激光全息法制作二、三维光子晶体的模拟计算及禁带分析

激光全息法制作二、三维光子晶体相比于传统半导体微加工及精密机械加工技术具有很多优势，比如通过一次光辐射就可以制作出大体积、均匀的周期性结构，且能更自由、更容易地控制光子晶体结构.提出一种多光束干涉模型，通过设计模型中光束的各项参数，计算分析出二、三维光子晶体的结构.基于平面波展开法，理论计算了fcc结构光子晶体的完全禁带随填充率和介电常数比变化的情况.以上计算结果为后期实验中采用激光全息法制作二、三维光子晶体结构提供了良好的指导方向和理论依据. 关键词： 光子晶体 激光全息 多光束干涉 完全禁带     

飞秒激光加工铌酸锂晶体：原理与应用

由于具有超短的脉冲宽度和极高的峰值强度,飞秒激光微加工是一种有效的材料加工方法, 已广泛应用于光子集成器件的加工。铌酸锂晶体具有优异的电光、非线性光学和压电特性,是集成 光学和导波光学中常见的材料。本文综述了飞秒激光对铌酸锂晶体的处理,重点介绍了飞秒激光加 工的物理原理及其制备的铌酸锂基光子器件的最新进展。飞秒激光技术使铌酸锂晶体在微纳光子学 领域具有广阔的应用前景。     

飞秒激光湿法刻蚀微纳制造

飞秒激光微加工作为一种新型微纳制造技术,在复杂三维构型制作方面具有其独特的优势,但激光加工效率问题严重制约了飞秒激光微加工技术走向实际工程应用,提出一种飞秒激光湿法刻蚀微纳制造方法,以提高飞秒激光微加工的效率为突破口,通过调控激光与物质相互作用获得材料的目标靶向改性,进而结合化学湿法刻蚀实现硬质材料上的高效和高精度三维微加工,采用这一方法制作出的微透镜尺寸为80 m,球冠高6.7 m,表面粗糙度小于10 nm。利用这种方法,实现了不同结构与特性的高质量微透镜阵列的超精密制备,在石英内部也实现了螺旋微通道的复杂三维结构,螺旋通道直径为20 m,长径比超过100。     

飞秒激光湿法刻蚀微纳制造

飞秒激光微加工作为一种新型微纳制造技术,在复杂三维构型制作方面具有其独特的优势,但激光加工效率问题严重制约了飞秒激光微加工技术走向实际工程应用,提出一种飞秒激光湿法刻蚀微纳制造方法,以提高飞秒激光微加工的效率为突破口,通过调控激光与物质相互作用获得材料的目标靶向改性,进而结合化学湿法刻蚀实现硬质材料上的高效和高精度三维微加工,采用这一方法制作出的微透镜尺寸为80 μm,球冠高67 μm,表面粗糙度小于10 nm。利用这种方法,实现了不同结构与特性的高质量微透镜阵列的超精密制备,在石英内部也实现了螺旋微通道的复杂三维结构,螺旋通道直径为20 μm,长径比超过100。     

若干新型微纳光子学器件研究

光子晶体和纳米光纤是两种重要的微纳光子学材料,各自具有非常独特的控制光子传输状态的功能,是研究微纳尺度下光与物质相互作用的重要平台,也是实现新型微纳光子学器件的重要基础.文章简要介绍了超快速低功率光子晶体全光开关、纳米光纤传感器、干涉器和介质-金属纳米线复合结构器件的研究进展.     

染料掺杂光子晶体荧光带隙边缘的激射研究

利用激光全息光刻技术, 在重铬酸盐明胶 感光材料中制备了掺杂有机染料的层状光子晶体. 在532 nm纳秒脉冲激光激励下, 样品的荧光光谱表现出良好的带隙特征; 随着抽运能量的增加, 在荧光带隙带边位置获得了激射光, 并进一步研究了光子晶体的带边位置与染料荧光峰的匹配对激射的影响.带边位置越靠近染料的荧光峰, 激射阈值越低, 反之则不易产生激射.该研究为超低阈值光子晶体激光器的发展提供了思路和方法. 关键词： 全息光刻 光子晶体 荧光带隙 低阈值激射     

非水溶性光致聚合物光子晶体的研制

报道了一种新型的利用激光全息技术制作光子晶体的记录材料,即自制的非水溶性光致聚合物.用绿光作为光源对材料性能参量做简单测试,经测试其衍射效率可达85%,在波长为514.5 nm处拥有较高的吸收率,且该材料的后处理过程简单,只需热烘.利用Matlab简单模拟全息法制作光子晶体的过程,经模拟得到干涉的光束越多,光子晶体的晶...     

全息制作不同晶面取向光子晶体模板

用单向光入射和单次曝光的激光全息技术制作了类金刚石结构, 此类金刚石结构有宽完全带隙和低介质折射率要求等优点. 在同一种光束配置下，引入恰当的匹配棱镜，用激光全息技术制作了大面积的类金刚石光学晶格不同晶面取向的亚微米周期结构. 满足如负折射效应等研究中所需的特殊晶面取向要求. 关键词： 激光全息技术 光学晶格 光子晶体     

飞秒激光加工铌酸锂晶体：原理与应用（英文）

由于具有超短的脉冲宽度和极高的峰值强度,飞秒激光微加工是一种有效的材料加工方法,已广泛应用于光子集成器件的加工。铌酸锂晶体具有优异的电光、非线性光学和压电特性,是集成光学和导波光学中常见的材料。本文综述了飞秒激光对铌酸锂晶体的处理,重点介绍了飞秒激光加工的物理原理及其制备的铌酸锂基光子器件的最新进展。飞秒激光技术使铌酸锂晶体在微纳光子学领域具有广阔的应用前景。     

非水溶性光致聚合物光子晶体的研制

报道了一种新型的利用激光全息技术制作光子晶体的记录材料,即自制的非水溶性光致聚合物.用绿光作为光源对材料性能参量做简单测试,经测试其衍射效率可达85%,在波长为514.5 nm处拥有较高的吸收率,且该材料的后处理过程简单,只需热烘.利用Matlab简单模拟全息法制作光子晶体的过程,经模拟得到干涉的光束越多,光子晶体的晶格结构越复杂.设计了制作二维、三维光子晶体的实验光路,分光元件分别为掩模板和去顶棱镜.实验结果表明,利用非水溶性光致聚合物可制作大面积、大体积、耐高温和高强度的二、三维光子晶体,且其晶体结构与Matlab模拟的结果基本一致|利用非水溶性光致聚合物作为记录材料时,光路的搭建是影响实验结果的重要因素.     

非对称光束干涉制备二维微纳光子结构研究

研究了基于不同偏振组合的非对称4束和5束光干涉制备二维微纳光子结构.通过改变光束的参数组合获得了枝节状、波形状等结构.在非对称光束干涉中,光束的构型和偏振改变了波矢差分布,从而改变晶格形貌和对比度.利用CHP-C感光胶开展了全息光刻实验制备,获得了与模拟一致的光子结构.该研究为制备新颖光子结构提供了有效途径,此类光子结构还可以为制备不同类型的金属点阵结构提供模板,对新型光子器件的制备和应用研究具有一定的促进作用.     

亚微米结构的可见光聚合全息制作

报道用激光全息技术结合可见光光聚合制作周期结构的方法和物理机理;对多束激光相干产生的空间干涉光场进行了讨论;提供了一组激光束的偏振态的最佳组合,使激光全息技术制作理想的亚微米单晶结构更有效和快捷.分析了曝光量与制作效果的关系,此法可实现小球自排无法实现的大幅度占空比调节.与紫外光光聚合相比,可见光光聚合可在监视下调节,操作方便安全. 关键词： 激光全息技术 光学晶格 光子晶体     

二维光子晶体的软平板印刷技术制作研究

分析了软平板印刷技术制作二维光子晶体的特点和方法.利用绝缘PDMS模板,采用软平板印刷技术制造了三角晶系结构的二维聚合物光子晶体,采用同样的技术成功制成尺寸为150~500 nm,纵横比达1.25的高密度二维光子晶体.与其他制作技术相比,平板印刷技术具有大尺寸和易于制作的优点.结果表明,制作获得的微结构有很高的保真度.     

Fabrication of Two-Dimensional Photonic Crystals with Triangular Rods by Single-Exposure Holographic Lithography

We demonstrate a single-exposure holographic fabrication of two-dimensional photonic crystal with round- cornered triangular ＇atoms＇ arranged in a triangular lattice. Simulation results show that double absolute photonic band gaps exist in this structure. Our experimental results show that holographic lithography can be used to fabricate photonic crystals not only with various lattice structures but also with various kinds of structures of the atoms, to obtain absolute band gaps or a particular band gap structure. Furthermore, the single-exposure holographic method not only makes the fabrication process simple and convenient but also makes the structures of the atoms more perfect.     

Fabrication of semiconductor-and polymer-based photonic crystals using nanoimprint lithography

The technology of fabricating photonic crystals with the use of nanoimprint lithography is described. One-and two-dimensional photonic crystals are produced by direct extrusion of polymethyl methacrylate by Si moulds obtained via interference lithography and reactive ion etching. The period of 2D photonic crystals, which present a square array of holes, ranges from 270 to 700 nm; the aperture diameter amounts to the half-period of the structure. The holes are round-shaped with even edges. One-dimensional GaAs-based photonic crystals are fabricated by reactive ion etching of GaAs to a depth of 1 μm through a mask formed using nanoimprint lithography. The resulting crystals have a period of 800 nm, a ridge width of 200 nm, and smooth nearly vertical side walls.     

Photonic band gaps based on tetragonal lattices of slanted pores

We describe broad new classes of three-dimensional (3D) structures which, when made of silicon, exhibit robust 3D photonic band gaps of up to 25% of the gap center frequency. The proposed photonic crystals are readily amenable to very high precision microfabrication using established techniques such as x-ray lithography and template inversion. Each architecture consists of a set of oriented cylindrical pores emanating from a two-dimensional (2D) square lattice mask with a two-point basis. Large bandwidth, microcircuits for light may be incorporated within the resulting photonic band gaps using an intercalated 2D photonic crystal layer.     

Compact photonic delay line constructed by holographic optical elements

To fully support phased-array antenna and other applications, a 3-range (long time, moderate time, and short time) delay line structures with holographic optical elements is proposed. Flexibility, light-weight, on-axis coupling, easy alignment, easy fabrication, and compactness are their advantages. When use holographic optical elements to build the photonic delay line system, all of the delay and non-delay paths in these three photonic delay lines are setting in a compact structure. They do not need any extra components, such as mirrors and optical paths in free space, and can bear stronger vibration. Therefore, the holographic optical elements are more suitable to design the photonic delay lines. In these three structures, their losses and crosstalk s are balanced. All of delay and non-delay cases in these three delay line structures, their crosstalk, signal-to-noise ratio, and loss are 1/81,000, 59.1 dB, and 3.2 dB, respectively. Finally, to support complete applications, a polarization independent photonic delay line system with holographic optical elements is proposed, too.     

Two modes of laser lithography fabrication of three-dimensional submicrometer structures

The modes of laser lithography fabrication of three-dimensional submicrometer structures have been studied. The method is based on the effect of threshold two-photon polymerization of a photosensitive material at the laser beam focus. To determine the lithograph workspace in the coordinates “laser power-speed of the sample displacement with respect to the laser focus,” a series of photonic crystals with the woodpile structure is prepared. Two methods for fabricating three-dimensional structures, i.e., raster scanning and vector graphics (or the vector method) are analyzed in detail. The advantages of the vector method for fabricating periodic structures are demonstrated using crystals of inverted yablonovite as an example. The prepared samples are studied by scanning electron microscopy.     

Three-color photonic crystal demultiplexer based on ultralow-refractive-index metamaterial technology

We numerically demonstrate the operation of a novel class of wavelength-division demultiplexing circuit based on photonic crystal waveguides that are entirely synthesized by ultralow-refractive-index metallic nanopillars. The operational principle of the newly proposed device is based on the phenomenon of total external reflections in ultralow-refractive-index metallic photonic crystal structures (metamaterials). In addition we provide detailed design guidelines for optimum device performance. The low propagation losses and compact size, as well as temperature-insensitive operation over a wide temperature range, are only a few of the advantages of the proposed technology, making this new type of demultiplexer an excellent candidate for applications in the visible spectrum.