Interaction enhanced imaging of individual atoms embedded in dense   atomic gases
  We propose a new all-optical method to image individual atoms within dense atomic gases. The scheme exploits interaction induced shifts on highly polarizable excited states, which can be spatially resolved via an electromagnetically induced transparency resonance. We focus in particular on imaging strongly interacting many-body states of Rydberg atoms embedded in an ultracold gas of ground state atoms. Using a realistic model we show that it is possible to image individual impurity atoms with enhanced sensitivity and high resolution despite photon shot noise and atomic density fluctuations. This new imaging scheme is ideally suited to equilibrium and dynamical studies of complex many-body phenomena involving strongly interacting atoms. As an example we study blockade effects and correlations in the distribution of Rydberg atoms optically excited from a dense gas. 
G. G\"unter, M. Robert-de-Saint-Vincent, H. Schempp, C. S. Hofmann, S.   Whitlock, M. Weidem\"uller
physics.atom-ph cond-mat.quant-gas quant-ph