【作者】 王井伟；

【导师】 韩培德；

【作者基本信息】 太原理工大学 ， 材料学， 2010， 硕士

【摘要】 光子晶体是在光学尺度上具有周期性介电结构的人工设计和制造的晶体。自从Yablonovitch和John分别提出光子晶体概念以来,在实验与理论研究上受到了广泛关注并得到了飞速的发展。光子晶体因为“光子带隙”的存在而具有许多崭新特性,类似于半导体材料中电子在周期性势场作用下形成能带结构,在光子晶体中光子由于受到周期性介电结构的调制,于是出现了光子带隙,一些特定频率范围的光不能在光子晶体中传播。由于光子存在许多电子没有的优势:如速度快,没有相互作用等,我们可以通过对光子晶体带隙结构的设计来实现对光子的控制,因此光子晶体材料有望实现光子领域的一次变革。工作在可见及近红外光波段的光子晶体是近年来人们研究的热点,由于在该波段范围内可选材料少、所得带隙窄,至今研究进展都很缓慢。研究发现:增大介质材料的介电常数是提高光子晶体光学性能的有效手段之一;将光子晶体的常规结构改进为由不同材料构成的异质结构也可有效改善其光学特性。本文从材料选择和结构优化两个方面对三维光子晶体进行了研究。采用密度泛函理论计算了氮掺杂五氧化二钽的光学性质,并将其运用到了三维光子晶体的研究之中。最后采用传输矩阵方法和平面波展开法分别研究了氮掺杂Ta₂O₅金刚石结构三维光子晶体以及由Ta₂O₅/MgF₂组成的异质结构三维光子晶体的带隙特性。研究结果表明:氮掺杂明显提高了Ta₂O₅的折射率,当氮掺杂量为7.14%即Ta₂O_4.5N_0.5结构的折射率最高,光学性质最佳。金刚石结构Ta₂O_4.5N_0.5三维光子晶体具有完全光子带隙,宽度Δω=0.05（a/λ, a为晶格常数）,为实验制备具有高反射性能的三维光子晶体提供了理论依据,也为新型光学器件的开发奠定了理论基础。Ta₂O₅/MgF₂异质结构三维光子晶体具有“带隙叠加”的特性,显著增大了带隙宽度,调节其晶格常数可出现几乎涵盖整个红光波段的光子带隙;同时在TM模式下在820¹020nm范围内具有一不受入射光角度影响的全方位光子带隙,该结构有望被用于制备偏振器件;更多还原

【Abstract】 Photonic crystal, are artificially arranged periodic electromagnetic structures in optical wavelength scale. Since the pioneering work of Yablonovitch and John there has been an enormous amount of interest in the fabrication and theoretical research of the so-called PC, has obtained the rapid development. This kind of system can be used to control light propagation in a way analogous to what semiconductors band structure do with electrons, photonic band gaps inhibit the existence of light in certain frequency ranges. Photonic have the advantage of fast and no interaction over electron, we can control light by designing photonic band gaps structure, so PC hopeful to realize revolution in photonic field.PC of the near infrared and visible regions is the focus of research in recent years, but research progress was slow because of a limited number of optional dielectric materials and a narrow band gaps. Usually, PCs properties may be modified via increasing dielectric constant of the dielectric materials; Subsequent to growth, research shows that the heterostructure PCs which was formed with various materials can improve optical properties.In this paper, we studied the material selection and structural optimization for three-dimensional photonic crystal. We calculated the optical properties of nitrogen doped Ta₂O₅ by density functional theory and applied it to the study of three-dimensional photonic crystal. Finally, we studied the diamond structure with nitrogen doped Ta₂O₅ and Ta₂O₅/MgF₂ heterostructure three-dimensional photonic crystal by calculation of the transfer matrix method（TMM） and plane wave expansion method（PWEM）.It is shown that the refractive index of Ta₂O₅ could be remarkably increased by nitrogen doping, when the doping content was 7.14%, molecular formula is Ta₂O_4.5N_0.5 had the best optical properties. The three-dimensional photonic crystal with diamond structure of Ta₂O_4.5N_0.5 has an omnidirectional band gap withΔω=0.05 （a/λ, a is the lattice constant）, this Provide theoretical support for the preparation of three-dimensional photonic crystal which have high reflectivity and application of novel optoelectronic devices. The three-dimensional photonic crystal with the heterostructure of Ta₂O₅/MgF₂ had characteristics of band gaps stacking, and remarkably increased the breadth of band gaps, adjusted the lattice constant could get better band gaps which can almost cover the whole red spectral band. At the same time, the three-dimensional photonic crystal with the heterostructure of Ta₂O₅/MgF₂ had omnidirectional band gaps without influence of incident angles around 820¹020 nm of near infrared region with TM polarization. The structure should enable new applications for polarizing devices.更多还原