Tuning the focusing spot of plasmonic nanolens by aspect ratio under linear polarization

• 来源期刊: 中国光学快报（英文版）
• 年，卷（期）: 2014,（1）
• 页码范围: 62-65
• 页数: 4页
• 语种: 英文
• DOI: 10.3788/COL201412.012401

摘要

A new plasmonic nanolens that can be tuned by varying the circular structure into an elliptical annulus and the aspect ratio from 1 to 0.1 and 1 to 2,respectively,is proposed.Using the rigorous finite-difference and time-domain algorithm,we find that when the aspect ratio ranges from 1 to 0.1,a good linear relationship exists between the aspect ratio and focusing spot size at the full-width at half-maximum in the x-and y-directions,respectively.The corresponding calculated FWHM ranges from 96 × 126 (nm) to 15 × 52 (nm) (Full Width at Half Maximum).