A comparative study of media polarity effects on the linear and third-order nonlinear optical responses of thiazine dyes

摘要

In this paper, solvent effects on the linear and nonlinear optical responses of thiazine dyes were investigated. Spectroscopic and open aperture Z-scan techniques were used for studying linear and nonlinear responses of azure A and methylene blue dyes. The experimental results show that linear and nonlinear optical properties of used dyes depend highly on the molecular structure and their surrounding media characteristics. The calculated contribution of various media-induced interactions indicate that solvent hydrogen bond acceptor and solvent dipolarity and polarizability abilities have significant effects on the linear and nonlinear absorption characteristics of thiazine dyes. Moreover, by transition of the linear optics domain to nonlinear optics, similar resonance structures were obtained for thiazine dyes. So, the spectroscopic technique can be considered as a simple method for prediction of dominant resonance structures and effective solvent polarity parameters on the third-order nonlinear properties of azure A and methylene blue dyes.