  We look for travelling wave fields $$ E(x,y,z,t)= U(x,y) \cos(kz+\omega t)+
\widetilde U(x,y)\sin(kz+\omega t),\quad (x,y,z)\in\mathbb{R}^3,\,
t\in\mathbb{R}, $$ satisfying Maxwell's equations in a nonlinear and
cylindrically symmetric medium. We obtain a sequence of solutions with
diverging energy that is different from that obtained by McLeod, Stuart, and
Troy. In addition, we consider a more general nonlinearity, controlled by an
\textit{N}-function.
