Dynamic tuning of near-field radiative transport between an overlapping pair of movable comb-like metamaterials.

We present a theoretical study of nanoscale radiative thermal transport between an overlapping pair of movable comb-like SiO2 gratings by an improved and more accurate near-field radiative heat transfer (NFRHT) method. This method does not rely on the effective medium theory (EMT) that does not take the geometric shape factors of nanostructures into account. Contrary to the EMT treating the grating structure as a homogeneous film, our improved NFRHT method can accurately predict the change of heat flux between the overlapping nanogratings for different scenarios considering surface pattern effects. The longitudinal and lateral movements of the comb-like overlapping nanogratings have been investigated to evaluate the dynamic control of NFRHT, which can be significantly modulated, resulting in heat flux ratios up to 23.5 and 5.5, respectively, for small-scale displacements. Furthermore, the NFRHT between overlapping non-contact metamaterials can exceed the intrinsic heat conduction limit for a contact mode by an order of magnitude while properly adjusting the period and relative position of the overlapping nanogratings. By taking advantage of movable metamaterials, the dynamic tuning of NFRHT and light manipulation can provide great benefit to the fields of energy harvesting and conversion, infrared sensing and detection, and thermal management technology. [ABSTRACT FROM AUTHOR]