衍射光学元件的解析分析方法

从波动光学传播的菲涅尔衍射出发，探讨一次光学转换形成任意要求的图形的问题。导得两平行传播平面的函数关系，从而在确定像面分布的条件下可以逆求出原始面的振幅与倍相分布。文中给出了几个实例，充分表明这是有实用价值的一种衍射光学元件设计方法。     

气密性碳涂覆光纤筛选强度与电阻关系研究

通过实验分析确立了把光纤电阻作为衡量气密性碳涂覆光纤通过２％应变筛选的过渡标准。要拉制２％应变筛选的碳涂覆光纤，其电阻值应小于３０ｋΩ／ｃｍ。     

Pt–Al2O3 nanocoatings for high temperature concentrated solar thermal power applications

Nano-phased structures based on metal–dielectric composites, also called cermets (ceramic–metal), are considered among the most effective spectral selective solar absorbers. For high temperature applications (stable up to 650 °C) noble metal nanoparticles and refractory oxide host matrices are ideal as per their high temperature chemical inertness and stability: Pt/Al₂O₃ cermet nano-composites are a representative family. This contribution reports on the optical properties of Pt/Al₂O₃ cermet nano-composites deposited in a multilayered tandem structure. The radio-frequency sputtering optimized Pt/Al₂O₃ solar absorbers consist of stainless steel substrate/ Mo coating layer/ Pt–Al₂O₃/ protective Al₂O₃ layer and stainless steel substrate/ Mo coating layer /Pt–Al₂O₃ for different composition and thickness of the Pt–Al₂O₃ cermet coatings. The microstructure, morphology, theoretical modeling and optical properties of the coatings were analyzed by the x-ray diffraction, atomic force, microscopy, effective medium approximation and UV–vis specular and diffuse reflectance.     

Structural and optical properties of nanocrystalline ZnO thin films synthesized by the citrate precursor route

Nanocrystalline zinc oxide (ZnO) thin films have been deposited by spin-coating polymeric precursors synthesized by the citrate precursor route using ethylene glycol and citric acid as chelating agents. The ZnO thin films were annealed in air at different temperatures for 10 min. The films were characterized by different structural and optical techniques, including X-ray diffraction (XRD), atomic force microscopy (AFM), optical transmission spectroscopy, and photoluminescence (PL). The thermal decomposition of polymeric precursor was studied by thermogravimetric analysis (TGA). XRD analysis with grazing incidence and rocking curves indicate that the ZnO films are polycrystalline with preferential orientation along the c-axis direction with a full-width at half-maximum (FWHM) of 0.31° for 600 °C-annealed samples. On annealing, the texturing in films increased along with a decrease in FWHM. AFM micrographs illustrate that the ZnO films are crack-free with well-dispersed homogeneous and uniformly distributed spherical morphology. The synthesized ZnO thin films have transparency >85% in the visible region exhibiting band edge at 375 nm, which becomes sharper with anneal. Room temperature PL spectra of these films show strong ultraviolet (UV) emission around 392 nm with an increase in intensity with annealing temperature, attributed to grain growth. Deconvolution of the PL spectra reveals that there is coupling of free excitons with higher orders of longitudinal optical (LO) phonon replicas leading to a broad asymmetric near-band-edge peak.     

Consistency and variations in optical characteristics of four-layer polymeric waveguides

In the present work, four-layer polymeric waveguides have been fabricated and characterized by interchanging the film layer. Using polyvinyl alcohol (PVA) and styrene acrylonitrile (SAN) polymer it has been shown that polymers do not loose their own property in multilayer structure and better efficiency can be achieved in the form of low propagation losses and mode filtration. Due to high contrast of PVA and SAN films, a broad spectrum of refractive index in four-layer structure has been achieved.     

Spectroscopic ellipsometric characterization of TiAlN/TiAlON/Si3N4 tandem absorber for solar selective applications

Sputter deposited TiAlN/TiAlON/Si₃N₄ tandem absorber has been characterized by spectroscopic ellipsometry in the wavelength range of 450-1200 nm. Each layer of the tandem absorber viz., TiAlN, TiAlON and Si₃N₄ has been deposited separately on copper substrate (Cu) and ellipsometric measurements have been carried out on each of these layers. The measured ellipsometric spectra were fitted with theoretically simulated spectra and the sample structure and wavelength dispersion of optical constants of each layers have been determined. The ellipsometric measurements have also been carried out on the three-layer tandem absorber deposited on Cu substrate. By analyzing the ellipsometric data, depth profiling of the tandem absorber has been carried out using the derived optical constants of the individual layers.     

Nanoparticle-Coated Silicon Nanowires

The synthesis of silicon nanowires that are densely coated with silicon nanoparticles is reported. These structures were produced in a two-step process, using a method known as hypersonic plasma particle deposition. In the first step, a Ti–Si nanoparticle film was deposited. In the second step the Ti-source was switched off, and nanoparticle-coated nanowires grew under the simultaneous action of Si vapor deposition and bombardment by Si nanoparticles. Total process time, including both steps, equaled 5 min, and resulted in formation of a dense network of randomly oriented nanowires covering1.5 cm² of substrate area. The nanowires are composed of single-crystal Si. The diameters of the nanowires vary over the range 100–800 nm. Each nanowire has a crystalline TiSi₂ catalyst particle, believed to have been solid during nanowire growth, at its tip.     

用耦合波法分析平面镀膜分频光栅的特性

使用严格的耦合波理论分析了ICF系统的色分离光栅(CSG)特性,特别针对平面镀膜减反后的情况进行了详细的讨论.模拟计算结果表明,与未镀膜的裸光栅相比,采用文中所述方法设计的镀膜光栅有很好的减反增透效果,具有良好的应用前景.     

Effect of Ce2(SO4)3 on structure and properties of Ni-Co/Al2O3 composite coating deposited by pulse reverse current method

Composite coating of Ni-Co/Al₂O₃ was deposited in Ce₂(SO₄)₃ containing electrolyte by pulse reverse current (PRC) method. The effect of Ce₂(SO₄)₃ in electrolyte on morphology, microstructure, composition, micro-hardness and residual macrostress of composite coating was investigated. The results indicates that with addition of Ce₂(SO₄)₃ in electrolyte, the composite coating becomes uniform, compact and possesses finer grains, the composite content of Al₂O₃ is enhanced, the micro-hardness of composite coating is improved, while the residual macrostress is decreased.     

光纤涂料对光纤衰减的影响

分析光纤涂料的厚度、应力松驰、热处理及辐射等对光纤衰减的影响。提出应根据光纤技术要求选择既符合工艺条件又与光纤材料相匹配的涂料,并严格控制涂料厚度和同心度,以保证光纤质量。