engleski

Coherent accumulation in rubidium atoms excited by a train of femtosecond pulses

We present a direct observation of the velocity selective optical pumping of the Rb ground hyperfine levels induced by the coherent accumulation. The coherent accumulation comes as a result of the femtosecond pulse train and rubidium system interaction. The pulse train effects were observed in the frequency domain, corresponding to the different atomic velocity groups, weighted by the Doppler profile. A modified DFCS spectroscopy which, in addition to the fs laser, uses a weak probe laser for monitoring the population distribution between the hyperfine ground state Rb levels was developed. The Liuville equation for the density-matrix elements of a four-level Rb system was employed for the theoretical interpretation of the observed fenomena.

coherent accumulation; pulse train

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