Experimental investigations of the role of proximity approximation in near-field radiative transfer
type: CreativeWork
description: The nature of thermal radiative transfer changes significantly as the nominal gap between two objects becomes comparable to or smaller than the characteristic wavelength given by Wien's displacement law. At larger gaps, conventional theory of blackbody radiation is sufficient to describe the radiative transfer; at smaller gaps, however, wave effects such as evanescent wave tunneling, interference and diffraction render the classical theory invalid. The change in radiative transfer between two objects is most dramatic when they can support electromagnetic surface polaritons because of the high local density of states at the interface between the object and vacuum. When two objects of polar dielectric materials are close enough, the enhanced near-field radiation due to surface phonon polariton tunneling can exceed the blackbody limit by several orders of magnitude. This enhanced radiation at nanoscale has potential applications in energy transfer, heat assisted magnetic recording and near-field radiative cooling. In recent years, several experiments measuring the enhanced near-field radiation between a micro-sphere and a plane substrate have been reported. To measure the radiative transfer, the magnitude of which can be less than 10 nW, the sensor of choice is the bi-material micro-cantilever. My thesis has focused on two aspects of near-field radiative transfer between a micro-sphere and a substrate: (1) to enable quantitative comparison between experimental measurement and theoretical/numerical prediction of near-field radiative transfer. (2) to develop a comprehensive thermal model for the experimental measurement procedure. To enable the first task, an improved experimental apparatus to measure the near-field radiation between a micro-sphere and a substrate has been developed. In previous experimental apparatuses, radiative transfer was measured between a micro-sphere and a truncated plane surface. This was necessary because of the optical configuration. Our new a…
abstract: The nature of thermal radiative transfer changes significantly as the nominal gap between two objects becomes comparable to or smaller than the characteristic wavelength given by Wien's displacement law. At larger gaps, conventional theory of blackbody radiation is sufficient to describe the radiative transfer; at smaller gaps, however, wave effects such as evanescent wave tunneling, interference and diffraction render the classical theory invalid. The change in radiative transfer between two objects is most dramatic when they can support electromagnetic surface polaritons because of the high local density of states at the interface between the object and vacuum. When two objects of polar dielectric materials are close enough, the enhanced near-field radiation due to surface phonon polariton tunneling can exceed the blackbody limit by several orders of magnitude. This enhanced radiation at nanoscale has potential applications in energy transfer, heat assisted magnetic recording and near-field radiative cooling. In recent years, several experiments measuring the enhanced near-field radiation between a micro-sphere and a plane substrate have been reported. To measure the radiative transfer, the magnitude of which can be less than 10 nW, the sensor of choice is the bi-material micro-cantilever. My thesis has focused on two aspects of near-field radiative transfer between a micro-sphere and a substrate: (1) to enable quantitative comparison between experimental measurement and theoretical/numerical prediction of near-field radiative transfer. (2) to develop a comprehensive thermal model for the experimental measurement procedure. To enable the first task, an improved experimental apparatus to measure the near-field radiation between a micro-sphere and a substrate has been developed. In previous experimental apparatuses, radiative transfer was measured between a micro-sphere and a truncated plane surface. This was necessary because of the optical configuration. Our new a…
author: Gu, Ning
language: English
keywords: Mechanical engineering, Electrical engineering, Physics
date published: 2013
date modified: 2026-07-24T01:44:34Z
provider: Columbia University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Columbia University

PropertyValue
property ID: DOI
value: 10.7916/D89P311Q