Experimental and theoretical study of reflection and coherent thermal emission by a SiC grating supporting a surface-phonon polariton

J. Le Gall (1) , M. Olivier (1) , J.-J Greffet (2)

1 CEA-CESTA - Commissariat à l'Energie Atomique et aux Energies Alternatives
2 EM2C - Laboratoire d'Énergétique Moléculaire et Macroscopique, Combustion

Polarized directional reflectivity and emissivity of a SiC one-dimensional grating are studied. Measurements and calculations are performed between 10 and 11.5 m where the real part of the permittivity of SiC is negative. Pronounced dips due to surface-phonon polariton excitations are observed in the reflectivity spectra in p polarization. Thermal emission displays peaks in the same directions and at the same particular frequencies. A comparison between theory and experiments shows a good agreement for both cases. The dispersion relation is obtained theoretically and experimentally. Finally, we discuss the spatial coherence of the mono-chromatic thermal emission. Indeed, it is shown that the existence of peaks of the emitted-monochromatic radiation, in particular angular directions, implies that, due to surface waves, the thermally excited field is partially spatially coherent along the interface.

Domaines: Optique [physics.optics]

J. Le Gall, M. Olivier, J.-J Greffet. Experimental and theoretical study of reflection and coherent thermal emission by a SiC grating supporting a surface-phonon polariton. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 1997, 55 (15), pp.10105. ⟨10.1103/PhysRevB.55.10105⟩. ⟨hal-01620075⟩