Bioinspired Broadband Antireflection Coatings at Long Wavelengths for Space Applications

This UF interdisciplinary research team, collaborated with David Broadway at the NASA Marshall Space Flight Center, will develop a new broadband antireflection (AR) coating technology, which is inspired by the periodic nanostructures found on the cornea of a moth's eye, to significantly reduce specular optical reflection from silicon refractive optics over a wide range of light incident angles and wavelengths (from near-infrared to millimeter wavebands). With the guidance of theoretical modeling, broadband moth-eye AR coatings with optimal structures will be fabricated by using both standard top-down lithography and nontraditional bottom-up colloidal lithography approaches. This research focuses on addressing the technical challenges as listed in NASA's space technology roadmaps, including TA 08 − Science Instruments, Observatories and Sensor Systems, TA 10-10 − Coatings, and TA 12-24 − Electronics and Optics Manufacturing Process. The most significant technical achievement for the entire grant award period include: •Identified optimal moth-eye AR structures for different IR wavebands by using rigorous coupled-wave analysis (RCWA) simulations •Developed two new scalable bottom-up technologies for assembling silica microspheres as templates for templating broadband infrared AR coatings •Optimized reactive ion etching (RIE) conditions (with and without inductively coupled plasma modes) for fabricating optimal moth-eye AR coatings on silicon wafers •Microfabricated moth-eye silicon AR coatings exhibit superior broadband antireflection over a wide range of NIR and MIR wavebands •Pioneered a new metal-assisted chemical etching approach for fabricating silicon moth-eye AR pillars with very high aspect ratios •Achieved tunable antireflection coatings using new, smart, multi-stimuli-responsive shape memory polymers (SMPs)