Abstract

Nd-doped crystals and glasses are very efficient laser materials on several transitions, i.e. the ⁴F_3/2 → ⁴I_9/2 transition between 910nm and 950nm, the ⁴f_3/2 → ⁴I_11/2 transition between 1040nm and 1100nm, and the ⁴F_3/2 → ⁴i_13/2 transition between 1320nm and 1450nm. Operation on the main laser line (⁴F_3/2 → ⁴i_11/2) near 1060nm generally shows slope efficiencies close to the theoretical limit, which is under ideal conditions the quantum yield between absorption photon energy and laser emission photon energy. In contrary, the laser transition to the ⁴I_13/2 level exhibits in some crystals smaller slope efficiencies than expected from the quantum yield. In this paper detailed excited state absorption and stimulated emission measurements in the wavelength region of the ⁴F_3/2 → ⁴i_13/2 transition are presented and discussed for a variety of well known neodymium doped laser crystals.

© 1998 IEEE