GUEST-HOST POLED POLYMERS WITH HIGH LOADING LEVEL BY USING CHROMOPHORES WITH SMALL DIPOLE MOMENT

Abstract

Poled polymers are currently of great interest in second-order nonlinear optical (NLO) applications such as electro-optic (EO) modulation, optical switching, etc. The EO active chromophores doped in polymer matrices generally have large dipole moment. The strong electrostatic interaction between molecular dipoles causes orientation relaxation after poling, decrease of poling efficiency, phase separation, and etc. at high doping concentration. A new type of NLO chromophore with low ground-state dipole moment has been designed and synthesized. It was doped in PMMA polymer matrix. The electrostatic interaction between chromophore molecules in this doped film is reduced greatly. This provides a way to increase the doping level in guest-host poled polymer system. At a very high loading level of 52% wt. (N = 6.41 × 1020/ cm 3), which is over 2 times of the theoretically predicated value for the spherical shape molecules, reasonable film quality and dipole orientation stability have been achieved.