复合纳米光学变色薄膜

用热蒸发和磁控溅射的物理镀膜方法和溶胶-凝胶化学涂布的方法相结合制备了有机和无机复合纳米光学变色薄膜。光学变色薄膜为多层薄膜,当有自然光进入光学变色薄膜时,随着入射光和视角的变化在薄膜上可以看到明显的光变色效果。这种薄膜可以单独或与油墨组合作为一种新颖的防伪材料。根据多层复合膜光干涉原理经设计和计算确定薄膜为PET／Cr／介质／Al膜系结构。介质分别是有机高聚物和SiO2。SiO2是多孔纳米材料,用溶胶-凝胶方法制备,通过调节催化和凝胶的方式和条件,折射率在1.15～1．45之间。介绍了制作方法和薄膜特性。     

共轭读出法消除光致变色材料全息记录中的相位畸变

采用有机光致变色材料-吲哚俘精酰胺/PMMA薄膜作为可擦写全息记录介质,建立了一种能消除全息光存储中相位畸变的光路.此光路采用参考光的相位共轭光再现全息图,能有效消除物光路中由于光学元件失调和记录材料缺陷引起的相位畸变,是全息光存储中提高再现像像质的一种有用光路.     

基底微缺陷对介质薄膜光学性能影响的理论研究

基于非均匀膜理论提出一种存在微缺陷的介质基底的折射率分层模型，将基底依次分为表面层、亚表面层和体材料层，其中表面层和亚面层分别等效为折射率服从统计分布的非均匀膜，将它们分别再次细分为N₁和N₂个子层，每一子层均视为均匀介质 膜.应用光学薄膜特征矩阵法对其进行理论分析，并对单层介质膜的光学性能进行数值计算. 研究结果表明：基底的表面和亚表面微缺陷改变了薄膜和基底的等效折射率，导致了准Brew ster角和组合反射率与理想情形的偏离.同时这些微缺陷也改变了光在薄膜和基底中的传播 特性，因此反射相移和相位差均偏离理想情形.在研究基底的微缺陷对多层介质膜光学性能 影响的分析和计算时，该模型同样适用. 关键词： 微缺陷 介质薄膜 非均匀膜 光学性能     

基于Ⅲ-Ⅴ与Ⅱ-Ⅵ族半导体材料色散特性的高灵敏度慢光干涉仪

分析了Ⅲ-Ⅴ与Ⅱ-Ⅵ族半导体材料的光学特性,证明半导体慢光介质不但可以提高干涉仪的光谱灵敏度,而且可以获得远大于气体慢光介质的工作光谱范围.实验证明,基于慢光介质GaAs的干涉仪光谱灵敏度相对于传统的干涉仪提高约3.2倍. 关键词： 干涉仪 非线性光学 Ⅲ-Ⅴ与Ⅱ-Ⅵ族半导体材料     

航天用热致变色材料低太阳吸收率研究

La_0.7Ca_0.2Sr_0.1MnO₃热致变色材料是一种发射率随温度变化的热控功能材料,不足的是这种材料的太阳吸收率过大。针对此问题,本文从多层薄膜理论和最优化理论出发,获得了基于多层薄膜的低太阳吸收率热致变色材料。根据计算得到的膜系结构参数,采用电子束蒸发法在热致变色材料表面沉积了多层薄膜,并对设计计算与实验测试结果进行研究和分析。研究表明:多层薄膜结构的设计能将热致变色材料的太阳吸收率从0.78降低至0.27,提高了热致变色材料的实用性。     

GaN晶体在飞秒紫外波段激发下的可变非线性吸收效应和光动力学过程研究

采用Z扫描和泵浦-探测技术研究了GaN薄膜在370 nm时的非线性光学效应和非线性光动力学过程。首先,基于GaN薄膜的透射光谱,结合线性光学理论分析得到了其在370 nm的线性折射率n₀、线性吸收系数α₀、光学带隙E_g等线性光学性质。采用飞秒激光Z扫描技术,得到了不同光强激发下的Z扫描实验响应结果,结合非线性光学理论提取出GaN薄膜可变的光学非线性吸收效应。在激发光子能量接近GaN带隙情况下,低光强时材料表现为饱和吸收而高光强时为反饱和吸收,这是因为低光强下单光子吸收占主导而高光强下以单光子感应自由载流子吸收为主。闭孔Z扫描测量得到了GaN薄膜的三阶非线性折射系数为n₂=-(1.0±0.1)×10-3 cm2·GW-1,它几乎比传统非线性介质的高出一个数量级。为了探究上述非线性过程的动力学弛豫时间以及进一步探究GaN薄膜非线性光动力学过程的深层物理机制,采用了交叉偏振飞秒退相泵浦探测技术观察GaN薄膜的光激发载流子动力学弛豫过程。实验结果表明,在低光强下,饱和吸收效应来源于瞬态单光子吸收,高光强下单光子感应自由载流子吸收为非瞬态光动力学过程,其自由载流子弛豫时间约为17 ps。该工作将为GaN薄膜在紫外非线性纳米器件应用以及GaN薄膜非线性过程的机制分析理解提供新的思路。     

基于相变材料的慢光和吸收可切换多功能太赫兹超材料

基于相变材料Ge₂Sb₂Te₅(GST)设计了一种太赫兹超材料,在太赫兹波段实现了慢光和吸收功能的切换.该超材料由三部分构成,分别是金环构成的微结构层、SiO₂介质层和GST薄膜.研究结果表明:当GST薄膜处于绝缘态时,由于两个谐振环的电磁诱导透明效应,入射THz光脉冲通过该THz超材料时群速度会减慢,最大群延迟可以达到3.6 ps;当GST薄膜转变为金属态时, THz超材料可实现双波段吸收,在0.365 THz处吸收率可以达到97%,在0.609 THz处吸收率可以实现完美吸收(吸收率100%).另外还研究了该THz超材料的入射光偏振不敏感特性,发现当入射光脉冲的偏振角从0°变化到90°时, THz超材料的慢光和吸收特性不受影响.所设计的THz超材料在光缓存器、光传感器、光开关等领域具有潜在的应用价值.     

全固态塑料电致变色器件

电致变色器件是一种典型的光学薄膜和电子学薄膜相结合的光电子薄膜器件,能够在外加低压驱动的作用下实现可逆的色彩变化。将电致变色材料制备在塑料衬底上,将极大地推动电致变色器件的应用。讨论了全固态塑料电致变色器件的制备工艺和电致变色特性,通过采用低压反应离子镀工艺分别在ITO塑料衬底上制备了WO3和NiO电致变色薄膜。采用高分子聚合物MPEO-LiClO4作电解质,制备plastic/ITO/WO3/MPEO-LiClO4/NiO/ITO/plastic透射型全固态塑料电致变色器件。在二电极电池石英盒中采用恒电位方式测试全固态塑料电致变色器件的电致变色特性,驱动电压为±3V。采用分光光度计直接测试透射光谱的变化,测试范围为300～900nm,经过十几次循环后达到稳定的变色,变色调制范围达到30%左右,器件样品显示出均匀深蓝色的电致变色效果。实验结果证明了所提出的全固态塑料电致变色器件的制备工艺的可行性。     

热致变色材料辐射和光学特性研究

采用固相反应法制备了相变温度接近室温的热致变色材料,研究了不同掺杂元素和掺杂浓度对热致变色材料辐射和光学特性的影响,并利用K-K分析模型导出了热致变色材料的光学常数。结果表明:热致变色材料LCSMO和LSMO(x=0.175)的发射率在相变温度附近出现剧烈变化,并且光常数在很大的频域范围内可自主调制。     

基于VO2@SiO2核壳纳米粒子的热致变色薄膜

为解决VO_2热致变色薄膜可见光透射率低、耐候性差以及热分解法制备VO_2纳米颗粒易团聚等问题,提出了一种基于VO_2@SiO_2核壳纳米粒子的热致变色薄膜。首先利用VO(OH)_2表面负电荷和γ-氨丙基三乙氧基硅烷中氨基正电荷间的静电相互作用,在前驱体VO(OH)_2表面进行SiO_2包覆得到VO(OH)_2@SiO_2核壳纳米粒子,然后在Ar气氛下对其进行高温热处理得到VO_2@SiO_2核壳纳米粒子,将其分散至树脂中并涂覆在玻璃基材上得到热致变色薄膜,并对热致变色薄膜的热致变色性能及核壳粒子的耐候性进行了研究。从透射电镜照片可以看出SiO_2壳层可以阻止前驱体VO(OH)_2在热分解过程中的团聚长大,对光学性能的研究表明低折射率的SiO_2和空气能够提高热致变色薄膜的光学性能,并且当VO(OH)_2@SiO_2纳米粒子的质量分数为10wt%时复合薄膜的光学性能最佳。SiO_2壳层对VO_2的保护作用可以有效提高其抗氧化性,并且可以提升纳米颗粒在酸性环境下的耐腐蚀性,延长热致变色薄膜的使用寿命。     

掺杂非醚聚苯基喹噁啉薄膜电致发光的研究

聚合物薄膜电致发光(PTFEL)器件的主要特点是制造方便、设备简单、成本低廉并且可以通过改变材料体系、掺杂或调节工作电压来改变发光颜色.目前蓝色发光已达到相当的程度[1,2],即彩色化的前景比无机材料的要光明得多[3].     

Semicylindrical acoustic transducer from a dielectric elastomer film with compliant electrodes

A semicylindrical acoustic transducer was constructed using a dielectric elastomer film with compliant electrodes that is an electroactive polymer composed of a polyurethane elastomer base and polyethylene dioxythiophene/polystyrene sulfonate electrodes. The use of this dielectric elastomer is advantageous because polyurethane is a common material that keeps its shape without any rigid frame. Because the dielectric elastomer films are essentially incompressible, electric-field-induced thickness changes are usually translated into much larger changes of the film area and side length. Here it is proposed that this change in side length can be utilized for sound generation when the film is bent into a semicylindrical shape. Accordingly, a semicylindrical acoustic transducer was fabricated using a film of thickness of 300 μm and its acoustic characteristics were investigated. The transducer can be operated at low applied voltages by reducing the film thickness, as long as the film is thick enough to generate sufficient force to overcome sound radiation impedance. The second harmonic distortion of the transducer was also investigated as a function of the ratio of the direct current bias voltage to the alternating current audio signal amplitude.     

顶发射白光OLED微型显示器的蓝光掺杂特性研究

白光OLED微型显示器在信息显示领域具有重要的应用。采用真空镀膜系统,依次蒸镀Ag/ITO复合薄膜作为阳极结构,共蒸制备Mg∶Ag复合膜作为半透明阴极结构,NPB作为空穴传输材料和黄光主体材料,rubrene作为黄光掺杂料,AND作为蓝光主体料,DSA-Ph作为蓝光掺杂料,Alq3作为电子传输材料,以结构和工艺简化的蓝、黄光互补色来实现白光,通过共蒸发形式制备了结构为Ag/ITO/NPB/NPB∶rubrene（1.5%）/ADN∶DSA-Ph（x%/x=2,5,8）/Alq3/Mg∶Ag的白光OLED微型显示器,利用由Photo Research PR655光谱仪、Keithley 2400程控电源组成的光谱测试系统对器件的光电性能进行表征,研究了蓝光掺杂比对白光OLED微型显器性能的影响。结果表明,随着蓝光掺杂比的增加,白光OLED微型显示器的亮度先增加后降低,蓝光、黄光峰位有所偏移,色坐标发生一定的漂移,蓝光色纯度增加,可通过调控发光材料掺杂比实现白光OLED微型显示器性能的可控制备。初步优化获得的蓝、黄混合白光OLED微型显示器的器件,当驱动电压为5.0 V时,器件亮度达到3 679 cd·m-2,CIE坐标为（0.263,0.355）。     

Preparation and XPS study of X-ray photochromic transparent BiOI/nylon11 composite film

Nylon11 film immersed in BiI₃–ethanol solution was used for in situ generation of transparent BiOI/nylon11 X-ray photochromic composite materials via integration of the hydrolyzate (BiOI) of BiI₃ into nylon11. The obtained BiOI/nylon11 composite film shows a reversible photochromic effect, changing the color from orange-red to brownish black under soft X-ray irradiation and back to orange-red after air exposure. X-ray photoelectron spectroscopy (XPS) results show that the oxidation state of Bi atoms in BiOI/nylon11 composite film does not change before and after changing the color. Angle-resolved XPS analysis reveals that BiOI in nylon11 film is well distributed within an infiltration depth of about 10 nm. The source of the X-ray photochromic effect for transparent BiOI/nylon11 composite film may be related to oxygen as well as the interaction between BiOI and the amide groups. The oxygen AT% in the composite film decreases with increasing X-ray irradiation time. The present method for preparing transparent BiOI/nylon11 X-ray photochromic composite materials is facile and low cost. The X-ray photochromic effect has potential applications in some technology fields. For example, it can be used to create temporary patterning in a colored composite material surface.     

利用三色光栅实现彩色图像相减

本文提出了一种彩色图像相减的新方法.该方法利用互相错动半个周期的两组三色光栅,在黑白底片上分别对待处理的两幅图像进行一次编码记录,然后在白光处理器上对黑白编码片进行彩色译码,即可实现彩色图像的强度相减,文中讨论了三色光栅实时生成和两组三色光栅条纹自动错动半个周期的方法,并给出了实验结果。     

基于InP/ZnS核壳结构量子点的色转换层设计及制作

提出了采用环境友好型InP/ZnS核壳结构量子点材料制备匹配蓝光Micro-LED阵列的量子点色转换层以实现Micro-LED阵列器件全彩化的技术方案。通过采用倒置式量子点色转换层方案,实现了InP/ZnS量子点材料和Micro-LED阵列的非直接接触,从而可以缓解LED中热量聚集导致的量子点材料发光主波长偏移、半峰宽展宽以及发光效率衰减等问题。量子点色转换层中内嵌PDMS聚合物柔性膜层,可以消除咖啡环效应,同时,色转换层中内嵌飞秒激光图案化处理的500 nm长波通滤光膜层,可以抑制蓝光从非蓝色像素单元出射。最后,实验制备了像素单元中心间距90μm的16×16 InP/ZnS量子点色转换层。该设计可以实现基于蓝光Micro-LED阵列的全彩色Micro-LED显示器件的制备,并且该制备方法可以降低全彩色Micro-LED阵列显示器件的制备成本。     

Piezoelectricity in polymers

In the last few years it has been shown that polyvinylidene fluoride, a polymer which can.readily be formed into very thin, flexible, and transparent films, is a ferroelectric material. The availability of a ferroelectric material in this unusual form has led to a large number of possible new applications, and the Japanese company, Pioneer Electronic Corporation, has already developed a commercial product.¹ They are producing headphones in which the active element is an 8-pm-thick film of polyvinylidene fluoride. Indicative of the kind of creativity this new material permits, the headphones do not use the change in thickness of the film at all. The polymer film is stretched over a flexible polyurethane foam and application of a voltage causes a change in the area of the film so that the foam, functioning like a spring, is either compressed or allowed to expand, depending on the polarity of the applied voltage.     

Improving pattern precision of chromium based black matrix by annealing

Black matrix is a major component of color filter used for blocking light in flat panel industry. Films made of chromium (Cr) and its two oxide/nitride combination layers are commonly used in black matrix for its high optical density and material stability. Each single Cr based layer film of the three multilayer combinations was produced on glass and then annealed in low pressure hydrogen environment. Etching, transmittance of visible light, and microstructure of these films without and with annealing were compared. It was found that annealing can mend the interference between the incident and reflected light for Cr based black matrix. Annealing can also improve the undercut defect and thus pattern precision. The lateral etching rates of Cr based films were found to be much lower and close to one another after annealing. It can be explained the film density and adhesion increase caused by the annealing process. This article provides a potential method in color filter fabrication to improve contrast and color interference issues if Cr based black matrix is used in display application.     

Tuning the extraordinary optical transmission through subwavelength hole array by applying a magnetic field

The transmission of light through a thin Ag film with a periodic subwavelength hole array can be influenced by the presence of the externally applied magnetic field H. Using a three-dimensional finite element method, we show that the spectral locations of the transmission peak resonances can be shifted by varying the magnitude and direction of the H. The transmission peaks have blueshift, and the higher the magnitude of H the larger the blueshift. The shift is due to the change of cavity resonance condition as a result of the magneto-induced anisotropy in the optical properties of the Ag film. Hence, high transmittance for any desired wavelength can be achieved by applying an appropriate H to the metallic film of optimized material and hole parameters.     

新型胶片影像判读仪的应用研究

针对狭缝摄影胶片参数测量和处理的自动化低,人为因素多,提出一种新型胶片影像判读仪。通过将光源照射到待扫描的材料上完成图像的获取,光源照射到CCD上实现光电转换。对胶片图像进行数字化处理,利用软件进行图像处理。结果表明,应用该判读仪实现了大幅面（830 mm190 mm）彩色胶片图像输入。平面结构和精密的传动系统保证了测量要求的全幅面小于0.1 mm的精度,提高了胶片判读的自动化程度和数据的精确测量及处理。