Ultra-sensitive fluorescence spectroscopy of isolated surface-adsorbed molecules using an optical nanofiber

Abstract

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-perylenetetracarboxylic dianhydride molecules (PTCDA) at ambient conditions. Surface coverages as small as 1 per thousand 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.

Vibronic line shapes of PTCDA oligomers in helium nanodroplets

“…Isolated PTCDA molecules have already been studied in different liquid solvents [40], in solid SiO 2 matrix [41], on optical nanofibers [42] (sub-monolayer deposition) and with UPS in the gas phase [43,44]. In all these cases there is a strong interaction of the PTCDA with an environment.…”

Strong Coupling between Single Atoms and Nontransversal Photons

“…For essentially plane waves in isotropic media, it has been quantitatively investigated in a number of groundbreaking experiments at the level of single atoms and single photons in high-finesse cavities [1][2][3][4][5][6][7][8]. In order to further enhance the light-matter coupling strength, an increasing number of recent experiments rely on waveguide structures [9][10][11], or high NA objectives [12][13][14]. However, in these situations, the physics changes drastically from the plane wave case because the polarization of the light fields is in general no longer transversal but exhibits a longitudinal component in the direction of propagation.…”

Tapered fiber coupling of single photons emitted by a deterministically positioned single nitrogen vacancy center

“…Due to the strong evanescent field at the surface, such TOFs promise coupling efficiencies up to 36% 13,14 and approaching unity when combined with Bragg-grating cavities 15,16 . Until now, evanescent coupling of fluorescence photons to a single guided mode of a TOF has been achieved for a) email: lars.liebermeister@physik.uni-muenchen.de b) email: markusweber@lmu.de various solid state quantum emitters [17][18][19][20] , molecules 21 , and laser-cooled atomic vapors 22 . To bring these emitters into the strong evanescent optical field at the surface of the nano-fiber several non-deterministic deposition techniques like dip-coating 17,18 , picoliter-dispensers 19,20 , and optical surface traps 23 have been applied.…”