The Infra-red Suppression in the Incandescent Light from a Surface with Submicron Holes

The surface structure of the incandescent body effects on the emissivity of the infra-red light. If an adequate surface structure can suppress the infra-red emission, the efficacy of the incandescent lamp could increase. The main purpose of the present work is to measure the change of the infra-red emission due to the surface structure. Tungsten films with submicron-sized deep holes (the diameter of 2-4 hundreds nanometer and the depth of 2-4 micrometers) were prepared and heating them. The spectra of incandescent light were measured at high temperature up to 1400K. We found that the amount of the infra-red emitted from the surface with submicron holes is almost a half of that from a surface with macroscopic holes.