Single beam Z-scan measurement of the third order optical nonlinearities of styryl7 dye

Abstract

The optical nonlinearity of styryl7 dye in ethanol solution at different concentrations has been studied using pulsed Nd:YAG laser at 532nm as the source of excitation. The optical responses were characterized by measuring the intensity dependent refractive index (n2) of the medium using the Z-scan technique. The open aperture Z-scan trace of the dye in solution displayed saturable absorption. The closed aperture Z-scan trace of the dye exhibited a negative nonlinearity. The styryl7 dye at 1mM concentration exhibited nonlinear refractive co-efficient n2=−1.24×10−8cm2/W, nonlinear absorption coefficient β=−3.9×10−4cm/W and real and imaginary parts of third-order nonlinear optical susceptibility χ3=3.26×10−6esu in ethanol. These results showed that the dye has potential application in nonlinear optics.