Quantum state reconstruction for strongly excited Rydberg atom wave packets via a two-state Ramsey fringe inversion method

We show that wave-packet interference techniques can reconstruct the quantu m state of wave packets excited by strong laser pulses. The measurement may be accomplished even when the strength of the excitation is sufficient to significantly deplete the ground state. The probe of the wave packet can st ill remain perturbative. An inversion algorithm is also developed that is a generalization of the standard Ramsey fringe probe of a wave packet. The n ormalized sums and differences of the populations of two of the Rydberg sta tes display Ramsey fringes and from these fringes the relative phase betwee n these two states can be found. The algorithm offers advantages in efficie ncy over previous interferometric algorithms. The algorithm is not sensitiv e to the precise nature;of the distribution of the phase between the pump a nd probe pulses. [S1050-2947(99)08712-0].