Effect of Cu²⁺ ion on single crystal of nonlinear optical material (glycinium oxalate)

Single crystals of pure and Cu²⁺doped glycinium oxalate of dimensions 18 × 10 × 2 mm³ and 10 × 7 × 2 mm³ were grown by the solvent evaporation technique, respectively. Influences of Cu²⁺ ions on the crystalline quality of glycinium oxalate (GOX) crystal were studied. The grown pure and doped crystals were characterized by using powder X-ray diffraction, FT-IR, and FT-Raman techniques. UV–Vis–NIR spectra of GOX and Cu²⁺ doped GOX single crystals had transparency in the entire visible region with cut off wavelengths, 257 nm and 265 nm, respectively. Mechanical properties of pure and doped crystals were studied using Vicker’s micro-hardness test. The presence of transition metal ion has been confirmed by energy dispersive X-ray spectroscopy (EDAX) and EPR analyses. The g-value (2.4899) was calculated from EPR analysis. The TGA/DTA analysis was performed to find the thermal stability of samples. The dielectric behavior of pure and doped crystal have been reported from 10² to 10⁶ Hz. The third-order NLO properties such as nonlinear absorption coefficient (β), third-order nonlinear susceptibility (χ⁽³⁾) and nonlinear refractive indices (n₂) of pure and doped crystal were estimated in the order of 10⁻⁶ esu.