SPECTROSCOPIC ANALYSIS AND THE EFFECTS OF COLOR-CENTERS ON THE LASER PERFORMANCE OF ND3+CAZN2Y2GE3O(12)

Spectroscopic and EPR investigations of Nd3+-doped CaZn2Y2Ge3O12 (CAZG AR) have been performed. The absorption, fluorescence, excitation spec tra and fluorescence lifetime have been measured at room temperature. The Judd-Ofelt theory has been applied to the measured optical absorpt ion intensities to predict the radiative decay rates, branching ratios , and peak stimulated emission cross section from the metastable F-4(3 /2) state to the I-4(9/2) manifold. The fluorescence lifetime of the F -4(3/2) level of Nd3+ at low concentration in this host was measured t o be 285 +/- 10 mu s, which is longer than that for Nd3+:YAG. Color ce nters located at zinc octahedral sites have been produced in these cry stals by ultraviolet irradiation and have been detected by EPR techniq ues. The effects of the color centers on the potential laser character istics of this material are discussed.