Population transfer in N-level systems assisted by dressing fields

We analyze N-level systems for population transfer by counterintuitive pulse delay, in which N-2 intermediate states are strongly coupled by dressing laser fields. We have carried out specific analysis for the four- and five-level systems using a dressed-state picture, as representatives for even-N- and odd-N-level systems, respectively. We have found that the dynamics of the systems are essentially different for even-N- and odd-N-level systems, and that complete population transfer assisted by dressing fields is more restrictive for even-N-level systems than for odd-N-level systems.