A DESIGN TOOL FOR NEAR-FIELD RADIATIVE TRANSFER: THE DEVELOPMENTAL STEPS OF THE NF-RT-FDTD CODE

2016 ◽  
Author(s):  
Azadeh Didari ◽  
M. Pinar Menguc
Keyword(s):  
Radiative Transfer ◽  
Near Field ◽  
Design Tool

Heat Transfer Spectroscopy and “Heat Transfer-Distance” Curves

2008 ◽  
Author(s):  
Arvind Narayanaswamy ◽  
Sheng Shen ◽  
Gang Chen
Keyword(s):  
Heat Transfer ◽  
Radiative Transfer ◽  
Atomic Force Microscope ◽  
Near Field ◽  
Surface Force ◽  
Casimir Forces ◽  
Distance Curve ◽  
Transfer Distance ◽  
Atomic Force ◽  
Order Of Magnitude

Thermal radiative transfer between objects as well as near-field forces such as van der Waals or Casimir forces have their origins in the fluctuations of the electrodynamic field. Near-field radiative transfer between two objects can be enhanced by a few order of magnitude compared to the far-field radiative transfer that can be described by Planck’s theory of blackbody radiation and Kirchoff’s laws. Despite this common origin, experimental techniques of measuring near-field forces (using the surface force apparatus and the atomic force microscope) are more sophisticated than techniques of measuring near-field radiative transfer. In this work, we present an ultra-sensitive experimental technique of measuring near-field using a bi-material atomic force microscope cantilever as the thermal sensor. Just as measurements of near-field forces results in a “force distance curve”, measurement of near-field radiative transfer results in a “heat transfer-distance” curve. Results from the measurement of near-field radiative transfer will be presented.

Non-Surface Polaritonic Peaks in Near-Field Radiative Transfer

2014 ◽  
Author(s):  
Braden Czapla ◽  
Yi Zheng ◽  
Karthik Sasihithlu ◽  
Arvind Narayanaswamy
Keyword(s):  
Energy Transfer ◽  
Radiative Transfer ◽  
Near Field ◽  
Surface Polaritons ◽  
Field Effects ◽  
Polar Materials ◽  
Electro Magnetic ◽  
Collective Influence ◽  
Magnetic Waves

Near-field effects in radiative transfer refer to the collective influence of interference, diffraction, and tunneling of electro-magnetic waves on energy transfer between two or more objects. Most studies of near-field radiative transfer have so far focused on the enhancement due to tunneling of surface polaritons. In this work, we show the existence of sharp peaks in the radiative transfer spectrum between two spheres of polar materials that are not due to surface polaritons. The peaks, which are present on either side of the restrahlen band, are because of Mie resonances.

Near-field radiative transfer in spectrally tunable double-layer phonon-polaritonic metamaterials

2018 ◽  
Vol 212 ◽  
pp. 120-127 ◽  
Author(s):  
Azadeh Didari ◽  
Elif Begüm Elçioğlu ◽  
Tuba Okutucu-Özyurt ◽  
M. Pinar Mengüç
Keyword(s):  
Radiative Transfer ◽  
Double Layer ◽  
Near Field

Near-Field Radiative Transfer, Dispersion Forces, and Dyadic Green’s Functions

2009 ◽  
Author(s):  
Arvind Narayanaswamy
Keyword(s):  
Radiative Transfer ◽  
Near Field ◽  
Field Enhancement ◽  
Zero Point ◽  
Thermal Fluctuations ◽  
Function Technique ◽  
Dispersion Forces ◽  
Maxwell Stress Tensor ◽  
Open Questions ◽  
Greens Function

Near–field force and energy exchange between two objects due to electrodynamic fluctuations give rise to dispersion forces such as Casimir and van der Waals forces, and thermal radiative transfer exceeding Plancks theory of blackbody radiation. The two phenomena dispersion forces and near–field enhancement of thermal radiation have common origins in the electromagnetic fluctuations. However, dispersion forces have contributions from quantum (zero–point) as well as thermal fluctuations whereas nearfield radiative transfer has contributions from thermal fluctuations alone. The forces are manifested through the Maxwell stress tensor of the electromagnetic field and radiative transfer through the Poynling vector. Both phenomena are elegantly described in terms of the Dyadic Greens function of the vector Helmholtz equation that governs the electromagnetic fields. In this talk, I will focus on the application of the Dyadic Greens function technique to near–field radiative transfer and dispersion forces. Despite the similarities, radiative transfer and forces have important differences that will be stressed on. I will end the talk with some open questions about the Dyadic Greens function formalism and its application to near–field radiative transfer.

Near-Field Radiative Heat Transfer Between Spherical Surfaces

2009 ◽  
Author(s):  
Arvind Narayanaswamy ◽  
Sheng Shen ◽  
Gang Chen
Keyword(s):  
Heat Transfer ◽  
Radiative Transfer ◽  
Near Field ◽  
Blackbody Radiation ◽  
Experimental Investigations ◽  
Flat Substrate ◽  
Spherical Surfaces ◽  
Radiation Theory ◽  
Theoretical Predictions ◽  
Afm Cantilever

Nearfield radiative transfer is known to be significantly different from that of far-field radiative transfer based on Plancks theory of blackbody radiation. Theoretical predictions point to a significant enhancement of radiative transfer between closely spaced objects due to the tunneling of surface phonon polaritons. Despite extensive theoretical predictions of enhancement between parallel surfaces, experimental evidence of near-field radiative transfer in excess of Plancks limit has been elusive due to experimental difficulties. In this talk, we will present results of our theoretical and experimental investigations into near-field radiative transfer between spherical surfaces. We have developed a sensitive technique of measuring nearfield radiative transfer between a microsphere and a substrate using a bimaterial atomic force microscope (AFM) cantilever, resulting in heat transfer-distance curves. Measurements of radiative transfer between a sphere and a flat substrate show the presence of strong nearfield effects resulting in enhancement of heat transfer over the predictions of the Planck blackbody radiation theory.

Energy Transmission by Photon Tunneling in Multilayer Structures Including Negative Index Materials

2005 ◽  
Vol 127 (9) ◽  
pp. 1046-1052 ◽  
Author(s):  
C. J. Fu ◽  
Z. M. Zhang ◽  
D. B. Tanner
Keyword(s):  
Radiative Transfer ◽  
Near Field ◽  
Multilayer Structures ◽  
Negative Index ◽  
Material Loss ◽  
Surface Polaritons ◽  
Negative Index Materials ◽  
Photon Tunneling ◽  
Energy Conversion Devices ◽  
Positive Index

The phenomenon of photon tunneling, which depends on evanescent waves for radiative transfer, has important applications in microscale energy conversion devices and near-field optical microscopy. In recent years, there has been a surge of interest in the so-called negative index materials (NIMs), which have simultaneously negative electric permittivity and negative magnetic permeability. The present work investigates photon tunneling in multilayer structures consisting of positive index materials (PIMs) and NIMs. Some features, such as the enhancement of radiative transfer by the excitation of surface polaritons for both polarizations, are observed in the predicted transmittance spectra. The influence of the number of layers on the transmittance is also examined. The results suggest that the enhanced tunneling transmittance by polaritons also depends on the NIM layer thickness and that subdividing the PIM/NIM layers to enhance polariton coupling can reduce the effect of material loss on the tunneling transmittance.

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