Cooperative cascade emission

研介 池田, 淳平 岡田, 正浩 松岡

H. H. Jen, S. D. Jenkins, Brian J. Kennedy

Paul A. Schmidt

Kensuke S. Ikeda, Jumpei Okada, Masahiro Matsuoka

The characteristics of the cooperative cascade emission is studied by taking into account of the nonlinearity due to depopulation. It is shown that the emitted radiation exhibits considerably different behaviors in three regimes of the atomic number density. In the lowest density regime the radiation is essentially a quasi-stationary amplified spontaneous emission (ASE), in the intermediate one it becomes superradiant, and in the highest one it shows a new cooperative behavior peculiar to the cascade system. By using the present theory the experimental results recently observed in Li vapour is explained. It is also shown that the present theory describes the two-level cooperative emission as a specific limiting case.

Galina A. Nemova

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.