Heat transfer between closely-spaced objects may be greatly enhanced with efficiency far beyond than the classic blackbody radiation limit under the participation of evanescent waves. Metamaterials with high density of optical surface states have been particularly explored to improve the heat flux upper limit but mostly confined in theoretical discussions due to the experimental challenges. In the near-field context, the effective medium theory (EMT) as widely used in the discussions is also lack of practical inspections. In this work, we managed to fabricate two 2 × 2 cm² sized high-quality infrared hyperbolic metamaterials made of silicon nanorod array and studied their near-field thermophotonic interaction using home-made setup. At the 500 nm vacuum gap, a strong heat flux density of 830 W/m² is observed, which is 4.7 times larger than the blackbody value. A local uniaxial model with parameters retrieved from the full-wave simulation was built to reproduce the measured results, which unambiguously validated the widely-adopted semi-empirical condition on the relationship between vacuum gap and lattice constant for the application of the EMT in the near-field regime. These results are believed essential for the future development of metamaterials for novel thermophotonic devices.

在e逝波的参与下，紧密间隔的物体之间的传热可以大大提高，效率远远超过经典的黑体辐射极限。为了提高热通量上限，已经特别探索了具有高光学表面态密度的超材料，但是由于实验上的挑战，这种材料大多局限于理论讨论中。在近场环境中，讨论中广泛使用的有效介质理论（EMT）也缺乏实际检查。在这项工作中，我们设法制造了两种由硅纳米棒阵列制成的2×2 cm ²尺寸的高质量红外双曲线超材料，并使用自制装置研究了它们的近场热光子相互作用。在500 nm的真空间隙下，830 W / m ²的强大热通量密度观察到它是黑体值的4.7倍。建立了从全波模拟中获取参数的局部单轴模型，以再现测量结果，从而明确验证了广泛应用的关于真空间隙与晶格常数之间关系的半经验条件，从而在近距离内应用了EMT。领域政权。这些结果被认为对于用于新型热光子器件的超材料的未来发展至关重要。