On the dynamics of population inversion for 3 mu m Er/sup 3+/ lasers

A generalized model for 3- mu m (/sup 4/I/sub 11/2/ to /sup 4/I/sub 13/2/)Er lasers is proposed. The essential energy transfer processes present in the single-doped Er/sup 3+/ systems (up-conversion from /sup 4/I/sub 13/2/, up-conversion from /sup 4/I/sub 11/2/, cross-relaxation from /sup 4/S/sub 3/2/), as well as those present in Cr/sup 3+/ codoped Er/sup 3+/ systems, are taken into account. In the frame of this model, the main features of 3 mu m Er/sup 3+/ lasers, such as long pulse or CW operation, the change of emission wavelength as a function of pumping conditions, and the effects of codoping with Ho/sup 3+/ or Tm/sup 3+/ ions, are explained.<
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