Plasmonic all-optical switching based on metamaterial/metal waveguides with local nonlinearity

We present a plasmonic all-optical switch based on Mach-Zehnder interferometer (MZI) with local nonlinearity. The design of the miniaturized all-optical switch is possible by employing surface-plasmon polaritons (SPPs) that confine the energy of electromagnetic (EM) waves at sub-wavelength scale. The coupling between sub-wavelength plasmonic waveguides in MZI and a control beam generates 'ON' and 'OFF' states at the switch and switching between 'ON' and 'OFF' states happens when the control beam is turned on or off. The waveguides cladding in the switch structure is made of lossy media including metamaterials with positive and negative EM susceptibilities and metals; the core consists of nonlinear and dielectric media. Employing materials with negative EM susceptibilities in the switch structure facilitates the propagation of both transverse electric and transverse magnetic SPPs along the waveguides. Our all-optical switch design enables multi-frequency switching with low-intensity control field. Ascertaining the capabilities of multi-frequency plasmonic all-optical switches facilities their applications in miniaturized photonic circuits and in biosensors.