Cancellation of atmospheric turbulence effects in entangled two-photon   beams
  Turbulent airflow in the atmosphere and the resulting random fluctuations in its refractive index have long been known as a major cause of image deterioration in astronomical imaging and figures among the obstacles for reliable optical communication when information is encoded in the spatial profile of a laser beam. Here we show that using correlation imaging and a suitably prepared source of photon pairs, the most severe of the disturbances inflicted on the beam by turbulence can be cancelled out. Other than a two-photon light source, only linear passive optical elements are needed and, as opposed to adaptive optics techniques, our scheme does not rely on active wavefront correction. 
Marcelo V. da Cunha Pereira, Lu\'isa A. P. Filpi, and Carlos H. Monken
quant-ph physics.optics