Spectral properties of optical anisotropy induced by laser radiation in dye solutions

Spectral studies of induced quasi-crystal properties (which can be quantitatively characterised by the difference in the refractive indices of ordinary and extraordinary waves, Δn=n_o—n_e) in Rhodamine 6G and Rhodamine 4C solutions in glycerine excited in the visible and UV ranges of the absorption spectrum are presented. It is demonstrated that the observed spectral dependences of Δn of these dye solutions excited in the visible (long-wavelength) and UV (short-wavelength) ranges of the absorption spectrum can be interpreted in terms of an oscillator model of a molecule. The proposed method for the analysis of induced optical anisotropy in solutions of organic compounds allows the relative orientation of oscillators in a molecule and, thus, the relative orientation of electronic transitions in a molecule to be determined in a reliable way.