Competitive interplay between de-aggregation and thermal optical nonlinear effect in Azure A and its application in all-optical logic gates

Herein, we systematically investigated the interplay between the de-aggregation and the thermal optical nonlinear effect in Azure A (AA) using spatial self-phase modulation (SSPM) and transient dynamics measurements. The thermal optical nonlinear refractive index coefficients 𝑛 𝑡 ℎ 2 were measured to be −6.32 × 10 -8 cm 2 /W (−2.01 × 10 -7 esu) at 532 nm and −5.42 × 10 -8 cm 2 /W (−1.72 × 10 -7 esu) at 671 nm. The results reveal that de-aggregation plays the dominant role under low power excitation, whereas thermal optical nonlinear effect becomes dominant at high power. This transition is cooperatively regulated by both dye concentration and excitation power. Based on this mechanism, we further demonstrated both AND and INHIBIT all-optical logic functions using the spatial cross-phase modulation (SXPM) by simply adjusting the control light power or the concentration. These findings establish a foundation for the design of reconfigurable all-optical logic devices based on tunable intermolecular interactions in organic dyes.