Topological stability of stored Bessel beams via electromagnetically-induced transparency in rubidium vapor

We report on experimental and theoretical work in which we first store a Gaussian beam via electromagnetically-induced transparency (EIT) in ⁸⁷Rb vapor, and study the evolution of its intensity profile. We show how the size of the input Gaussian beam gets enlarged due to diffusion, and discuss degrading effects on storage. Next, we produce a Bessel beam with an axicon and show that the topological features of the beam help combat the degradation from diffusion. For comparison, we store an "imposter Bessel beam" - a Gaussian beam carrying two dark rings resembling the central part of a Bessel beam - and show that the imposter is unstable and quickly degrades into a Gaussian. This work suggests the possibility of enhancing alkali atom-based information storage by engineering the electric field profile of the beam.