EXCITED-STATES ABSORPTION OF IMPURITY IONS WITH D(5) SHELLS IN CRYSTALS - 1 - THEORETICAL-ANALYSIS

The characteristics of transitions from excited states of impurity ion s with d(5) shells are considered in weak and strong crystalline field s. The expressions for the oscillator strength in such transitions are obtained in terms of semi-empirical parameters. The possibility of es timating the frequency and the intensity characteristics of absorption from excited states using the data of ground-state absorption spectru m are also studied. The conditions for minimizing absorption from the a(4)T(1) excited state and nonradiative relaxation from the a(2)T(2) e xcited state (which hinders the use of crystals doped with ions having the d(5) shells as tunable lasers) are also discussed.