Growth, spectral and laser properties of La2Be2O5:Nd3+ crystals in the 4Fsub(3/2) → 4Isub(11/2) and 4Fsub(3/2) → 4Isub(13/2) transitions

Detailed investigations of intermanifold luminescence intensity anisotropy in the main 4Fsub(3/2) → 4Isub(11/2) and additional 4Fsub(3/2 → 4Isub(13/2) channels of the Nd3+ ion in La2Be2O5 crystals are carried out for three crystallographic orientations a, b, and c at 77 and 300 K. Orientational values of main spectroscopic characteristics, including Stark luminescence branching ratios βsub(ij)sup(or), peak and effective cross-sections (σsub(e,ij)sup(or) and σsub(e)sup(eff)) of the transitions, at the wavelengths of which stimulated emission is excited, are determined for the 4Fsub(3/2) → 4Isub(11/2, 13/2) channels. The temperature behaviour of laser lines in the La2Be2O5:Nd3+ (F parallel c) crystals is studied for the 4Fsub(3/2) → 4Isub(11/2) channel in the temperature region of 77 to 300 K. Reswitching of laser lines, 1.0694 and 1.0785 μm, is observed in the temperature region of liquid nitrogen. The explanation of this effect is done on the basis of spectroscopic investigations. The energy of Stark levels of Nd3+ ions in La2Be2O5 crystals is refined and all excited laser lines are identificated. Preliminary analysis of spectroscopic properties is carried out for Pr3+ ions in La2Be2O5 and the crystal-field splitting scheme is defined for the manifolds, transitions among levels of which correspond to the optical transparency band of La2Be2O5 crystals. (author)