Unidirectional and bidirectional photon transport blockade in driven atomic lattices of parity-time antisymmetry

Abstract

We propose a scheme for realizing the exact parity-time (PT ) antisymmetry in terms of complex probe susceptibility in a one-dimensional lattice of cold atoms driven into the simplest three-level configuration. This is attained by modulating the intensity of a standing-wave coupling field with a proper phase shift to counteract the product of a single-photon detuning and a two-photon detuning. Such a dynamically controlled PT -antisymmetric lattice supports a few nontrivial scattering behaviors including unidirectional light reflectionless, asymmetric perfect absorption, and directional signal quenching. These behaviors, depending in particular on atomic densities and lattice lengths, facilitate the on-demand realization of unidirectional or bidirectional photon transport blockade.