Preparation Of One-dimensional Photonic Crystals Based On Periodic Arrangement Of Nanoparticles

In recent years, photonic crystals have become an important research field in many disciplines such as materials science, photonics, applied physics and so on. A photonic crystal is a kind of artificial material with its refractive index periodically arranged in one, two, or three directions. It can produce photonic bandgaps. If the frequency of light falls within the photonic bandgap, regardless of its polarization and propagation direction, light is prohibited to propagate in the photonic crystal.After many years of theoretical and application researches, photonic crystals have potential applications in many fields. The fabrication of photonic crystals is the basis of its application. At present, the common fabrication methods of photonic crystals include self-assembly, photolithography and optical holography etc.. In this thesis, we use two-beam interferometry to prepare a one-dimensional photonic crystal based on the periodic arrangement of semiconductor nanoparticles. The preparation method has the advantages of simple process, good reproducibility and good compatibility with current optical integration processes. The fabrication method may make it possible to realize the fabrication of large area photonic crystals.The main contents of this thesis are as follows:1. Preparation of quantum dots and preparation of thin films containing large amounts of quantum dots(QDs). In the experiment, CdSe QDs and CdSe/CdS core-shell structure quantum dots (CdSe/CdS QDs) were prepared by a colloid synthesis, and the prepared quantum dots are characterized by transmission electron microscopy and luminescence properties. The prepared CdSe/CdS QDs were mixed into a small amount of polyvinylpyrrolidone (PVP) polymer, and the mixture was mixed so that CdSe/CdS QDs were uniformally distributed. If the polymer containing the quantum dots was cured, we could obtain a solid film.2. A one-dimensional photonic crystal based on the periodic arrangement of nanoparticles was prepared by a double-beam interferometry. In the experiment,through the construction of a simple, easy to achieve the two-beam interference optical path, the formation of periodically arranged bright and dark interference light fields were formed. The periodic light field was irradiated on a PVP sample containing CdSe/CdS QDs, and a periodic potential well was formed on the sample to capture the CdSe/CdS nanoparticles. After a long period of irradiation, the PVP mixed solution containing CdSe/CdS nanoparticles would be cured to form a solid film containing a large number of CdSe CdS nanoparticles which were periodically arranged. By analysis of samples from diffraction property and elemental microanalysis,we find that the solid film is a one-dimensional photonic crystal.