Investigation Of Nanoporous Polymer Films Applied In Antireflection Coatings And Photonic Crystals

It is a dream for the information industry that photons can substitute electrons to transmit information, for photons have many advantages such as high speed, no interactions with each other. Although man have make great progress in this aspect ——the widely use of optical fiber, electronic devices must be involved in the input and output of optical fiber, which reduce the efficiency greatly. Here, nanoporous polymer films give us a new idea. Not only we are able to fabricate optical waveguide devices with fine-controllability of its refractive index, but block copolymer based photonic crystals can also be fabricated with it. The technique of this kind of photonic crystals is very simple and it provides sufficient dielectric contrast which is one of the main challenges to polymer-based photonic crystals. So it provides an easy way to control the flow of photons. In the beginning of this thesis, basic theory of optical antireflection coating is described in detail. From the Maxwell's equations, the physical essential of antireflection coating is analyzed, and then the conventional technique of the antireflection coating is introduced. And the comparison between polymer nanoporous antireflection coating and traditional antireflection coating is performed. In the following third chapter, process and condition of polymer nanoporous film forming are discussed in detail at first, including experimental materials, equipments and analyzed instruments. Then the influences of some experimental conditions are also discussed. It is indicated that using low molecular weight polymer, increasing the environment temperature, reducing the humidity and adopting low boiling point solvent are the key points for the fabrication of the nanoporous antireflection coatings. In the fourth chapter, basic knowledge about photonic crystals is introduced and the conception of nanoporous polymer films based photonic crystals is created innovatively. Finite-difference time-domain (FDTD) is the most widely used numerical tool in the photonic crystals community. In the fifth chapter, we discuss the FDTD basic theory and then introduce a novel FDTD method which is based on the nonorthogonal coordinate to simulate the light transmission in the photonic crystals. Using the method we obtain the photonic bands of the nanoporous polymer films based photonic crystals .