Thursday, 31 March 2016, 15:00
Sala Grande Palazzina C via alla Cascata 56/C
Nd3+ - Lu3+ clusters in CaF2 Laser Crystals for high power lasers
Centre de recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252
CEA-CNRS-ENSICAEN, Université de Caen, 6 Blvd Maréchal Juin, 14050 Caen,
It was recently demonstrated that efficient and broadband laser emission was possible with Nd-doped CaF2 and SrF2 single crystals around 1.055 μm by cooping the crystals with buffer ions. This 1.055 μm emission is known to be quenched because of cross-relaxation processes among Nd3+ clusters in Nd3+ singly doped fluorites, but increases spectacularly by co-doping with non-optically active “buffer” ions like Y3+ or Lu3+. Broadband laser emission and ultra-short laser operation have been very recently demonstrated and large scale high peak power diode-pumped amplifiers can be anticipated. A detailed investigation of both spectral and dynamical properties of CaF2:Nd3+ crystals co-doped with various amounts of Lu3+ ions was performed using various optical spectroscopy techniques. The results show that an increase in Lu3+ concentration increases the Nd3+ transitions quantum efficiency, as a result of the replacement of Nd3+ clusters by Nd3+ - Lu3+ clusters. By carefully spectroscopic analysis we were able to estimate the concentration of each type of Nd3+ centers as a function of the Lu3+ concentration, showing in particular that with 5% Lu3+, all quenched Nd3+ clusters have been replaced by emitting Nd3+ - Lu3+ clusters.