Polymer-encapsulated organic nanocrystals for single photon emission

Theory of Energy Transfer in Organic Nanocrystals

Recent experiments have shown that highly efficient energy transfer can take place in organic nanocrystals at extremely low acceptor densities. This striking phenomenon has been ascribed to the formation of exciton polaritons thanks to the photon confinement provided by the crystal itself. We propose an alternative theoretical model that accurately reproduces fluorescence lifetime and spectrum measurements in these systems without such an assumption. Our approach treats molecule-photon interactions in the weak-coupling regime, and describes the donor and acceptor population dynamics by means o…

Photostable single-photon emission from self-assembled nanocrystals of polycyclic aromatic hydrocarbons

Quantum technologies could largely benefit from the control of quantum emitters in sub-micrometric size crystals. These are naturally prone to the integration in hybrid devices, including heterostructures and complex photonic devices. Currently available quantum emitters sculpted in nanocrystals suffer from spectral instability, preventing their use as single photon sources e.g., for most quantum optics operations. In this work we report on unprecedented performances of single-photon emission from organic nanocrystals (average size of hundreds \SI{}{\nano\meter}), made of anthracene (Ac) and d…

High Photon Upconversion Efficiency with Hybrid Triplet Sensitizers by Ultrafast Hole-Routing in Electronic-Doped Nanocrystals

Low power photon upconversion (UC) based on sensitized triplet-triplet annihilation (sTTA) is considered as the most promising upwards wavelength-shifting technique to enhance the light harvesting capability of solar devices by recovering the low-energy tail of the solar spectrum. Semiconductor nanocrystals (NCs) with conjugated organic ligands have been proposed as broadband sensitizers for extending the light-harvesting capability of sTTA-UC molecular absorbers. Key to their functioning is efficient energy transfer (ET) from the NC to the triplet state of the ligands that sensitizes the trip…

Indistinguishable photons on demand from an organic dye molecule

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…

Highly Polarized Light Emission from 6T@BNNT Nanohybrids

The polarized fluorescence emission of organic fluorophores has been extensively studied in photonics and is increasingly exploited in single molecule scale bio-imaging. Expanding the polarization properties of compact molecular assemblies is, however, extremely challenging due to depolarization and quenching effects associated with the self-aggregation of molecules into the sub-nanometer scale. Here we demonstrate that Boron Nitride Nanotubes (BNNTs) can act as a 1D host-template for the alignment of encapsulated a-sexithiophene (6T) inside BNNTs, leading to an optically active 6T@BNNT nanohy…

分子单光子发射器中光饱和 regime 的崩溃

Breakdown of the optical saturation regime in molecular single-photon emitters

研究发现蒽纳米晶体中单个DBT分子在强连续波驱动下出现反常饱和，提出强度依赖的ESA到短寿命暗态的模型解释该现象，还指出基质质量与脉冲激发方案的相关作用。