Control of rubidium low-lying Rydberg states with trichromatic femtosecond π pulses for ultrafast quantum information processing

Abstract

We propose an ultrafast femtosecond time scale trichromatic $\ensuremath{\pi}$-pulse illumination scheme for coherent excitation and manipulation of low-lying Rydberg states in rubidium. Selective population of ${nP}_{3/2}$ levels with principal quantum numbers $n\ensuremath{\lesssim}12$ using 75-fs laser pulses is achieved. The density-matrix equations of a four-level ladder system beyond the rotating-wave approximation have to be solved to clarify the balance between the principal quantum numbers, the duration of the laser pulses, and the associated ac-Stark effects for the fastest optimal excitation. The mechanism is robust for femtosecond control using different level configurations for applications in ultrafast quantum information processing and spectroscopy.