Quantitative Measurement of Local Infrared Absorption and Dielectric Function with Tip-Enhanced Near-Field Microscopy
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- 作者：Alexander A. Govyadinov ; Iban Amenabar ; Florian Huth ; P. Scott Carney ; Rainer Hillenbrand
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2013
- 出版时间：May 2, 2013
- 年：2013
- 卷：4
- 期：9
- 页码：1526-1531
- 全文大小：325K
- 年卷期：v.4,no.9(May 2, 2013)
- ISSN：1948-7185
文摘
Scattering-type scanning near-field optical microscopy (s-SNOM) and Fourier transform infrared nanospectroscopy (nano-FTIR) are emerging tools for nanoscale chemical material identification. Here, we push s-SNOM and nano-FTIR one important step further by enabling them to quantitatively measure local dielectric constants and infrared absorption. Our technique is based on an analytical model, which allows for a simple inversion of the near-field scattering problem. It yields the dielectric permittivity and absorption of samples with 2 orders of magnitude improved spatial resolution compared to far-field measurements and is applicable to a large class of samples including polymers and biological matter. We verify the capabilities by determining the local dielectric permittivity of a PMMA film from nano-FTIR measurements, which is in excellent agreement with far-field ellipsometric data. We further obtain local infrared absorption spectra with unprecedented accuracy in peak position and shape, which is the key to quantitative chemometrics on the nanometer scale.