Replication technology for optical microsystems

Replication technology is playing an increasingly important role in the production of optical microsystems and micro-optical elements. Hot embossing, injection moulding and UV-embossing all can produce high-quality optical elements in very cost-effective processes. New sol-gel materials allow the combination of replication with lithography to leave selected areas material-free for sawing and bonding. The development of wafer-scale replication technology using UV-curable sol-gel and polymer materials enables refractive and diffractive micro-optical elements as well as micro-mechanical alignment features to be replicated directly onto glass substrates or onto semiconductor device wafers. Grating nanostructures with linewidths less than 100 nm have been replicated into polymer and sol-gel materials for the cost-effective fabrication of large area subwavelength structures for applications such as polarisers and buried grating security features.