Formation of antireflective surface structures on diamond films by laser patterning

Experimental results on the formation of antireflective periodical microrelief on the surface of CVD diamond films are presented. Diamond surface microstructuring was performed by a laser ablation technique by using either a tightly focused beam of a Nd:YAP laser (lambda = 1078 nm) or a projection optical scheme with a KrF excimer laser (lambda = 248 nm). The minimal period of the produced one- and two-dimensional surface gratings, consisting of parallel microgrooves or microcraters, was 3 mu m. The optical transmission of the structured diamond surface was found to increase in the IR spectral region depending on the relief depth. The rise of the transmission at a wavelength of 10.6 mu m from 70% to 80% was achieved for the diamond films, both sides of which were patterned.