Near-field microscopy by elastic light scattering from a tip
Near-field microscopy by elastic light scattering from a tip
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DOI：
10.1098/rsta.2003.1347
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发表时间：
2004-04-15
期刊：
影响因子：
5
通讯作者：
Hillenbrand, R
中科院分区：
文献类型：
--
作者：
Keilmann, F;Hillenbrand, R
我们描述的超分辨率显微镜远远超出经典的阿贝衍射极限的一半波长（λ/2），也超出了实际的限制（约。λ/10）的孔径为基础的扫描近场光学显微镜（SNOM）。这里讨论的“无孔”SNOM使用来自尖锐尖端的光散射（因此是散射型或s-SNOM），并且没有与光相关的分辨率限制。相反，它的分辨率近似等于探测尖端的半径a（对于商业尖端，a < 20 nm），使得在可见光（λ/60）中获得10 nm。λ/500的分辨率已获得在中红外在λ = 10 μ m。红外线、太赫兹甚至微波照明的优点是可以利用特定的激发来产生特定的对比度，例如，分子振动提供光谱指纹来识别化学成分。S-SNOM可以常规地获得同时图像、振幅图像和相位图像，以获得关于折射和吸收特性的信息。等离子体或声子共振材料可以通过其特别高的近场信号水平来突出。此外，s-SNOM可以映射小的光学共振粒子的特征光学本征场。最后，我们描述的理论建模，解释和预测的基础上的局部介电函数的s-SNOM对比。
We describe ultraresolution microscopy far beyond the classical Abbe diffraction limit of one half wavelength (lambda/2) and also beyond the practical limit (ca. lambda/10) of aperture-based scanning near-field optical microscopy (SNOM). The 'apertureless' SNOM discussed here uses light scattering from a sharp tip (hence scattering-type or s-SNOM) and has no lambda-related resolution limit. Rather, its resolution is approximately equal to the radius a of the probing tip (for commercial tips, a < 20 nm) so that 10 nm is obtained in the visible (lambda/60). A resolution of lambda/500 has been obtained in the mid-infrared at lambda = 10 mum. The advantage of infrared, terahertz and even microwave illumination is that specific excitations can be exploited to yield specific contrast, e.g. the molecular vibration offering a spectroscopic fingerprint to identify chemical composition. S-SNOM can routiuely acquire simultaneous, amplitude and phase images to obtain information on refractive and absorptive properties. Plasmon- or phonon-resonant materials can be highlighted by their particularly high near-field signal level. Furthermore, s-SNOM can map the characteristic optical eigenfields of small, optically resonant particles. Lastly, we describe theoretical modelling that explains and predicts s-SNOM contrast on the basis of the local dielectric function.