Abstract

In this talk, we discuss the long wavelength optical properties of a LiNbO₃ (LN) ferroelectric superlattice composed of laminar domains with spontaneous polarization perpendicular to domain walls. This periodic elastic medium is a one-dimensional (1D) phononic crystal with ferroelectric domains and piezoelectric coefficients as the modulation parameter. In such a superlattice, the boundaries of neighboring domains are charged periodically. The domain boundary can be viewed not only as the concentration of mass but also as the charge center. This phononic crystal can thus be viewed as a 1D diatom chain with positive and negative "ions" connected periodically, similar to a real ionic crystal. Therefore, this kind of superlattice is termed an ionic-type photonic crystal (ITPC).¹

© 2001 IEEE