Plasmonic Superlensing in Doped GaAs
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- 作者：Markus Fehrenbacher ; Stephan Winnerl ; Harald Schneider ; Jonathan D枚ring ; Susanne C. Kehr ; Lukas M. Eng ; Yongheng Huo ; Oliver G. Schmidt ; Kan Yao ; Yongmin Liu ; Manfred Helm
- 刊名：Nano Letters
- 出版年：2015
- 出版时间：February 11, 2015
- 年：2015
- 卷：15
- 期：2
- 页码：1057-1061
- 全文大小：315K
- ISSN：1530-6992
文摘
We demonstrate a semiconductor based broadband near-field superlens in the mid-infrared regime. Here, the Drude response of a highly doped n-GaAs layer induces a resonant enhancement of evanescent waves accompanied by a significantly improved spatial resolution at radiation wavelengths around 位 = 20 渭m, adjustable by changing the doping concentration. In our experiments, gold stripes below the GaAs superlens are imaged with a 位/6 subwavelength resolution by an apertureless near-field optical microscope utilizing infrared radiation from a free-electron laser. The resonant behavior of the observed superlensing effect is in excellent agreement with simulations based on the Drude鈥揕orentz model. Our results demonstrate a rather simple superlens implementation for infrared nanospectroscopy.