the nano particles each channel has stepped and slanted side walls which may be rough in nature as shown in fig6 which is a diagram of an individual nano dot in addition fig1 is another view of the same pore area the anodized substrate surface having the nano dots functions in the same manner as prior art masking materials to etch the emissive surface of substrate 10 the substrate metal may be any metal or oxide or nitride having a melting point x in excess of 2000 u00b0 c while this method of anodizing represents an electrochemical etching process the same may be accomplished using plasma etching or other etching techniques known in the art however the anodization etching method disclosed herein results in pore walls having stepped surfaces that are rough in nature this is important to creating the largest surface area possible which results in amore efficient suppression of undesirable wavelength emissions in that instance where the substrate is tungsten as with many lamps the etching process can be carried out in a sodium hydroxide solution for example under 0 14 volts direct current with 40 milli amps current though selection of the operational parameters of the process are within the purview of the skilled artisan the anodized and etched.