Magnetically-Controlled Logic Gates of Graphene Plasmons Based on Non-Reciprocal Coupling

In this paper, we propose magnetically-controlled logic gates of graphene plasmons based on non-reciprocal coupling within the multilayer graphene waveguide structure. The magnetooptical effect of semiconductor substrate leads to the difference in modal indices of graphene plasmons in opposite directions and non-reciprocal coupling, which is investigated by both coupled mode theory (CMT) and finite elements methods (FEM). Such a mechanism enables the design of magnetically- controlled NOT logic gate, whose output logic can be inversed by reversing the plasmons propagation directions. Furthermore, according to the Boolean algebra, we design two functional logic gates performing as OR (AND) logic gates for one direction of input plasmons, while NAND (NOR) logic gates for the reversed input direction. Minimum extinction ratios as 13.6 or 17.5 dB can be obtained for OR (NAND) or AND (NOR) logic gate. The proposed magnetically-controlled logic gates may provide new inspiration to non-reciprocal graphene plasmons devices.