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Author Heilman, A. L. ♦ Gordon, M. J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ ANTENNAS ♦ COMPARATIVE EVALUATIONS ♦ COPPER ♦ COPPER COMPLEXES ♦ DIFFRACTION ♦ EXCITATION ♦ GEOMETRY ♦ ILLUMINANCE ♦ IMAGES ♦ OPTICAL MICROSCOPES ♦ PHOTONS ♦ PHTHALOCYANINES ♦ PLASMONS ♦ POLARONS ♦ RAMAN EFFECT ♦ RAMAN SPECTROSCOPY ♦ SPATIAL RESOLUTION ♦ SURFACES ♦ THIN FILMS
Abstract A tip-enhanced near-field optical microscope with side-on and attenuated total reflectance (ATR) excitation and collection is described and used to demonstrate sub-diffraction-limited (super-resolution) optical and chemical characterization of surfaces. ATR illumination is combined with an Au optical antenna tip to show that (i) the tip can quantitatively transduce the optical near-field (evanescent waves) above the surface by scattering photons into the far-field, (ii) the ATR geometry enables excitation and characterization of surface plasmon polaritons (SPPs), whose associated optical fields are shown to enhance Raman scattering from a thin layer of copper phthalocyanine (CuPc), and (iii) SPPs can be used to plasmonically excite the tip for super-resolution chemical imaging of patterned CuPc via tip-enhanced Raman spectroscopy (TERS). ATR-illumination TERS is also quantitatively compared with the more conventional side-on illumination scheme. In both cases, spatial resolution was better than 40 nm and tip on/tip off Raman enhancement factors were >6500. Furthermore, ATR illumination was shown to provide similar Raman signal levels at lower “effective” pump powers due to additional optical energy delivered by SPPs to the active region in the tip-surface gap.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-06-14
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 119
Issue Number 22


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