Regensburg 2019 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Poster Session III

CPP 37.23: Poster

Mittwoch, 3. April 2019, 11:00–13:00, Poster B1

Micro-Refractometry and Local-Field Mapping with Single Molecules — Andrei V. Naumov^1,2, Alexey A. Gorshelev¹, Maxim G. Gladush^1,2, Tatiana A. Anikushina^1,2, Alina V. Golovanova^1,2, Jürgen Köhler^3,4,5, and •Lothar Kador³ — ¹Institute for Spectroscopy, Russian Academy of Sciences, Moscow 108840, Russia — ²Moscow State Pedagogical University, Moscow 119435, Russia — ³University of Bayreuth, Institute of Physics, 95440 Bayreuth, Germany — ⁴University of Bayreuth, Spectroscopy of Soft Matter, 95440 Bayreuth, Germany — ⁵Bavarian Polymer Institute, 95440 Bayreuth, Germany

Single-molecule spectroscopy at cryogenic temperatures was used to measure and map the local index of refraction in a solid with nanometer resolution. The natural zero-phonon linewidth of 1950 single terrylene molecules in a matrix of polycrystalline n-hexadecane was measured at T = 1.5 K where thermal broadening effects are absent. The linewidth is then determined by the excited-state lifetime which depends on the local density of states of the electromagnetic field, i.e., the local refractive index. The spatial resolution is on the order of a few nanometers; it is given by the accuracy with which fluorescing single molecules can be localized. Unexpectedly large fluctuations of the local refractive index between 1.1 and 1.9 were found. Three different distance ranges could be roughly identified, in which the fluctuations have different magnitudes.