Investigation of optical nonlinearity of 3,3′-dimethylbiphenyl 4,4′-diamine and 4,4′-diisocyano-3,3′-dimethylbiphenyl using a Z-scan technique

A Z-scan technique has been used to investigate the nonlinear optical properties of 3,3'-dimethylbiphenyl 4,4'-diamine and 4,4'-diisocyano-3,3'-dimethylbiphenyl. Measurements were performed with a CW diode laser at 635 nm wavelength and 14.5 mW power. The nonlinear optical absorption coefficient (beta) and nonlinear refraction index (n(2)) of the two investigated compounds were affected by the presence of both NC and NH2 functional groups and are more affected with NC group in particular. The reverse saturable absorption (RSA) mechanism was responsible for the optical limiting effect. The results suggest that this material can be considered as a promising candidate for future optical devices applications. (C) 2015 Elsevier Ltd. All rights reserved.