It is shown how a coherent optical signal that contains only a finite number of Hermite-Gauss modes, can be reconstructed from the knowledge of its Radon-Wigner transform - associated with the intensity distribution in a fractional Fourier transform optical system - at only two transversal points. The proposed method can be generalized to any fractional system whose generator transform has a complete orthogonal set of eigenfunctions.
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http://www.opticsinfobase.org/abstract.cfm?URI=josaa-19-3-481