For inhomogeneous electromagnetic waves in isotropic media the operator evolution solutions of Maxwell equations are obtained. These solutions are functions of the complex spatial variable. In the case of homogeneous waves an evolution operator is associated with a set of right-handed and left-handed generalized helices. In this set the helices of straight circular cylinders are geodetic lines. It is shown that one of the branches of the evolution operators is generated by traceless operators and that it correspond to standing evanescent waves. These evolution operators are elements of the group . For this Maxwell group a new parametrization is introduced and appropriate composition laws are derived. The introduced parametrization is compared with the known Fedorov parametrization.