Enhancing single-molecule photostability by optical feedback from quantum-jump detection

TL;DR

This paper introduces an optical feedback method that significantly enhances the photostability of single molecules by suppressing triplet-state-related photobleaching, enabling longer observation times and more photon detection.

Contribution

The study presents a dynamic laser switching technique based on quantum-jump detection to reduce triplet-state photoexcitation, improving single-molecule stability.

Findings

Increased single-molecule observation time

Higher total photon counts per molecule

Confirmed triplet-state photoexcitation's role in photobleaching

Abstract

We report an optical technique that yields an enhancement of single-molecule photostability, by greatly suppressing photobleaching pathways which involve photoexcitation from the triplet state. This is accomplished by dynamically switching off the excitation laser when a quantum-jump of the molecule to the triplet state is optically detected. This procedure leads to a lengthened single-molecule observation time and an increased total number of detected photons. The resulting improvement in photostability unambiguously confirms the importance of photoexcitation from the triplet state in photobleaching dynamics, and may allow the investigation of new phenomena at the single-molecule level.