A stable, single-photon emitter in a thin organic crystal for application to quantum-photonic devices

摘要

Single organic molecules offer great promise as bright, reliable sources ofidentical single photons on demand, capable of integration into solid-statedevices. It has been proposed that such molecules in a crystalline organicmatrix might be placed close to an optical waveguide for this purpose, but sofar there have been no demonstrations of sufficiently thin crystals, with acontrolled concentration of suitable dopant molecules. Here we present a methodfor growing very thin anthracene crystals from super-saturated vapour, whichproduces crystals of extreme flatness and controlled thickness. We show howthis crystal can be doped with a widely adjustable concentration ofdibenzoterrylene (DBT) molecules and we examine the optical properties of thesemolecules to demonstrate their suitability as quantum emitters in nanophotonicdevices. Our measurements show that the molecules are available in the crystalas single quantum emitters, with a well-defined polarisation relative to thecrystal axes, making them amenable to alignment with optical nanostructures. Wefind that the radiative lifetime and saturation intensity vary little withinthe crystal and are not in any way compromised by the unusual matrixenvironment. We show that a large fraction of these emitters are able todeliver more than $10^{12}$ photons without photo-bleaching, making themsuitable for real applications.