Open AccessImaging of near-field interference patterns by aperture-type SNOM – influence of illumination wavelength and polarization state
Author(s) -
Petr Dvořák,
Zoltán Édes,
Michal Kvapil,
Tomáš Šamořil,
Filip Ligmajer,
Martin Hrtoň,
Radek Kalousek,
Vlastimil Křápek,
Petr Dub,
J. Spousta,
П. Варга,
Tomáš Šikola
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.016560
Subject(s) - near field scanning optical microscope , optics , polarizer , polarization (electrochemistry) , surface plasmon polariton , wavelength , aperture (computer memory) , microscopy , near and far field , interference microscopy , materials science , optical microscope , physics , surface plasmon , plasmon , scanning electron microscope , birefringence , acoustics , chemistry
Scanning near-field optical microscopy (SNOM) in combination with interference structures is a powerful tool for imaging and analysis of surface plasmon polaritons (SPPs). However, the correct interpretation of SNOM images requires profound understanding of principles behind their formation. To study fundamental principles of SNOM imaging in detail, we performed spectroscopic measurements by an aperture-type SNOM setup equipped with a supercontinuum laser and a polarizer, which gave us all the degrees of freedom necessary for our investigation. The series of wavelength- and polarization-resolved measurements, together with results of numerical simulations, then allowed us to identify the role of individual near-field components in formation of SNOM images, and to show that the out-of-plane component generally dominates within a broad range of parameters explored in our study. Our results challenge the widespread notion that this component does not couple to the aperture-type SNOM probe and indicate that the issue of SNOM probe sensitivity towards the in-plane and out-of-plane near-field components - one of the most challenging tasks of near field interference SNOM measurements - is not yet fully resolved.