Search

Vibrations and buckling of Kirchhoff nano plates are investigated using second-order strain gradient theory. The Navier displacement field has been considered for two different sets of boundary conditions and stacking sequences. Different geometries and material properties for isotropic, orthotropic cross- and angle-ply laminates are considered, and numerical simulations are discussed in terms of plate aspect ratio and non local ratio. A comparison with the classical analytical solution is provided whenever possible for buckling loads and fundamental frequencies. [ABSTRACT FROM AUTHOR]

Broad absorption and emission bandwidth laser crystals were used to develop tunable and mode locked diode-pumped lasers.

Abstract: We report on the spectroscopic investigation of Erbium and Cerium co-doped Czochralski-grown NaLa(WO4)2 crystals. We measured the Er energy levels positions and calculated the Judd–Ofelt parameters as well as the radiative lifetimes and branching ratios for the transitions under investigation. The dynamics of population of the 4S3/2, 4I11/2 and 4I13/2 multiplets of Er3+ was analyzed in order to determine the influence of the energy transfer mechanism Er–Ce onto the 1.5μm emission. The results of Er room temperature lifetimes measurements show that the 4I11/2 lifetime reduces significantly as the Ce concentration increases, starting from 183μs for the 0.4 at% Er doped sample to 15μs for the 16% Ce-codoped crystal. On the contrary, the lifetime of 4I13/2 Er state reduces simultaneously of only about 10%. The obtained results suggest the possibility to obtain efficient 1.5μm laser emission from NaLa(WO4)2. [Copyright &y& Elsevier]

A novel LiGdF4 crystal doped with Thulium ions has been grown using the Czochralski technique. Three samples with doping concentrations of 0.3 at.%, 8 at.%, and 12 at.% have been extensively spectroscopically analyzed. We also performed room-temperature preliminary laser experiments, pumping the samples with a laser diode at 792 nm obtaining 53% as maximum slope efficiency with a maximum output power of 205 mW and a minimum lasing threshold of 22 mW. The laser emission spectrum in free running condition typically spans between 1990 and 2018 nm. [ABSTRACT FROM AUTHOR]

Abstract: In the present work we present a review of the laser based on fluoride crystals. We will provide a brief description of the theoretical aspects of rare earth ions embedded in insulating crystals, with particular attention to the advantages in using fluoride single crystals and the growth technique. The core article is represented by an overall survey of the laser and spectroscopic properties: and will present the spectroscopic properties of the Tm,Ho and Tm, respectively, explained in the frame of the rate equation formalism and we will report a summary of the literature results. Finally will describe the state-of-the-art for the two systems. [Copyright &y& Elsevier]