Chirped adiabatic passage with temporally delayed pulses

We study the dynamics of chirped adiabatic passage (CHIRAP) with temporally delayed pulses to selectively and fully transfer population in atoms and molecules. We show that the transfer of population via stimulated Raman adiabatic passage (STIRAP) and stimulated two-photon adiabatic absorption with temporally delayed laser pulses is not adversely affected by applying a chirp to the pulses, provided the intensity of the laser is sufficiently large to allow adiabatic passage. We then proceed to consider systems in which a near degeneracy of terminal state levels results in nonselective population of the terminal levels using nonchirped STIRAP or two-photon absorption stimulated passage, because the dynamics within the nearly degenerate pair of levels is not adiabatic. However, the CHIRAP process selectively populates only one of the terminal levels.