Investigating the Optical Switch Using Dimer Plasmonic Nano-Rods

The optical switch based on the dimer plasmonic nano-rods on the silicon waveguide has been numerically analyzed. In the proposed switch, the optical switch has been excited by two monochromatic incident plan-waves with the same frequency and two angles of incident theta = 0 and theta = 90. When only the signal with theta = 0 is applied, the incident wave is transmitted and when both signals are applied to the switch simultaneously, the coherent perfect absorption (CPA) occurs and the two incident waves are suppressed. Therefore, the signal with theta = 90 acts as control signal. Since the CPA efficiency depends strongly on the number of plasmonic nano-rods and the nano-rods location, a new efficient binary optimization method based on the teaching-learning-based optimization (TLBO) algorithm is proposed to design an optimized array of the plasmonic nano-rods in order to achieve the maximum absorption coefficient in the "off" state and the minimum absorption coefficient in the "on" state. In binary TLBO, a group of learner includes a matrix with binary entries, and is used to control the presence ("1") or the absence ("0") of nano-rods in the array.