I. Savatinova

Stretching vibrations of water in isotope-diluted ferroelectric potassium ferrocyanide trihydrate

Abstract A partially deuterated and a pure K 4 Fe(CN) 6 · 3H 2 O crystal have been investigated by low-temperature Raman and IR spectroscopy. Five unperturbed OH frequencies of the HDO molecules were found and are discussed in comparison with the corresponding OD frequencies obtained previously. The temperature behaviour of both unperturbed and perturbed OH(OD) modes has shown that not the isotope isolation but the dynamic disorder of the crystal is the major contributor to the spectral bandwidths.

IR absorbance in proton-exchanged LiNbO3 optical waveguides

Abstract An investigation of PE-waveguides in Z- and X-cut LiNbO 3 by means of ir-absorption spectroscopy is performed, the proton source being benzoic acid with 1 % lithium benzoate added. The spectra of unexchanged samples indicate mainly three OH-bands at 3649, 3480 and 3486 cm −1 . A strong band at 3508 cm −1 is present only in the spectra of PE-waveguides. A very broad diffuse shoulder is observed at lower frequency due to OH-modes localized not only in the plane perpendicular to, but also along the optical axis. An attempt to explain this polarization behaviour is made.

Raman study of planar optical waveguides in LiNbO3 and LiTaO3

Abstract Proton-exchange (PE) technology has been used to form planar optical waveguides in LiNbO 3 and LiTaO 3 single crystals. Studying post-exchange annealed (APE) waveguides, the evolution of guide properties with decreasing the proton concentration is followed. Raman spectroscopy is used to investigate the vibrational characteristics of PE and APE layers. The spectra of PE layers show a high degree of disorder and a “paraelectric-like” form.