基于SU8的远红外超材料完美吸收器理论研究（英文）

设计了一种基于SU8介质材料的工作波段为20-30微米范围内的的多层超材料吸收器.该吸收器由金属颗粒周期阵列、介质间隔层和金属底层组成.利用LC模型和FDTD数值模拟方法,通过对SU8介质层厚度、金属颗粒阵列周期、金属颗粒尺寸等参数的优化,实现了对20-30微米波段范围内入射波的接近100%的完美吸收.并在上述研究基础上进一步设计了具有双层谐振腔的双模完美吸收器.通过数值模拟发现,由于SU8介质间隔层厚度的增加,上下两个谐振吸收器可以分别独立实现对特定波长的完美吸收.相应的特征共振吸收波长符合LC模型的预测.同时,数值模拟结果进一步证实了共振吸收频率与入射角度无关.该完美吸收机制可以归因于入射光在金属底层-SU8介质层-金属颗粒层所组成的谐振腔内多次反射吸收.     

基于纳米压印的超材料近红外吸收器的制备研究

超材料吸收器的高吸收率源于表面金属颗粒与介质层之间产生的局域等离激元共振以及由金属颗粒--介质层--金属反射层构成的微腔所导致的共振吸收。其吸收特性与金属颗粒的尺寸、形貌和介质层的材料和厚度密切相关。设计优化了一个在近红外波段1.2 μm处具有近完美吸收的超材料吸收器。以该设计为蓝图,利用纳米压印技术制备了一系列具有不同介质层厚度的器件,并利用红外反射谱定量研究了这些器件的吸收特性。实验结果证实,用纳米压印技术制备的超材料器件具有工艺可靠性好、加工精度高等优点。实验测得的吸收率变化趋势与理论预期相符,吸收率较高。     

数值研究一种基于腔共振和电共振的近红外双频段超材料吸收器

设计, 数值模拟和讨论了一种具有两个宽带和扁平的吸收带的超材料吸收器, 其中一个是腔共振吸收带, 另一个是电共振吸收带.电共振的吸收带由于空腔尺寸(d)或者介质层厚度(H)的增加而蓝移, 而腔共振吸收带则表现出红移的现象.同时, 电共振和腔共振吸收带可以通过优化吸收器的结构设计耦合为一个吸收带.最后, 数值模拟研究了入射角度的改变对电共振和腔共振吸收带的影响.利用不同波段的共振模式形成不同吸收带的方式提供了将双吸收带调制为单吸收带的可能性.     

数值研究一种基于腔共振和电共振的近红外双频段超材料吸收器（英文）

设计,数值模拟和讨论了一种具有两个宽带和扁平的吸收带的超材料吸收器,其中一个是腔共振吸收带,另一个是电共振吸收带.电共振的吸收带由于空腔尺寸(d)或者介质层厚度(H)的增加而蓝移,而腔共振吸收带则表现出红移的现象.同时,电共振和腔共振吸收带可以通过优化吸收器的结构设计耦合为一个吸收带.最后,数值模拟研究了入射角度的改变对电共振和腔共振吸收带的影响.利用不同波段的共振模式形成不同吸收带的方式提供了将双吸收带调制为单吸收带的可能性.     

基于等离子体共振1～10μm波段内可调节的双波段 超吸收研究

亚波长人工超构材料可以实现特定波长的近完美吸收,在红外光电器件应用中能够克服传统红外材料吸收效率低、厚度较大、工作波长受限于带隙等缺陷.本文利用金属/介质/金属结构构造了一种可大面积制备的亚波长结构,可以实现1-10μm波段内的双波段红外超吸收.通过时域有限差分法模拟和实验分析,我们认为该吸收器高频的吸收峰,主要来源F-P共振干涉增强吸收;而低频红外波段的吸收峰,主要得益于电偶极共振和磁共振模式的激发.利用退火工艺调节上层金颗粒的大小,可以有效地调节两个吸收峰的位置.     

铝基平面超构材料可见-近红外光超吸收研究

增强可见-近红外光吸收在光电信号转换、探测、通信及传感等众多领域具有重要应用潜力。本文基于吉尔-图诺伊斯谐振腔(Gires-Tournois resonator)共振吸收原理,利用Al/Al_2O_3/Al三层膜结构制备了可见到近红外波段全铝基平面薄膜堆栈型超构吸收器。通过合适的参数优化选取,实现了吸收峰位连续可调。吸收峰值接近100%,变角度反射光谱显示器件对入射角度不敏感,理论数值模拟计算结果与实验结果相互吻合。完美吸收峰在500 nm附近的吸收器在532 nm激光照射下快速升温,最高温度可达55.4℃,表明该结构在光热转化领域的潜在应用。     

基于哑铃型光栅宽带吸收器的优化设计

本文基于哑铃型光栅设计了基底/金膜/二氧化硅 /石墨烯/光栅五层结构近红外宽带吸收器。采用时 域有限差分法(FDTD)数值模拟了不同结构参数下吸收光谱带宽的变化规律,优化了结构设 计。结果证明,吸收器在近红外波段呈现完美吸收特性,且当二氧化硅层厚度为200 nm、哑铃型光栅函数取 0.2x²⁺0.07,厚 度为300 nm,周期在0.89 μm范围内,吸收谱带宽最大可达300 nm;同时在缓冲层 与光栅之间引入单层石墨烯可以明显增大吸收率。本结构吸收器在医药安全、宽带通信和隐 身技术等领域具有许多潜在的应用价值。     

超宽带太阳能电磁吸收器优化设计研究

基于不同材料和尺寸的三光栅级联顶层结构设计 了一种太阳能超宽带吸收器。采用时域有限差分法FDTD数值 模拟了铬膜厚度、缓冲层折射率和厚度、吸收器单元周期及三光栅宽度比和高度比等结构设 计参数对共振吸收光谱带宽 和吸收率的影响规律。同时借助选取波长下的电磁场分布规律、结合局域表面等离子体共振 探究了宽光谱、高吸收率产 生的物理机制。仿真结果表明,材料和结构参数不同的三个单光栅级联可明显拓宽入射光的 吸收光谱带宽;优化吸收器 结构设计参数后,获得了横跨部分紫外光、全部可见光和部分红外波段的宽频带,高达2.2 μm的吸收谱宽,近1μm红外频 段的吸收率可达完美吸收;并且吸收器在较宽的入射角范围内依然能保持良好的吸收性能和 极化的敏感特性。本文所设 计的吸收器结构简单,尺寸小,易与芯片集成,可在光伏发电、太阳能热处理和光探测等方 面均具有潜在的应用前景。     

基于超材料的多频带可调谐太赫兹吸收器

设计了一种多频带可调谐的太赫兹超材料吸收器。在超材料吸收器的结构中,引入光敏半导体硅材料,设计特殊的顶层金属谐振器,分析开口长度、线宽、介质层厚度等参数尺寸对太赫兹超材料吸收器的吸收光谱特性影响。根据光照与光敏半导体硅电导率之间的关系,研究太赫兹超材料吸收器的频率调谐特性。仿真结果得到太赫兹波段的12个吸收频率调制,其中有10处吸收峰的吸收率超过90%近完美吸收,且有6处吸收率达到99%的完美吸收,而且吸收率调制深度和相对带宽分别达到85.9 %和85.5%,具有很强的可调谐特性。设计的光激励太赫兹超材料吸收器结构简单,具有多频带可调谐和完美吸收特性,扩大了吸收器的应用范围。     

1维石墨烯光子晶体的电磁吸收特性

为了研究1维石墨烯光子晶体在可见光波段的吸收特性,采用传输矩阵的方法进行了理论分析和数值仿真,得到了1维石墨烯吸收特性与石墨烯层数、缺陷层介质厚度、电磁波模式有关的结果。结果表明,增加石墨烯层数时,对波长为556nm左右的绿光的吸收作用明显增强;缺陷层介质厚度增加时会引起吸收峰的增加;在TE模式下,入射角对石墨烯光子晶体吸收特性影响较小。该研究结果为1维石墨烯光子晶体吸收器的设计提供了理论依据。     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-