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

• New organic “biphenyl derivatives” were investigated using a Z-scan technique.
• The nonlinear optical parameters (β, n2 and χ3) of the samples are estimated.
• Our results show that the ligand of CN–biphenyl gives better nonlinearity than NH2–biphenyl.

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 (β) and nonlinear refraction index (n2) 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.