No abstract

No abstract

No abstract

A compact nanoscale electro-plasmonic 1 × 2 switch based on asymmetrical metal-insulator-metal stub filters is introduced. The structure is designed and analyzed based on the transmission line method, and the switching operation of the device is numerically simulated and verified by the finite element method. It is found that by adjusting the length of the stubs on each output branch of the structure the surface plasmon polaritons (SPPs) are guided to only one of the output ports. By altering the refractive index of the electro-optical material (DAST) as the core of the structure with a 35 V applied voltage, the SPPs are steered to the opposite port. The reflected SPPs from one stub filter enhance the output intensity of another filter. The operating wavelength of the switch is the communication wavelength λ=1550 nm. Nevertheless, it can be easily redesigned for another wavelength in the range of 800-2000 nm. The insertion losses and the extinction ratios guarantee an almost symmetrical switching for two outputs. The overall size of the switch is 800 nm × 450 nm × 750 nm. The bandwidth of the switch is anticipated over 100 GHz.

We have investigated an amplifier which operates on surface plasmon polaritons (SPPs). A semiconductor is considered instead of dielectric since its interface with metal can support transverse-magnetic-polarized SPP propagation. A T-shaped cross section for the analyzed waveguide is considered. Metal-semiconductor interface conditions in particular can be regarded as a Schottky junction that has the capability of being pumped electrically. So compensation of propagation loss imposed by metal is possible and beyond that, amplification occurs. This configuration has advantages such as a simple fabrication process and compact size. This scheme has been implemented previously in 3.16, 1.7, and 0.8 μm for increasing the propagation length of the SPP but here, the free-space wavelength of 1.55 μm is considered for designing a plasmonic amplifier. This wavelength is selected because this is the most used wavelength in fiber-optic telecommunications due to its ultralow attenuation in silica. However, designing such an amplifier with too many effects that arise in a Schottky junction may be an extremely difficult process. So simplification, which regards essential effects and ignores nonimportant ones, is included. In this work, gold is considered as the metal and n⁺-doped In_0.53Ga_0.47As as the semiconductor to form a Schottky junction. The semiconductor has a doping concentration of 1×10¹⁸ cm^-3. In forward bias of 1.25 V, the gain coefficient of the SPP mode is estimated up to 337  cm^-1 which corresponds to 14.62 dB power gain for a 100 μm long amplifier.