Open AccessMeasuring large numerical apertures by imaging the angular distribution of radiation of fluorescing molecules
Author(s) -
Luru Dai,
Ingo Gregor,
Iris von der Hocht,
Thomas Ruckstuhl,
Jörg Enderlein
Publication year - 2005
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/opex.13.009409
Subject(s) - numerical aperture , optics , microscope , wavelength , confocal , aperture (computer memory) , microscopy , materials science , point spread function , physics , acoustics
Exact knowledge of the numerical aperture is crucial in many applications using high-aperture objectives such as confocal microscopy, optical trapping, or advanced sub-wavelength imaging methods. We propose and apply a precise and straightforward method for measuring this fundamental parameter of microscope objectives with numerical apertures above unity. Our method exploits the peculiarities of the fluorescence emission of molecules at a glass/air interface.