NONLINEAR INDEX OF REFRACTION OF CU-IMPLANTED AND PB-IMPLANTED FUSED-SILICA

We have measured the nonlinear index of refraction in high-purity fused silica implanted with Pb and Cu ions, using 100-ps pulses from a cw, mode-locked, frequency-doubled Nd:YAG laser (lambda = 532 nm). The nonlinear index measured for the Pb-implanted silica is an order of magnitude larger than that for Cu:silica. Qualitative evidence from infrared reflectance spectra suggests that these differences may result from distinctive ways in which these implanted ions are incorporated into the glass network: the Cu appears to form nm-size colloids, while the Pb may be incorporated into a Pb-O-Si glassy phase.