352 research outputs found
Quantum Emission From Hexagonal Boron Nitride Monolayers
Atomically thin van der Waals crystals have recently enabled new scientific
and technological breakthroughs across a variety of disciplines in materials
science, nanophotonics and physics. However, non-classical photon emission from
these materials has not been achieved to date. Here we report room temperature
quantum emission from hexagonal boron nitride nanoflakes. The single photon
emitter exhibits a combination of superb quantum optical properties at room
temperature that include the highest brightness reported in the visible part of
the spectrum, narrow line width, absolute photo-stability, a short excited
state lifetime and a high quantum efficiency. Density functional theory
modeling suggests that the emitter is the antisite nitrogen vacancy defect that
is present in single and multi-layer hexagonal boron nitride. Our results
constitute the unprecedented potential of van der Waals crystals for
nanophotonics, optoelectronics and quantum information processing
Effect of charging on CdSe/CdS dot-in-rods single-photon emission
The photon statistics of CdSe/CdS dot-in-rods nanocrystals is studied with a
method involving post-selection of the photon detection events based on the
photoluminescence count rate. We show that flickering between two states needs
to be taken into account to interpret the single-photon emission properties.
With post-selection we are able to identify two emitting states: the exciton
and the charged exciton (trion), characterized by different lifetimes and
different second order correlation functions. Measurements of the second order
autocorrelation function at zero delay with post- selection shows a degradation
of the single photon emission for CdSe/CdS dot-in-rods in a charged state that
we explain by deriving the neutral and charged biexciton quantum yields.Comment: 10 pages, 5 figure
Libertà va postando …. Sul blog di Vanini
EnThe debate on the relationship between human freedom and (religious or scientific) determinism finds its place, in this article, in a forum closer to young sensitivity: the blog, managed by Vanini for this purpose. Answering the questions of a student, the criticisms of a theologian and the statements of a philosopher, Vanini reaffirms the firm points of his thought.ItIl dibattito sul rapporto tra la libertà umana e il determinismo (religioso o scientifico) trova ospitalità, in questo articolo, in una sede prossima alla sensibilità giovanile: il blog, nell'occasione gestito da Vanini. Rispondendo alle domande di una studentessa, alle critiche di un teologo e alle affermazioni di un filosofo, Vanini ribadisce i punti fermi del suo pensiero
Il Museo Papirologico: la Biblioteca di Egittologia e di Papirologia “Luca Trombi”, il Soknopaiou Nesos Project e gli Archivi della Missione Archeologica del Centro
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