Influence of the sol-gel growth parameters on the optical and structural properties on LiNbO3 samples

We report on the structural, morphological and optical characterization of Er doped lithium niobate (LiNbO3) grown in a glass matrix prepared by sol-gel route. The samples were grown from a mixture with nominal composition of 91SiO2-4Li2O-4Nb2O5-1Er2O3 (Er:LN) and the crystallization process was followed up in the temperature range between 500 deg. C and 750 deg. C. The Er:LN samples start to crystallize at temperatures above 600 deg. C and besides the LiNbO3 crystalline phase sub micron ErNbO4 precipitates were identified by X-ray diffraction and Raman measurements. A comparison with glass matrices grown without NbO2 or Li2O was carry out in order to identify both the structural and optical properties of the Er:LN samples. The fingerprint emission lines of Er3+ ion in the Er:LN samples are discussed in terms of distinct crystalline environments for the Er ion in samples