Bi-convex aspheric optical lenses

Aspheric optical lenses are important for a variety of optical applications but are difficult to fabricate in conventional top-down processes. Here, we have presented a bottom-up approach involving controlled spreading of a thermally crosslinkable polymeric liquid dispensed on specially prepared substrates for making aspheric bi-convex lenses. In particular, the substrate is a solid film with a tiny hole drilled on it through which the liquid can flow in and out from the top to the bottom side of the substrate. In addition, the two surfaces of the substrate are made to have similar or different wettabilities so that the combined effect of gravity and surface wettability determines the distribution of the liquid between its two sides. The substrate is maintained at an elevated temperature, so that the liquid spreads on its surfaces but only to a limited extent because of rapid crosslinking at the vicinity of the moving front. This process leads to bi-convex, hyperboloids and prolate spheroids, which yield aberration free images with optical resolution that far exceeds that generated by conventional microscope objectives.