On the compositional nature of bulk doped periodic poled lithium niobate crystals

The compositional nature of the Erbium, Neodymium and Yttrium bulk doped pe riodic poled lithium niobate crystals obtained by the off-centered Czochral ski technique has been studied. It has been observed that, in all cases, th e impurity concentration is constant along the periodic domain structure. M oreover, it is shown that there exists a periodical variation in the Nb con centration, which is directly related with an inversion in the Li/Nb ratio along the periodic domain structure. The magnitude of the Nb variation seem s to depend on the nature of the dopant and its position in the lithium nio bate lattice, together with the value of the segregation coefficient of the impurity and the shape of the solid-liquid interface during growth. (C) 20 00 Elsevier Science Ltd. All rights reserved.