Controlling atomic wave interference by counter-propagating light pulses of different carrier frequencies

Abstract

We consider the interaction of a two-level atom with two counter-propagating light pulses of different carrier frequencies. To ensure adiabatic interaction, the pulse duration is much longer than both the inverse frequency difference and the maximum Rabi frequencies of the pulses. For the first time, we examine the case where the atom is initially prepared in a superposition of the ground and excited states with a momentum difference corresponding to one-photon recoil. We identify the conditions under which the atom’s final state is determined by the phase difference of the momentum components of the initial atomic wave. Given the large pulse duration, the interference effects depend critically on the rate of spontaneous emission from the excited state. We analyze the role of spontaneous emission using the Monte Carlo wave function method. The results of our calculations elucidate the influence of spontaneous radiation on both the momentum transferred to the atom and the interference outcome of the two atomic waves.