scholarly journals Near-field thermal radiative transfer between two coated spheres

2017 ◽  
Vol 96 (12) ◽  
Author(s):  
Braden Czapla ◽  
Arvind Narayanaswamy
Keyword(s):  
Radiative Transfer ◽  
Near Field ◽  
Thermal Radiative Transfer ◽  
Coated Spheres

Nanoscale Thermal Radiation Between Coated Spheres

2017 ◽  
Author(s):  
Braden Czapla ◽  
Arvind Narayanaswamy
Keyword(s):  
Radiative Transfer ◽  
Thermal Radiation ◽  
Near Field ◽  
Reflection Coefficients ◽  
Far Field ◽  
Surface Phonon ◽  
Surface Phonon Polariton ◽  
Silver Spheres ◽  
New Formula ◽  
Coated Spheres

In this work, we present a new formula for the near-field thermal radiative transfer between two spheres. The formula is identical for coated or uncoated spheres and captures the effect of the coatings in the effective Mie reflection coefficients of the spheres. We also numerically demonstrate that silica coated silver spheres transition from silver-like conductance in the far-field to surface phonon polariton dominated silica-like behavior in the extreme near-field.

A Generalized Landauer Formalism of Nanoscale Thermal Radiative Transfer

2012 ◽  
Author(s):  
Arvind Narayanaswamy
Keyword(s):  
Radiative Transfer ◽  
General Theory ◽  
General Framework ◽  
Near Field ◽  
Length Scale ◽  
Thermal Radiative Transfer ◽  
Curved Objects ◽  
Fluctuational Electrodynamics

Though the dependence of near-field radiative transfer on the gap between two planar objects is well understood and that between curved objects is becoming clearer, a general theory of micro and nanoscale radiative transfer is still unavailable. Here, I describe a general framework based on Rytov’s theory of fluctuational electrodynamics that can be used to analyze radiative transfer between any two structures, independent of their length scale.

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.

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