Study On Self-Assembly To Photonic Crystals And It's Properties

Photonic crystals are synthetic crystals, made of two or more kinds of dielectricbuilding blocks arried in 1D, 2D, and 3D period structure of light wave length scale.Due to the Bragg diffraction, lightwave in some frequency rang is forbidden topropagate in it, forming photonic band gap. In this dissertation, the opline photoniccrystal is made by self-assembly, the photonic bandgap is measured, and theproperties of the bandgap is studied by numerical analysis based on the plane wavemethod and Bragg diffraction theory. The contents are as follows:In the first chapter, there is an illumination about the concept of photonic crystal,theory of photonic band, the mechanism of manipulating light, and so on. At the sametime, the classifications and applications are introduced.The second chapter shows the different caculation method on photonic crystals,especially emphasizes on the physical signification, mathematics base, and algorithmimplementation of plane wave method. Utilizing its functions, the properties ofbandgap of 1D, 2D, and 3D photonic crystals are analysied. In the end, the structureparameters of face-centred-cubic photonic crystals are designed.In the third chapter, there is a brief comment on different kinds of fabricationapproaches to photonic crystals. This chapter describes the process of theself-assembly, and discusses the influences in the process;meanwhile the convectiveassembly hypothesis is given to explain the strong tendency towards the fcc structureand the reason of stacking faults.In the chapter four, the opaline photonic crystals is fabricated by self-assembly,and the micrography is obtained by ESEM, as a result of indicating the structure isclose-packed, refered as the fcc structure. The bandgap of the sample is detected, withthe result basically matching the calculation, moreover the relation between centrewavelength of bandgap and incident angle is studied. Then the influences ofenvironmental parameter on the procedure rate, quanlity, and thickness is investigated.