Nonlinear optical investigations of Quinine and Quinotoxine salts by Z-scan technique

Z-scan technique was used to investigate the nonlinear optical properties of Quinine and 1-(carboxymethyl)-6-methoxy-4-(3-(3-vinylpiperidin-4-yl) propanoyl) quinolin-1-ium chloride (Quinotoxine) salts. The two salts were characterized using UV-visible, FTIR and NMR measurements. The characterization spectra confirm the expected molecular structure of the prepared Quinotoxine salt. The z-scan measurements were performed with a CW Diode laser at 635 nm wavelength and 26 mW power. The nonlinear absorption coefficient (beta), nonlinear refractive index (n(2)), the ground-state absorption cross sections (sigma(g)), the excited-state absorption cross sections (sigma(ex)) and thermo-optic coefficient of the samples were determined. Our results reveal that the sigma(ex) is higher than the sigma(g) indicating that the reverse saturable absorption (RSA) is the dominating mechanism for the observed absorption nonlinearities. The results suggest that this material should be considered as a promising candidate for future optical devices applications.