Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1994 · 11 citations · 0 references
Natural SciencesMaterials EngineeringMaterials ScienceOptical MaterialsOpticsPolymer ChemistryOptical PolymersOptical Thin FilmsPolymer Thin FilmsPolymeric NanomaterialsRefractive IndexThin Film Optical PropertiesLight IntensityOptical Polymer CompositesOptical Polymer ProcessingOptical Thickness MeasurementOrganic-inorganic NanocompositesPolymer-inorganic NanocompositesPolymerization-induced Optical PropertiesThickness-dependent Optical Properties
Micro Fresnel lenses were prepared from photosensitive organic-inorganic nanocomposites of the Ormocer-type by irradiation of films of 10 micrometers in thickness with an interference pattern of two laser beams, mixing a planar reference wavefront and a spherical object wavefront. To monitor the polymerization behavior of the organic groups during irradiation under real time conditions, a characterization method was developed to study changes in optical thickness nd by measuring changes of index of refraction and shrinkage during polymerization. Three-dimensional Fresnel structures were obtained by removing the unpolymerized areas by a solvent. Variation of index of refraction can also be obtained by diffusion of monomers in regions of higher light intensity. A model, similar to the Colburn- Haines model, is presented.