Environment-Induced Effects on The Nonlinear Refractive Index of Methyl Orange at Different Spectral Regions

Abstract

Abstract The current study investigates the effects of solvent on the linear absorption and nonlinear refraction n 2 of Methyl orange dye at different spectral regions. The study shows that the effects of the solvent depend on the excitation wavelength. The peak value of the dye absorbance is similar in water and ethanol. However, the properties of water lead to shift the absorption curve to the short wavelengths side. At wavelengths located outside the resonance band, the dye dissolved in ethanol shows almost identical nonlinear response. This response is lower than that at wavelength within the resonance band. The behaviour of the dye is different in water where n 2 is maximum at short wavelength (405 nm) and decreases at longer wavelengths (473 and 532 nm). Water induces dissimilar effects at different wavelengths. Increasing the polarity of water by adding large amounts of NaCl does not clearly affect the absorbance or the nonlinear refraction of the dye.