Optical tomography of Kerr electro-optic measurements with axisymmetric electric field

Dielectrics become birefringent (Kerr effect) when stressed by high electric fields so that incident linearly or circularly polarized light propagating through the medium becomes elliptically polarized. Most past experimental work has been limited to cases when the electric field magnitude and direction have been constant along the light path, while recent analysis and point/plane electrode measurements have developed the Abel transformation which describes Kerr effect measurements when an axisymmetric electric field has magnitude but not direction varying along the light path. The present work develops the governing Kerr effect differential equations for an axisymmetric electric field for the case when both magnitude and direction vary along the light path. The specific case of point/plane electrodes are studied where analytical electric field solutions are used for the space charge free case and finite element computer analyses are used to calculate the electric field distribution for postulated space charge injection from the point electrode. The authors then calculate the Kerr electro optic fringe patterns that would result. They use the “onion peeling” method previously used for photoelastic analysis to calculate the electric field magnitude and direction from computer-simulated optical measurements