Spectroscopy of gadolinium gallium garnet crystals doped with Y b3 + revisited
The optical spectroscopy measurements of gadolinium gallium garnet (GGG) crystals doped with Yb show evidence of the presence of non-equivalent optical centers with very similar radiative decay rates. The energy level schemes of those centers have been determined on the basis of optical absorption, luminescence and Raman experiments. Crystal field fitting resulted in two sets of slightly different crystal field parameters for two non-equivalent Yb centers. Both sets of parameters describe perfectly the experimentally detected Y b3 + energy levels. Correlation between systematic trends in the experimental energy level schemes and crystal field parameters is discussed.
Diode-pumped Yb:GGG laser: comparison with Yb:YAG
Abstract A diode-pumped ytterbium-doped Gd 3 Ga 5 O 12 (Yb:GGG) laser is reported for the first time. We report up to 4.2 W of CW laser power when pumping on the 971 nm absorption band with a 14 W fiber-coupled diode. The easy growth and the high thermal conductivity of Yb:GGG make it a challenger of Yb:YAG for high power applications. The efficiencies of these two crystals have been compared under the same pumping conditions, and turn out to be comparable.
Monte Carlo simulations of magnetovolume instabilities in anti-Invar systems
We perform constant pressure Monte Carlo simulations of a spin-analogous model which describes coupled spatial and magnetic degrees of freedom on an fcc lattice. Our calculations qualitatively reproduce magnetovolume effects observed in some rare earth manganese compounds, especially in the anti-Invar material YMn2. These are a sudden collapse of the magnetic moment which is connected with a huge volume change, and a largely enhanced thermal expansion coefficient.