偏振型发光二极管的设计研究

发布时间：2018-08-31 13:45

【摘要】：随着生产工艺的不断提高和成本的下降,发光二极管已经成为21世纪的理想照明光源。随着发光二极管应用范围的扩大和应用要求的提高,对其的偏振度的要求也越来越高。以二维光子晶体作为集成偏振层的发光二极管以其出光效率高、结构紧凑、工艺兼容性好、可调谐等优点成为解决这一问题的重要方案。集成于LED表面的二维光子晶体层是在传统光子晶体偏振片的基础上针对LED的出光特点制成的。其原理是光子晶体对不同模式光拥有不同传输特性,通过合理设置光子晶体的结构参数,如占空比、晶格结构、介质孔形状等,可以实现对模式的分离,从而为高出光效率、高偏振度的LED的制造提供了可能。而利用向列型液晶重构过程中折射率的变化,还可以制作可调谐的光子晶体偏振层。本文基于二维光子晶体偏振层的优异特性,对其进行结构设计和参数优化。采用的具体数值模拟算法是平面波展开法。为了克服常用设计软件对光子晶体结构的限制,本文从基础理论出发,设计了一种可用于任意晶胞形状的离散化数值模拟算法并编写了相应的程序。在此基础上对光子晶体的各个参数逐一进行优化。得出了光子晶体占空比对带宽影响的非线性关系,晶格结构的比较与选择,介质孔拓扑结构对禁带宽度的影响与其拓扑荷数量有关等经验结论,并在大量模拟数据的支持下给出了一个较优的基础结构。在上述结构的基础上,本文通过模拟分析了传统液晶掺杂光子晶体偏振片中,利用禁带边缘移动实现调谐的方案的优缺点。进而提出了利用缺陷态实现光子晶体偏振开关的模型。模拟结果显示该模型可以在LED的蓝光谱段创造一个2nm宽的窗口区,可用于偏振片的开关。上述模型开关效果相对于传统方法有较大的提升,为LED上的集成光子晶体层设计提供了新思路,可以作为进一步实用化研究的理论基础。
[Abstract]:With the continuous improvement of production technology and the decrease of cost, LED has become the ideal lighting source in the 21st century. With the enlargement of the application range and the improvement of the application requirements, the polarization degree of LEDs is becoming more and more important. The light-emitting diode with two-dimensional photonic crystal as the integrated polarization layer has the advantages of high light efficiency, compact structure, good process compatibility and tunable. The two-dimensional photonic crystal layer integrated on the surface of LED is based on the traditional photonic crystal polarizer. The principle is that photonic crystals have different transmission characteristics to different modes of light. By setting reasonable structure parameters of photonic crystals, such as duty cycle, lattice structure, shape of dielectric holes and so on, the mode can be separated and the light efficiency can be increased. The manufacture of LED with high degree of polarization is possible. The tunable photonic crystal polarization layer can also be made by the change of refractive index during the reconstruction of nematic liquid crystal. Based on the excellent properties of the polarization layer of two-dimensional photonic crystal, the structure design and parameter optimization are carried out in this paper. The numerical simulation algorithm is the plane wave expansion method. In order to overcome the limitation of common design software on photonic crystal structure, a discrete numerical simulation algorithm for arbitrary cell shape is designed and a corresponding program is written. On this basis, the parameters of the photonic crystal are optimized one by one. Some empirical conclusions are obtained, such as the nonlinear relation of the duty cycle ratio of photonic crystal, the comparison and selection of lattice structure, the influence of dielectric hole topology on the band gap and the amount of topological charge. A better infrastructure is given under the support of a large number of simulation data. On the basis of the above structure, the advantages and disadvantages of the traditional LCD-doped photonic crystal polarizer with bandgap edge moving to realize tuning are analyzed. Furthermore, a model of photonic crystal polarization switch based on defect state is proposed. The simulation results show that the model can create a wide window region of 2nm in the blue spectrum of LED and can be used in the switch of polarizer. Compared with the traditional method, the switching effect of the model is improved greatly, which provides a new idea for the design of integrated photonic crystal layer on LED, and can be used as the theoretical basis for further practical research.
【学位授予单位】：中国科学院研究生院(长春光学精密机械与物理研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8;O734

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