The work discloses a flexible, non-destructive, aberration-free, and automated periodic poling quality evaluation technique of the periodically poled crystals in the whole volume of the crystal with very high control and resolution. The method is based on a crystal translation in the directions perpendicular to the pump laser beam and the simultaneous recording of the parametric signal conversion efficiency in a simple single-pass parametric light generator setup. This technique allowed us to investigate and quantitatively describe the ferroelectric domain structure homogeneity of the periodically poled lithium niobate and potassium titanyl phosphate crystals with single, multi, and fan-out grating designs and offers a practicable overall efficiency assessment of the quasi-phase-matched device.
J. Banys, J. Pimpė, O. Balachninaite, V. Jarutis, J. Vengelis, Non-destructive periodic poling quality evaluation of MgO:PPLN and Rb:PPKTP crystals based on crystal translation and parametric light generation, Optik 277, 170686 (2023).