Francoeur Mathieu, Basu Soumyadipta, Petersen Spencer J
Radiative Energy Transfer Lab, Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA.
Opt Express. 2011 Sep 26;19(20):18774-88. doi: 10.1364/OE.19.018774.
Near-field radiative heat transfer between isotropic, dielectric-based metamaterials is analyzed. A potassium bromide host medium comprised of silicon carbide (SiC) spheres with a volume filling fraction of 0.4 is considered for the metamaterial. The relative electric permittivity and relative magnetic permeability of the metamaterial are modeled via the Clausius-Mossotti relations linking the macroscopic response of the medium with the polarizabilities of the spheres. We show for the first time that electric and magnetic surface polariton (SP) mediated near-field radiative heat transfer occurs between dielectric-based structures. Magnetic SPs, existing in TE polarization, are physically due to strong magnetic dipole resonances of the spheres. We find that spherical inclusions with radii of 1 μm (or greater) are needed in order to induce SPs in TE polarization. On the other hand, electric SPs existing in TM polarization are generated by surface modes of the spheres, and are thus almost insensitive to the size of the inclusions. We estimate that the total heat flux around SP resonance for the metamaterial comprised of SiC spheres with radii of 1 μm is about 35% greater than the flux predicted between two bulks of SiC, where only surface phonon-polaritons in TM polarization are excited. The results presented in this work show that the near-field thermal spectrum can be engineered via dielectric-based metamaterials, which is crucial in many emerging technologies, such as in nanoscale-gap thermophotovoltaic power generation.
分析了各向同性、基于电介质的超材料之间的近场辐射热传递。对于超材料，考虑了一种由碳化硅（SiC）球体组成、体积填充率为0.4的溴化钾主体介质。超材料的相对电容率和相对磁导率通过克劳修斯-莫索蒂关系进行建模，该关系将介质的宏观响应与球体的极化率联系起来。我们首次表明，基于电介质的结构之间会发生电和磁表面极化激元（SP）介导的近场辐射热传递。存在于TE极化中的磁SP，实际上是由于球体的强磁偶极共振。我们发现，为了在TE极化中诱导出SP，需要半径为1μm（或更大）的球形内含物。另一方面，存在于TM极化中的电SP由球体的表面模式产生，因此几乎对内含物的尺寸不敏感。我们估计，对于由半径为1μm的SiC球体组成的超材料，在SP共振附近的总热流比两块SiC之间预测的热流大约大35%，在两块SiC之间仅激发TM极化中的表面声子极化激元。这项工作中给出的结果表明，近场热谱可以通过基于电介质的超材料来设计，这在许多新兴技术中至关重要，比如在纳米级间隙热光伏发电中。
