Plasmonic Superlensing in Doped GaAs
Plasmonic Superlensing in Doped GaAs
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DOI：
10.1021/nl503996q
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发表时间：
2015-02-01
期刊：
影响因子：
10.8
通讯作者：
Helm, Manfred
中科院分区：
文献类型：
--
作者：
Fehrenbacher, Markus;Winnerl, Stephan;Helm, Manfred
我们展示了一种基于半导体的中红外宽带近场超级透镜。在这里，高掺杂 n-GaAs 层的德鲁德响应引起倏逝波的共振增强，同时在 lambda = 20 μm 左右的辐射波长处显着提高空间分辨率，可通过改变掺杂浓度进行调节。在我们的实验中，GaAs 超级透镜下方的金条纹通过无孔近场光学显微镜利用自由电子激光器的红外辐射以 lambda/6 亚波长分辨率成像。观察到的超透镜效应的共振行为与基于德鲁德-洛伦兹模型的模拟非常一致。我们的结果证明了红外纳米光谱学的相当简单的超级透镜实现。
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 lambda = 20 mu m, adjustable by changing the doping concentration. In our experiments, gold stripes below the GaAs superlens are imaged with a lambda/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-Lorentz model. Our results demonstrate a rather simple superlens implementation for infrared nanospectroscopy.