PolyU Uses DLP to 3D Print Optical MicroresonatorsMorgan Humburg
Optical microresonator is one of the most promising photonic technologies for ultra-sensitive, single-molecule detection. Fabrication of these micrometre-scale structures typically involve a four-step process made up of integrated circuit wafer processes: photolithography, pattern transfer, selective etching, and selective pattern reflow of patterned structures. These processes can be as time-consuming as they are complicated and expensive, hindering our ability to produce optical microresonators quickly. Along with his team at the Department of Electrical Engineering from The Hong Kong Polytechnic University (PolyU), Dr. A. Ping Zhang has developed a new microfabrication technique using DLP technology that promises to be more flexible and more efficient than before.
Because of its ability to withstand extremely high levels of ultraviolet light, the PolyU team could integrate a UV-grade digital micromirroring device (DMD) – in this case, the 0.7″ XGA-resolution DMD from DLi’s DLi4120 Bundle Kit – into an optical maskless stereolithography system they developed themselves, which features a high-power UV light source and high-precision motorized stages on an inverted optical microscope. Due to the dynamic pattern generation capability of the DMD chip within the DLi4120, UV light illuminating the DMD is reflected as light patterns according to images sliced from a 3D model of an optical microresonator and then projected on a thin layer of photoresist, spin-coated on a substrate, after passing through a set of projection optics. The monotonically additive light absorption property of the photoresist allows for a layer-by-layer polymerization process resulting in rapid fabrication of a polymer optical microresonator in less than 30 seconds. Click the Read More button below for the entire paper from The Hong Kong Polytechnic University, entitled “Rapid 3D µ-printing of polymer optical whispering-gallery mode resonators”.