Transverse nonlinear optics in heavy-metal-oxide glass

We investigate beam propagation in a heavy-metal-oxide glass of the group Nb2O5-PbO-GeO2 using picosecond pulses in the near infrared. We observe a wavelength-dependent self-focusing, with beam collapse and modulation instability in the Kerr regime at 1.064 mu m and stable spatial solitons at 820 nm where multiphoton absorption is present. We report near-infrared beam self-confinement and solitons, filamentation, interactions, and conical emission in the ps regime and discuss them with the aid of a numerical model.