New evaluation of ytterbium-doped materials for CW laser applications

In this paper, it is proposed a new evaluation of ytterbium-doped laser crystals valid for CW laser applications. Starting from a theoretical model that makes possible to express analytically the output characteristics of a CW Yb-doped laser, a graphic technique allowing the computation of the global efficiency for the optimum amplifier length and the coupling mirror reflectivity is proposed. This technique is applied for evaluating the efficiency corresponding to various ytterbium-doped crystals. We find that the performances depend on the pump intensity. By comparing this evaluation to the classical one based on the respective values of the emission cross-section and the pump intensity need for getting crystal transparency at laser wavelength and we find that, in CW regime, more parameters must be taken into account. (C) 2001 Published by Elsevier Science B.V.