Measurements of electrical birefringence by using a transverse-field Pockels cell as a compensator

Abstract

A new method of electric field measurements in corona discharge using Pockels device An improved device for electrical birefringence measurements is described. The novel features of this apparatus include a new design of the Kerr cell and use of the Pockels cell as a compensator. These features show enhanced sensitivity and great improvement in reproducibility of results. A relationship between the intensity detected and the relative phase shifts in the Kerr and Pockels cells is determined by a matrix analysis of the amplitude of radiation passing through each optical element. Based on this analysis, a comparative study under different experimental configurations, as well as an evaluation ofthe effects of misalignments and methods to cancel the static birefringence, are made. From the results, the best experimental arrangement and procedure of measurement are deduced. Finally, the apparatus is checked by measuring Kerr constants (B) of several nearly isotropic solvents used for the study of polymers in solution.