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Label-Free Single-Molecule Imaging with Numerical-Aperture-Shaped Interferometric Scattering Microscopy
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posted on 2017-01-18, 00:00 authored by Daniel Cole, Gavin Young, Alexander Weigel, Aleksandar Sebesta, Philipp KukuraOur
ability to optically interrogate nanoscopic objects is controlled
by the difference between their extinction cross sections and the
diffraction-limited area to which light can be confined in the far
field. We show that a partially transmissive spatial mask placed near
the back focal plane of a high numerical aperture microscope objective
enhances the extinction contrast of a scatterer near an interface
by approximately T–1/2, where T is the transmissivity of the mask. Numerical-aperture-based
differentiation of background from scattered light represents a general
approach to increasing extinction contrast and enables routine label-free
imaging down to the single-molecule level.