Proposal for a Plasmonic Mach–Zehnder Modulator Utilizing Quantum Interference Effect

In this paper, we propose a novel plasmonic Mach-Zehnder modulator utilizing the quantum interference effect. The modulator controls the oscillations in the electron density along two arms of the Mach-Zehnder interference circuit consisting of metal-dielectric interfaces. The quantum interference effect produces the interference between the electron density oscillations; i.e., magnetic fluxes (vector potentials) or electric voltages (scalar potentials) in the domain bounded by the two arms produce the interference between the two electron waves in the arms of the Mach-Zehnder interferometer. Current flows in or voltages applied to electric wires arranged parallel to the arms regulate the magnetic fluxes or electric voltages. A very small device, on the order of micrometer, low power consumption and ultrafast operation are expected to be a result of the extreme sensitivity of the quantum interference effects to the electromagnetic field. However, successful operation of the proposed modulator requires a coherent plasmon wave, which is extremely difficult to achieve and cannot be achieved in any currently available material. We look forward to the development of such a material.