2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84489Elements of a vector theory of open resonators and experiments on excitation of a fundamental mode with transverse and longitudinal polarization in such resonators are discussed.2 pages, LaTeX, Presented to Proc. 23 Int. Free Electron Laser Conf. FEL2001, 20-24 Aug. 2001, Darmstadt, GermanyClassical Physicstext