POLARIZATION STATE EVOLUTION AND EIGENMODE SWITCHING IN PHOTOREFRACTIVE BSO

In dealing with the problem of the passage of polarized light through birefringent and optically active media, a simple planar graphic repre sentation of the state of light polarization is introduced. Using this representation, the polarization state evolution is studied of both t ransmitted and diffracted waves in a two-wave mixing experiment using a crystal of bismuth silicon oxide (Bi12SiO20). Examples are given whe n the input incident polarization is a linearly polarized wave, an eig enmode and a circularly polarized wave, assuming a single diffracted b eam and an undepleted readout beam. The possibility of eigenmode switc hing is analyzed. Finally, an experiment is performed to follow the ev olution of the output polarization versus the applied field that allow s one to find the eigenwaves of propagation.