Fig. 1. (a) 3D schematic diagram of OFC device; the inset is the optical photo of the real device. (b) Comparison schematic diagram of the cross section along the center of the circle. (c) SEM image of the metallic ring resonator. (d) SEM image of a single ring section; contrast image obtained by depositing metallic platinum by FIB. (e) AFM scan image of the metal on quartz by the same deposition process showing a surface roughness of RMS = 0.6 nm. (f) SEM image of perovskite nanosheets.

Fig. 2. (a) OFCs spectral pattern with seven comb lines. (b) Simulated absorption spectrum of MMR resonator; the absorption peak is located at 544 nm, which is close to the lasing peak at 541 nm. (c) Simulated electric field distribution of three-dimensional structure at 541 nm. (d) Top view of simulated electric field distribution at the interface of Al2O3/Au at 541 nm; the inset shows the light field distribution of one mode in the whispering gallery mode cavities near the innermost ring. (e) Simulated electric field distribution along a section passing through the axis of symmetry at 541 nm.

Fig. 3. (a) Fluorescence spectra of OFC devices with excitation power from 2 to 15 μW. The fluorescence peak is located at 527 nm, the lasing peak is located at 541 nm, and the comb lines spread out to both sides with the lasing peak as the center. (b) Integrated emission intensity (black) and FWHM (full-width at half-maximum) (red) of OFCs as a function of pump energy density. The lasing threshold is located at about 9 μW. (c) Fluorescence spectra of perovskite nanosheets. (d) Power-dependent profiles of integrated intensity (black) and FWHM (red) of the nanosheets on quartz around the mode peak 541 nm. The lasing threshold is located at about 1.9 μW.

Fig. 4. Waterfall diagram of the lasing peak intensity of perovskite nanosheets changing with the delay time; the intensity of the two pump lights is 0.95Pth.

Fig. 5. Dual pump fluorescence lifetime curve for OFCs based on (a) ultrathin MMR nanoresonator and (b) perovskite nanosheet on quartz. (c) Time-resolved fluorescence spectra of perovskite materials.

Fig. 6. (a) Optical micrograph of perovskite nanosheet, scale bar 40 μm. (b) Steady-state fluorescence spectrum of perovskite materials. (c) XRD profile of perovskite materials.

Fig. 7. Schematic diagram of the multiplexing optical path of the dual-pump time-resolved test optical path and variable pump power fluorescence test optical path.