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Enhanced image contrast with delocalized near‐field excitation
Author(s) -
Sánchez E.,
Dunham A.,
Nowak D.,
Straton J.,
Doughty J.
Publication year - 2014
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201300325
Subject(s) - excitation , optics , signal (programming language) , materials science , excitation wavelength , aperture (computer memory) , nanolithography , image resolution , wavelength , field (mathematics) , raman spectroscopy , microscopy , delocalized electron , physics , acoustics , computer science , medicine , alternative medicine , mathematics , pathology , quantum mechanics , fabrication , pure mathematics , programming language
For Tip Enhanced Near‐field Optical Microscopy (TENOM) utilizing detection of fluorescence or Raman emission, signal to noise amplification is highly desirable for higher resolution imaging. This goal may be achieved by amplifying the signal produced by the probe at the sample through a highly resonant geometry and/or by filtering out the unwanted signal of the excitation source through the addition of an aperture in the collection optical pathway. Making highly resonant tip geometries via nanofabrication can be a difficult process, while the aperture method is a much easier method. With this technique, even tips with undesirably low resonance can be utilized for imaging. We demonstrate the concept through the use of a low field enhancement probe by showing the spatial separation of the excitation and field enhancement locations. We also are able to predict this effect using finite difference time domain modeling of the potential geometries for a desired wavelength.