Angular variation of absorption and thermal emission from photonic crystals

The absorption and thermal exitance of two-dimensional (2D) metallic and metallodielectric photonic crystals (PCs) is simulated with rigorous scattering matrix methods. These PCs have strong thermal exitance and absorption peaks in the normal direction that shift to larger and smaller wavelengths as the angle varies away from the normal direction. These PCs redistribute the thermal emission at different wavelengths into different emission angles. There is partial suppression of photon emission at long wavelengths and enhancement at the shorter wavelength spectral range where the thermal exitance has a maximum. Surface plasmon models describe well the angular dependent absorption. Thermophotovoltaic devices utilizing PCs need to account for the strong spectral variation of the thermal exitance with angle. (C) 2009 Optical Society of America