Nanoimprinting for optical device fabrication: some polymer issues

Summary form only given, as follows. We review the salient aspects of nanoimprinting, nanoembossing and molding for optical device fabrication and report on our study of nanoimprint lithography oriented towards the fabrication of waveguides and MSM detectors. The driving force is the possibility to use this parallel fabrication approach to make integrated optical devices in planar geometry, which, in some parts, exhibit a higher resolution than optical lithography. The minimum feature size we have reliably obtained is 50 nm over areas of 2/spl times/2 square cm. Most of the work has concentrated on the investigation of suitable polymers, for which a set of thermoplastic properties and a window of parameters have been identified for both printing and dry etching. The example of the Y-junction planar waveguide on a SOI wafer is described in detail, since this incorporates micrometer and sub-micrometer features, the latter in the form of a photonic crystal mirror in one of its arms. Graphite and triangular lattices have been printed to investigate the limits of this nanofabrication approach with respect to high packing density, high aspect ratio and submicron feature sizes. We report on the optical characterization of these waveguides and discuss the prospects of three-dimensional molding using a templating approach for optical devices.