Tunable optical vortex array in a two-dimensional electromagnetically induced atomic lattice.

ABSTRACT

Optical vortex arrays (OVAs) containing multiple vortices have been in demand for multi-channel optical communications and multiple-particle trapping. In this Letter, an OVA with tunable intensity and spatial distribution was implemented all-optically in a two-dimensional (2D) electromagnetically induced atomic lattice (EIL). Such a square lattice is constructed by two orthogonal standing-wave fields in 85Rb vapor, resulting in the periodically modulated susceptibility of the probe beam based on electromagnetically induced transparency (EIT). An OVA with dark-hollow intensity distribution based on 2D EIL was observed in the experiment first. This work thus studied the nonlinear 2D EIL process both theoretically and experimentally, presenting, to the best of our knowledge, a novel method of dynamically obtaining and controlling an OVA and further promoting the construction of all-optical networks with atomic ensembles.