Normal Spectral Emittance of a Nickel Metal Surface with Rectangular Microcavities

Spectral control of thermal radiation emitted from rectangular microcavities (0.5 x 0.5 x 0.5 mu m(3)) was investigated through emission experiments at high temperatures. The microcavities were fabricated on a mirror-finished Ni metal surface. Through measurement of the normal spectral emittance, the maximum emittance was obtained around a wavelength of 0.87 mu m, which was very close to that (0.894 mu m) estimated from the cavity resonance theory. The emittance reached a maximum value of 0.95, and then decreased drastically with increasing wavelength, from the cut-off wavelength. For a longer wavelength range from 1.7 mu m, it was equal to the emittance of the mirror-finished surface. (C) 2009 Wiley Periodicals, Inc.