Near-field radiative heat transfer in three-body systems with periodic structures

Near-field radiative heat transfer has attracted increased attention in recent years for surpassing the far-field blackbody limit. Recently, it has been developed into three-body scenario to further enhance the heat transfer rate. Here we propose the exact formulation of near-field radiative heat transfer in three-body systems with periodic structures. We demonstrate that a three-grating system could provide the possibility to enhance radiative heat transfer over two-grating and three-slab counterparts. This enhancement is attributed to an additional heat transport channel provided by the intermediate grating, which can support hyperbolic surface modes in a specific wavelength range. Moreover, asymmetric situations are analyzed for weighting the impacts of both structure and position asymmetries on modulation of the near-field properties in the system. These findings open new pathways toward extended control over radiative heat transfer in the near-field regime.