Influence of fluorescent dye on the linear polarization direction of stimulated Raman Stokes scattering in liquid-core optical fibers



We present a simple analytical model to describe the stimulated Raman Stokes scattering (SRS) linear polarization spectroscopy of fluorescent dye solutions in liquid-core optical fibers (LCOFs). In this scheme, the linear polarization direction of the pump pulse is set parallel to the y-axis through a straight polarization-maintaining LCOF, in which the energy of the total optical field equation image is kept invariant, and different fluorescence dyes are used to generate different first-order Stokes intensities. We demonstrate the SRS of all-trans-β-carotene and fluorescein in carbon disulfide (CS2) solutions due to the optical field-induced reorientation effect, which makes the first-order Stokes polarization direction rotate by an angle of 88° or 61°, respectively. This demonstrates the good agreement between the theory presented and the experiment. Copyright © 2010 John Wiley & Sons, Ltd.