Wavelength-dependent nonlinear optical properties of 8-(4-methoxyphenyl)-6-oxo-3-p-tolyl-6H-pyrido[1,2-b][1,2,4]triazine-7,9-dicarbonitrile

In this study, 8-(4-methoxyphenyl)-6-oxo-3-p-tolyl-6H-pyrido[1,2-b][1,2,4]triazine-7,9-dicarbonitrile (A) was prepared and then the nonlinear optical properties of this compound, including nonlinear refractive index (n₂) and nonlinear absorption coefficient (β) were measured using Z-scan technique by continuous wave laser diode at wavelengths of 405 and 532 nm. At wavelength of 532 nm, by increasing the incident intensity a switch over from saturable absorption (SA) to reverse saturable absorption (RSA) was observed. The results showed that the nonlinear optical properties of this compound depend on the wavelength. It was also observed that with decreasing incident intensity, the thermal nonlinear refractive coefficient increased accordingly, while its thermo-optic coefficient decreased. In addition, the third-order susceptibility of this compound in wavelength of 532 nm was obtained higher than 405 nm.