Numerical investigation of a nano-scale electro-plasmonic switch based on metal-insulator-metal stub filter

We present a nano-scale electro-plasmonic scheme operating at 1550 nm based on plasmonic Metal-Insulator-Metal waveguide and stub filter configuration. The linear dependency of the transmission spectra of the stub filter to the length of the stubs allows designing a switch that works as normally ON or OFF switch by selecting the length of the stubs 300 or 410 nm, respectively. In our proposed waveguide-based structure, the core is an electro-optic material known as 4-dimethyl-amino-Nmethyl-4-stilbazolium tosylate with the refractive index 2.2 while the metal cladding is silver. Three-dimensional Finite Element Method simulations demonstrated that by applying a 10 V voltage to the silver cladding, a red-shift in the transmission spectra of the filter leads to turn the switch OFF or ON with calculated extinction ratio and 11.81 dB, respectively. The calculation of the capacitance implies that the switching rise-time of the switch is less than 20 fs and the bandwidth is far beyond the 18 GHz. At the maximum dimension , the subwavelength size of the switch promises the potential for future compact integrated plasmonic circuitry. For the verification of three dimensional simulation results, we have tried it, using two-dimensional transmission line method for modeling the stub filter, which demonstrates a reasonable accuracy in comparison with three-dimensional finite element method.