Visible coloration in oxide glasses induced by two-photon absorption

The observation of visible coloration induced through two-photon absorption with intense laser beam in oxide glasses containing lead oxide or cadmium oxide as the major component is reported. The coloration is uniform sufficiently along the beam propagating direction within the glass, differing from the nominal photochemical coloration due to fundamental absorption of light at the thin incident-surface region. A model for formation dynamics of color center which causes the visible coloration is examined by analyzing the propagation of intense beam within the glasses.