Photoinduced molecular alignment relaxation in poled electro-optic polymer thin films

• Published in: Applied physics letters 1996-02, Vol.68 (8), p.1040-1042
• Main Authors: Shi, Yongqiang, Olson, David J., Bechtel, James H., Kalluri, Srinath, Steier, William H., Wang, Wenshen, Chen, Datong, Fetterman, Harold R.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.116241

The photoinduced nonlinearity decay in poled nonlinear optical polymer, polyurethane/Disperse Red 19, films was studied at wavelengths from 543 to 1320 nm. Electro-optic gratings and waveguide modulators were used in measuring and monitoring material’s nonlinearity. No photoinduced nonlinearity decay was detected at near infrared wavelengths. However, the photoinduced relaxation rate increased approximately 5 orders of magnitude from 670 to 543 nm, as the excitation wavelength approaches π-π* transition of the chromophores. The photoinduced chromophore reorientation was identified as the dominant relaxation mechanism.