Optical characterization of Erioglaucine using z-scan technique, beam radius variations and diffraction pattern in far-field

In this paper, we observed optical responses of Erioglaucine (acid blue 9) with several techniques in different concentrations. Experimental setups are similar to standard z-scan; close and open setups were employed to determine the nonlinear refraction and nonlinear absorption coefficients, respectively. It is interesting during the experiments, every concentration has various behaviors. As the phase shift in some concentrations is greater than π  , then z-can equations are not valid; therefore, we indicated the nonlinear responses by beam radius variations for π<|ΔΦ0|<2π,π<|ΔΦ0|<2π, and then compared some numerical calculations and diffraction patterns observed in far-field for |ΔΦ0|⩾2π.|ΔΦ0|⩾2π.