Characteristic of surface layer of periodic segment proton-exchanged and annealed LiTaO3

Proton-exchanged and annealed film in z-cut LiTaO3 with and without the periodic segment are fabricated. The refractive index, lattice constant, proton concentration, and infrared absorption spectrum of samples are measured by prism coupling, x-ray rocking, SIMS, and spectrometer, respectively. The refractive index increase and the change in lattice constant of the surface layer are noticed during the annealed process.