- The infrared normal spectral emissions from degenerate (metallic-like) silicon and metallic (nickel) lamellar grating structures were investigated. The gratings were micromachined on (110) silicon wafer was with differing periods, groove widths and groove depths, where the dimensions of all samples were with feature sizes comparable to the measurement wavelengths (2.5 25 mum). The measurement temperatures for all samples were in the range 27 to 740 °C. Infrared normal transmission through diffraction was also measured. In general, it was found that the spectral emission of the metallic gratings was different from the degenerate silicon grating. This because the bulk absorption in the silicon samples was affecting the emission.