Fano Resonances in Topological Photonic Systems
Though Fano resonances were originally discovered in quantum physics, they can emerge in the variety of wave processes including photonic systems. In this chapter, we demonstrate how the concept of Fano resonances can be applied in topological photonics to describe photonic topological states supported by metasurfaces. As we prove, leaky nature of metasurface's modes allows one to probe them from the far field, while the observed Fano type features in transmittance spectrum can be unequivocally related to the topological properties of photonic bands. This fundamental link between Fano resonances in transmittance and photonic topological states opens an appealing perspective to control scattering of light through the topological characteristics of metasurface.