An alternative nondestructive experimental approach to tangential static field detection in SAW structures imaging

The electrostatic electric field is the dominant excitation mechanism of the SAW interdigital transducer. A method to obtain measured interelectrode field strengths using the electro-optic effect in piezoelectric materials has been previously presented. This paper is an extension of the previous work in which the birefringence property and the linear electro-optic effect present in SAW substrates was utilized for obtaining images of the field distribution present in the interelectrode gap of a SAW IDT. An optical data acquisition system has been constructed capable of acquiring three dimensional profile data of the tangential field present in a SAW structure fabricated on a YZ-cut LiNbO₃ wafer which has been polished on both sides. This technique is utilized for analysis of the predicted end effects at the end of the array of electrodes, and the end effects present in narrow aperture IDT transducers. Three dimensional simulations of the tangential field were carried out for simple structures by using the method of moments for the purpose of comparison between the experimental and theoretical results