OPTICAL-DETECTION OF ION IMPURITY SITES IN DOPED LINBO3

In this work the site location of several M3+ (M = Cr, Nd, Eu, Ho, Er, Tm) dopant ions in LiNbO3 has been investigated by using optical (abs orption and site-selective fluorescence) techniques. Experimental resu lts reveal that the regular cation sites, Li+ and Nb5+, are occupied i n all cases and can be characterized optically. Additional crystal fie ld sites, for M = Nd and M = Eu, have been detected by site selective spectroscopy. The effects on the M3+ optical spectra of the stoichiome try and the codoping with MgO have been systematically investigated. T he appearance of new sites for the M3+ ions, M3+-Mg2+, is ascertained for M = Cr, Nd, Ho, Ho, and Tm.