The Atomic Inversion and the Purity of a Quantum Dot Two-Level Systems

利正 藤澤

D. A. M. Abo-Kahla, M. M. A. Ahmed

In this paper, we present the analytical solution for the model that describes the interaction between a three level atom and two systems of N-two level atoms. The effect of the quantum numbers on the atomic inversion and the purity, for some special cases of the initial states, are investigated. We observe that the atomic inversion and the purity change remarkably by the change of the quantum numbers.

Li-Xin Xia, Hui Liu

Investigated the dynamics of a two-level atom in a cavity filled with a nonlinear medium by two-photon process,elucidated that the atom-field detuning δ and the nonlinear parameter χ~((3)) may be combined to yield a periodic dynamics,showed the statistic property of this quantum system,and analyzed the atomic inversion and the field purity.

K. Berrada

Shaolin Liao, M. A. Eriksson, Mark G. Friesen

Hiroyuki Takeda

I theoretically demonstrate all-optical modulation and amplification in a one-dimensional photonic-crystal (PC) cavity with a large number of two-level quantum dots (QD's). Populations in the ground and excited states of two-level QD's with large transition dipole moments are greatly changed by an external laser, and this affects the electrical susceptibility of the QD's. In other words, all-optical modulation, in which light (the signal light) is modulated by light (the external laser), becomes possible. Moreover, a large contrast of the electromagnetic local densities of states in the PC cavity enables steady-state population inversion in two-level systems, which is generally considered impossible. The output signal power is more than twice as large as the input power at certain frequencies.