Electronic Polarizabilities of ions in Lithium Tantalate (LiTa03) optical wave guide from natural birefringence data

The ever increasing demand in the field of signal processing, computing and communication has ushered in integrated devices in optical systems. Several materials have been used for fabricating optical waveguides, components and devices adopting a variety of techniques. However, among the many device materials, lithium Tantalate remains one of the prime candidates owing to its excellent piezo electric, Electro-optical and waveguiding properties. The active and passive structures of dielectrics also include two dimensional optical waveguides. The field of integrated optics is primarily based on the fact that light can be guided and coupled in very thin films of transparent materials on suitable substrates. - optical waveguides in lithium tantalate crystal form the basis of many integrated optical devices. In characterising these devices the refractive index is an important parameter and understanding of this parameter from atomic point of view is very essential . since RI is due to dipole moments of ions it can be expressed in terms of polarizabilities of the ions and electric field. The electronic polarizabilities of ions in lithium tantalate (LiTaO 3 ) crystals are evaluated from the data on the natural birefringence of these crystals. An accurate calculation of electronic polarizabilities of ions is indispensable in the understanding of problems regarding the piezo -optical and electro-optical behaviour of these crystals.