Validity of the Effective Medium Theory for Modeling Near-Field Thermal Emission by Nanowire Arrays

2021 ◽  
Author(s):  
Saman Zare ◽  
Sheila Edalatpour
Keyword(s):  
Thermal Emission ◽  
Effective Medium Theory ◽  
Near Field ◽  
Effective Medium ◽  
Nanowire Arrays ◽  
Medium Theory

Application Conditions of Effective Medium Theory in Near-Field Radiative Heat Transfer Between Multilayered Metamaterials

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
X. L. Liu ◽  
T. J. Bright ◽  
Z. M. Zhang
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Effective Medium Theory ◽  
Near Field ◽  
Effective Medium ◽  
Medium Theory ◽  
Metal Metal ◽  
Doped Silicon ◽  
Silicon And Germanium

This work addresses the validity of the local effective medium theory (EMT) in predicting the near-field radiative heat transfer between multilayered metamaterials, separated by a vacuum gap. Doped silicon and germanium are used to form the metallodielectric superlattice. Different configurations are considered by setting the layers adjacent to the vacuum spacer as metal–metal (MM), metal–dielectric (MD), or dielectric–dielectric (DD) (where M refers to metallic doped silicon and D refers to dielectric germanium). The calculation is based on fluctuational electrodynamics using the Green's function formulation. The cutoff wave vectors for surface plasmon polaritons (SPPs) and hyperbolic modes are evaluated. Combining the Bloch theory with the cutoff wave vector, the application condition of EMT in predicting near-field radiative heat transfer is presented quantitatively and is verified by exact calculations based on the multilayer formulation.

Retrieval of Uniaxial Permittivity and Permeability for the Study of Near-Field Radiative Transport Between Metallic Nanowire Arrays

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Jui-Yung Chang ◽  
Payam Sabbaghi ◽  
Yu-Shao Weng ◽  
Yu-Bin Chen ◽  
Liping Wang
Keyword(s):  
Magnetic Permeability ◽  
Effective Medium Theory ◽  
Near Field ◽  
Nanowire Arrays ◽  
Radiative Properties ◽  
Electric Permittivity ◽  
Medium Theory ◽  
Wave Interference ◽  
Guided Mode ◽  
Magnetic Resonances

Abstract Recently metamaterials made of periodic nanowire arrays, multilayers, and grating structures have been studied for near-field thermal radiation with enhanced coupling of evanescent waves due to surface plasmon/phonon polariton, hyperbolic mode, epsilon-near-zero and epsilon-near-pole (ENP) modes, guided mode, and wave interference. In this work, both effective uniaxial electric permittivity and magnetic permeability of a nanowire-based metamaterial are retrieved theoretically through the far-field radiative properties obtained by finite difference time-domain (FDTD) simulations. The artificial magnetic response of metamaterials, which cannot be obtained by traditional effective medium theory (EMT) based on electric permittivity of constitutes only, is successfully captured by the nonunity magnetic permeability, whose resonant frequency is verified by an inductor-capacitor model. By incorporating the retrieved electric permittivity and magnetic permeability into fluctuational electrodynamics with multilayer uniaxial wave optics, the near-field radiative heat transfer between the metallic nanowire arrays is theoretically studied and spectral near-field heat enhancements are found for both transverse electric and magnetic waves due to artificial magnetic resonances. The understanding and insights obtained here will facilitate the application of metamaterials in near-field radiative transfer.

Effective-medium theory for multilayer metamaterials: Role of near-field corrections

2020 ◽  
Vol 102 (17) ◽  
Author(s):  
Tong Liu ◽  
Shaojie Ma ◽  
Bowen Yang ◽  
Shiyi Xiao ◽  
Lei Zhou
Keyword(s):  
Effective Medium Theory ◽  
Near Field ◽  
Effective Medium ◽  
Medium Theory
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