Elasto-Optic Effect of Lanthanum-Modified Lead Zirconate-Lead Titanate Transparent Ceramics: Application in Optical-Stress Sensors

Elasto-optic materials have extensive applications, particularly in sensors, filters, and acousto-optic modulators in optical-mechanical-coupled devices. Ferroelectric phenomenological theoretical analyses have shown that materials with large ferroelastic responses also have high elasto-optic effects, and morphotropic phase-boundary (MPB) ferroelectrics have substantial ferroelastic coupling; thus, a large elasto-optic effect can be obtained. In this study, guided by phenomenological theories, lanthanum-modified lead zirconate-lead titanate (PLZT) transparent ceramics close to MPB are successfully prepared using the hot-pressing method. The elasto-optic properties of the PLZT transparent ceramics are investigated using the half-wave stress and the Senarmont compensator methods. The results indicate that the PLZT ceramics have high transmittance (higher than 70% in near-infrared) and a large elasto-optic effect with a stress-optic coefficient of 10.41 x 10(-12) m(2) N-1 (approximately three times that of SiO2). Based on these properties, intensity- and interference-type optical-stress sensors are designed and realized; better anti-interference ability can be achieved using the interference-type sensor. These results indicate that PLZT transparent ceramics are promising candidates for optical-mechanical-coupled device applications. This study also substantiates that transparent ceramics are novel elasto-optic materials, which uncover new avenues for the development of elasto-optic materials with excellent properties.