Second-order nonlinear susceptibilities in nonelectrically poled DR1-PMMA guest-host polymers

摘要

The presentation will report nonelectrical poling behaviors of guest-host polymers, consisting of Disperse Redl (DR1) and poly (methyl methacrylate) and related second-order nonlinear optical susceptibilities. Our present experimental results found the emissions of the second harmonic generations from the polymer thin films on SiO_2 glass substrates after annealing the materials at the temperatures higher than the glass transition temperatures of the PMMA even in the absence of applying the external electric fields. The hydrogen bonds between the hydroxyl groups of the DR1 and the silanols of the substrate surely played essential roles for breaking the centrosymmetry in the alignments of the guests. The optimized conditions of the nonelectrical poling procedures were examined from the standpoints of the polymer film thickness and the concentrations of the guest chromophores.