Direct-growth and nonlinear properties of micron DAST hydrate waveguides

Organic non-linear waveguides based on 4-N,N-Dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST) were directly grown by a cooling soft template method. Results revealed that as-yielded DAST hydrate waveguides (HWs) exhibit excellent waveguide performance, exciton polariton, and fluorescence properties, which can be rationally controlled by the annealing temperature. The red shift fluorescence excitation and emission spectra in the annealed DAST HWs are attributed to the recrystallization and J-aggregation of the chromophore cations in a head-to-tail stacking mode, which increase the charge transfer efficiency from one chromophore to another. Particularly, the fluorescence can propagate along the DAST HWs axis due to the produced exciton polaritons. Moreover, the annealed DAST HWs exhibit strong second harmonic generation (SHG) intensity, but no SHG activity was observed in DAST HWs. These findings further extend the applications of DAST HWs into a wide range of fields, such as integrated optical modulation, micro lasers, and fluorescent waveguides.