Seminar Announcement: Simone Normani

Data pubblicazione: 1-apr-2016 7.14.11

Announcement

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"

Simone Normani

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,

France

simone.normani@ensicaen.fr

Abstract

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as a function of the Lu³⁺ concentration, showing in particular that with 5% Lu³⁺, all quenched Nd³⁺ clusters have been replaced by emitting Nd³⁺ - Lu³⁺ clusters.