Nonlinear refraction and absorption through phase transition in a Nd:SBN laser crystal

Time-resolved Z-scan measurements were performed in a Nd(3+)-doped Sr(0.61)Ba(0.39)Nb(2)O(6) laser crystal through ferroelectric phase transition. Both the differences in electronic polarizability (Delta alpha(p)) and cross section (Delta sigma) of the neodymium ions have been found to be strongly modified in the surroundings of the transition temperature. This observed unusual behavior is concluded to be caused by the remarkable influence that the structural changes associated to the ferro-to-paraelectric phase transition has on the 4f -> 5d transition probabilities. The maximum polarizability change value Delta alpha(p)=1.2x10(-25) cm(3) obtained at room temperature is the largest ever measured for a Nd(3+)-doped transparent material.Spanish Comunidad Autonoma de Madrid (CAM)Universidad Autonoma de Madrid (UAM)[MAT2004-03347]Universidad Autonoma de Madrid (UAM)[MAT2007-64686]Universidad Autonoma de Madrid (UAM)[CCG07-UAM/MAT-1861]CNPqFAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)FAPEALFINE