利用金之超穎介面產生光學近場軌域角動量

Creation of Optical Near-field Orbital Angular Momentum in a Gold Metasurface

陳境馥(Ching-Fu Chen)

《光學工程》 133期 (2016/05) Pp. 82-86

摘要

在本論文中，我們利用不帶任何光學角動量的線性極化光激發金之超穎介面，在模擬及實驗上成功產生攜帶光學近場軌域角動量的表面電漿光漩渦。除此之外，更進一步藉由調控不同方向的線性極化入射光，達到表面電漿光漩渦或次波長聚焦現象之間、甚至是不同旋向的表面電漿光漩渦之間的動態切換。比對經由近場掃描式光學顯微鏡所量測到的實驗結果與透過有限時域差分法所計算的數值模擬結果，兩者具有非常好的相似性。

關鍵字

電漿子 ； 超穎介面 ； 軌域角動量 ； 光漩渦

並列摘要

Nanocavities inscribed in a gold thin film are optimized and designed to form a metasurface. We demonstrate both numerically and experimentally the creation of surface plasmon (SP) vortex carrying orbital angular momentum in the metasurface under linearly polarized optical excitation that carries no optical angular momentum. Moreover, depending on the orientation of the exciting linearly polarized light, we show that the metasurface is capable of providing dynamic switching between SP vortex formation or SP subwavelength focusing. The resulting SP intensities are experimentally measured using a near-field scanning optical microscope and are found in excellent quantitative agreements as compared to the numerical results.

並列關鍵字

plasmonics ； metasurface ； orbital angular momentum ； optical vortex