title: Replicated, high-aspect-ratio micro-optical components fabricated from inorganic solgel materials.
abstract: A replication process for the fabrication of refractive microlenses from a purely inorganic solgel material based on tetraethoxysilane is presented. The geometrical dimensions and optical properties of the inorganic microlenses are characterized and compared with those of microlenses replicated in a hybrid xerogel containing organic additives. By a reduced solvent content in the sol composition, together with modifications in the replication process, it was possible to obtain inorganic xerogel lenses with exceptionally high sagittal height values of as much as 28 microm. Compared with the hybrid xerogel, the inorganic xerogel has the advantage of an absorption coefficient that is five times lower in the visible spectral range and exhibits optical transparency in the near-ultraviolet range for wavelengths down to 200 nm.
authors.affiliation: Laboratory for Micro-optics, Department of Microsystems Engineering-IMTEK, University of Freiburg, Freiburg, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Krause
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Mönch
authors.forename: Hans
authors.initials: H
authors.lastname: Zappe