SOLARIZATION OF GLASS SUBSTRATES DURING THIN-FILM DEPOSITION

We demonstrate that solarization occurs in glass substrates during thi n-film deposition and that it induces high absorption near the surface of the substrate. Solarization has been observed especially in ion-pl ating deposition. We show that the solarization of the substrate is ca used by electromagnetic radiation emitted from the material to be evap orated. The radiation is due to the energy losses of the heating beam of electrons (bremsstrahlung radiation). Multicomponent glasses such a s BK7 are much more sensitive to solarization than fused-silica substr ates. The photoinduced high absorption can be partially reversed by th ermal annealing. (C) 1998 Optical Society of America.