Measurement of Near-field Thermal Radiation between Multilayered Metamaterials

TL;DR

This study experimentally investigates near-field radiative heat transfer between multilayered metamaterials, revealing the limitations of effective medium theory and observing super-Planckian radiation, with results aligning well with transmission matrix predictions.

Contribution

It provides experimental validation of near-field heat transfer in multilayered metamaterials and highlights the conditions where effective medium theory fails or succeeds.

Findings

Good agreement between experiments and transmission matrix theory.

Observation of super-Planckian blackbody radiation.

Failure of EMT in predicting heat flux with bounded surface modes.

Abstract

The near-field radiative heat transfer (NFRHT) between one-dimensional metamaterials comprising phonon dielectric multilayers was experimented. Large sized (1cm x 1cm) near-field samples were fabricated using SiC, SiO2 and Ge layers at a certain gap distance, and the effect of layer stacking order and phonon resonance quality on the NFRHT was examined. The measured results show good agreement with those obtained theoretically employing the transmission matrix method. Super-Planckian blackbody radiation was observed between the emitters and receivers with identical structures. Measurements demonstrate failure of the effective medium theory (EMT) in predicting the near-field heat flux especially in the presence of bounded surface modes, such as the epsilon-near-zero (ENZ) mode. Analyses also indicate that, in certain cases, the EMT can provide reasonable physical insight into the underlying coupling process from the perspective of homogenized media. The conditions to apply the EMT in the near-field regime was also touched upon.