Accession Number : ADP007605

Title :   Theory of Photo Induced Second Harmonic Generation Caused by Phase Transition in Defects System in Silica Glass,

Corporate Author : AKADEMIYA NAUK SSSR MOSCOW

Personal Author(s) : Dianov, E. M. ; Sokolov, V. O. ; Sulimov, V. B.

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : To describe inducing of non-zero macroscopic second-order susceptibility in a centro-symmetric media such as the glass we suppose that a pump wave excites electrons from certain donor states in the middle of the v-SiO2 forbidden gap to defect states near the conduction band edge and the conformation of each defect changes significantly owing to pseudo-Jahn-Teller effect with a certain number of electrons placed in the proper state of the defect. Our cluster calculation performed by MNDO method proves the pseudo-effect to occur in Ge and Al atom substituted for the Si one and in =Ge-O-Ge= diatomio center with a certain defect state occupied by two electrons or by one electron, respectively. The relaxed conformation of the defects is stable since their spontaneous decay is forbidden.

Descriptors :   *OPTICAL PUMPING, *FREQUENCY CONVERSION, CONDUCTION BANDS, DECAY, EDGES, ELECTRONS, SYMPOSIA, USSR, SILICA GLASS, GLASS FIBERS.

Subject Categories : Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE