Structural and optical properties of Er3+ ion in sol-gel grown LiNbO3

Abstract

Er-doped lithium niobate (LiNbO3) ceramics embedded in silica were grown by the sol–gel method. The dried gel 91SiO2–4Li2O–4Nb2O5–Er2O3 (mol%) was subsequently heat treated between 500 and 750 °C. X-ray diffraction and Raman spectroscopy have detected the crystallization of LiNbO3 and ErNbO4 in samples treated at temperatures above 600 °C. At least two Er-related optical centres have been identified by low-temperature optical absorption and photoluminescence studies. The dominant intra-ionic transition arises from the Er3+ ion, in C2v site symmetry, in the ErNbO4 lattice.