Telescope-Performance Reciprocity for Propagation in a Turbulent Medium

Abstract : The authors demonstrate that, with the effects of atmospheric turbulence included, reciprocity exists between the performance of a telescope (i.e., an antenna) when it functions as part of an optical heterodyne receiver and its performance when it functions as part of a laser transmitter. For a given optical antenna operating through atmospheric turbulence to some distant point, the effect of atmospheric turbulence upon antenna gain is the same whether the antenna is used as part of a laser transmitter, of an optical heterodyne receiver, or of an image-forming device. It follows that, if the same antenna is used in two or more ways simultaneously, e.g., as a transmitter and as an imaging device, measurements of the performance in one role may be used to gauge the concurrent performance in the other role. (Author)