Nonlinear optical response of thermal origin of sunset yellow chromonic liquid crystal

The present study is dedicated to investigating the nonlinear optical response of thermal origin of lyotropic chromonic liquid-crystal phases composed of sunset yellow azo dye and water. Using time-resolved Z-scan and two-dimensional x-ray diffraction (XRD) techniques, the influence of molecular organization on the thermal responses of the isotropic and nematic phases is analyzed. The results indicate that the nonlinear optical response is strongly dependent on the dye concentration and on the selective light absorption by the system, highlighting the interaction between molecular aggregation and heat transfer. The structural analysis by XRD reveals significant changes in the organization of the molecular aggregates across the isotropic and nematic phases, directly affecting the amplitude of the phase distortion observed in the Z-scan experiments. The correlation between structural and optical data suggests that the supramolecular organization plays a crucial role in the thermal response of the mixture, influencing its nonlinear optical properties. These findings provide profound insights into the thermal mechanisms of chromonic liquid crystals.