Growth of divalent Mn2+ metal ion-doped potassium acid phthalate (KAP) single crystals and its structural, spectroscopic, optical and mechanical properties for SHG device applications

Abstract

Divalent Mn2+ ion-doped potassium acid phthalate (KAP), a semi-organic non-linear optical (NLO) single crystals were grown by slow evaporation solution technique (SEST) at ambient temperature. Good optical quality single crystals of size 5 × 6 × 5 mm3 were grown in a period of 1 week. The pure and Mn2+ ion-doped KAP crystals were characterised by single-crystal X-ray diffraction (XRD) analysis to study the crystal structure. Single-crystal XRD analysis confirmed that the doped KAP crystallises in orthorhombic system with the space group Pca21. Powder X-ray diffraction (XRD) has confirmed the formation of the dopant in the KAP crystal. The functional groups of the grown crystals were identified by Fourier transform infrared spectrum (FTIR). UV–Vis NIR spectrum was recorded to study the optical transparency of the grown doped KAP crystals. The mechanical strength of the crystal is estimated by Vickers microhardness test. The stiffness constant and work hardening co-efficient were also calculated. The second harmonic generation (SHG) efficiency for device application was confirmed by NLO studies.