Abstract
We theoretically investigate the optical bistability in the metal nanoparticles-graphene nanodisks-quantum dots hybrid plasmonic system in the infrared regime of the electromagnetic radiation. The quantum dot is considered to be a three-level atomic-like system of type interacting with probe and control fields. By using the standard model of the optical bistability where a nonlinear medium is situated in an optical ring cavity, we numerically solve the equation of motion for the density matrix elements that describe the dynamics of the system in steady-state conditions along with the boundary conditions of the cavity to analyze the optical bistability of the system. The effect of the geometrical features of the system and the parameters of the interacting fields including the strength and detuning of the fields on the optical bistability behavior are investigated. Our proposed hybrid plasmonic system shows an ultralow-threshold controllable optical bistability, providing a promising platform for optical bistable devices at the terahertz, such as all-optical switches and biosensors.
Highlights
The terahertz (THz) spectral range of the electromagnetic radiation, of the wavelength range between 1 mm to 30 μm, has attracted much attention due to its wide potential applications, including sensing [1], imaging [2], spectroscopy [3], and medical diagnostic [4], because of the low attenuation of the terahertz radiation in addition to its frequencies that match the rotational and vibrational transition frequencies of molecules
In order to investigate the THz optical bistability in the MNP-GND-QD hybrid system, we consider a monolayer of GND of the thickness Lx = 0.35 nm and the radius of Lz = 7 nm [35]
We have studied the optical bistability behavior in the MNP-GND-QD hybrid plasmonic system at the THz frequencies
Summary
The terahertz (THz) spectral range of the electromagnetic radiation, of the wavelength range between 1 mm to 30 μm, has attracted much attention due to its wide potential applications, including sensing [1], imaging [2], spectroscopy [3], and medical diagnostic [4], because of the low attenuation of the terahertz radiation in addition to its frequencies that match the rotational and vibrational transition frequencies of molecules. It has been shown that the linear dispersion properties of graphene should result in strong nonlinear optical behavior at the microwave and THz frequencies [20,21] Nonlinear phenomena such as optical bistability have recently been studied for several graphene-based materials in order to achieve low thresholds and efficient optical control at the THz frequencies [22,23,24,25,26]. Giant and controllable self-Kerr nonlinearity has been demonstrated in the metal nanoparticles-graphene nanodisks-quantum dots (MNP-GND-QD) hybrid system at the optical region of the electromagnetic radiation [29] This novel hybrid plasmonic system has shown ultralow threshold controllable optical multistability at the optical frequencies with transitions to optical bistability under certain conditions on the geometrical features of the system and the parameters of the interacting fields [30]. The effect of the parameters of both the system setup and the interacting fields are investigated in order to achieve the ultralow threshold of the controllable optical bistability demonstrated by our proposed plasmonic system at the THz regime of the electromagnetic spectrum
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