Resonant photonic nanostructures exhibiting enhanced nonlinear response and efficient frequency conversion are an emergent platform in optics. High-index semiconductor metasurfaces with rapidly tuned high-quality-factor (high-Q) resonances enable a novel class of time-variant metasurfaces, which expands the toolbox color management at nanoscale. Here, we report on dynamic control optical suppor...

This paper presents certain generalisations to the classical concepts of wellposedness and internal stability. Input consistency and output uniqueness of the closed-loop system in the standard control feedback configurations are discussed. Based on this, a number of notions are introduced such as fully internal wellposedness, externally internal wellposedness, and externally internal stability,...