Sensitivities of different nonlinear optical characterization techniques

A generalization of the I-scan method is considered by using one, two, three and four waves mixing experiments inside a 4-f imaging system for nonlinear optical measurements. By placing the material at the focus, the sensitivities of the measurements are compared systematically showing the same order of magnitude for all the studied configurations. Moreover the determination of the cubic optical nonlinearity is simplified by providing quadratic relations that relate the nonlinear phase shift to the measured signal. Experimental and simulated images are presented to validate our approach.