等离子体光学的研究现状与发展前景

等离子体介质由于具有极高的储能密度、无光致损伤阈值和丰富的光学特性,利用它改善光束输出性能是发展高功率激光技术的一条重要技术路线。系统介绍了近年来等离子体光学的研究现状,并论述了今后等离子体光学的发展趋势。

突破衍射极限的表面等离子体激元

表面等离子体激元是外部电磁场诱导金属表面自由电子的集体共振,产生沿金属-介质界面传输的表面波,具有亚波长局域、近场增强和新颖的色散特性,在纳米光子学中发挥着重要的角色。利用表面等离子体激元构成的光学器件能够突破衍射极限,实现微电子与光子在同一个芯片上的集成。系统介绍了表面等离子体激元的基本原理,及其在光波导、探测器、调制器和太阳能电池等方面的重要应用。

用银壳层调节单分散金纳米棒的局域表面等离子体共振光学性能

为将单分散金纳米棒的纵向局域表面等离子体共振(LSPR)波长从近红外光区调节到可见光区,通过表面原位还原反应合成了以银为壳层的单分散双金属核壳复合纳米棒(Au@AgNRs),其Ag壳层厚度可由Ag NO3的用量进行调节。用高分辨透射电镜和X射线能量色散谱仪确证了Au@AgNRs的形态结构、单分散性和化学组成。随着Ag壳层厚度的增加,Au@AgNRs的LSPR效应逐渐增强,纵向LSPR吸收峰由近红外光区蓝移到可见光区。Ag壳层厚度每增加1 nm,Au@AgNRs的纵向LSPR波长减小约12 nm。制得的Au@AgNRs在可视化传感器上有良好的应用前景。

光学厚柱对称等离子体的有限元分析

在实验和生产中,人们经常遇到光学厚柱对称等离子体.从实际测得的辐射情况可了解到等离子体的内部辐射性质.在光学厚柱对称条件下,有Able方程:

表面等离子体亚波长光学原理和新颖效应

表面等离子体是沿着导体表面传播的波,当改变金属表面结构时,表面等离子体激元(surface plasmon polaritons,SPPs)的性质、色散关系、激发模式、耦合效应等都将产生重大的变化.通过SPPs与光场之间相互作用,能够实现对光传播的主动操控.表面等离子体光子学(plasmonics)已成为一门新兴的学科,它的原理、新颖效应以及机制的探究,都极大地吸引研究者们的兴趣.SPPs具有广阔的应用前景,例如,应用于制作各种SPPs元器件和回路,制作纳米波导、表面等离子体光子芯片、耦合器、调制器和开关,应用于亚波长光学数据存储、新型光源、突破衍射极限的超分辨成像、SPPs纳米光刻蚀术、以及生物光学(作为传感器和探测器).文章介绍了表面等离子体光子学原理、新颖效应和物理机制,并简述若干应用.

基于表面等离子体效应的光开关研究现状和进展

目前表面等离子体(surface plasmons,SPs)效应在光传感、光存储及生物光子学等领域的应用前景受到了广泛关注,通过计算模拟或实验基于SPs效应的光开关也层出不穷.文章较为系统地介绍了各种基于SPs效应的光开关原理和优缺点,对SPs全光开关做了重点介绍.

新兴的表面等离子体光子学——在纳米尺度上实现光子学与电子学完美联姻

众所周知，电子回路提供了控制电子输运和储存能力。但是，利用电路进行数字信息保真传送时，面临着相当大的限制，而光子学给出了一个解决难题的有效途径，构筑基于光纤和光子回路的光通信系统，便是一个很好的方案。不幸的是，光子元件的尺寸是微米量级，而电子元件和回路尺寸要小的多（纳米量级），因此，不可能将它们二者集成一体于纳米尺度的芯片中。表面等离子体光子学的诞生，使基于表面等离子体激元的元件和回路，具有纳米尺度，从而可实现光子与电子元器件，在纳米尺度上完美的联姻。本文简单介绍表面等离子体光子学的原理，目前现状，各种应用，例如等离子体激元芯片，新型光源，纳米尺度光刘蚀术，突破衍射极限的高分辨率成像等，以及面临的挑战和未来前景。

空气动力学发展中值得关注的一些问题

本文阐述了空气动力学研究的特点；分析了21世纪初空气动力学面临的形势，提出了空气动力学发展中值得关注的一些问题，包括新流型的研究与先进气动布局、流动控制与增升减阻、流动的逢适应控制与智能化空气动力学、低雷诺数流动与微流体力学、等离子体减阻技术、等离子体隐身与电空气动力学、机载激光武器的发展与气动光学等。

ICP-AES法同时测定土壤、水系沉积物中多种元素

用全谱直读等离子体光学发射光谱法测定土壤、水系沉积物中Be、Ce、Cu、Li、Pb、Sc、Sr、Zn的含量,优选了仪器条件,方法简单、快速、灵敏度高,其检出限(μg/g)分别为0.005、0.5、0.5、0.05、0.6、0.02、0.5、0.02。已成功地应用于土壤、水系沉积物样品的测试,获得满意的结果。

新型芯片的潮头正在涌起

等离子体波在金属表面的传输距离已经得到了显著提高,这一进展可能导致与目前电子微芯片控制电子的方式相类似的控制光的新型芯片。本文综合了等离子体光学领域的多篇文章,简要介绍了这一崭新技术及其进展。

工作气压对管内壁沉积Si/O-DLC薄膜结构与性能的影响

目的探讨工作气压对管内等离子体放电光学现象以及Si/O-DLC(Si and O Incorporated DLC,Si/O-DLC)薄膜结构与性能的影响,为获得管内高质量、均匀的Si/O-DLC薄膜制备工艺技术提供指导。方法利用空心阴极等离子体增强化学气相沉积(Hollow Cathode Plasma Enhanced Chemical Vapor Deposition,HC-PECVD)技术,通过改变工作气压在管内沉积Si/O-DLC薄膜。利用高速摄像机记录并对比不同工作气压下管内等离子体放电光学现象。通过SPM、XPS和Raman光谱仪表征不同工作气压下薄膜的三维立体表面形貌和微观结构,并利用SEM、纳米压痕仪以及划痕测试系统,对比研究管内Si/O-DLC薄膜的硬度、弹性模量、膜基结合力以及沿管轴向的薄膜厚度分布。结果随着工作气压的上升,管径向中心处亮斑面积和光强先增大增强后趋于缩小暗淡。在不同工作气压下,均能够在管内获得表面光滑的Si/O-DLC薄膜,粗糙度为3~10 nm。随着工作气压的上升,管内Si/O-DLC薄膜的平均厚度从1.42μm增大到2.06μm,且沿管轴向的薄膜厚度分布均匀度从24%显著提高到65%;不同工作气压下管内Si/O-DLC薄膜沿管轴向平均硬度呈先增大后减小的趋势,总体平均硬度可达(14±1)GPa。管内Si/O-DLC薄膜在工作气压上升到25 mTorr时获得较高的平均膜基结合力。结论改变工作气压能够显著影响管内壁Si/O-DLC薄膜的结构与性能,当工作气压为25 m Torr时,在管内获得均匀性最优、结合力较高的Si/O-DLC薄膜。

Plasmonic Field Enhancement for Vibration Spectroscopy at Metal/Water Interfaces

Electrochemical （EC） reactions play vital roles in many disciplines, and its molecular-level understanding is highly desired, in particular under reactions. The vibration spectroscopy is a powerful in situ technique for chemical analysis, yet its application to EC reactions is hindered by the strong attenuation of infrared （IR） light in both electrodes and electrolytes. Here we demonstrate that by incorporating appropriate sub-wavelength plasmonic structures at the metal electrode, the IR field at the EC interface can be greatly enhanced via the excitation of surface plasmon. This scheme facilitates in situ vibrational spectroscopic studies, especially using the surface-specific sum-frequency generation technique.

A comparison among optical emission spectroscopic methods of determining electron temperature in low pressure argon plasmas

In this article, four kinds of optical emission spectroscopic methods of determining electron temperature are used to investigate the relationship between electron temperature and pressure in the cylindrical plasmas of dc glow discharges at low pressures in laboratory by measuring the relative intensities of ArI lines at various pressures. These methods are developed respectively on the basis of the Fermi-Dirac model, corona model, and two kinds of electron collision cross section models according to the kinetic analysis. Their theoretical bases and the conditions to which they are applicable are reviewed, and their calculation results and fitting errors are compared with each other. The investigation has indicated that the electron temperatures obtained by the four methods become consistent with each other when the pressure increases in the low pressure argon plasmas.

Inorganic Elemental Determinations of Marine Traditional Chinese Medicine Meretricis concha from Jiaozhou Bay:The construction of Inorganic Elemental Fingerprint Based on Chemometric Analysis

The goal of this paper is to explore the relationship between the inorganic elemental fingerprint and the geographical origin identification ofMeretricis concha, which is a commonly used marine traditional Chinese medicine （TCM） for the treatment of asthma and scald bums. For that, the inorganic elemental contents ofMeretricis concha from five sampling points in Jiaozhou Bay have been determined by means of inductively coupled plasma optical emission spectrometry, and the comparative investigations based on the contents of 14 inorganic elements （A1, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se and Zn） of the samples from Jiaozhou Bay and the previous reported Rushan Bay were performed. It has been found that the samples from the two bays are ap- proximately classified into two kinds using hierarchical cluster analysis, and a four-factor model based on principle component analysis could explain approximately 75% of the detection data, also linear discriminant analysis can be used to develop a prediction model to distinguish the samples from Jiaozhou Bay and Rushan Bay with accuracy of about 93%. The results of the present investi- gation suggested that the inorganic elemental fingerprint based on the combination of the measured elemental content and chemom- etric analysis is a promising approach for verifying the geographical origin ofMeretricis concha, and this strategy should be valuable for the authenticity discrimination of some marine TCM.

Effect of high-voltage discharge non-thermal plasma on g-C_3N_4 in a plasma-photocatalyst system

The synergistic effect of high voltage discharge non‐thermal plasma(NTP)and photocatalysts on contaminant removal has repeatedly confirmed by plenty of researches.Most previous plasma‐photocatalyst synergistic systems focused on the utilization of the ultraviolet light but ignored the visible light generated by high voltage discharge.Graphitic carbon nitride(g‐C3N4),a metal‐free semiconductor that exhibits high chemical stability,can utilize both the ultraviolet and visible light from high voltage discharge.However,the synergistic system of NTP and g‐C3N4 has been researched little.In this paper,the effect of NTP generated by dielectric barrier discharge(DBD)on g‐C3N4 is studied by comparing the photocatalytic activities,the surface physical structure and the surface chemical characteristics of pristine and plasma treated g‐C3N4.Experimental results indicate that the DBD plasma can change the physical structure and the chemical characteristics and to further affect the photocatalytic activity of g‐C3N4.The effect of NTP on g‐C3N4 is associated with the discharge intensity and the discharge time.For a long time scale,the effect of NTP on g‐C3N4 photocatalysts presents a periodic change trend.

Concentrations and Distribution of Trace Metals of PM10 and TSP Particles Collected in the Qingdao Area

Aerosol samples of PM10 (particulate matter with aerodynamic diameters less than 10μm) and TSP (total suspended particles) were simultaneously collected from April 2001 to March 2002 at the top of Mount Baguan on the downtown campus of Ocean University of China, Qingdao, China. The concentrations of Al, Fe, Mn, Cu, Pb and Zn were determined by means of inductively coupled plasma atomic emission spectrometry (ICP-AES). The monthly variability of the mass concentrations of aerosol particles and the concentrations of trace metals are presented and discussed. The distribution pattern of these metals in PM10 and TSP is also discussed. During the observation period, the mass concentration of PM10 at this site ranged from 13.80 to 306.42μgm-3 , while that of TSP ranged from 31.02 to 568.82μgm-3. Both PM10 and TSP reached their highest concentrations in springtime, while the lowest values occurred in summertime. The concentrations of crustal metals followed the same variation pattern, while those of anthropogenic metals did not. A closer examination led to the conclusion that anthropogenic metals are mainly from local sources. The average concentration ratios of anthropogenic metals in PM10 to TSP were higher than the average mass ratio of PM10 to TSP, suggesting that there was a higher proportion of anthropogenic metals on smaller particles although there were a few exceptions. For crustal metals, however, the metal concentration ratios were close to the particle mass ratio, indicating that the distribution of crustal metals was much more homogeneous on aerosol particles with different sizes. The correlation analysis indicated that Al, Fe and Mn were originated from similar sources and were mainly controlled by the particle mass, while Cu, Pb and Zn were predominated by local anthropogenic sources, with Pb and Zn having similar origins.

Studies on the Authenticity of Local Wines by Spectroscopic and Chemometric Analysis

The authenticity of 91 wines produced in Cyprus from both indigenous and other vine varieties were investigated by a holistic approach, using, advanced technology such as SNIF-NMR （site-specific natural isotopic fractionation-nuclear magnetic resonance） and 1R-MS （isotope ratio-mass spectrometry） for the determination of the stable isotopes and ICP （inductively coupled plasma spectroscopy） for some heavy metals. The spectroscopic characteristics were evaluated statistically using different chemometric methods. The dependency of the D/H （deuterium/hydrogen） ratio of the methylene site in the ethanol molecule （D/H）ll and also theδ ^18O values of the wine water, were the most useful discriminators. Isotopic results allow us to have a complete idea about the regional variability of the isotopes. Among the metals, Ni followed by Pb was the ones with the highest discrimination value. The determined concentrations of Pb, Ni, Cr and Cd that are related to the safety of wines were within the acceptable limits that have been established by the OIV （international organization of vine and wine） or comparable with the results of the wines of other European countries. The study of the correlation between the load of heavy metals and isotopes in wines showed a dependence on the grape variety but not the geographical location of the vineyard. This is probably due to the close proximity of wine regions in Cyprus.

Ghezeljeh nanoclay as a new natural adsorbent for the removal of copper and mercury ions: Equilibrium, kinetics and thermodynamics studies

Heavy metal determination was carried out by applying the solid phase extraction （SPE） method in batch mode followed by atomic absorption spectroscopy （AAS） and inductively coupled plasma atomic emission spectrosco py （ICP-AES） from aqueous solutions using Ghezeljeh montmorillonite nanoclay as a new natural adsorbent. The Ghezeljeh clay is characterized by using Fourier Transform Infrared （FT-IR） Spectroscopy, Scanning Electron Mi- croscopy-Energy Dispersive Spectrometry （SEM-EDS） and X-ray Diffractometry （XRD） and X-ray Fluorescence （XRF）. The results of XRD and FT-IR of nanoclay confirm that montmorillonite is the dominant mineral phase. Based on SEM images of Ghezeljeh clay, it can be seen that the distance between the plates is Nano. The effects of varying parameters such as initial concentration of metal ions, pH and type of buffer solutions, amount of ad- sorbent, contact time, and temperature on the adsorption process were examined. The effect of various interfer- ing ions was studied. The adsorption data correlated with Freundlich, Langmuir, Dubinin-Radushkevich （D-R）, and Temkin isotherms. The Langmuir and Freundlich isotherms showed the best fit to the equilibrium data for Hg（II）, but the equilibrium nature of Cu（ll） adsorption has been described by the Langmuir isotherm. The kinetic data were described with pseudo-first-order, pseudo-second-order and double-exponential models, The adsorp- tion process follows a pseudo-second-order reaction scheme, Calculation of AGσ, △Hσ and ASσ showed that tilenature of Hg（II） ion sorption onto the Ghezeljeh nanoclay was endothermic and was favored at higher temper- attire, and the nature of Cu（II） ion sorption was exothermic and was favored at lower temperature,

Adaptive optical design in surface plasma resonance sensor

A double-prism adaptive optical design in surface plasma resonance （SPR） sensor is proposed,which consists of two identical isosceles right-triangular prisms. One prism is used as a component of Kretschmann configuration, and the other is for regulation of the optical path. When double-prism structure is angle-scanned by an immovable incident ray, the output ray will be always parallel with the incident ray and just has a small displacement with the shift of output point. The output ray can be focused on a fixed photodetector by a convex lens. Thus it can be avoided that a prism and a photodetector rotate by 8 and 28 respectively in conventional angular scanning SPR sensor. This new design reduces the number of the movable components, makes the structure simple and compact, and makes the manipulation convenient.

Dynamic Characteristics of Growing Modes of Raman Instability from Intense Laser Beam Propagating Through Plasma

An essential dispersion relation,which can describe the dynamic properties of stimulated Raman scattering instability as a laser beam propagates through plasmas,is derived analytically.The development of growth mode,angle distribution,and temperature dependence of the instabilities are presented by solving this dispersion relation numerically.A significant dynamic characteristic has been revealed that the temperature increasing of the electron would result in redshift of scattered spectrum at high laser intensities.Furthermore,a novel modulational instability with double-peak temporal structure appears in a limited density region because of the coupling of scattered upshift and downshift waves.