Orbit-Resolved Imaging of Paired Resonances in a Wave-Chaotic Microcavity.

Orbit-resolved paired resonances, sharing the same orbital period but arising from distinct phase-space structures, provide a direct probe of wave localization in chaotic microcavities. Here, we report the orbit-resolved visualization of paired resonances in a chaotic optical microcavity using a multiphoton fluorescence scheme. The high-Q island modes on stable periodic orbits and scarlike modes by partial-barrier localization in the chaotic sea are identified across multiple orbital periods. Guided by the orbit-resolved modal morphologies, phase-space selective excitation is demonstrated by tailoring the waveguide injection. Furthermore, tunneling-mediated modal hybridization between classically disjoint orbits is revealed through directly visualized superposed patterns and anticrossing spectra. Our results establish a direct link between photon dynamics and modal structure, opening a route to exploring nonlinear physics in wave-chaotic systems.