Coherent sources of radiation: from LWI to cooperative emission of radiation

R. A. McFarlane

Ji‐Cai Liu, Wang Chun-Xin, Faris Gel’mukhanov +1 more

This paper investigates the dynamics of cooperative emissions in a cascade three-level system driven by an ultrashort laser pulse by solving numerically the full-wave Maxwell–Bloch equations. The 4, 4'-bis(dimethylamino) stilbene molecule is used as the model molecule because of its strong two-photon absorption property. The two-colour cooperative emissions are studied as functions of molecular number density and dephasing rate of the dipole coherence. The propagation effects on the evolution of the cooperative radiations are also taken into account. The cooperative radiations are enhanced for large number density of the molecule, while the fast dephasing of the dipole coherence reduces the intensity of the cooperative radiations and delays the emission times or even inhibits the formation of the emissions. The delay time of the radiation decreases with the increase of the molecular number density and the propagation distance.

Nelly Ciobanu, Enachi, N.A., Enaki, N.A.

The cooperative spontaneous emission from an ensemble of A type three-level atoms dressed by standing wave in resonance with coherent field is discussed. It is analyzed the spatial interference effect of fluorescent field as function of the distance between the radiators and relative position of atoms in the standing wave. The equations that describe the cooperative effect between the atom a and b are obtained.

Zoltan Fried, Lloyd C. Kannenberg

A. Grimm, F. Blanchet, R. Albert +8 more

Single-photon generation is an important proof of the underlying quantum nature of a physical process and a ubiquitous tool for scientific exploration, with applications ranging from spectroscopy and metrology to quantum computing.In the microwave regime, emission of antibunched radiation has so far relied on coherent control of Josephson qubits requiring precisely calibrated microwave pulses.In this work, we experimentally demonstrate the operation of a bright on-demand source of quantum microwave radiation driven by a simple dc voltage bias across a Josephson junction.Our source is based on photon emission into a microwave resonator through inelastic Cooper pair tunneling regulated by a high-impedance RC circuit preventing simultaneous tunnel events.It is characterized by its normalized second-order correlation function of g ð2Þ ð0Þ ≈ 0.43 corresponding to antibunching in the single-photon regime.Our device can be triggered, and its in situ tunable emission rate exceeds those obtained with current microwave singlephoton sources by more than 1 order of magnitude.