Optical emission properties of Nd3+ in NaBi(WO4)(2) single crystal

Abstract

Room temperature optical absorption measurements of Nd3+ in NaBi(WO4)2 single crystals grown by the Czochralski method have been used to calculate the following Judd-Ofelt intensity parameters: Omega2 =30.9 × 10-20 cm2, Omega4 = 12.0 × 10-20 cm2 and Omega6 =9.3 × 10-20 cm2. Using these parameters the emission properties of Nd3+ in this host have been estimated with particular attention to the 4F3/2 energy level responsible for stimulated emission channels. The experimental branching ratios of this level are obtained from photoluminescence and agree with those calculated using the above Omegak parameters. The 4F3/2 emission has negligible non-radiative intrinsic losses and the 10 K lifetime at low Nd concentration, 0.9× 1018 cm-3, is tauexp= 143 mus. Even at 300 K and for a much higher Nd concentration, 4.0× 1019 cm-3, non-radiative losses are moderate, giving a quantum efficiency eta ap 0.85. The 4F3/2 emissions show a strongly polarized character. The largest emission cross-section occurs at lambda =1060.9 nm for the 4F3/2 rarr4I11/2 laser channel with a pi-polarized character, sigmaEMI= 16× 10-20 cm2.