Multiplexing and demultiplexing in hexagonal plasmonic lens induced on Weyl semimetals

Abstract

In this study, a hexagonal plasmonic lens engraved on Weyl semimetals has been designed. The modulation of plasmonic vortices caused by plasmonic lens as a function of wavelength modulation have been demonstrated using FDTD simulations. Further, a concentric hexagonal lens having 3 rings satisfying Bragg condition has been proposed. Due to the constructive interference caused by the lens' design, the maximum intensity is greater than the single ring plasmonic lens. The number of vortices also increases according to a non-linear quadratic formula when lens radius is changed, imbibing Moore's law followed in semiconductor industry. The mathematical calculation followed by the MATLAB visualizations of the theoretically computed electrical field intensity and phase distribution corroborates quite well with the FDTD simulation results. Finally, a device scheme based on spatial light modulator is presented for information encoding by multiplexing and demultiplexing the plasmonic vortices. We also derived the electric field equations of different optical vortices of arbitrary topological order (t_m), conceive different weight coefficients (a_m) and positions (ρ_n, θ_n) in the far field emerging from hexagonal plasmonic lens. This method could significantly impact optical communication, potentially marking one of the very first deep exploration of this topic using plasmonic lenses.