Nanowires as Optoelectronic and Photonic Elements

Abstract

Integrated photonic circuits require small photonic elements. Recent progress in nanowire synthesis and nanofabrication enables us to investigate the potential of nanowires in novel integrated photonic devices. This thesis explores light manipulation on two material platforms – metallic nanostructures that support surface plasmon polaritons (SPPs), and periodic dielectric arrays for mode engineering. In Chapters 2 and 3, I will show that chemically-synthesized metallic nanowires are attractive candidates to support SPPs and enhance light- matter interactions. The first model device consists of a single quantum emitter in close proximity to a highly crystalline Ag nanowire. When the quantum emitter is optically excited, its emission rate is enhanced by a factor of 2.5, and 60% of the emission couples into the Ag nanowire, generating single SPPs. In addition to optically exciting SPPs, we demonstrate an optoelectronic device that generates and detects SPPs electrically, paving the way for seamless integration between electronic and plasmonic elements in a single circuit. In Chapter 4, I present a general strategy to create stretchable and flexible photonic devices. Flexible photonics has garnered a lot of interest because mechanical properties can be exploited to generate highly conformal devices with novel optical characteristics. We fabricated Si nanowire photonic crystal cavities and transferred them into polydimethylsiloxane (PDMS). The composite photonic crystal cavity supports high quality factor (Q) modes in the telecommunication range. We achieve mechanical reconfiguration of the cavity by stretching it, and observe tuning of the resonance wavelength over 67 nm, 134 times the resonance linewidth. The above demonstrations, when taken together, underscore the promise and potential of nanowires in integrated photonic circuits.