Tunable Three-Channel Mesoscopic Demultiplexer Based on Detuned Stubs

We study analytically and numerically the possibility of implementing a simple mesoscopic demultiplexer based on bound states in the continuum (BICs), induced transparency, and Fano resonances. The demultiplexer is made of a Y-shaped waveguide with an input line and two output lines where each output line contains two stubs grafted on two different sites in a U-shape far from the input line. The BICs are obtained for specific values of the lengths of the stubs of U-shaped structures and the segment separating them. By detuning the two stubs slightly in an appropriate way, BIC transforms into Fano or electromagnetic induced transparency (EIT) resonances. We give closed-form expressions of the geometrical parameters that allow a selective transfer of the given state in the first waveguide without perturbing the second waveguide. The effect of temperature on the transmission resonances is also examined using Landauer–Buttiker formula.