Numerical Analysis of Laterally and Vertically Coupled Hybrid Plasmonic Modes in Silicon Tip

Hybrid plasmonic waveguides have emerged as one of the most emerging tools for long-range subwavelength optical guidance. We propose the coupling of a hybrid plasmonic (HP) mode into a silicon tip. The HP mode is made to confine in the silicon tip through lateral as well as a vertical coupling, which provides moderately good field enhancement with long-range propagation. The lateral coupling exhibits a field enhancement of more than 200 in a silicon tip with a propagation length of 110 mu m. Field enhancement in the vertically coupled case is 25 with a propagation length of 1.1 mm. In both cases, mode area remains around 50-60 nm(2). In addition, both structures show broadband propagation of HP modes where propagation length remains long over a broad range wavelength. The proposed waveguide structures can be useful in realizing nanophotonic devices for broad range of applications including spectroscopy, optical fiber communication and bio-chemical sensing.

Automated summary

This article proposes a method of coupling hybrid plasmonic mode into a silicon tip, achieving a waveguide structure with moderate field enhancement and long-range propagation through lateral and vertical coupling. The proposed waveguide structures have broadband propagation capabilities and long propagation lengths, making them ideal for various nanophotonic devices.