Аннотация:Resonant nanostructures, such as metasurfaces, have created an unprecedented case for enhanced light–matter interactions through local field engineering. However, the presence of resonances funda- mentally limits the bandwidth of such interactions. Here, we report on amending the nonlinear optical response of a semiconducting metasurface through Q-boosting, where the Q-factor of a metasurface rapidly increases with time. The coupled-mode theory reveals overcoming the band- width limit by coupling a broadband signal to a bandwidth- matched resonance and Q-boosting at a timescale faster than a resonator lifetime. A control–excitation experiment simulation using a tailored Q-boosting silicon-germanium metasurface predicts the third-harmonic enhancement by factors of 8 (peak) and 4.5 (integrated) against the best-case static metasurface. An analysis of free-carrier losses based on experimental data shows robustness to nonradiative losses and offers a viable pathway to increas- ing the light–matter interactions beyond the bandwidth limit, with implications in nonlinear and quantum optics, sensing, and telecommunication technologies.