All optical poling of KTP crystal for phase matched second harmonic generation

We demonstrate periodic ferroelectric domain inversion in KTiOPO4 (KTP) crystals using the femtosecond laser poling technique. The effects of laser parameters on the morphological characteristics of these light-induced domains were systematically investigated. A periodically poled KTP crystal was fabricated through this optical approach, achieving quasi-phase matched second harmonic generation. This work provides a convenient method for engineering ferroelectric domains in KTP crystals and expands the applicability of all optical poling to a broader range of ferroelectric materials.