Introduction to Photophysics

Jonas K. Hannestad

Gur Lubin, Ron Tenne, Arin Can Ülkü +7 more

Since the introduction of the intensity interferometer by Hanbury Brown and Twiss in the '50s and its subsequent adaptations to quantum optic experiments, photon correlations have played a significant role in optical research. An emerging detector technology, SPAD arrays, presents new opportunities to scale these experiments and exploit photon correlations in new regimes. I will describe a new temporal-spectral photon correlation technique based on these detectors, single-particle heralded spectroscopy. I will present new insights into the photophysics of multiply-excited semiconductor quantum dots uncovered by this method, hitherto inaccessible to existing approaches.

Moses Gaither-Ganim, Scott A Newlon, Michael G. Anderson +1 more

Abstract Since the onset of the 1990s, the development of single-molecule spectroscopy has led to the discovery of various quantum optical signatures in organic single molecules. The single-photon nature of an organic chromophore is of particular importance because of its potential as a nonclassical photon source at room temperature for quantum information science and optical quantum computing. This condensed review focuses on the introduction of fundamental knowledge and basic experimental methods for single-photon sources and organic molecular photophysics and summarizes the research developments in this field, providing an understanding of quantum emission from organic single molecules.

Ksenia Dolgaleva

Martin Berthel, Oriane Mollet, Géraldine Dantelle +3 more

A study of the photophysical properties of nitrogen-vacancy (NV) color centers in diamond nanocrystals of size 50 nm or below is carried out by means of second-order time-intensity photon correlation and cross-correlation measurements as a function of the excitation power for both pure charge states, neutral and negatively charged, as well as for the photochromic state, where the center switches between both states at any power. A dedicated three-level model implying a shelving level is developed to extract the relevant photophysical parameters coupling all three levels. Our analysis confirms the very existence of the shelving level for the neutral NV center. It is found that it plays a negligible role on the photophysics of this center, whereas it is responsible for an increasing photon bunching behavior of the negative NV center with increasing power. From the photophysical parameters, we infer a quantum efficiency for both centers, showing that it remains close to unity for the neutral center over the entire power range, whereas it drops with increasing power from near unity to approximately 0.5 for the negative center. The photophysics of the photochromic center reveals a rich phenomenology that is to a large extent dominated by that of the negative state, in agreement with the excess charge release of the negative center being much slower than the photon emission process.