Investigating third-order nonlinear optical properties of potassium dichromate-doped l-alanine (LAKDC) single crystal using z-scan technique

Abstract

The crystal of potassium dichromate-doped l-alanine (LAKDC), a nonlinear optical material, was made from an aqueous solution using a slow evaporation process with excellent transparency. The crystal’s lattice parameters of the grown single crystal’s orthorhombic structure of P2₁2₁2₁ with lattice parameter values are a = 6.074 Å, b = 12.390 Å and c = 5.809 Å. FTIR analysis was used to ascertain qualitatively the presence of pure and dopant functional groups. Transmission and absorption spectra in the wavelength range of 200–800 nm were used to measure the crystal’s optical and electronic properties in the UV–Vis–NIR range. The bandgap of the LAKDC crystal was noticed to be 4.81 eV. Differential thermal analysis and thermogravimetric analysis were used to investigate the crystal’s thermal stability. The samples had better relative NLO efficiency and emitted a quantity of green light. The continuous-wave Nd:YAG laser was used to perform single beam z-scan tests of third-order nonlinearity. Open and closed aperture z-scan experiments demonstrate that the crystals exhibit negative nonlinearity and saturation absorption, respectively.