Focusing on a turbulent layer: Principle of the "generalized SCIDAR"

During the last two decades, much effort has been put into the remote sensing of atmospheric turbulent layers, using optical devices. The main scientific interest concerns optical path fluctuations relevant to communication and astronomy and the widening of our understanding of atmospheric physics. Hen we describe an original technique that involves moving a virtual plane of analysis in the atmosphere. Using this technique, a simple optical combination allows us to explore the atmosphere, wiping out a particular layer while distant layers located beneath or above are reinforced. When combined with the SCIDAR technique, this phenomenon leads to the "generalized SCIDAR" concept, allowing turbulence profiles to be remotely assessed throughout the whole atmosphere, including the boundary layer. The potential of this new concept is shown in a laboratory experiment using a vein to simulate an atmospheric turbulent layer.