“…Optical microcavities guiding resonant light along a ring trajectory (i.e., the path of resonant light) in carefully designed geometries form whispering-gallery-mode (WGM) resonances by self-interferences and have been employed as a versatile photonic structure for many applications in lasing, nonlinear optics, and light–matter interactions. − To further explore the manipulation of resonant light, optically coupled WGM microcavities with hybridized resonant trajectories were explored to tune the resonant eigenfrequency and the spatial distribution of the resonant modes, indicating a variety of nontrivial physical phenomena and practical applications ranging from mode-selective lasing to non-Hermitian photonics. − In these coupling systems, the microcavity geometries ( i.e. , microtoroids, , microdisks, − microrings, − or microspheres , ) and the intercavity coupling gap play important roles to ensure sufficient spectral match and efficient coupling. In general, the optical coupling and energy transfer happen at a tangent site of two or multiple resonant trajectories located separately in the neighboring WGM microcavities. ,, It should be noted that the above-mentioned WGM microcavities support 2D confined resonant modes where the corresponding optical coupling is fixed at one 2D plane.…”