Date of Original Version




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Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article may be found at

Abstract or Description

In this letter, we measured the nanoscale thermal radiation between a microsphere and a substrate which were both coated with thick goldfilms. Although gold is highly reflective for thermal radiation, the radiative heat transfer between two goldsurfaces was demonstrated to be significantly enhanced at nanoscale gaps beyond the blackbody radiation limit due to the tunneling of non-resonant evanescent waves. The measured heat transfer coefficient between two goldsurfaces agreed well with theoretical prediction. At a gap d = 30 nm ± 5 nm, the heat transfer coefficient between two goldsurfaces was observed to be as large as ∼400 W/m2·K, much greater than the blackbody radiation limit (∼5 W/m2·K).





Published In

Applied Physics Letters, 100, 233114.