Tunable Bioinspired Spatially Varying Random Photonic Crystals

Naturally occurring periodic nanostructures have long been of interest due to their striking optical effects and potential biological roles. They have been recognized not only as interesting curiosities but potential design inspirations that can lead to improvements in biochemical sensors, laser surgery, photovoltaics, and other mission-critical applications. This work will focus on one such application of significant human safety and national security concern: chemical warfare agent (CWA) sensors inspired by naturally occurring nanophotonic structures like those of the morpho butterfly. Recent efforts on this front have concluded that naturally occurring structures offer more sensitivity than synthetic ones due to their complex periodicity. This puts our team in an advantageous position to push this effort forward: with leaders in the synthesis of spatially variant photonic crystals (SVPCs), the team brings expertise in one of the most promising techniques to generate complex structures incorporating spatially variant period, randomness, and other naturally occurring features; these structures can then be fabricated by multi-photon lithography (MPL), where the team offers a pioneer and internationally recognized leader in the field in its application for creating functional 3D nanophotonic devices. This work aims to support the development of practical, field-deployable sensors based on artificial substrates inspired by nanophotonic structures found in nature. The proposed tasks will develop fundamental knowledge and engineering design principles to support this effort. First, to determine the fabrication limits of MPL, a range of peacock-feather-inspired SVPCs will be fabricated to systematically and randomly vary in fill-factor extremes. Next, SVPCs will be fabricated to incorporate periodic “tree-like” structures that imbue the morpho butterfly with its unusual structural coloration properties. Leveraging the knowledge generated in these tasks, large-area bioinspired SVPCs will be fabricated to extend the development of novel chemical sensors based on nanoparticle-decorated morpho butterfly wings and other natural photonic crystals. All tasks will be accompanied by modeling and simulation efforts to validate and broaden the design space.