Contrast enhancement using polarization-modulation scanning near-field optical microscopy (PM-SNOM)

Th Lacoste, Thomas R Huser, R. Prioli, H. Heinzelmann

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

Polarization contrast scanning near-field optical microscopy (SNOM) provides information on the orientation of molecules and molecular aggregates on surfaces. Other than in transmission or fluorescence SNOM, the control of polarization demands for SNOM probes having extinction ratios better than 20:1 in at least two perpendicular polarization directions. Most common SNOM probes consist of tapered and metal-coated fiber tips. While the birefringence of fibers can be compensated, the tapering often exhibits depolarizing effects that make good qualitative or even quantitative measurements difficult. In an attempt to improve the quality of the apertures, we have modified metal-coated fiber probes with a focused ion beam (FIB). As an example of investigations where a very good polarization control is needed, we present and discuss polarization-modulation SNOM (PM-SNOM) measurements on dye crystals. The modulation of the direction of linearly polarized light and the use of lock-in techniques allows the simultaneous detection of absorption together with magnitude and orientation of optical anisotropy.

Original languageEnglish (US)
Pages (from-to)333-340
Number of pages8
JournalUltramicroscopy
Volume71
Issue number1-4
DOIs
StatePublished - Mar 1 1998
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Instrumentation

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