Influence of grain size and Nd3+ concentration on the stimulated emission of LiLa1-xNdxP4O12 crystal powders

The influence of grain size and neodymium concentration on the threshold and absolute slope efficiency of the stimulated emission of LiLa1-xNdxP4O12 (x = 0.1, 0.5, and 1) crystalline powders has been investigated by using a pulsed Ti-sapphire pumping. The absolute slope efficiencies are similar for the studied samples with x = 0.5 and 1 whereas the lowest threshold pump energy corresponds to the stoichiometric sample with an average grain size of around 20 μm. The grain size also affects the emitting surface of the random laser due to the reduction of the difussive length as grain size decreases. The experimental results show the importance of seeking the optimal grain size for a given material.