Operator Form of the Generalized Optical Theorem for Wave Problems

The operator form of the generalized optical theorem (OT) obtained earlier for the scalar wave equation is extended to the case of electromagnetic radiation, as well as other wave equations. It is shown that in the transition from the operator to the usual OT, instead of the “forward” scattering amplitude, the diagonal matrix element of the T-scattering operator corresponding to the incident wave appears. The transitions to known forms of OT following from operator OT as special cases are also illustrated.