Preparation Of Photonic Micro-and Nano Structure, Characterization, Simulation And Applied Research

Micro- and nano- photonic structures are currently one of the main research subjects in photonics, aiming at controlling the light transport, absorption and emission properties through structural designs. Although the study and applications of micro- and nano- photonic structures have been carried out over 20 years, there are still some unsolved difficulties and challenges, in particular, high dissipation on textured metallic surfaces, the influence on photo-electrochemical processes, light scattering in random photonic structures and the fabrication of micro and nano photonic structure at low cost.The thesis consists of six chapters. In Chapter One, an introduction to the properties and applications of micro- and nano- photonic structures is given.Chapter Two discusses the fabrications, the experimental measurements and theoretical simulation methods.Chapters Three and Four present the optical response of a structure consisting of a flat metallic surface coated with a monolayer array of latex spheres and its applications in fluorescence emission and chemical sensors. Such a structure can support two types of surface modes with high Q factors:the surface plasmon-polariton modes bound at the metallic surface and the guided modes confined to the array of latex spheres, or their hybrids. Our approach may provide a way to reduce optical loss on metallic surfaces. In the application in fluorescence emission, nearly 200 times enhancement of directional fluorescence emission has been achieved. In the application in chemical sensors, we not only realize atomic layer sensitivity but also reveal the relationship between high sensitivity of chemical sensors and the local field distributions in this structure.Chapter Five discusses the optical and photo-electrochemical properties of the array of metallic spherical voids. A tunable high absorption property of the metallic spherical voids is discussed first. Then in the photo-electrochemical experiment, photo catalyze nitrate and oxygen reaction process are studied, and the influence of high absorption of light on the enhancement of photo-electrochemical processes is discussed. Surface chemical modifications are found to play an important role in the photo-electrochemical processes. The accumulation of surface charges with increasing intensity of incident light has also been observed.In Chapter Six,3-D macroporous SiO2 and TiO2 structures were fabricated by using parrot feather barbs as hard-templates. The replicated macroporous structures are bi-continuous random networks of silica or titania backbones with only short-range order, manifesting a special kind of amorphous photonic structures. The fabricated disordered macroporous structures of both silica and titania display bright blue colors stemming from coherent ligh scattering due to short-range order. Non-iridescence is due to the structural feature of the fabricated macroporous structures that can scatter light evenly in all directions. The biomimetic macroporous structures could have potential applications in photonics and other fields.