Change In The Morphology Of Rbtiopo4 Introduced By The Presence Of Nb

RbTiOPO4 crystals doped with Nb show an important flattening of the morphology that makes their use difficult in nonlinear optics applications. Here, we identify the possible causes of this morphological change: Nb acts as an impurity that brakes the velocity of growth of the {100} faces and modifies the growth mechanism of {201} faces of the crystals. We also propose a way of obtaining isometric crystals by forcing crystal growth in the a crystallographic direction. This causes a new change in morphology with benefits for later nonlinear optics applications due to the larger useful area obtained in the x-y plane.