Spectroscopic analysis of Er3+ transition in Mg/Er-codoped LiNbO3 crystal

We present a Judd-Ofelt spectroscopic analysis on the Mg/Er-codoped congruent lithium niobate (LiNbO3) crystals. The Judd-Ofelt model is applied to the room temperature unpolarized absorption intensities of Er 31 ions on eleven transition bands to determine their intensity parameters: Omega(2) = 2.36 x 10(-20)cm(2), Omega(4) = 0.76 x 10(-20) cm(2), Omega(6) = 0.30 x 10(-20) cm(2) in Er:LiNbO3 crystal heavily codoped with MgO. The radiative lifetime of H-2(9/2) becomes longer when MgO is added into Er:LiNbO3 crystal. The experimental lifetimes are obtained using microsecond time-resolved spectra at 400 nm femtosecond pulse excitation to predict radiative quantum efficiency. Combining higher radiative quantum efficiency with longer radiative lifetime, we conclude that Mg/Er-codoped LiNbO3 crystals are more suitable than Er: LiNbO3 ones in laser materials. (c) 2007 Elsevier B.V. All rights reserved.