Method with a phase object for measurement of optical nonlinearities

A new and simple technique is presented to investigate nonlinear optical properties. In this technique, a phase object is introduced into the measurement system. Both the nonlinear absorption coefficient and nonlinear refraction index can be determined conveniently by measuring the transmittance of the sample. The optical nonlinearities of the ZnSe are investigated by using this technique with 19 ps pulses at 532 nm wavelength as a test.