Diffraction entre un émetteur et un récepteur localement toriques. Application à l'étude des systèmes astigmates

The transfer of the electromagnetic field from a toric emitter to a receiver of same kind is expressed by a two-dimensional integral which can be split into two one-dimensional integrals. Each one-dimensional integral can be seen as a fractionnal Fourier transform whose order is related to the distance between the emitter and the receiver and to their principal curvatures. The knowledge of these orders is alone sufficient to solve practical problems (such as image formation) without explicit use of the integral formulae.