Sensitivity of Z-scan using diffraction efficiency

We report Z-scan and eclipsing Z-scan experimental traces measuring diffraction efficiency in the image plane of the 4f system. Using nonlinearly diffracted energy, the sensitivity of both techniques is compared in order to increase the signal-to-noise ratio. The optimization of the optical signal for nonlinear characterization is proposed. A simple linear relation is provided in order to characterize nonlinear refraction from diffraction efficiency measurements. The influence of the nonlinear absorption is discussed.

Research highlights
► Z-scan and EZ-scan experiments are performed inside the 4f coherent imaging system.
► Diffraction efficiency is defined as a signal to be measured in Z-scan technique.
► Sensitivity of Z-scan and EZ-scan is the same using diffraction efficiency.
► Sensitivity and signal-to-noise ratio are optimized for Z-scan measurements.
► Relation between diffraction efficiency and nonlinear phase shift is provided.