Manipulating Light at Micro- and Nano-Scale: Enable Photonic Structures Toward Real-World Applications

Abstract

Recent advances in fabrication and processing methods have spurred many breakthroughs in the field of nano- and micro-structures that provide novel ways of manipulating light interaction in a well controllable manner, thereby enabling various innovative applications. In this dissertation, new photonic design concepts and materials featuring high performance and long-term stability are investigated for bridging the gap between the research and the real-world applications. Firstly, angle-insensitive and high-purity structural color filters based on one-dimensional layered structures that are suitable for mass-production are studied. Various scenarios including reducing the layer number and depositing the whole device via an all-solution process have been proposed to simplify the fabrication, thereby lowering the manufacturing cost. The proposed structures offer significant advantages over existing colorant-based filters in terms of high efficiency, slim dimension, and being free from photobleaching. They have been successfully adapted into practical applications including decorative paints, visibly-opaque but near-infrared-transmitting camouflage coatings, and highly-efficient colored photovoltaics. As a special color, ‘black’ has been studied separately based on ultrabroadband absorbers that are achieved by simultaneously exciting multiple absorption resonances. It can significantly enhance the efficiency of energy harvesting and conversion in various applications. In addition, optical designs are incorporated into vehicle interiors, opening up a new path to the extensive use of optics in automobiles: Anti-glare colored dashboard with the potential for high-resolution dashboard displays are demonstrated with micro-scale lenticular lenses; Invisible vehicle pillars for safe driving are realized with compact optical cloaks using different optical components, including polarizers and mirrors. The next part is the research into a cost-effective and easy-to-fabricate method for flexible transparent electrodes employing ultrathin (thickness < 10 nm), ultra-smooth (roughness < 1 nm), and low-loss copper-doped silver. This novel silver alloy requires only room-temperature deposition and presents outstanding optical and electrical properties, mechanical flexibility, and environmental stability, which are greatly desired in potential high-performance flexible optoelectronic devices. Lastly, other optical structures inspired by methods employed in above researches that have impactful applications, including retro-reflective particles that can be embedded in transparent glasses for light detection and ranging and omnidirectional planar solar concentrators based on curved micro-reflectors, are briefly discussed. All the strategies and methodologies proposed here could bring optical researches out of the labs and open up more opportunities for further advancement.