Quantum Efficiency of Single Dibenzoterrylene Molecules in p-Dichlorobenzene at Cryogenic Temperatures

We measure the quantumefficiency (QE) of individual dibenzoterrylene(DBT) molecules embedded in p-dichlorobenzene atcryogenic temperatures. To achieve this, we combine two distinct methodsbased on the maximal photon emission and on the power required tosaturate the zero-phonon line to compensate for uncertainties in somekey system parameters. We find that the outcomes of the two approachesare in good agreement for reasonable values of the parameters involved,reporting a large fraction of molecules with QE values above 50%,with some exceeding 70%. Furthermore, we observe no correlation betweenthe observed lower bound on the QE and the lifetime of the molecule,suggesting that most of the molecules have a QE exceeding the establishedlower bound. This confirms the suitability of DBT for quantum opticsexperiments. In light of previous reports of low QE values at ambientconditions, our results hint at the possibility of a strong temperaturedependence of the QE.

Automated summary

In this study, we measured the quantum efficiency (QE) of individual dibenzoterrylene (DBT) molecules embedded in p-dichlorobenzene at cryogenic temperatures using two distinct methods. The results obtained from both methods were in good agreement and showed that a large fraction of molecules had QE values above 50%, with some exceeding 70%. We also observed no correlation between the observed lower bound on QE and the lifetime of the molecule, suggesting that most of the molecules had a QE exceeding the established lower bound. This confirms the suitability of DBT for quantum optics experiments and indicates a strong temperature dependence of QE.