Engineering infrared emission properties of silicon in the near field and the far field

We study numerically the thermal emission of highly doped silicon surfaces. We show that by modifying the doping, we can tune the frequency of emission. We also show that by taking advantage of the large local density of states due to surface-plasmon polaritons, radiative properties in the far field can be drastically modified. It is possible to realize a spatially partially coherent thermal source as well as a quasi-isotropic source. Finally, we study the radiative transfer between two doped silicon bodies. Surface-plasmon polaritons produce an enhancement of several orders of magnitude of the radiative energy transfer at nanometric distances. (C) 2004 Elsevier B.V. All rights reserved.