Growth and characteristics of Fe-doped KTiOPO4 crystals

Single crystals of Fe-doped KTiOPO4 (Fe : KTP) of optical quality and dimensions up to 15 x 25 x 30 mm were grown by the flux method. During the growth process the formation of twin consisting of bicrystals was observed, even in the case of single-crystalline seeds. The Fe doping level in crystals is about 0.08-0.1wt%. The following physical properties were investigated: refractive indices, dielectric, piezoelectric, electro optical, elastic and thermoelastic constants. In order to determine whether Fe ions play a major role in photorefractive effect (PRE) of KTP, light-induced index change was measured and the results indicate that in KTP crystals Fe ions do not play a major role in PRE. It is also found that Fe:KTP shows different diffusion properties during the Rb:K ion exchange process in comparison with undoped KTP. (C) 1999 Elsevier Science B.V. All rights reserved.