Plasmonic metamaterials: from fundamental resonances to light manipulation and applications

電漿子超穎物質：從基本共振至光操控與應用

Pin Chieh Wu(吳品頡)

《光學工程》 133期 (2016/05) Pp. 1-9

摘要

Photonic metamaterials composed of artificial structures in subwavelength scale exhibit many unconventional properties for light manipulation, and it is also very promising for photonic devices and high-sensitivity optical sensor. In this dissertation, a novel three dimensional vertical split-ring resonators (VSRRs) as well as tunable metasurface device will be designed and investigated. The resonant properties arose from the electric and magnetic interactions between the VSRR and light are theoretically and experimentally studied. Tuning the configuration of VSRR unit cells are able to generate various novel coupling phenomena such as magnetic plasmonic hybridization and Fano resonance. The VSRR-based high-sensitivity refractive-index sensor and optical metasurface are studied as well. For the development of tunable metasurface device, the microfluidics technology is employed for the control of the shapes, dimensions, and the configuration of the liquid metal antennas. Based on the micro-fluidic-meta-surface, the reflection direction can be tuned actively for the dynamic beam steering.

並列摘要

本文利用電子束微影技術於玻璃基板上製作三維直立式裂環共振器，探討其本身於光波段之電漿子共振模態以及結構之間的電、磁耦合響應。有別於一般平面式電漿子超穎物質，三維直立式裂環共振器具有將侷域的電漿子場有效遠離介電質基板的能力，因此能有效提升結構之間的電磁交互作用。基於此光學行為，不同的結構組合方式可產生具有特殊磁響應的電漿子混和模態（Plasmon Hybridization）以及法諾共振（Fano Resonance）等耦合現象。此結構亦可用於材料感測元件，以增強電漿子折射率感測元件之靈敏度，以及應用於電漿子超穎介面（Plasmonic Metasurface）等光操控元件。除了光波段之外，本文亦結合微流道（Microfluidics）技術將超穎物質發展為可調控式元件，工作頻率以千兆赫茲（GHz）波段為主。後半部分將展示主動可調控式超穎介面（Metasurface）。有別於一般固態超穎物質，微流道超穎物質可藉由控制流體的形狀大小或排列週期改變超穎介面的光學行為，進而達到主動調控反射光傳播特性之目的，如傳播方向以及偏振狀態等。此研究結果相信對於瞬時調控聚焦透鏡以及光偏振轉換器等主動式超穎元件（Meta-devices）有著極大的貢獻與助益。