NANOSCALE STRUCTURES FOR TUNABLE AND LOW-LOSS RESONATORS

Abstract

Light manipulation at the nanoscale, which is known as nanophotonics, has attracted enormous attention. Particularly, metallic nano-resonators, which support localized surface plasmons, have been under intense study. The potential applications include plasmon-enhanced solar energy harvesting, ultra-thin optical components, etc. However, two issues hinder their applications in real life. On one hand, the optical response lacks tunability once the nano-resonators are fabricated. On the other hand, the large Ohmic losses inherent in noble metals severely limit their performance. In this thesis, these two issues are investigated through both numerical and experimental studies. In the first part, phase-change material Ge2Sb2Te5 (GST) is introduced to add tunability to the nano-resonators. In the second part, nano-resonators made of polar crystals (SiC and hex-BN) that support phonon polaritons are investigated. The physics and practical applications are studied in detail, providing fundamental knowledge for future nanophotonic designs.