硬水铝石（α-AlOOH）是铝土矿的主要组成矿物之一, 常用于工业提炼铝以及制作耐火材料。 近年来, 一种具有变色效应的硬水铝石晶体开始在市场中出现。 采用X射线荧光能谱仪、 红外光谱仪、 拉曼光谱仪、 紫外可见近红外分光光度计以及测量颜色参数等方法获得了变色硬水铝石和无变色效应硬水铝石的光谱学特征, 并探讨了其变色效应的成因。 变色硬水铝石在日光下常呈黄绿色而在白炽灯下呈褐红色, 其红外光谱与拉曼光谱与普通硬水铝石的特征峰较为一致, 其中红外光谱中的特征峰主要集中在400~1 200, 1 800~2 110和2 900~3 000 cm-1三个范围内, 拉曼特征峰则主要位于154, 331, 448, 665和1 189 cm-1附近。 对比化学成分分析和紫外可见吸收光谱的测试结果, 认为Fe3+和Cr3+的d—d电子跃迁导致变色硬水铝石在可见光绿-黄绿色光区（500~560 nm）和橙黄-红色光区（600~780 nm）的透射程度较为接近, 环境光源中红光和绿光相对功率分布的差异使硬水铝石产生变色效应。 对变色硬水铝石在模拟日光和白炽灯光条件下的颜色参数进行了测定, 结果显示不同光源下样品颜色参数a*和h0的变化, 可定量地描述变色硬水铝石的变色效应。 为硬水铝石的应用拓展、 性能改善以及氢氧化物材料光学性质的深入探讨提供了科学依据和数据支持。

We propose two technologies to extend the number of layers in order to complete the three-dimensional (3D) array diffraction-limited foci, which means there are two-dimensional array foci at multi-focal planes. One technology is the diffractive optical lever; the other is multi-hybrid Fibonacci structures. Based on the aperiodic Fibonacci structures and binary phase modulation, various kinds of devices can be designed to produce 3D array foci whose focusing properties approximately satisfy the mathematical characteristics of the Fibonacci sequences. With those technologies, the diffraction-limited array foci are freely designed or distributed as required at the desired multiple focal planes.

We propose two technologies to extend the number of layers in order to complete the three-dimensional (3D) array diffraction-limited foci, which means there are two-dimensional array foci at multi-focal planes. One technology is the diffractive optical lever; the other is multi-hybrid Fibonacci structures. Based on the aperiodic Fibonacci structures and binary phase modulation, various kinds of devices can be designed to produce 3D array foci whose focusing properties approximately satisfy the mathematical characteristics of the Fibonacci sequences. With those technologies, the diffraction-limited array foci are freely designed or distributed as required at the desired multiple focal planes.

We propose a new algorithm to extend the standard Fibonacci photon sieve to the phase-only gen-eralized Fibonacci photon sieve (GFi PS) and find that the focusing properties of the phase-only GFi PS are only relevant to the characteristic roots of the recursion relation of the generalized Fibonacci sequences. By switching the transparent and opaque zones on the basis of the generalized Fibonacci sequences, we not only realize adjustable bifocal lengths, but also give their corresponding analytic expressions. Besides, we investigate a special phase-only GFi PS, a spiral-phase GFi PS, which can present twin vortices along the axial coordinate. Compared with the single focusing system, bifocal system can be exploited to enhance the processing speed, and offer a broad range of applications, such as direct laser writing, optical tweezers or atom trapping and paralleled fluorescence microscope.

The traditional Dammann grating is a phase-only modulation, and its theoretical foundation is based on far-field diffraction. Here we extend the traditional Fresnel zone plate (FZP) into a Fresnel–Dammann zone plate (FDZP), which is, in essence, considered as a FZP with Dammann modulation. Different from the Dammann grating, a single FDZP can generate array illumination from the near field to the far field by means of amplitude-only modulation in the absence of phase modulation. We then give some array illuminations operated in a water window to validate the feasibility and validity. This kind of wave-front modulation technology can be applied to array focusing and imaging from the x-ray to the EUV region.

近来, 一种产自老挝的新型印章石（俗称“老挝石”）涌进国内市场, 对我国印章石市场造成一定影响, “老挝石”的研究尚处于起步阶段, 对其颜色成因的研究更为缺乏。 采用漫反射光谱（DRS）结合X射线粉晶衍射（XRD）、 红外光谱（FTIR）、 X射线荧光光谱（EDXRF）等测试对红色“老挝石”的矿物成分和致色机理进行深入研究。 结果显示, “老挝石”的主要矿物成分为地开石, 并含有少量高岭石, 化学成分中的Fe含量和“老挝石”红色色调呈正相关关系, 即颜色越深Fe的含量越高。 铁质矿物呈微晶集合体浸染分布于地开石的颗粒间, 由于其含量低、 粒度细小, 常规的微区测试方法无法确认其种属。 相比之下, 漫反射光谱对微晶铁矿物的鉴定十分有效, 对可见光波段漫反射光谱处理得到导数等, 在土壤沉积物中已经被用来定量测定针铁矿和赤铁矿。 该研究中“老挝石”基体与土壤沉积物均为粘土矿物, 可以用漫反射光谱来判定“老挝石”中铁矿物种属。 漫反射光谱一阶导数法显示, 其谱峰位于565～570 nm, 由此确认铁矿物的种属为赤铁矿。 微晶赤铁矿分布于“老挝石”矿物颗粒间, 使样品产生红色, 赤铁矿含量越高, 红色调越深。

We propose a type of diffractive optical element, a modified Fibonacci photon sieve (MFiPS), designed by using the Fibonacci sequence with two different initial seed elements. Focusing properties of MFiPS show that it not only has less secondary foci, but also presents two equal intensity foci by optimizing the diameters of pinholes of MFiPS whose ratio of the two focal distances approaches the golden mean. Higher transverse resolution on the two focal spots is improved by using a super-Gaussian amplitude modulation technology.

A kind of diffractive optical elements (DOE) with star-ring topological structure is proposed and their focusing and imaging properties are studied in detail. The so-called star-ring topological structure denotes that a large number of pinholes distributed in many specific zone orbits. In two dimensional plane, this structure can be constructed by two constrains, one is a mapping function, which yields total potential zone orbits, corresponding to the optical path difference (OPD); the other is a switching sequence based on the given encoded seed elements and recursion relation to operate the valid zone orbits. The focusing and imaging properties of DOE with star-ring topological structure are only determined by the aperiodic sequence, and not relevant to the concrete geometry structure. In this way, we can not only complete the traditional symmetrical DOE, such as circular Dammam grating, Fresnel zone plates, photon sieves, and their derivatives, but also construct asymmetrical elements with anisotropic diffraction pattern. Similarly, free-form surface or three dimensional DOE with star-ring topological structure can be constructed by the same method proposed. In consequence of smaller size, lighter weight, more flexible design, these elements may allow for some new applications in micro and nanphotonics.

We successfully extend the standard Fibonacci zone plates with two on-axis foci to the generalized Fibonacci photon sieves (GFiPS) with multiple on-axis foci. We also propose the direct and inverse design methods based on the characteristic roots of the recursion relation of the generalized Fibonacci sequences. By switching the transparent and opaque zones, according to the generalized Fibonacci sequences, we not only realize adjustable multifocal distances but also fulfill the adjustable compression ratio of focal spots in different directions.

A new photon sieve with Fibonacci sequence is proposed and a focusing and imaging model of the Fibonacci photon sieve (FiPS) is presented based on the Huygens-Fresnel principle.The results show that the FiPS presents two longitudinal foci with the ratio of golden mean.When the diameters of pinholes are equal to 1.165 times the width of corresponding orbits,the intensity of the two foci is almost the same.Compared with the resolution of Fibonacci zone plate (FiZP),FiPS has higher transverse resolution.Finally,higher transverse resolution on the two focal planes is improved by applying Gaussian apodized technology to the numbers of pinholes of FiPS.In consequence of smaller size,lighter weight,more flexible design and bifocal property,the FiPS can be applied to optical switches,nanometer lithography,bionic eyes,multi-focus imaging and ranging,even some new applications such as ranging from X-ray microscopy and THz imaging.