Effect of La3+ dopant on pyromellitic acid and investigation of its nonlinear optical property

Lanthanum doped pyromellitic acid semi-organic nonlinear optical (NLO) crystals were prepared using slow evaporation solution growth technique (SEST) at two different ratios of lanthanum and pyromellitic acid (PMA) such as 1:1 (LP11) and 4:3 (LP43) respectively. Elemental analysis and energy dispersive X-ray analysis spectroscopy (EDX) confirm the presence of carbon and inclusion of La3+ ions in the grown crystals. Surface morphology of grown crystals was studied using scanning electron microscopy (SEM) analysis. Single crystal and powder X-ray diffraction (XRD) analysis were carried out. The lattice parameters established the presence of triclinic P crystal system. Effect of La3+ dopant concentration on centrosymmetric PMA and the crystalline nature of the prepared samples were confirmed by structural analysis. Functional groups were identified using FTIR and transparency of the crystals was compared by UV-Vis-NIR spectroscopic technique. The second harmonic generation (SHG) efficiency of crystals from the Kurtz-Perry experiment was found to be 1.649 times for LP11 and 1.489 times for LP43 more with that of potassium di hydrogen phosphate (KDP). The Vicker's micro hardness value was found to be 45.9 kg/mm(2) for LP11 and 75.5 kg/mm(2) for LP43 for a load of 100 gm. Lanthanum doped PMA crystals are an effective tool to create SHG and may be extended for various device applications.