Fig. 1. Basic principle and model of fluorescence-doped gain microbottle cavities. (a) Basic principle of molecular fluorescence;

Fig. 2. Preparation of fluorescent microbottle cavities. (a)‒(c) Preparation process of fluorescent solution; (d) laboratory-prepared WGM fluorescent microbottle cavities

Fig. 3. Schematic diagram of experimental setup

Fig. 4. Characterization of fluorescent microbottle cavities. (a) Normalized electric field distribution of fluorescent microbottle cavities; (b) two-dimensional mode field distribution of fluorescent microbottle cavities; (c) fluorescent microbottle cavity and its transmission spectrum

Fig. 5. Spatial light path system diagram with fluorescent microcavity excitation shown in inset

Fig. 6. Experimentally measured spectral phenomena. (a) Fluorescence spectrum of rhodamine B; (b) comparison of fluorescence microcavity excitation and rhodamine B fluorescence spectra; (c) microbottle cavity excitation spectrum without fluorescence, in which microbottle cavity without fluorescence is shown in inset; (d) microbottle cavity excitation spectrum with fluorescence, in which fluorescent-containing microbottle cavity is shown in inset

Fig. 7. Fluorescence excitation resonance spectra of fluorescent microbottle cavities under different conditions