要約

In most macroscale radiative heat transfer systems, diffraction and other near-field effects do not play any significant role unless the temperatures are extremely low. With advances in microfabrication techniques and nanotechnology, structures with characteristic dimensions of the order of hundreds of nanometers to a few microns are being routinely made. Thermal radiation in such structures must include wave effects at room and higher temperatures. In order to analyze thermal radiation from and radiative transfer between such structures, a thorough understanding of electromagnetic methods is necessary. Computation of radiative heat transfer in such nanostructures is often based on an indirect method, i.e., obtaining reflectivity and transmissivity of the structures for an external incident radiation by solving Maxwell equations. Although the indirect method is adequate for most cases, direct computation of thermal emission from within the structure provides new insight and can deal with certain problems that are more difficult for indirect methods. The direct method is based on a combination of the Maxwell equation and the fluctuation-dissipation theorem in statistical mechanics. In this paper, we discuss direct thermal emission calculations and some of their applications for radiative properties and radiation heat transfer in nanostructures.