Switchable Multimode Microlaser based on AIE Microsphere

Switchable multimode microlasers are of great significance to the development of photonic devices with high integration levels. Herein, we demonstrate an acid/alkaline gas responsive multimode AIEgen@starch microsphere-based microlaser. The aggregation-induced emission (AIE) active fluorescent dye ASCPI is used as the gain medium in this study. ASCPI was weakly emissive in water but became highly emissive when introduced to the starch microsphere as a guest molecule. The resultant ASCPI@starch microsphere worked well as a typical whispering-gallery-mode microlaser. The laser mode wavelengths were size dependent. Due to the sensitivity of ASCPI to pH, the output wavelength of the microlaser could be switched to shorter wavelength by acetic acid vapor treatment or longer wavelength by NH₃ vapor treatment. This work will provide a useful enlightenment for the rational design of effective switchable lasers using AIE materials with a simple preparation procedure.