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.

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.

scholarly journals A transmit/reflect switchable frequency selective surface based on all dielectric metamaterials

2015 ◽  
Vol 05 (04) ◽  
pp. 1550035 ◽  
Author(s):  
Fei Yu ◽  
Jun Wang ◽  
Jiafu Wang ◽  
Hua Ma ◽  
Hongliang Du ◽  
...  
Keyword(s):  
Effective Medium Theory ◽  
Frequency Selective Surface ◽  
Wave Band ◽  
Medium Theory ◽  
Left Handed ◽  
Resonance Frequencies ◽  
Induced Field ◽  
Millimeter Wave Band ◽  
Frequency Selective ◽  
Magnetic Resonances

In this paper, we propose a novel transmit/reflect switchable frequency selective surface (FSS) in millimeter wave band based on the effective medium theory under quasi-static limit, which is designed with square-hole elements cut from continuum dielectric plates. The building elements of the surface are composed of all dielectric metamaterial rather than metal material. With proper structural design and parameters tuning, the resonance frequencies can be tuned appropriately. The frequency response of the surface can be switched from that of a reflecting structure to a transmitting one by rotating the surface [Formula: see text], which means under different incident polarizations. The reflective response can be realized due to the effect of electric and magnetic resonances. Theoretical analysis shows that the reflective response arises from impedance mismatching by electric and magnetic resonances. And the transmitting response is the left-handed passband, arises from the coupling of the electric and magnetic resonances. In addition, effective electromagnetic parameters and the dynamic induced field distributions are analyzed to explain the mechanism of the responses. The method can also be used to design switchable all-dielectric FSS with continuum structures in other frequencies.

Effects of Nanoscale Patterns on the Spectral Absorptance of Wafers

2010 ◽  
Vol 26-28 ◽  
pp. 145-148
Author(s):  
Ai Hua Wang ◽  
Jiu Ju Cai
Keyword(s):  
Effective Medium Theory ◽  
Grating Period ◽  
Radiative Properties ◽  
Medium Theory ◽  
Pure Silicon ◽  
Patterned Wafers ◽  
Tm Mode ◽  
Polysilicon Gate ◽  
Diffraction Effects ◽  
Difference Time

This paper presents a parametric study of the radiative properties of patterned wafers with a polysilicon gate array on the Si substrate, considering the effect of wavelength and polarization. While the gate sizes are very small compared to wavelength, the results show rather unusual phenomena. The absorptance calculated by effective medium theory (EMT) is in agreement with finite-difference time-domain (FDTD) in the cases with small gate and period sizes. With the increase of period and decrease of the ratio of the gate width to the pattern pitch, both EMT and FDTD results for TM mode approach to pure silicon since the grating effect diminishes. Besides, the TE absorptance curve separates from that of plain Si at the wavelength equals to the grating period, this is because the gate can interact with its neighboring region by diffraction and the diffraction effects are weak, when the wavelength is small. It also shows a slight increase in the gate height can drastically increase the absorptance and the increased gate height shifts the peak absorptance to longer wavelength. This work is of great importance for optimization of advanced annealing techniques in semiconductor manufacturing.

scholarly journals Magnetic Field Effect of Near-Field Radiative Heat Transfer for SiC Nanowires/Plates

2018 ◽  
Vol 8 (11) ◽  
pp. 2023
Author(s):  
Zhiyuan Shen ◽  
Hao Wu ◽  
Han Wang
Keyword(s):  
Magnetic Field ◽  
Dielectric Constant ◽  
Field Intensity ◽  
Effective Medium Theory ◽  
Near Field ◽  
Magnetic Field Effect ◽  
Medium Theory ◽  
Sic Nanowires ◽  
Magneto Optical Effect ◽  
Field Radiation

The SiC micro/nano-scale structure has advantages for enhancing nonreciprocal absorptance for photovoltaic use due to the magneto optical effect. In this work, we demonstrate the near-field radiative transfer between two aligned SiC nanowires/plates under different magnetic field intensities, in which Lorentz-Drude equations of the dielectric constant tensor are proposed to describe the dielectric constant as a magnetic field applied on the SiC structure. The magnetic field strength is qualified in this study. Using local effective medium theory and the fluctuation-dissipation theorem, we evaluate the near-field radiation between SiC nanowires with different filling ratios and gap distances under an external magnetic field. Compared to the near-field heat flux between two SiC plates, the one between SiC nanowires can be enhanced with magnetic field intensity, a high filling ratio, and a small gap distance. The electric field intensity is also presented for understanding light coupling, propagation, and absorption nature of SiC grating under variable incidence angles and magnetic field strengths. This relative study is useful for thermal radiative design in optical instruments.

Band structure of one-dimensional doped photonic crystal with three level atoms using the Fresnel coefficients method

2018 ◽  
Vol 32 (01) ◽  
pp. 1750277
Author(s):  
A. Jafari ◽  
A. Rahmat ◽  
S. Bakkeshizadeh
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Band Structure ◽  
Effective Medium Theory ◽  
Electric Permittivity ◽  
Filling Rate ◽  
Medium Theory ◽  
One Dimensional ◽  
Layered Dielectrics ◽  
Fresnel Coefficients

We consider a one-dimensional photonic crystal (1DPC) composed of double-layered dielectrics. Electric permittivity and magnetic permeability of this crystal depends on the incident electromagnetic wave frequency. We suppose that three level atoms have been added to the second layer of each dielectric and this photonic crystal (PC) has been doped. These atoms can be added to the layer with different rates. In this paper, we have calculated and compared the band structure of the mentioned PC considering the effect of added atoms to the second layer with different rates through the Fresnel coefficients method. We find out that according to the effective medium theory, the electric permittivity of the second layer changes. Also the band structure of PC for both TE and TM polarizations changes, too. The width of bandgaps related to “zero averaged refractive index” and “Bragg” increases. Moreover, new gap branches appear in new frequencies at both TE and TM polarizations. In specific state, two branches of “zero permittivity” gap appear in the PC band structure related to TM polarization. With increasing the amount of the filling rate of total volume with three level atoms, we observe a lot of changes in the PC band structure.

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