Improved Second Harmonic Generation from Organic-Dye-Doped Polymer/Silica Hybrid Materials

In this study, we investigated the second-order optical nonlinearity and its thermal stability of DR1 (disperse red 1) doped poly(methyl methacrylate) (PMMA)/silica gel films. We found that in situ polymerization of sol−gel precursors (tetraethoxysilane, TEOS) in a polymer generated a hybrid matrix which is a good tradeoff between a silica gel and a polymer matrix. The nonlinear thermal stability of the hybrid system increased significantly compared to that of a poled DR1/PMMA film. Our result proved that the combination of a poled polymer and the sol−gel technique provides a way to increase the thermal stability of nonlinear optical thin films fabricated from existing materials rather than synthesizing new chemical compounds. Several factors which affect the second-order optical nonlinearity of the hybrid system were also examined.