Efficient and enhanced optical switches based on saturation absorption via composite of 2D materials. (June 2023) - Balaei, Mohsen
Abstract: In this study, linear and nonlinear optical absorption has been investigated in a composite consisting of thin film wrapped nano-sphere dielectrics. This type of plasmonic coupled hybridized nano-elements can lay the groundwork for many functional devices. The graphene-based coupled plasmonic structure could benefit from superior plasmons and new coupled plasmon modes. By taking advantage of theoretical concepts based on quasi-static approximation and experimental data, it is shown that achieving high modulation depth ( ∼ 94 % ) is possible. Apart from the high modulation depth, saturation intensity, linear and nonlinear absorption can be controlled through adjusting optical and geometrical parameters of the composite. This model proves excellent saturable absorber characteristics particularly its outstanding nonlinear optical properties, which show outstanding potential in manufacturing high-performance and new functional optoelectronic devices. Highlights: Transmission, refraction, and absorption in a composite of nano-spherical dielectrics coated with thin-film (mono-layer of graphene or WS 2 ) are investigated. The magnitude of nonlinearity properties is controllable by the optical and geometric parameters of nanoparticles. Nonlinearity can be enhanced from 2.5% (for a monolayer of graphene) to 82% (for a designed composite with graphene coating layer) and from 4.7% (for a monolayer of WS 2 ) to 94% (for designed composite with graphene coating layer). This saturable absorber can be realized for practical passive Q-switching as the main technique to modulate CW into a pulse state or reduce pulse duration.