Low loss second‐order nonlinear optical polymers based on all organic sol‐gel materials

A new class of all organic sol‐gel second‐order nonlinear optical (NLO) materials based on hexa(methoxymethyl) melamine (HMM) was developed. Two NLO active chromophores, 4 (4′‐nitrophenylazo) aniline (DO3) and 4‐amino‐4′‐nitrobiphenyl (ANB), were incorporated into the melamine matrices. The samples exhibited second‐order optical nonlinearity after poling and curing at 220°C for 30 min. DO3/HMM and ANB/HMM samples showed a second harmonic coefficient, d33 of 10.7 and 1.8 pm/V at 1064 nm, respectively. The temporal stability of both systems was studied at room temperature as well as at 100°C. Waveguide optical losses of samples at 633 and 830 nm were found.