Dispersion and dipolar orientational effects on the linear electroabsorption and electro-optic responses in a model guest/host nonlinear optical system

Linear electroabsorption (LEA) and linear electro-optic (LEG) measurements are demonstrated using a model guest/host system consisting of disperse red 1 (DR1) doped in poly(methyl)methacrylate (PMMA). The LEA response is measured over a wavelength range of 300-700 nm. Electro-optic measurements of the real and imaginary parts of the electric field-induced Pockels coefficient are carried out at wavelengths near and far from the resonant absorption. A shift in the absorption maximum and change in the band shape of the LEA spectrum are related to the linear Stark effect and dipolar orientation. Expressions for the real and imaginary parts of the Pockels coefficient derived from the two experiments are provided. Induced dipolar order as a result of the contact poling process is investigated by the LEE measurement. information concerning the relaxation of the induced dipolar order, investigated by the LEA measurement, is compared to the relaxation results obtained by using the second-harmonic generation technique. (C) 1996 American Institute of Physics.