Kamoshita Aya, Kohno Jun-Ya
Department of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
J Phys Chem A. 2023 Sep 14;127(36):7605-7611. doi: 10.1021/acs.jpca.3c03667. Epub 2023 Aug 8.
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.
液滴可通过回音壁模式充当微尺度高Q光学腔，光在其中以增强强度共振。两个液滴碰撞时会暂时呈现出独特的形态，这提供了比单个液滴更有效的光学腔。我们研究了罗丹明6G水溶液碰撞液滴中腔增强荧光的机制。获取了激光激发光谱和荧光产生时间。荧光光谱有两个峰：一个归因于放大自发发射（ASE），另一个归因于激光发射。激光发射的产生时间相对于ASE有更长的延迟，这表明正反馈需要更长的传播距离。总体而言，这为利用碰撞液滴开发高效染料激光器提供了基础。
