Single Molecule DNA Detection with an Atomic Vapor Notch Filter

TL;DR

This paper introduces a novel method using hot atomic vapor as a narrow-band filter to improve the detection efficiency of single-molecule DNA fluorescence, enhancing signal strength by over 15%.

Contribution

It demonstrates the use of atomic sodium vapor as an optical filter to improve fluorescence detection of single DNA molecules, enabling more efficient photon collection.

Findings

Over 15% enhancement in optical signal detection.

Effective filtering of excitation light using atomic vapor.

Applicable to confocal and wide-field microscopy.

Abstract

The detection of single molecules has facilitated many advances in life- and material-sciences. Commonly, it founds on the fluorescence detection of single molecules, which are for example attached to the structures under study. For fluorescence microscopy and sensing the crucial parameters are the collection and detection efficiency, such that photons can be discriminated with low background from a labeled sample. Here we show a scheme for filtering the excitation light in the optical detection of single stranded labeled DNA molecules. We use the narrow-band filtering properties of a hot atomic vapor to filter the excitation light from the emitted fluorescence of a single emitter. The choice of atomic sodium allows for the use of fluorescent dyes, which are common in life-science. This scheme enables efficient photon detection, and a statistical analysis proves an enhancement of the optical signal of more than 15% in a confocal and in a wide-field configuration.