Coherent generation and efficient manipulation of dual-channel robust stationary light pulses in ultracold atoms

Abstract

We study the dynamic processes of reversible dual-channel light memory in a double-tripod atomic system by modulating only a pair of counterpropagating control fields in time. We find that two pairs of stationary light pulses (SLPs) can be simultaneously generated when we switch on both control fields after storage. Two incident signal fields in two channels can be released either simultaneously from the same surface of the sample, or at different times from the same or different surfaces of the sample, depending on the time modulation of the two control fields, the time sequence of the input signal fields, and the group velocities of the signal fields propagating in medium, which could be successfully manipulated in each channel. Comparing with the light storage in spin-wave excitations, the SLPs may suffer a little space-dependent diffusion but maintain optical components required for nonlinear optical interactions. These results could be used to study the enhanced low-noises nonlinear interaction between dual-channel SLPs, which can maximize the interaction time. Besides, this scheme could also be explored to design synchronous multitasking information processing during light memory processes at low-light even below single-photon level.