Extraction of Natural Pigment from Ocimum tenuiflorum Using Different Polar Solvents and Their Nonlinear Optical Characteristics.

Herein, we report the extraction, characterization, linear and third-order nonlinear optical (TONLO) features of the natural pigment from Ocimum tenuiflorum leaves using different polar solvents. The polar solvents such as, ethanol, acetone, methanol and dimethyl sulfonate (DMSO) were used to extract the natural pigment from Ocimum tenuiflorum leaves. The effect of solvent on linear and TONLO properties of the natural pigment was studied and multi- parameter scale known as Kamlet-Abboud-Taft was used to analyse the solvent characteristics on solute molecule. The functional groups of the extracted natural pigments were examined via Fourier transform infrared (FT-IR) spectrometer. TONLO characteristics of the natural pigment was scrutinised by a continuous wave (CW) diode laser working at 650 nm wavelength. The nonlinear refractive index (n) and nonlinear coefficient of absorption (β) of the natural pigment was ascribed to the behavior of self-defocusing, saturable absorption (SA) and reverse saturable absorption (RSA). The TONLO susceptibility (χ) of the natural pigment in polar solvents was found to be the order of 10 esu. The natural pigment extracted from Ocimum tenuiflorum leaves is a potential material for applications in nonlinear optical.