<title>Birefringence Mode Of Operation Of 9/65/35 Plzt Ceramic</title>

Abstract

Ferroelectric ceramic material lanthanum-modified lead zirconate titanate (PLZT) has the unusual property that thin plates of fine grained material are transparent. PLZT offers a variety of properties of interest, including electrically controlled birefringence (Ref. 1) and electrically controlled scattering of light (Ref. 2), and ferroelectric, pyroelectric and piezoelectric properties. The first two properties are of particular interest as the basis for constructing light switches, insulators, displays, and optical memories. Parameters entering into the material preparation process, such as impurities, modifiers, dopants, conditions of hot pressing, and the grain size of the ceramic influence the device performance characteristics (Ref. 3). Materials in the PLZT family can exhibit an electro-optic memory effect (related to variations of ceramic birefringence with remanent polarization), a quadratic (Kerr) electro-optic effect, or a linear (Pockels) electro-optic effect depending on the lanthanum content and the Zr/Ti ratio. Land (Ref. 4) indicates that electro-optic memory effects are found in low coercivity rhombohedral and tetragonal PLZT compositions. The Kerr quad-ratic electro-optic effect occurs in slim-loop ferroelectric PLZT compositions for electric fields in the range 0 s lE 1 <Es , where ES is the value of electric field at which the ferroelectric polarization begins to saturate. The linear electro-optic effect is found in high-coercivity tetragonal PLZT compositions.