Strain-induced non-linear optical characteristics of pyroelectric PbVO₃ epitaxial thin films

Highly strained PbVO₃ films have potential applications in pyroelectric sensors and optoelectronic devices. To understand how strain influences the nonlinear optical characteristic of PbVO₃, highly distorted tetragonal PbVO₃ epitaxial thin films were grown on LaAlO₃ and SrTiO₃ substrates. Using Raman scattering spectroscopy, theoretical and experimental studies on the phonon spectra yield insights on the strained structures of V-O apical bondings. Effects of applied strain on the linear optical properties of PbVO₃ thin films were experimentally characterized by spectroscopic ellipsometry. Second-order nonlinear susceptibility tensor components of PbVO₃/SrTiO₃ thin films were determined to be almost twice as large as those of PbVO₃/LaAlO₃ thin films.