Single-molecule spectromicroscopy: the door into sub-diffraction refractometry

TL;DR

This paper introduces a new single-molecule spectromicroscopy method to measure local refractive index fluctuations in solids by analyzing the radiative lifetime dependence of dye centers, enabling sub-diffraction refractometry.

Contribution

It presents a novel approach using single-molecule spectroscopy to probe local refractive index variations in solids through lifetime measurements.

Findings

Demonstrated the method on amorphous polyethylene and polycrystalline naphthalene doped with terrylene.

Showed the ability to reveal local refractive index distributions.

Validated the approach with experimental data.

Abstract

We suggest a novel approach for probing of local fluctuations of the refractive index $n$ in solids by means of single-molecule (SM) spectroscopy. It is based on the dependence $T_1(n)$ of the effective radiative lifetime $T_1$ of dye centres in solids on $n$ due to the local field effects. Detection of SM zero-phonon lines at ultra-low temperatures gives the values of SM natural spectral linewidth (which is inverse proportional to $T_1$) and makes it possible to reveal the distribution of the local $n$ values in solids. Here we demonstrate this possibility on the example of amorphous polyethylene and polycrystalline naphthalene doped with terrylene.