ANISOTROPIC FOCUSING CHARACTERISTICS OF MICRODOMAIN STRUCTURES WITHINCRYSTALLINE SR0.61BA0.39NB2O6 - THE CRYSTAL BALL

We report the anisotropic focusing characteristics of a spherically co nfigured region of microdomains that have been induced within a cubic- shaped crystal of Ce-doped Sr0.61Ba0.39Nb2O6. structure focuses extrao rdinary polarized light, but not ordinary polarized light. which is ea sily observed via scattering, is formed as the crystal cools after a r epoling cycle through the Curie temperature, with an applied field. An alytic modeling of the thermal gradients that exist within the crystal during cooling reveals a small (<1 degrees C) temperature difference between the central and the outside regions. The similarity in shape b etween these temperature profiles and the observed scattering region s uggests a possible mechanism for the growth of this spherical microdom ained structure. (C) 1997 Optical Society of America.