Indistinguishable photons on demand from an organic dye molecule

Abstract

Single molecules in solid-state matrices have been proposed as sources of single-photon Fock states back 20 years ago. Their success in quantum optics and in many other research fields stems from the simple recipes used in the preparation of samples, with hundreds of nominally identical and isolated molecules. Main challenges as of today for their application in photonic quantum technologies are the optimization of light extraction and the on-demand emission of indistinguishable photons. We here present Hong-Ou-Mandel experiments with photons emitted by a single molecule of dibenzoterrylene in an anthracene nanocrystal at 3 K, under continuous wave and also pulsed excitation. A detailed theoretical model is applied, which relies on independent measurements for most experimental parameters, hence allowing for an analysis of the different contributions to the two-photon interference visibility, from residual dephasing to spectral filtering.

Time-resolved two-photon interference of weak coherent pulses

“…To date, the time-resolved measurement of the TPI effect of two phase-independent pulse-mode photons has been commonly utilized to verify indistinguishability between single photons generated from quantum systems such as the atom-cavity system [15], quantum dots [19], and nitrogen-vacancy centers [20], organic dye molecule [21], as well as from two highly different light sources at the single-photon level [22].…”

“…When the two photons are overlapped temporally within the pulse duration, the TPI effect can be identified as a reduction in the integrated coincidence counting events [15,[19][20][21][22]. Therefore, the characteristic interference fringe reveals different shape upon varying the mutual coherence time between the two interfering photons.…”