EXPLANATION OF THE CW OPERATION OF THE ER3-MU-M CRYSTAL LASER( 3)

A computer simulation of the Er3+ 3-mum crystal laser considering the full rate-equation scheme up to the F-4(7/2) level has been performed. The influence of the important system parameters on lasing and the in teraction of these parameters has been clarified with multiple-paramet er variations. Stimulated emission is fed mainly by up-conversion from the lower laser level and in many cases is reduced by the quenching o f the lifetime of this level. However, also without up-conversion a se t of parameters can be found that allows lasing. Up-conversion from th e upper laser level is detrimental to stimulated emission but may be c ompensated by cross relaxation from the S-4(3/2) level. For a typical experimental situation we started with the parameters of Er3+:LiYF4. I n addition, the host materials Y3Al5O12 (YAG), YAlO3, Y3Sc2Al3O12 (YSG G), and BaY2F8, as well as the possibilities of codoping, are discusse d. In view of the consideration of all excited levels up to F-4(7/2), all lifetimes and branching ratios, ground-state depletion, excited-st ate absorption, three up-conversion processes as well as their inverse processes, stimulated emission, and a realistic resonator design, thi s is, to our knowledge, the most detailed investigation of the Er3+ 3- mum crystal laser performed so far.