Stark-shift-chirped rapid-adiabatic-passage technique in tripod systems

Abstract

We show that the technique of Stark-chirped rapid adiabatic passage (SCRAP), can be implemented in tripod quantum systems. We propose a scheme for coherent superposition among two ground states via Stark-shiftchirped rapid adiabatic passage technique in a tripod system. Tripod-SCRAP uses four laser pulses: an intense far-off-resonance Stark laser pulse modifies the transition frequency between the states by Stark shifting their energies and three nearly resonant pump, Stokes, and control laser pulses that fractionally transfer the population between the ground states via adiabatic passage. In our scheme, the pulse duration of the pump pulse must be larger than the pulse duration of the Stokes and control pulses, although with a smaller amplitude, and the atom encounters with the pump, Stokes, control, and Stark laser pulses with counterintuitive order (Stokes pulse arrives before the rest of the pulses). This technique can be applied to one-photon as well as multiphoton transitions and it is not necessary to vanish the pulses (pump and Stokes) simultaneously and it is a powerful alternative tool for f-STIRAP and tripod-STIRAP techniques at least when inhomogeneous broadenings are included. inhomogeneous broadening. This technique is robust against moderate variations in the intensities of the laser pulses,in detunings, and in delays between the pulses.