By using the Fresnel operator we derive a multiplication rule for the Collins diffraction formula; the inverse of Collins diffraction integration can also be conveniently derived in this way in the context of quantum optics theory.
Based on the displacement-squeezing related squeezed coherent state representation | z⟩ g and using the technique of integration within an ordered product of operators, this paper finds a generalized Fresnel operator, whose matrix element in the coordinate representation leads to a generalized Collins formula (Huygens–Fresnel integration transformation describing optical diffraction). The generalized Fresnel operator is derived by a quantum mechanical mapping from z to sz - rz * in the | z⟩ g representation, while | z⟩ g in phase space is graphically denoted by an ellipse.