Resonances provide a universal language for understanding and engineering light-matter interactions. This final talk presents a resonance-centric framework for metaphotonics, demonstrating how eigenmodes and coupled-mode theory yield minimal physical models that capture essential phenomena.

We first examine single resonators, showing that Mie-resonant particles enable strong, spectrally selective enhancement of optical forces and torques. New dynamical regimes are identified, including dynamic switching between trapping and anti-trapping, bistable hopping, super-torque motion, and angular sorting of particles.

We then turn to periodic arrangements of resonators, namely resonant metasurfaces. We develop a symmetry-based strategy for engineering chirality in linear and nonlinear transmission, where strong circular dichroism emerges from mode coupling and symmetry breaking. We revisit the importance of the symmetry of the arrangement of resonances. Resonances act as symmetry-selective amplifiers, enabling gradient chirality and efficient chiral light generation.

Together, these results establish general design principles for exploiting resonances to control mechanical, polarization, and nonlinear effects, with applications to optical trapping, particle sorting, and chiral nanophotonics.