Coherent Excitation of Two-Level Atoms by Pulse Trains

D. Felinto, C. A. C. Bosco, L. H. Acioli +1 more

Nataša Vujičić, Damir Aumiler, Ticijana Ban +1 more

M.H.M. Ahmed, Ekaterina Ilinova, Andrei Derevianko

Antônio Augusto Soares, Luı́s E. E. de Araujo

We study the effects of propagation through an extended sample of two- and three-level atoms on the coherent accumulation of excitation by an ultrashort pulse train. In the two-level case, previous pulses in the train may prepare the medium such that a later pulse may experience amplification and absorption in different positions inside the sample. For a large number of pulses, the atomic medium may be saturated by the train, and some pulses propagate without experiencing either absorption or amplification. In general, absorption of the resonant pulse frequency during propagation compromises the accumulation efficiency. In the three-level case, the coherent accumulation of excitation leads to electromagnetically induced transparency of the pulse train, and the pulses exit the medium without any distortion in their temporal profile.

PAUL M. RADMORE

Eiping Anhui

This paper discussed the solution of the Bloch equations of a two-level atom resonantly interacting with laser pulse trains in detail. In terms of the solution, we calculate the radiation spectrum of the two-level atom excited by the laser pulse trains and obtain the following conclusions: (1) for the atoms satisfying the condition K1/K = 1 (such as gas atoms broadened by spontaneous emission), the laser pulse trains are almost equivalent to a CW laser; (2) for the atoms K1/K《1, saying, some solid atoms like ruby, the radiation spectrum of the atom exhibits the multipeak structure induced by the strong interaction of the atom with the side frequency components of the laser pulse trains.