Enhanced Raman scattering in thermally poled sodium-niobium borophosphate glasses

Abstract

Micro-Raman analysis has been carried out on the cross section of thermally poled sodium-niobium borophosphate glasses. We were able to measure with accuracy an enhanced Raman response from the nonlinear optical (NLO) layer formed at the anode side of the poled glasses. The thickness of the NLO layer has been estimated. Several spectral changes were observed within this layer, which manifest important structural rearrangements after thermal poling. Possible mechanisms leading to structural reorganization in the space charge region are discussed.