Quantitative measurement of local infrared absorption and dielectric function with tip-enhanced near-field microscopy

Alexander A. Govyadinov, Iban Amenabar, Florian Huth, P. Scott Carney, Rainer Hillenbrand

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1526-1531
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume4
Issue number9
DOIs
StatePublished - May 2 2013

Keywords

  • chemical identification
  • ellipsometry
  • infrared nanospectroscopy
  • nano-FTIR
  • near-field scattering
  • s-SNOM
  • thin films

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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