光子晶体纳米梁腔的光学性能研究

发布时间：2018-07-18 17:18

【摘要】：光子晶体是一种由不同折射率的电介质周期性排列而成的人工微结构,如果在光子晶体中引入缺陷或无序而破坏光子晶体的周期性,则将形成光子晶体谐振腔。光子晶体纳米梁腔(Photonic Crystal Nanobeam Cavity,PCNC)就是一种典型的一维光子晶体谐振腔。相比于二维光子晶体谐振腔,PCNC的尺寸更小、制备相对容易,且同样具有较高的品质因子和较小的模体积,因而应用非常广泛。为了进一步提高PCNC的光学性能,获得具有极高品质因子和极小模体积的PCNC,从而增强PCNC中的光物相互作用,亟待提出新型的PCNC来代替传统的光学谐振腔。在本文中,我们首先阐述了PCNC的研究背景,对光子晶体进行了介绍,同时对光子晶体的特征和应用进行了分析。其次我们介绍了研究PCNC的基本理论和主要研究方法,重点对平面波展开法和时域有限差分方法进行了阐述。在本文中,我们提出了一种新型的具有H型空气孔的PCNC,与传统的纳米梁腔采用圆形空气孔或矩形空气孔不同的是,这种纳米梁腔采用的是H型的空气孔。利用平面波展开法我们研究了该纳米梁腔的光子能带结构,详细分析了不同的结构参数对光子带隙的影响,进而设计出对光子具有较强的限制作用的周期性波导结构,同时采用模式匹配方法,对周期性波导结构进行了改造,设计了一种具有渐变区域和周期区域的纳米梁腔。利用时域有限差分方法方法,我们研究了该纳米梁腔的品质因子与模体积等光学性能。为了对比,在本文中,我们也设计了一种具有与H型空气孔完全相同的结构但空气孔为矩形的纳米梁腔,同时对两种纳米梁腔的光子能带结构、品质因子和模体积等光学性能进行了比较。相对于传统的纳米梁腔,我们提出的新型H型空气孔纳米梁腔具有极高的品质因子Q=6.6×10~7、极小的模体积V=0.59(λ/n)~3,从而使得该纳米梁腔在低阙值激光器、高灵敏度光学传感器、高性能滤波器以及光力学系统等方面具有广泛的应用。
[Abstract]:Photonic crystals are artificial microstructures arranged periodically by dielectric with different refractive indices. If defects or disorder are introduced into photonic crystals to destroy the periodicity of photonic crystals, a photonic crystal resonator will be formed. Photonic Crystal Nanobeam cavity (PCNC) is a typical one-dimensional photonic crystal resonator. Compared with two-dimensional photonic crystal resonator (PCNC), the size of PCNC is smaller, its preparation is relatively easy, and it also has higher quality factor and smaller mode volume, so it is widely used. In order to further improve the optical performance of PCNC, obtain PCNC with high quality factor and minimal mode volume, so as to enhance the interaction of light in PCNC, it is urgent to propose a new PCNC to replace the traditional optical resonator. In this paper, we firstly introduce the research background of PCNC, introduce photonic crystals, and analyze the characteristics and applications of photonic crystals. Secondly, we introduce the basic theory and main research methods of PCNC, focusing on the plane wave expansion method and the finite-difference time-domain method. In this paper, we propose a new type of PCNC with H-type air holes, which is different from the traditional nano-beam cavities with circular air holes or rectangular air holes. The photonic band structure of the nanoscale beam cavity is studied by using the plane wave expansion method. The influence of different structure parameters on the photonic band gap is analyzed in detail, and a periodic waveguide structure with strong limiting effect on the photons is designed. At the same time, the periodic waveguide structure is modified by mode matching method, and a kind of nanoscale beam cavity with gradual and periodic region is designed. By using the finite-difference time-domain method, the optical properties such as the quality factor and the mode volume of the nano-beam cavity are studied. For comparison, in this paper, we also design a kind of nanoscale beam cavity with the same structure as the H-type air hole, but the air hole is rectangular. At the same time, we design the photonic band structure of the two kinds of nano-beam cavity. The optical properties such as quality factor and mode volume were compared. Compared with the traditional nano-beam cavity, the new H-type air hole nano-beam cavity has a very high quality factor Q _ (6.6 脳 10 ~ (7) and a very small mode volume V _ (0.59) (位 / n) ~ (3), which makes the nano-beam cavity in a low threshold laser and high sensitivity optical sensor. High performance filters and optomechanical systems are widely used.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O734

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