Optical computing at the subwavelength scale: a multifunctional MIM plasmonic logic gate

Abstract

Plasmonic logic gates are important components in integrated photonics. They are essential for high-speed Boolean computations and data transmission. For this purpose, an all-optical ultra-compact plasmonic logic gate is proposed in this paper. The design uses the metal–insulator–metal (MIM) configuration and the propagation of surface plasmon polaritons. The structure comprises three rectangular input slots coupled to the output slot through a rectangular resonator positioned on a gold (Au) surface with a footprint of 1000nm×800nm. The logic gate is numerically investigated using finite element method analysis. It has been demonstrated that the proposed design can operate as OR, XOR, NOT, and AND gates, and their transmission spectra for different input states are analyzed. This novel solution, to the best of our knowledge, excels in high contrast ratio values of 45.34 dB (OR), 18.29 dB (XOR), 18.29 dB (NOT), and 7.26 dB (AND). The resonant wavelengths of the logic gate are 821.21 nm (OR), 863.23 nm (XOR), 814.71 (NOT), and 787.69 nm (AND). The introduction of Au in this device significantly enhances its plasmonic properties, offering efficient light confinement, chemical stability, and a strong plasmonic response. This plasmonic logic gate not only expands the repertoire of integrated photonics components but also promises breakthroughs in high-speed data processing and communication technologies, positioning it as a crucial advancement in the field of nanophotonics.