today’s microelectronics devices, which have gradually encountered limitation in bandwidth and speed. We successfully worked out an analytical model for describing the optical bistability of a metal nano-antenna involving a Kerr nonlinear material, which will be addressed in this letter. We propose to investigate the optical bistability of an optical nano-antenna [13,14,15] because this structure can provide very strong field enhancement in the center gap due to surface plasmon resonance (SPR) and the SPR peak is very sensitive to the refractive index change of the Kerr material used to fill the gap.
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