Diffraction gratings of photosensitive ZrO2 gel films fabricated with the two-ultraviolet-beam interference method

Photosensitive ZrO2 gel films we:re patterned with a two-beam interference method by use of a 325-nm-wavelength He-Cd laser for the first time to our knowledge. The ZrO2 gel films were prepared from Zr(O-n-C4H9)(4) chemically modified with benzoylacetone. We fabricated uniform gratings with a 0.5-mu m period on Si or SiO2 substrates by etching the gel films in ethyl alcoho l after UV irradiation. A maximum diffraction efficiency of 28% was attaine d with the grating fabricated on Si substrate under a Littrow mounting cond ition by use of a 633-nm-wavelength He-Ne laser. Blazed gratings could also be fabricated. (C) 2000 Optical Society of America.