Abstract
We propose a modified Kretschmann-Raether configuration to realize the low threshold optical bistable devices at the terahertz frequencies. The metal layer is replaced by the dielectric sandwich structure with the insertion of graphene, and this configuration can support TM-polarization surface electromagnetic wave. The surface plasmon resonance is strongly dependent on the Fermi-level of graphene and the thickness of the sandwich structure. It is found that the switching-up and switching-down intensities required to observe the optical bistable behavior are lowered markedly due to the excitation of the graphene surface plasmons, thus making this configuration a prime candidate for experimental investigation at the terahertz range. And the switching threshold value can be further reduced by decreasing the Fermi-level or increasing the thickness of sandwich structure, hence providing a new way for realizing tunable optical bistable devices. Finally, the optical bistability at higher terahertz frequency and the influence of relaxation time under the actual experimental condition on Fermi-level are discussed.
Highlights
This larger nonlinear effect can be realized by using the medium with a high Kerr constant or by designing a nanostructure with high local field effect in the nonlinear regime
Bao et al demonstrated that graphene nanobubbles offer a new and promising type of optical nonlinear medium to overcome the optical path length limitation of atomically thin two-dimensional films, and so that the optical bistability and all optical switching are obtained in this graphene nanobubbles[34]
We have proposed a modified Kretschmann-Raether configuration where the metal layer is replaced by the dielectric sandwich structure with the insertion of monolayer graphene, which can be utilized to realize the tunable optical bistable devices with the ultralow threshold value at the terahertz frequencies due to the excitation of the transverse magnetic (TM)-polarization surface electromagnetic wave
Summary
This larger nonlinear effect can be realized by using the medium with a high Kerr constant or by designing a nanostructure with high local field effect in the nonlinear regime. The switching threshold value of the optical bistability for nonlinear graphene suspending in air is still high due to the lack of the effective coupling mechanism between the photons and graphene, and it requires very larger Fermi-level of graphene at the higher THz frequency.
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