Single molecule DNA detection with an atomic vapor notch filter

Denis Uhland,Torsten Rendler,Ilja Gerhardt,Matthias Widmann,Jörg Wrachtrup,Sang-Yun Lee

doi:10.1140/epjqt/s40507-015-0033-1

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.

Highlights

The optical detection of single molecules [ – ] has facilitated important progress in various fields of research
We show that filtering with atomic vapor is able to facilitate an enhanced detection of the fluorescence which originates from a single molecule
When a single molecule was identified in the confocal microscope, the spectrometer was introduced and a spectrum was acquired

Summary

Introduction

The optical detection of single molecules [ – ] has facilitated important progress in various fields of research. We compare the filtering performance of a high-end commercial filter with a hot atomic sodium vapor cell in context of detection of single fluorescing molecules in a confocal [ ] and a wide-field microscope [ ]. We show that filtering with atomic vapor is able to facilitate an enhanced detection of the fluorescence which originates from a single molecule.

Results

Conclusion