Kamoshita A, Kohno JY. Cavity-Enhanced Fluorescence in Colliding Droplets of Rhodamine 6G Aqueous Solutions.
J Phys Chem A 2023;
127:7605-7611. [PMID:
37552637 DOI:
10.1021/acs.jpca.3c03667]
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Abstract
A liquid droplet can act as a microscale high-Q optical cavity via a whispering gallery mode, where light resonates with enhanced intensity. A collision of two droplets temporarily exhibits a unique morphology, which provides a more effective optical cavity than a single droplet. We investigated the mechanisms of cavity-enhanced fluorescence in colliding droplets of aqueous rhodamine 6G. Laser-excited spectra and fluorescence generation times were acquired. The fluorescence spectra had two peaks: one attributed to amplified spontaneous emission (ASE) and the other to lasing. The lasing generation time had a longer delay relative to that of ASE, which indicated that it required a longer propagation distance for the positive feedback. Overall, this provides a basis for the development of a highly efficient dye laser using colliding droplets.
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