Antonio Calà Lesina

1 Introduction In modern optics, dielectric metasurfaces (i.e., 2D arrays of resonant building blocks) offer a compact strategy to control the properties of light beyond what is possible with flat surfaces [1, 2]. Typical applications include ultra-thin metalenses [3], metamirrors [4], polarization converters [5], sensitive bio and chemical sensors [6], efficient nonlinear generation and control [7], photovoltaics [8, 9], and nanolasers [10, 11], to name a few.

1 Introduction Nanophotonic structures are attractive for their property to scatter the incoming light in ways that can be engineered by design. In recent years, also via inverse design techniques, many designs have been proposed that can support charge–current distributions to sustain a large variety of radiated or non-radiated fields.