NONLINEAR REFRACTIVE INDEX MEASUREMENTS OF CURCUMIN WITH CW LASER

Abstract

We report on the measurements of the nonlinear reflective index coefficient for curcumin at three different wavelengths using a Z-scan technique. This material is found to be a new type of natural nonlinear media. It shows a large negative nonlinear refractive index of the order of 10 –6 cm 2 /W. The origin of the nonlinearity was investigated by comparison of the formalism that is known as the Gaussian decomposition model with the thermal lens model. The nonlinear refractive index was found to vary with intensity and reveals that curcumin can be a promising material for optical limiting.