Active control of surface plasmon polariton propagation using quantum-well gain medium

Abstract

Working beyond optical diffraction limit, Surface Plasmon Polaritons (SPPs) have shown their advantages on focusing and guiding light in high-density photonic integrated circuit. Meanwhile, the sensitivity of SPP modes to optical properties of their supporting materials not only benefits the practical applications like biomedical sensors and super-resolution imagers, but more interestingly all kinds of active modulators in telecommunication. The understanding of light-matter interaction in active SPP devices is established based on intensive researches on theoretical analysis and experimental prototype demonstration. Nowadays, increasing patience has been paid to electrical SPP control technology, for the prospective of developing high speed and compact SPP components. In this thesis, an InGaAsP Quantum Wells (QWs) based electrical SPP modulator is implemented and investigated. We obtained the increased SPP output signal when QWs under SPP waveguide are electrically pumped. With the assistance of numerical simulation and customized measurement strategy, the behaviors of SPP modes on devices with planar active SPP waveguides are studied. The QWs’ gain contribution to SPP propagation at metal-semiconductor interface is evaluated experimentally, which helps us to further optimize the device structure, for improving the light-matter interaction efficiency between the pumped gain media and propagating SPP signal.