Ultra-sensitive fluorescence spectroscopy of isolated surface-adsorbed molecules using an optical nanofiber
Author(s): A. Stiebeiner, O. Rehband, R. Garcia-Fernandez, A. Rauschenbeutel
Journal: Optics Express
DOI Number: 10.1364/OE.17.021704
Link: Link to publication
The strong radial confinement and the pronounced evanescent field of the guided light in optical nanofibers yield favorable conditions for ultra-sensitive surface spectroscopy of molecules deposited on the fiber. Using the guided mode of the nanofiber for both excitation and fluorescence collection, we present spectroscopic measurements on 3,4,9,10-perylene-tetracarboxylic dianhydride molecules (PTCDA) at ambient conditions. Surface coverages as small as 1 ‰ of a compact monolayer still give rise to fluorescence spectra with a good signal to noise ratio. Moreover, we analyze and quantify the self-absorption effects due to reabsorption of the emitted fluorescence light by circumjacent surface-adsorbed molecules distributed along the fiber waist.