  Light scattering is one of the most established wave phenomena in optics,
lying at the heart of light-matter interactions and of crucial importance for
nanophotonic applications. Passivity, causality and energy conservation imply
strict bounds on the degree of control over scattering from small particles,
with implications on the performance of many optical devices. Here, we
demonstrate that these bounds can be surpassed by considering excitations at
complex frequencies, yielding extreme scattering responses as tailored
nanoparticles reach a quasi-steady-state regime. These mechanisms can be used
to engineer light scattering of nanostructures beyond conventional limits for
noninvasive sensing, imaging, and nanoscale light manipulation.

Optics