基于金属-介质-金属结构的反射式彩色滤光片特性研究

研究了金属-介质-金属结构在可见光波段的反射滤光特性。该结构由柔性透明基底、金属层、介质-金属纳米光栅结构组成。利用严格耦合波分析法(RCWA)模拟了TM偏振光入射时,亚波长介质-金属光栅的占宽比、周期和厚度等结构参数对反射光谱特性的影响。理论模拟结果表明:光栅的结构参数变化可改变反射波段,进而调节滤光颜色。在此基础上,进一步优化结构参数,得到了基于减色法的彩色滤光片结构,获得了青色、品红色和黄色三原色。该结构的主要优点是,当入射角在0～45范围内变化时,反射光谱谷值位置和反射带宽基本不变。本文所提出的结构特别适合用于反射式彩色显示。     

Comparison of resonances and spectral properties for microstructures incorporating singular layered metal dielectric subwavelength grating with different profiles

A multilayered structure incorporating a single metal-dielectric subwavelength grating is a structure with characteristic of polarization separation for visible light, enabling creating visible color aspect. Based on that, two specific structures separately with grating layers of rectangular and sinusoidal refractive index profiles are designed and their related resonant behaviors and spectral properties are compared respectively for s and p polarized incident lights. The impacts of structural parameters of the structures together with dielectric materials on their resonances and spectra in reflection are studied in detailed. Similarities of resonant behaviors, reflection spectra and variations in resonant locations and spectral profiles between both structures are also demonstrated for both polarizations, especially for s polarized light. Due to such similarities and convenience in fabrication, the structure with a sinusoidal grating can replace that with a rectangular grating in mass production for color-based various applications such as color security, image reproduction.     

嵌入式三色光变器设计

为解决目前亚波长二元矩形结构在光学防伪应用方面存在的防伪性能有待提升、制作困难导致性能劣化等问题,提出正弦结构等效矩形结构实现基于嵌入式亚波长一维单周期正弦结构的三色光变器.模拟仿真表明,亚波长正弦结构与原亚波长矩形结构性能相似,可获得优越的三色变换功能.当自然光以45°角入射时,可在方位角0°,58°,90°分别获得相应的蓝光、绿光、红光三色反射峰,反射率分别达到90%,89%,100%.分析并提出了该器件周期、槽深、膜厚以及入射角变化对反射峰的影响规律,探索了运用无掩模的双光束干涉曝光法制作母版的实验过程.提出的正弦结构三色光变器实现了方位角调节的高衍射效率自然光三色光变效果,突破了目前两色光变防伪的局限,同时降低了制作难度,可用通用的全息生产技术制作光栅结构,在光变图像防伪领域有重要应用.     

Optical control of longitudinal periodic structures near the boundary of a rarefied resonance medium

The state of a rarefied gas medium is described theoretically upon reflection of intense resonance light from its surface. Conditions are found under which a longitudinal grating of the excited state population arises in the near-wall region of the medium. A new method for controlling parameters of the arising structure by means of the light is proposed.     

Polarization and Color Separator Using Binary Phase Grating with Subwavelength Period

A data projector using three liquid crystal display panels has a complex optical system. The illuminating optics separate the beam from a light source into three primary colors and separate those into opposite polarizations using multi-layer films and prisms. A reflection grating with the period of subwavelength has high diffraction efficiency for p polarized light and high regularly reflectance for s polarized light. The diffraction angle of a grating largely depends on the wavelength, because a diffractive optical element (DOE) has large chromatic dispersion. The grating with the period of subwavelength can separate the unpolarized light into polarization components effectively using its polarization dependency and can separate white light into color components using its chromatic dispersion simultaneously. The grating makes the optical system simpler and smaller than those with conventional devices. In this paper the efficiency of polarization separation for the grating is calculated by a rigorous analytical method. Next, the condition for color separation is calculated by Snell#x0027;s law, and an optical system using a grating that performs polarization and color separation is proposed. Experimental results of the DOE fabricated are well matched with those of this simulation.     

埋入式光栅双通道特性及其应用研究

利用严格耦合波理论分析了埋入式光栅在45°入射时,垂直和平行于光栅栅线的两个不同观察平面的零级共振反射衍射特性.在垂直于光栅栅线的平面内,TE、TM偏振下零级反射共振波长分别为432 am和420 am,在平行于光栅栅线的平面内,TE、TM偏振下零级反射共振主峰波长分别为623 nm和620 nm,在两个平面内,零级共振衍射光的共振波长差别较大,观察到的衍射光颜色差别明显,定义为双通道特性并用实验进行证明,制作了相应的光变色器件.     

红绿共振互补光变亚波长微结构制作与分析

剖析了双层亚波长光栅微结构的设计及制作原理,提出了一种亚波长微结构设计与制作的新方法,其特点是以矩形亚波长光栅设计微结构,用全息干涉光刻及涂布的方法制作,却不影响设计微结构的共振及光变特性,还能改善反射光的颜色质量。用该方法设计及制作了具有“红绿”共振互补光变效果的亚波长防伪微结构,检验了其共振光变光谱与颜色变化特征。研究表明：制作的全息光栅微结构的共振及光变特征如共振光谱、颜色、光谱峰及峰分裂等与预先设计的相同;矩形亚波长光栅并不是共振的必要条件,其他面形光栅微结构的衍射特性和等效波导若与矩形光栅微结构的相同,则其相关特性相同;用新方法设计及制作亚波长光变微结构的工艺是可行的,既降低了设计微结构的加工难度,又便于用现有的全息生产设备批量生产。     

Design of an augmented reality display based on polarization grating

A new optical system for an augmented reality(AR) display is proposed in this paper.The optical system mainly includes a ray deflector, coupling input grating, optical waveguide, and coupling output grating.Both the ray deflector and the coupling input grating are designed based on the diffraction characteristics of the polarization grating, and the coupling output grating is the Bragg reflection grating.Compared with other AR schemes, this AR optical system not only reduces the number of projections from two to one, but also improves the efficiency of light coupling into the optical waveguides.The energy loss is reduced by utilizing the single-order diffraction characteristics of the polarization grating in its coupling input structure.The light deflector uses the polarization selectivity of the polarization grating and the characteristics of the rotating light of the twisted nematic liquid crystal layer to realize beam deflection.The working principle of the optical system is experimentally and theoretically demonstrated.     

Characteristics of a three-mirror interference system with a noninverted response function in reflected light

It is demonstrated that a reflection interferometer with optical properties of a three-mirror system in transmitted light can be created by including a phase grating in the structure of an input mirror. The response function is determined, a technique for the selection of parameters for the formation of spectral characteristics of the reflection coefficient is considered, and results of calculations are presented.     

金属光栅对表面等离子体波的辐射抑制研究

对金属光栅进行严格耦合波理论计算, 得到了780和1500 nm波长入射光条件下不同光栅调制深度(20-80 nm)对应的反射谱. 根据Fano理论推导了描述反射谱线的经验公式, 最后应用有限元法计算光栅表面近场电场分布, 验证了公式的正确性. 反射谱线公式反映出光栅耦合表面等离子体的各个物理效应, 其中最重要的是反映出光栅在某一调制深度下对表面等离子体反耦合的抑制作用, 这一发现为设计光栅能量约束器件提供了物理依据.     

基于亚波长二维光栅的入射角不敏感颜色滤光片研究

提出了一种基于二维亚波长光栅的具有非偏振光入射下入射角不敏感特性的反射式颜色滤光片. 采用严格耦合波分析方法详细分析了光栅周期、光栅层厚度以及固定光栅占空比下光栅的结构尺寸对反射率峰值、反射带位置及带宽的影响. 结合入射角不敏感特性, 经过优化设计得到了光栅的最终结构参数, 获得了中心波长424 nm, 峰值反射率56%, 带宽45 nm的反射滤光片.模拟结果表明, 在非偏振光入射下, 此滤光片的反射光谱表现出显著的入射角不敏感特性. 当入射角高达60°时反射带的中心波长偏移6 nm 反射率下降6%带宽增加8 nm 其参数没有较大变化通过调整光栅的结构参数可在400–520 nm范围内调节滤光片的中心波长以获得不同颜色的入射角不敏感滤光片. 关键词： 反射式滤光片 二维亚波长光栅 入射角不敏感 严格耦合波分析     

A novel plasmonic refractive index sensor based on gold/silicon complementary grating structure

A novel complementary grating structure is proposed for plasmonic refractive index sensing due to its strong resonance at near-infrared wavelength.The reflection spectra and the electric field distributions are obtained via the finite-difference time-domain method.Numerical simulation results show that multiple surface plasmon resonance modes can be excited in this novel structure.Subsequently,one of the resonance modes shows appreciable potential in refractive index sensing due to its wide range of action with the environment of the analyte.After optimizing the grating geometric variables of the structure,the designed structure shows the stable sensing performance with a high refractive index sensitivity of 1642 nm per refractive index unit(nm/RIU)and the figure of merit of 409 RIU^-1.The promising simulation results indicate that such a sensor has a broad application prospect in biochemistry.     

一维金属光栅的光学反射吸收

利用RCWA(rigid coupled-wave analysis)方法研究了一维金属光栅的反射特性,考察了 瑞利反常、表面等离激元驻波共振和几何共振三种共振吸收机理,分析了这三种机理的相互作用,如表面等离激元驻波共振和几何共振可以形成混合模式. 在反射式复合金属光栅中,确认了第四种共振形式,即相位共振. 数值计算表明相位共振对光学吸收的影响有两种形式: 当光栅周期大于一个波长时,相位共振导致尖锐的吸收峰,峰位在几何共振吸收峰一侧;当光栅周期小于一个波长时,相位共振导致混合模式的共振吸收峰发生劈裂. 对一维金属光栅反射特性的研究增加了对金属光栅共振吸收模式及其相互作用的认识. 关键词： 一维金属光栅 瑞利反常 表面等离激元 相位共振     

Analysis of restriction factors of widening diffraction bandwidth of multilayer dielectric grating

In order to design a multilayer dielectric grating with wide-bandwidth diffraction spectrum, the restriction factors of both the reflection bandwidth of multilayer dielectric high-reflectivity mirror and the guided-mode resonance phenomenon are studied in detail. The reflection characteristics of high-reflectivity mirror in zeroth and 1st transmitted diffraction orders are quantitatively evaluated. It is found that the reflection bandwidth of high-reflectivity mirror in 1st transmitted diffraction order, which determines the final diffraction bandwidth of multilayer dielectric grating, is evidently compressed. Furthermore, it is demonstrated that the reducing of grating period is an effective approach to the elimination of guided mode resonance over a required broad band range both spectrally and angularly. In addition, the expressions for calculating the maximum period ensuring no guided mode resonance in the required bandwidth are derived. Finally, two high-efficiency pulse-compression gratings with broad-band are presented.     

Numerical Study on Efficient Optical Switching Based on the Nonlinear Phenomenon in a Guided-Mode Resonant Grating with Kerr Medium

Optical switching in a guided-mode resonant grating (GMRG) with a Kerr medium was numerically simulated by the nonlinear finite differential time domain (FDTD) method. The asymmetric resonant grating was adopted to have two resonant reflection peaks for the pump light and the probe light. When the pump light had a wavelength which was slightly longer than the resonant wavelength, the light was suddenly enhanced at a certain intensity because of the nonlinear resonance phenomenon. This resonance is effective in reducing the pump intensity for optical switching. When we assumed the resonant grating of polydiacetylene toluene sulphonate (PTS) with a linear refractive index of 1.88, a third-order susceptibility of 8.5 × 10⊃−0 esu and Q factors of resonant reflection which were ∼800, the pump light of 15 kW/mm⊃ changed transmittance of the probe light from 0 to 80%. 2005 The Optical Society of Japan     

基于金属狭缝阵列的各向异性偏振分束器

在金属-电介质结构的基础上提出了一种基于金属狭缝阵列的各向异性偏振分束器,并采用有限元法研究了横磁(TM)和横电(TE)偏振光入射后结构所表现出的负反射和镜面反射等特性.计算结果表明,当偏振光的入射角设定在20?—70?时,入射的TM光发生强烈的负反射,而TE光的负反射很弱,并随着波长的增加而急剧下降.分析可得偏振分束光栅的理想负反射点和反射面的完美对称响应效果.通过仿真得到了理想负反射点的取值范围.结合严格耦合波法软件,计算不同偏振光入射时负反射和镜面反射条件下的反射率,其消光比高达10~6.     

表面覆膜波导光栅共振光谱特性及传感机理分析

基于波导光栅共振原理和古斯-汉欣(Goos-Hänchen)位移理论,提出一种表面覆膜波导光栅传感结构,并研究其共振光谱特性。通过在光栅表面涂覆低折射率聚合物功能膜层优化其共振光谱特性,选用多孔硅作为待测物承载单元,可以使光学探针更充分地接触待测样本,从而提高其检测性能。根据波导光栅共振相位条件,建立了共振波长和样本折射率之间的数学模型,通过检测共振位置的改变进而对样本浓度进行检测。研究表明,该表面覆膜波导光栅传感结构具有线型对称和窄线宽的共振光谱特性,可实现高品质因数(Q值)和高灵敏度的传感特性,其Q值为1 488,对折射率的检测极限可达5×10-4 RIU(RIU为折射率单位)。通过检测不同浓度的葡萄糖溶液对其传感特性进行验证分析,结果表明,共振波长与葡萄糖溶液浓度之间具有良好的线性关系,对葡萄糖溶液的检测灵敏度为1.12nm/1%,证明了该表面覆膜波导光栅传感结构的有效性,可以用于对低浓度样本溶液的实时动态监测,并为波长调制型光学折射率传感器的研究提供理论指导。     

光栅光阀器件的结构改进与制作工艺研究

根据光栅光阀的工作原理,在结构上对传统的光栅光阀器件进行了改进,分析了改进后光栅光阀器件的光学特性、结构特性,以及制作工艺流程.改进后的光栅光阀结构中硅基底上设有二氧化硅隔离层,隔离层上沉积无定形硅作为牺牲层,可动梁的材料是氮化硅,固定梁为蒸镀的金属铝层.通过离子刻蚀的方法刻蚀图形,用化学腐蚀方法掏空牺牲层得到所需桥梁状结构.研究表明改进后的器件黑区范围小,驱动电压较低,光学效率较高,具有潜在的应用前景.     

An application of Pb(Zr,Ti)O3 Ceramic to opto-electronic devices

A lead-zirconate-titanate ceramic is used in an electrically controllable diffraction (ECD) grating for reflection of parallel polarized light. The ECD grating used consists of a PZT ceramic with ten pairs of interdigital electrodes having 400 μm period on its surface. The characteristics of the grating and its application to an optical modulator are demonstrated experimentllly with a He−Ne 0.63 μm laser, obtaining a modulation of 60% with the applied peak voltage of 60 V at 24 kHz signal for the incident angle of 60°.     

光栅光阀器件的结构改进与制作工艺研究

根据光栅光阀的工作原理,在结构上对传统的光栅光阀器件进行了改进,分析了改进后光栅光阀器件的光学特性、结构特性,以及制作工艺流程.改进后的光栅光阀结构中硅基底上设有二氧化硅隔离层,隔离层上沉积无定形硅作为牺牲层,可动梁的材料是氮化硅,固定梁为蒸镀的金属铝层.通过离子刻蚀的方法刻蚀图形,用化学腐蚀方法掏空牺牲层得到所需桥梁状结构.研究表明改进后的器件黑区范围小,驱动电压较低,光学效率较高,具有潜在的应用前景.