Abstract: In the first part of the talk, I will discuss resonant light scattering by a subwavelength ensemble of identical atoms. While N noninteracting atoms would scatter N2 more than a single atom, we find that N interacting atoms scatter less than a single atom. We analyse this counterintuitive effect in terms of collective modes resulting from the light-induced dipole-dipole interactions. In the second part of the talk, I will discuss single-photon emission and storage. We start with a one-dimensional atom which consists in a single two-level system (TLS) in a cavity with a large Purcell factor so that emission takes place in the cavity mode with high probability. However, a large Purcell factor is detrimental for long-time memory storage. We propose to replace the TLS by a pair of strongly coupled TLSs. The resulting antisymmetric state is a subradiant state and its decay rate can be tuned by controlling the detuning between the two TLS. As a result, the pair of atoms can be viewed as an effective TLS with a tunable decay rate. We discuss the potential of this system to generate time-shaped single photons and to implement a quantum memory.
Biography: Jean-Jacques Greffet is an alumni of Ecole Normale de Paris-Saclay. He received his PhD in solid state physics in 1988 from Université Paris-Sud working in light scattering by rough surfaces. Between 1994 and 2005, he worked on the theory of image formation in near-field optics. Since 1998, he made a number of seminal contributions to the field of thermal radiation at the nanoscale including the demonstration of coherent thermal sources and the giant radiative heat transfer at the nanoscale due to surface phonon polaritons. Since 2000, he has contributed to the field of quantum plasmonics and light emission with nanoantennas and metasurfaces. He is an OSA fellow and the recipient of the Ixcore foundation prize and the Servant prize of the French Academy of Science.