Fano resonance is a phenomenon observed in quantum systems where a discrete state interferes with a continuum of states. This interference leads to an asymmetric line shape in the spectrum, which is different from the typical Lorentzian profile seen in many resonant systems. Fano resonances are important in various fields, including optics, condensed matter physics, and quantum mechanics. The concept was first introduced by the Italian physicist Ugo Fano in 1961. Fano resonance can be seen in systems like atomic transitions, photonic crystals, and plasmonic nanostructures. Understanding this resonance helps researchers manipulate light and improve technologies such as sensors and lasers.