Optical and electron-spin-resonance spectra of Yb3+, Nd3+, and Cr3+ in LiNbO3 and LiTaO3

The results of optical-spectroscopic and electron-spin-resonance (ESR) studies of Yb3+, Nd3+, and Cr3+ impurities are presented. The spectra of Yb3+ are discussed in detail. Crystal-field parameters are obtained to fit the energy levels and the ESR results on the ground state. These parameters are not obtained by a least-squares fit but rather by physical considerations as to where, on the threefold axis, the ion could be to give crystal-field parameter ratios that can be used to fit the experimental results. © 1968 The American Physical Society.