Observation of Parity Time Symmetry in Optically Induced Atomic Lattices.
We experimentally demonstrate PT symmetric optical lattices with periodical gain and loss profiles in a coherently prepared four level N type atomic system. By appropriately tuning the pertinent atomic parameters, the onset of PT symmetry breaking is observed through measuring an abrupt phase shift jump between adjacent gain and loss waveguides. The experimental realization of such a readily reconfigurable and effectively controllable PT symmetric waveguide array structure sets a new stage for further exploiting and better understanding the peculiar physical properties of these non Hermitian systems in atomic settings.
Physical review letters