Nonlinear optical phenomena in the Al2O3-P2O5, Er- and Yb-doped silica glasses

UV-photoinduced optical second harmonic generation (PISHG) in Al2O3-P2O5-Si O2 glasses doped by Er and Yb rare earth ions has been investigated. The ma ximum output PISHG signal is observed at the delay time between the photoin ducing nitrogen laser (lambda = 337 nm) and probing laser (YAG:Nd; lambda = 1060 nm) beams at about 7 ps, at temperatures of about 4.2 K and photoindu cing beam powers lying within the range 0.45-0.82 GW cm(-2). The essential effect of external electrostatic field and hydrostatic pressure on the outp ut PISHG signal has been revealed. The Yb ions suppress the output PISHG. A ll the data are explained in terms of the ab initio molecular dynamics simu lations and take into account anharmonic electron-vibration interactions. T he problem of phase matching conditions is discussed.