Shaping High‐Q Planar Fano Resonant Metamaterials toward Futuristic Technologies

Abstract Advances in plasmonic metamaterials have been rapidly evolving with innovations aimed at developing metadevices for real‐world applications. In reality, energy losses in plasmonic systems are prevalent and it is of paramount importance to come up with solutions that could overcome the limitations that impede further advancements toward the miniaturization of optoelectronic metadevices. High‐ Q Fano resonance as a scattering phenomenon can be easily triggered by introducing asymmetry into plasmonic systems, and thus it offers a simple approach for reducing radiative losses through lineshape engineering. High‐ Q Fano resonance possesses narrow linewidth and intensely confined electromagnetic fields, which makes it viable for widespread applications. The purpose of this review is to consolidate the current advances and contributions that high‐ Q Fano resonance has made in the metamaterial community. Two general modes of energy loss including radiative and nonradiative losses are introduced and possible ways to overcome these challenges are examined. Furthermore, applications based on high‐ Q Fano resonance including sensors, lasing spasers, and optical switches are discussed, embracing the future of Fano resonance based high performance photonic technologies.