Ternary system Li2O-K2O-Nb2O5 : Re-examination of the 30mol% K2O isopleth and growth of fully stoichiometric potassium lithium niobate single crystals by the micro-pulling down technique

M. Ferriol (1) , M. Cochez (1) , M. Aillerie (1)

1 LMOPS - Laboratoire Matériaux Optiques, Photonique et Systèmes

Potassium lithium niobate (KLN) single crystals have attractive properties for non-linear optical applications based on frequency conversion of laser diodes in the blue range. Especially, fully stoichiometric K3Li2Nb5O15 crystals would be capable of doubling a laser light in the near UV range. Using powder X-ray diffraction and DSC experiments, we have re-investigated the 30 mol% K2O isopleth of the ternary system Li2O–K2O–Nb2O5 in order to explore the possibility of a limited existence field for this phase. From our results, it was shown that the stoichiometric KLN phase exists between 970 and 1040 °C, temperature at which it undergoes a non-congruent melting. From this conclusion, compositionally homogeneous a-axis oriented single crystals fibers of stoichiometric K3Li2Nb5O15 were successfully grown by the micro-pulling down technique with pulling rates in the range 0.3–0.7 mm min−1. The crystal length was between 10 and 120 mm for an apparent diameter near 500 μm. The fibers, characterized by optical microscopy, X-ray diffraction and Raman spectroscopy, appeared free of macro-defects and of good quality and their stoichiometric composition was also confirmed

Domaines: Optique [physics.optics]

M. Ferriol, M. Cochez, M. Aillerie. Ternary system Li2O-K2O-Nb2O5 : Re-examination of the 30mol% K2O isopleth and growth of fully stoichiometric potassium lithium niobate single crystals by the micro-pulling down technique. Journal of Crystal Growth, 2009, 311 (18), pp.4343-4349. ⟨10.1016/j.jcrysgro.2009.07.026⟩. ⟨hal-00448498⟩