Characteristics of diffraction gratings fabricated by the two-beam interference method using photosensitive hybrid gel films

Diffraction gratings of arbitrary periods have been fabricated by the two-b eam interference method using photosensitive ZrO2 gel films and characteriz ed. The ZrO2 gel films were formed on Si or silica glass substrates from so ls that were derived from Zr-butoxide modified chemically with benzoylaceto ne. The gel films were irradiated with two interference beams from a He-Cd laser (325 nm) and then leached in ethyl alcohol. The above process gave un iform surface-relief gratings of periods ranging from 1.0 to 0.5 mum, depen ding on the incidence angle of the interference beams. The diffraction effi ciency, measured in the Littrow configuration using a He-Ne laser (633 nm), showed polarization dependence for the grating of 0.5 mum period but not f or the gratings of 1.0 mum period. The maximum diffraction efficiency was 1 8% for the grating of 1.0 mum period and 28% for that of 0.5 mum period in the reflection mode. The present study has proved that the photosensitive g el films are versatile in fabrication of optical devices.