Periodically poled crystals of KTP family: a review

During the last decades, potassium titanyl phosphate (KTP) and its isomorphs have attracted much attention due to its application in various photonic devices. These materials possess large nonlinear optic and electro-optic coefficients, high optical damage threshold, as well as broad thermal and angular acceptance for second harmonic generation. The interest to increase of the frequency conversion efficiency by domain engineering in the crystals of KTP family is enormous. This paper provides an overview of the available data dedicated to study of the domain structure and creation of the periodical domain patterns in crystals of KTP family for nonlinear optical devices.