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.

Near-Field Thermal Radiation: Comparison of Numerical Results and Experiments

2008 ◽  
Author(s):  
Arvind Narayanaswamy ◽  
Sheng Shen ◽  
Gang Chen
Keyword(s):  
Radiative Transfer ◽  
Thermal Radiation ◽  
Numerical Technique ◽  
Near Field ◽  
Blackbody Radiation ◽  
Numerical Results ◽  
Silica Substrate ◽  
Order Of Magnitude ◽  
Proximity Force Approximation ◽  
Curved Objects

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 Kirchoffs laws. We have developed a numerical technique to determine the near–field thermal radiative transfer between two spheres. We have measured near–field thermal radiation between a silica sphere and a flat silica substrate as a function of gap between them using an bi–material cantilever as a thermal sensor. The experimental results show qualitative agreement with numerical results. The results of this work indicate that the proximity force approximation, widely used to determine forces between curved objects, is not applicable to near–field radiative transfer between curved objects.

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.

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