【作者】 刘广平；

【导师】 宣益民；

【作者基本信息】 南京理工大学 ， 工程热物理， 2008， 博士

【摘要】 随着人类认识水平的不断进步,热辐射研究由传统的宏观大尺度研究逐渐拓展至微观小尺度问题的研究。对于一个热辐射问题,当物体结构的特征尺度与热辐射波长相近时,热辐射与结构的耦合将会产生许多新现象,该过程便是热辐射与微结构耦合过程。研究结果发现,通过控制微结构形态特征,可人为地控制耦合过程,进而控制热辐射能量传递过程,此即微结构热辐射光谱控制问题。近年来,随着MEMS微结构技术的不断进步,微结构热辐射光谱控制问题引起了广泛关注,据信该技术方法在与热辐射相关的技术领域有着广阔的应用前景。本文以微结构热辐射光谱控制特性为主要研究对象,同时,开展微结构光谱控制应用方面的研究。具体研究内容包括以下几个方面:1.微/纳尺度热辐射能量传递基于电磁波理论,分析微结构热辐射光谱控制问题,采用麦克斯韦方程组描述热辐射电磁波场量的相互激励关系;讨论热辐射电磁波的传播特性和偏振方式,基于坡印亭矢量定义热辐射能流以及光谱特性,分析热辐射与微结构的相互耦合过程;将时域有限差分思想用于麦克斯韦方程组离散,给出FDTD数值计算方法,同时,建立与FDTD方法相对应的入射波引入方法和边界处理方法;讨论微结构材料光学参数,并概括归纳常用材料的光学特性。2.一维微结构光谱控制特性研究研究周期性一维微结构的反射控制特性和透射控制特性,深入分析入射角、偏振方式、形态特征参数、周期以及折射率比值对其光谱控制特性的影响;针对周期结构光谱控制带宽受限的问题,将一维微结构延伸至非周期结构,研究非周期结构的反射控制特性、透射控制特性以及反射透射兼容控制特性,研究入射角及偏振方式对其光谱控制特性的影响;分别讨论周期结构和非周期结构的设计方法。将周期性一维微结构的光谱控制特性用于Morpho蝴蝶的结构显色研究,建立表皮微结构物理模型,计算表皮微结构的光谱特性;研究分析表皮微结构参数、入射角以及表皮材料光学参数对其光谱特性的影响;最后,根据计算分析结果解释结构显色机理。3.一维微结构滤光器光谱控制研究针对GaSb（锑化镓）电池的热光伏系统,将一维微结构光谱控制特性用于滤光器的光谱控制研究,分析滤光器与辐射器的辐射能量光谱分布及电池转化能力的匹配特性;根据匹配特性优化设计滤光器结构,计算其光谱控制特性,研究入射角及偏振方式对滤光器光谱控制特性的影响;采用PVD真空镀膜技术加工制作滤光器,测试其光谱控制特性,并根据测试结果评估滤光器的光谱控制效率;将非周期性一维微结构用于滤光器的光谱控制研究,优化设计非周期结构滤光器,计算其光谱控制特性,研究入射角及偏振方式对滤光器光谱控制特性的影响,根据计算所得光谱特性评估其光谱控制效率。4.热致变色材料光谱控制研究针对(La_1-xSr_x)MnO₃型热致变色材料在太阳辐射波段吸收较大的问题,将一维微结构的光谱控制特性用于实现热致变色材料的光谱控制。根据热致变色材料的应用环境温度及自身的光谱特性,优化设计一维微结构,计算优化结构的光谱特性;根据计算得到的光谱特性,计算一维微结构对热致变色材料的光谱控制效果。5.二维粗糙表面光谱特性计算研究研究二维随机粗糙形态特征,建立随机粗糙表面模型;根据粗糙表面形态特征及表面模型,给出粗糙表面生成方法;将FDTD方法用于二维粗糙表面光谱特性的数值计算,将计算结果与现有的实验结果、GOA（几何光学近似方法）结果、EMT（电磁波解析法）结果进行比较,验证FDTD计算方法的有效性;根据FDTD计算结果研究粗糙表面的光谱特性,分析粗糙表面光谱特性的影响因素。研究二维光栅结构减反表面的结构特征,给出设计方法;针对0.2～0.3μm波段,选用Si作为基体材料,设计Si基二维光栅结构减反表面,采用FDTD方法计算减反表面的光谱特性,研究减反表面的特征单元高度、宽度、入射角以及偏振方式对其光谱特性的影响。更多还原

【Abstract】 With a growing progress in the realization of nature in the world, the conventional thermal radiation analyses in macroscopic and large scale gradually extends in microcosmic and small scale. When the characteristic length becomes comparable to thermal radiation photon wavelength, magical and complicated phenomena are showed in the course of interplay between thermal radiation and microstructure. The existed researches have given many evidences that the interplay effect and thermal radiation energy transmission could be controlled by adjusting its configuration of microstructure, and this topic is correlated to thermal spectral control using microstructure issue. Recently, with the development in MEMS microstructure fabrication technology, there has been a growing interest in realization of the theme of thermal spectral control using microstructure., and it is considered that this theme will be applied in many fields relating to thermal radiation widely. This dissertation will give explorations to its spectral control properties and applications on the theme of thermal spectral control using microstructure.The detailed contents in this dissertation are listed in the following aspects.1. Thermal radiation energy transmission in Nano/MicroscaleThermal spectral control using microstructure is explored based on electromagnetic wave theory. The Maxwell equations are used to show the inducing relations between the electric and magnetic component. Others aspects are also investigated including the propagation characteristics of thermal radiation wave and its polarization. The fundamental course of the interplay effect is presented between thermal radiation and microstructure, which will be used to direct the thermal spectral control investigation. The FDTD algorithm is proposed by discretizing the Maxwell curl equation in Yee cell. The incidence wave introduction and the boundary condition technique are given to apply in FDTD simulation. This dissertation also discusses the optic parameters of microstructure materials, and gives summaries on microstructure materials.2. Thermal spectral control properties of one-dimensional microstructureThe spectral control properties of one-dimensional periodic microstructure （1DPMS） are simulated and investigated by the proposed FDTD algorithm, also, the effects to the spectral control properties are simulated and analyzed from several influencing factors including incident angle, polarization, configuration parameters, period and the ratio of refraction index. The valuable methods are proposed in order to extend the limited spectral control band of 1DPMS, accordingly, 1DPMS is developed to one-dimensional non-periodic microstructure （1DNPMS）. The spectral control properties of 1DNPMS are presented and simulated by FDTD method. The effects from incident angle and polarization to the spectral control properties of 1DMPMS are simulated and analyzed with comparing to those of 1DPMS. The methods are proposed for designing 1DPMS and 1DNPMS, respectively.The spectral control properties of 1DPMS are used to explore the structure color of Morpho butterfly. This dissertation is proposed 1DPMS model for the scale microstructure of Morpho butterfly, and simulated its spectral properties by FDTD algorithm, simulated and analyzed the effect to the spectral properties from the microstructure parameters, incident angle and refraction index of the scale microstructure. Finally, the structure color of Morpho butterfly is analyzed and explained based the simulated results.3. The spectral control properties of one-dimensional microstructure filterThe spectral control properties of One-dimensional microstructure are introduced to develop spectral control filter for thermophotovoltaic （TPV） system with GaSb cell. This dissertation analyzed the matched characteristics with GaSb cell and the power distribution of radiator. 1DPMS filter is designed according to the matched characteristics. The designed filter is simulated and analyzed for its spectral control properties and the spectral control effect from incident angle and polarization. And the designed filter is fabricated by PVD technique. The spectral control properties of the fabricated component are measured and used to evaluate its spectral control performance. Also, 1DNPMS filter is designed according to the matched characteristics. And the 1DNPMS filter’s spectral control properties are simulated and used to evaluate its spectral control performance, which is compared to those of 1DPMS filter component.4. Spectral control to the variable emittance materialThe spectral control properties of one-dimensional microstructure are used to control the spectral properties of (La_1-xSr_x)MnO₃ in order to reduce and restrain its absorption within the solar radiation wavelength ,which is one kind of variable emittance material. One-dimensional microstructure is designed according to itself spectral properties and the temperature of its applied circumstance. The designed structure is simulated by FDTD method so that its spectral control performance is evaluated.5. The spectral properties of two-dimensional roughness surfaceThis dissertation investigates the shape of two-dimensional roughness surface, and proposes the model for the roughness surface. The method is given to form the roughness surface. The FDTD algorithm is used to simulate and calculate the bidirectional reflectivity of the two-dimensional roughness surface, and the simulated results are compared with the measured data, GOA simulating results and EMT simulating ones from other references. Also, the spectral properties distribution and its influencing factor are analyzed according to the FDTD simulating results.This dissertation presents the configuration characteristics of two-dimensional grating artireflection-structured surface, and provides designing method for the periodic surface. The artirecflection-structured surface is designed using silicon material in order to achieve spectral control in the wavelength of 0.2～0.3μm. FDTD method is used to simulate and investigate the spectral properties of the designed surface and the effects to its spectral properties from the height and width of characteristic cell, incident angle and polarization.更多还原