Ellipsometry and Michelson interferometry for fixed- and variable-frequency electro-optical measurements on poled polymers

Since the linear electro-optical or Pockels effect is one of the strongest and most useful effects in poled polymers, it can be employed for investigating the magnitude, the spatial distribution and the thermal and temporal stability of the dipole orientation. Some of the relevant ellipsometric and interferometric techniques are briefly described. Emphasis is given to frequency-dependent electro-optical measurements which permit a relaxation spectroscopy based on the probing of the dipole orientation by means of frequency scanning of the linear susceptibility (optical birefringence). Such a spectroscopy is of particular relevance for the recently introduced "orientational enhancement" in photorefractive polymers. In addition, scanning electro-optical microscopy and electro-optical phase-shift interferometry are described as useful methods for measuring spatial dipole-orientation patterns