Abstract The present study investigated the linear and nonlinear optical properties of Methyl green (MeG) dye in different environments such as H2O-EtOH binary solutions and microemulsions, as well as the effect of dynamic magnetic field. Fluorescence was described to be blueshifted from 358 to 405 nm in the weaker ethanol solutions with an increase in ethanol concentration. The results described and illustrated Z-scan for an increase in Reverse Saturable Absorption (RSA) and nonlinear absorption coefficients in ethanol-rich solutions, with limits of nonlinear absorption coefficient (β) of 8.77–26.18×10−5 cmW−1 ; and β=8.0×10−5 cmW−1 after encapsulation with a lower concentration of MeG. Dynamic magnetic fields (0–25 min) included a decline in absorbance and a change in the Rayleigh pattern of scattering, associated with the decrease in β. Study of magnetic water by Raman and FT-IR spectroscopy suggested that the change in MeG nonlinearity is a result of the change in polarization in the environment. This evidenced changing optical properties of MeG as influenced by solvent polarity, encapsulation.

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