We show that Fano interference can be realized in a macroscopic microwave cavity coupled to a spin ensemble at room temperature. Via a formalism developed from the linearized Jaynes-Cummings model of cavity electromagnonics, we show that generalized Fano interference emerges from the photon–magnon interaction at low cooperativity. In this regime, the reflectivity approximates the scattering cross-section derived from the Fano-Anderson model. Although asymmetric lineshapes in this system are often associated with the Fano formalism, we show that whilst Fano interference is actually present, an exact Fano form cannot be achieved from the linear Jaynes-Cummings model. In the Fano model an additional contribution arises, which is attributed to decoherence in other systems, and in this case is due to the resonant nature of the photonic mode. The formalism is experimentally verified and accounts for the asymmetric lineshapes arising from the interaction between magnon and photon channels. As the magnon–photon coupling strength is increased, these channels merge into hybridized magnon–photon modes and the generalized Fano interference picture breaks down. Our results are universally applicable to systems underlying the linearized Jaynes-Cummings Hamiltonian at low cooperativity and connect the microscopic parameters of the quantum optical model to generalized Fano lineshapes.

我们表明，Fano 干涉可以在室温下与自旋系综耦合的宏观微波腔中实现。通过从腔电磁学的线性化 Jaynes-Cummings 模型发展而来的形式主义，我们表明广义 Fano 干涉来自低协同性的光子 - 磁振子相互作用。在这种情况下，反射率近似于源自 Fano-Anderson 模型的散射截面。尽管该系统中的不对称线型通常与 Fano 形式主义相关联，但我们表明，虽然 Fano 干扰确实存在，但无法从线性 Jaynes-Cummings 模型中获得精确的 Fano 形式。在 Fano 模型中出现了额外的贡献，这归因于其他系统中的退相干，在这种情况下是由于光子模式的共振性质。形式主义经过实验验证，并解释了由磁振子和光子通道之间的相互作用引起的不对称线形。随着磁振子-光子耦合强度的增加，这些通道合并为混合的磁振子-光子模式，广义的 Fano 干涉图会崩溃。我们的结果普遍适用于低协同性下线性化 Jaynes-Cummings Hamiltonian 的系统，并将量子光学模型的微观参数连接到广义 Fano 线形。