Quantum Optics of Atomic Systems Confined in a Dielectric Environment

George Kountouris

Wang Dehuwa, Jie Zhang, Zhaopeng Sun +2 more

We calculate the energy and Shannon entropy for a hydrogen atom confined in a dielectric spherical microcavity for the fist time. In contrast to the hydrogen atom in the vacuum microcavity, some unexpected and interesting phenomena appear: First, the turning radius for the bound energy changes from positive to negative depends on the dielectric constant of the spherical microcavity sensitively. With the increase of the relative dielectric constant, the turning radius gets larger. Second, the dielectric spherical microcavity impacts the rearrangement of the excited state energy, and breaks the energy degeneracy of the excited states. At some given radius, there is energy crossover between different orbital. Third, the dielectric in the spherical microcavity affects the Shannon entropy for the confined hydrogen atom greatly. The Shannon entropy in the vacuum microcavity is the smallest and the Shannon entropy increases with the relative dielectric constant. For smaller size spherical microcavity, the Shannon entropy change is always negative, which suggests that the electron density is localized. With the increase of the radius of the microcavity, the Shannon entropy change becomes positive, and the confinement of the electron density gets delocalized. Our results show that we can control the confining effect of the spherical microcavity on the atom by changing the dielectric. This work can guide the future experimental studies for trapping and manipulating of atoms and molecules in the external environment and has some practical applications in metrology and quantum information processing.

Stephen Mark Barnett

M. Ducloy, Daniel Bloch

Samuel Cadellin Skipsey, M. Babiker, M. Al-Amri +1 more

The properties of localised dipole emitters in the form of a quantum dot or a colour centre embedded in a crystal environment can be drastically modified by a change in the composition, size and shape of the environment in which the emitter is embedded. Thanks to recent advances in material deposition techniques and lithography, as well as the advances in detection techniques and optical manipulation, experimental work is now capable of revealing a new range of physical phenomena when the typical dimensions are of the order of an optical dipole transition wavelength and below. These advances have arisen at a time of a heightened research effort devoted to the important goal of identifying a qubit and a suitable environment that forms the basis for a scalable hardware architecture for the practical realisation of quantum information processing. A physical system that we have recently put forward as a candidate for such a purpose involves localised emitters in the form of quantum dots or colour centres embedded in a nanocrystal. This suggestion became more persuasive following the success of experiments which, for the first time, were able to demonstrate quantum cryptography using a nitrogen vacancy in a diamond nanocrystal as a single-photon source. It has, however, been realised that a more versatile scenario could be achieved by making use of the interplay between dielectric cavity confinement and dipole orientation. Besides position dependence the main properties exhibit strong dipole orientational dependece suggesting that the system is a possible candidate as a qubit for a scalable hardward architecture for quantum information processing. Cavity confinement can control processes since it can lead to the enhancement and the complete suppression of the de-excitation process, with further control provided by the manipulation of the dipole orientation by optical means. This article is concerned with the modelling of quantum processes for quantum systems localised in artificially fabricated structures made of high conductivity metals and dielectric cavities. The essential features of cavity field confinement in this context are presented and the effects on de-excitation rates are assessed.

Hadiseh Alaeian, Brian Odom, Jorge Bravo‐Abad

Abstract The incorporation of neutral atoms in nanophotonic structures offers significant potential to realize novel quantum optical devices. Here, the possibility of creating low‐threshold integrated lasers in hybrid systems based on coupling room‐temperature atomic gases with both dielectric and metallic nanophotonic systems is investigated. Two different classes of devices resulting from incorporating an optically pumped Rb–ethane mixture in a dielectric ring resonator and a plasmonic lattice are studied. It is shown that the combination of the optical gain provided by the atomic vapor, along with the unique field‐confinement properties of nanophotonic structures, enables the generation of coherent radiation, that is, laser light, at moderate power levels. In addition, general design guidelines for these hybrid nanophotonic lasers are provided. These results pave the way toward a novel class of active nanophotonic and metamaterial systems.