Holey-Metal Lenses: Sieving Single Modes with Proper Phases

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• 作者：Satoshi Ishii ; Vladimir M. Shalaev ; Alexander V. Kildishev
• 刊名：Nano Letters
• 出版年：2013
• 出版时间：January 9, 2013
• 年：2013
• 卷：13
• 期：1
• 页码：159-163
• 全文大小：348K
• 年卷期：v.13,no.1(January 9, 2013)
• ISSN：1530-6992

文摘

We study a planar, holey-metal lens made as a set of concentric circular arrays (rings) of nanoscale holes milled in a subwavelength-thick metal film. Each nanohole鈥攁 finite-length, circular, single-mode waveguide with a radius-dependent mode index鈥攊s used as a phase-shifting element. Our experimental results confirm that the focusing properties of our polarization-independent, holey-metal lens milled in a 380-nm-thick gold film and illuminated with 531 nm light fits the analytical model well. The proposed concept could offer an alternative to conventional refraction microlenses and open up a vital path toward on-chip or fiber-end planar photonic devices for biosensing and imaging.

Keywords:

Planar lens; diffraction lens; plasmonic lens; phase control