Third-order nonlinear optical (NLO) properties of the synthesized conjugated organic molecules based on carbazole derivatives were studied at different input intensities and wave lengths, by the Z-scan method and using continuous wave (CW) lasers. The normalized transmittance results are explained by 5tting the data with theoretical models of the open and close aperture Z-scan technique. Measurements demonstrated the in6uence of saturation in absorption and thermal lensing effects on the nonlinear optical coef5cients and also indicate a strong correlation between linear and nonlinear optical absorption. Also, photoacoustic behaviour and photoluminescence of the components were investigated which shows the high optical potential of these organic molecules in different optical 5elds and devices. It was found that frequency spectra of photoacoustic signals were the same for all derivatives, but with different amplitudes.
