Diffraction gratings of photosensitive ZrO_2 gel films fabricated with the two-ultraviolet-beam interference method

Photosensitive ZrO(2) gel films were 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 ZrO(2) gel films were prepared from Zr(O-n-C(4)H(9))(4) chemically modified with benzoylacetone. We fabricated uniform gratings with a 0.5-microm period on Si or SiO(2) substrates by etching the gel films in ethyl alcohol after UV irradiation. A maximum diffraction efficiency of 28% was attained with the grating fabricated on Si substrate under a Littrow mounting condition by use of a 633-nm-wavelength He-Ne laser. Blazed gratings could also be fabricated.