Spectroscopic investigation of Nd3+ and Yb3+ in Ca4GdO(BO3)(3) crystals

Gadolinium calcium oxoborate Ca4GdO(BO3)(3) (GdCOB) is a new efficient non- linear optical crystal belonging to the rare-earth calcium berate group wit h general composition Ca4RB3O10 (R = La-Lu, Y). It exhibits efficient secon d harmonic generation (SHG) properties, a large transparency region and a h igh damage threshold. The compound Ca4GdO(BO3)(3) crystallises with a monoc linic acentric structure. The space group is Cm. Partial substitution of Gd 3+ ions by other lanthanide ions leads to interesting studies of new laser materials. In this paper we consider optical properties of Nd3+ and Yb3+ ions in Ca4Gd O(BO3)(3). In this crystal neodymium ions act as donors of excitation energ y, whereas ytterbium ions play the role of accepters. We are interested in ion-matrix and ion-ion interactions such as electron-phonon coupling, and N d-Yb excitation energy transfer. The infrared transmission and Raman scatte ring spectra were measured and the vibrational assignment is proposed. Abso rption, emission and lifetime measurements have been carried out within the 5-300 K temperature range. (C) 2000 Elsevier Science B.V. All rights reser ved.