Plasmon transmissivity and reflectivity of narrow grooves in a silver film

Surface plasmon (SP) reflectivity and transmissivity of narrow grooves in silver films are studied. The SP source is the probe of a scanning near-field optical microscope. Locally detected leakage radiation from the SP provides detailed information on the paths of SP propagation, in particular the influence of perturbations. Global detection provides representative average data on the SP properties of a given metal film and its structures. A groove of 200 nm width, for instance, reflects/transmits about 15%/80% of 'blue-green' SP radiation at normal incidence.     

Simulation of an aperture in the thick metallic screen that gives high intensity and small spot size using surface plasmon polariton

The optical wave behaviour around a subwavelength aperture in a thick metallic screen is examined through three‐dimensional computer simulation. Treating the metallic screen as a dielectric slab with complex‐valued permittivity, it is possible to design an aperture that simultaneously provides high intensity and small spot size through the excitation of surface plasmon polaritons on the side walls of the aperture.     

Experimental statistics of near-field intensity distributions at nanostructured surfaces

Scanning near‐field optical microscopy is a technique in which the resolution is primarily determined by the size of a probe and not by the wavelength of illumination as in classical (far‐field) microscopy. However, the relationship between a sample and its near‐field optical image is usually rather complex. Typical factors responsible, at least partially, for such a complexity are the conditions of illumination and detection, sample characteristics (e.g. roughness and dielectric constant) and optical properties of the probe. Theoretical and experimental works conducted to improve our understanding of the relation between the object and the image have been reported ( Greffet & Carminati, 1997 ). Recently, with the help of a photon scanning tunnelling microscope we have carried out an extensive study of the resultant near‐field intensity distributions due to the elastic (in the plane) scattering of surface plasmon polaritons (SPPs) at metal film surfaces. We have also directly observed (in similar experimental conditions) localized dipolar excitations in silver colloid fractals ( Bozhevolnyi et al., 1998 ). In both cases, the studied phenomena are intimately related to the regime of multiple light scattering, in which the interference effects are rather complicated and therefore a proper interpretation of them was far from being trivial. Thus, even though a certain understanding of many features inherent to the subwavelength light interference phenomena was gained ( Bozhevolnyi & Coello, 1998 ; Bozhevolnyi et al., 1998 ; Coello & Bozhevolnyi, 1999 ), it is clear from the outcome of the investigations that more systematic studies in this context are still needed. A different and more powerful approach may be a statistical study of the recorded near‐field intensity distributions. In this work, we report what we believe to be the first results on experimental statistics of near‐field optical images exhibiting localized optical excitations (related to the regime of multiple scattering of light). We investigated optical images obtained with SPPs excited at different light wavelengths and scattered at different film surfaces, and with different polarizations and wavelengths of light scattered by silver colloid fractal structures. We have found significant differences in statistics between near‐field intensity distributions taken at rough and smooth metal film surfaces and fractal structures. Finally, our predictions seem to be in agreement with theoretical studies reported by other authors ( Sanchez‐Gil & Garcia‐Ramos, 1998 ).     

Surface plasmon-enhanced micro-cylinder mode in photonic quasi-crystal

Two-dimensional micro-cylinder patterns of dodecagonal photonic quasi-crystal (12-PQC) and tetragonal photonic crystal (2-PC) were fabricated on the top surface of a GaN light-emitting diode (LED). The patterns were evaporated with a 10-nm-thick Ag film. Spatially resolved surface emission was recorded and analysed by scanning near-field optical microscopy. Electromagnetic energy was confined and enhanced at the top surface when the surface plasmon (SP) resonated. The enhancement factor for 12-PQC was 1.9 times that of 2-PC, 8.6 times that of non-patterned LED in the near field and 6.7 times in the far field, respectively. Finite-difference time-domain simulations are consistent with the experimental data. The results show that with a patterned structure on the top surface of an LED, the light emission can be greatly enhanced due to SP resonance.     

Development of an Experimental EUVL System

The authors have developed an experimental system for the studies of extreme ultraviolet projection lithography at 13.0nm wavelength, which includes a laser plasma source,an ellipsoidal condenser, a transmission mask and a Schwarzschild optics. The optical system is optimized to achieve 0.1μm resolution over a 0.1mm diameter image field of view and the mirrors of the objective were coated with Mo/Si multilayer to provide 60% reflectance atnear-normal incidence angle for 13.0nm radiation.     

不同本底真空度对SiC/Mg极紫外多层膜性能的影响

摘要：为研究SiC/Mg极紫外多层膜光学性能随制作时不同本底真空度的变化,利用直流磁控溅射方法在不同本底真空条件下制备了峰值反射波长在30.4nm的SiC/Mg周期膜。X射线掠入射反射测试结果表明不同本底真空度条件下制备的SiC/Mg周期多层膜膜层质量有明显差异。用同步辐射测试了SiC/Mg多层膜在工作波长处的反射率,本底真空度为6.0E-5 Pa时的SiC/Mg周期膜反射率为43%,而本底真空度在5.0E-4 Pa时的SiC/Mg多层膜反射率仅为30%。同步辐射反射曲线拟合结果表明：反射率随着本底真空度降低的原因是由于多层膜Mg膜层中Mg的氧化物含量增多造成的。     

Leakage radiation microscopy of surface plasmon coupled emission: investigation of gain‐assisted propagation in an integrated plasmonic waveguide

Using a single‐mode dielectric‐loaded surface plasmon polariton waveguide doped with quantum dots, we were able to slightly increase the propagation length of the mode by stimulated emission of plasmon. We analyse the amplification phenomenon in the visible range by combining leakage radiation microscopy and surface plasmon coupled emission techniques.     

Present Status of EUV Interferometer Development at the Research Center for Soft X-ray Microscopy

A new interferometer for extreme ultraviolet (EUV) radiation with a laser produced plasma (LPP) laboratory source is under construction. The LPP source is operated with a Sn solid rod target on which pulsed YAG laser is focused to produce high temperature plasma emitting EUV radiation. The source is equipped with a newly designed debris stopper protecting a condenser multilayer mirror from the particle debris of the target. The condenser mirror focuses the light onto an EUV beam - splitter to form transmitted and reflected paths for producing interference fringes of a sharing type. The optical configuration is of a common path based on a triangular path type with a focusing at the beam- splitter, which is enabled to produce fringes by a low coherence radiation with a standard optical quality beam - splitter. The fringes are recorded by an imaging plate with pixels as small as 25μm. The dynamic range of linearity in detection of the EUV light was found to be more than 10^4 with sensitivity of 10^4 photo ns/pixel, enough for the purpose of interferogram recording possibly with one laser shot.     

压缩机曲轴机械喷丸耐磨性能研究

为了研究机械喷丸对压缩机曲轴耐磨性能的影响,利用表面机械喷丸技术对压缩机曲轴用Q T600-3球墨铸铁进行表面强化处理。研究未处理及机械喷丸处理压缩机曲轴材料表面显微硬度,分析机械喷丸前后压缩机曲轴球墨铸铁材料的摩擦磨损性能的不同,对机械喷丸处理前后球墨铸铁材料表面显微硬度进行初步分析,利用SEM扫描电镜对曲轴处理部位进行分析。实验结果表明：经过表面机械喷丸处理后,Q T600-3压缩机曲轴用球墨铸铁表面硬度值显著提高,磨损性能大幅改善;强化层优异的耐摩擦能力及强韧性很好地提高了曲轴的力学性能,扫描电镜分析发现机械喷丸处理试样断口形貌较为平整,强化层与基体清晰可见。     

基于动态粒子参数选择的水雾透过率计算

为了研究多次散射效应对辐射在雾中传输特性的影响,提出了一种多粒子雾层模型,该模型中雾滴粒子为半径不同的球形水滴粒子。雾滴粒子半径被分为多个区间,计算了不同半径区间内雾滴粒子的传输近似光学参数。提出了一种基于动态粒子参数选择的蒙特卡罗法,并模拟0.85μm和4μm辐射在重度平流雾、中度平流雾、重度辐射雾和中度辐射雾中的传输。分析了传输距离对透过率和计算时间的影响,并与传统的蒙特卡罗法的计算结果进行比较。结果表明:相比于4μm辐射,0.85μm辐射在雾中的透射能力更强;基于动态粒子参数选择的蒙特卡罗法与传统蒙特卡罗法计算得到的透过率随传输距离的变化曲线具有相同的趋势,传输距离为150 m时,两种方法对0.85 μm和4 μm辐射在重度平流雾中的透过率的绝对误差分别为0.0483和0.0015;传输距离为400 m时,相较于传统的蒙特卡罗法,基于动态粒子参数选择的蒙特卡罗法对4 μm辐射在重度平流雾中的传输计算效率可提升44%。基于动态粒子参数选择的蒙特卡罗法计算雾中的远距离辐射传输,可有效缩短计算时间。该研究结果对雾天的目标识别与探测有重要意义。     

气溶胶对天空偏振辐射影响的测量

研究了气溶胶光学特性对天空偏振辐射的影响以获得实际的天空偏振分布模式.采用自主搭建的天空偏振辐射测量系统,于不同日期、同一地点在太阳子午面内进行了若干实验,分别测量了太阳高度角约为60°时,435～465 nm,535～565 nm,685～715 nm 3个波段光在散射角为90°时对应的偏振度和辐射强度.用大气压强、能见度等参数进行理论计算获得了气溶胶光学厚度.当气溶胶光学厚度在0.2～0.55间逐渐增大时,3个波段对应的最大偏振度分别从43％减小到22％、从41％减小到21％、从38％减小到19％,而对应的辐射量不断增大.实验结果表明:随着气溶胶光学厚度的增大,偏振度不断减小,尤其是对长波长,偏振度的衰减更明显,从而不利于偏振光导航.     

Non-regularly shaped plasmon resonant nanoparticle as localized light source for near-field microscopy

We study numerically two-dimensional nanoparticles with a non-regular shape and demonstrate that these particles can support many more plasmon resonances than a particle with a regular shape (e.g. an ellipse). The electric field distributions associated with these different resonances are investigated in detail in the context of near-field microscopy. Depending on the particle shape, extremely strong and localized near-fields, with intensity larger than 10⁵ that of the illumination wave, can be generated. We also discuss the spectral dependence of these near-fields and show that different spatial distributions are observed, depending which plasmon resonance is excited in the particle.     

喷丸强化因素对钛合金固体粒子冲蚀抗力的影响

探讨了喷丸强化(SP)因素(残余压应力引入、表面粗糙度增大和表面加工硬化等)对Ti6Al4V钛合金固体粒子冲蚀(SPE)行为的影响和作用机制,为充分发挥SP改进航空发动机零部件服役性能的潜力提供依据。结果表明:Ti6Al4V合金表面直接喷丸处理,其SPE抗力无明显改变;SP处理后进行表面抛光,Ti6Al4V合金SPE抗力明显增加。SP造成的表面粗糙度增大导致了钛合金在大小冲击攻角下的SPE抗力的下降;SP引入的表面残余压应力对提高钛合金在90°大攻角下的SPE抗力起了重要作用,原因是SP残余压应力增加了裂纹闭合力和抑制了疲劳裂纹早期扩展;SP引起的表面加工硬化作用对提高钛合金在30°小攻角下的SPE抗力有重要贡献,这归于加工硬化提高了材料表面在小攻角下的微犁削抗力。     

SP88 — The painkiller in validation

The process of establishing a pharmaceutical plant requires a well controlled engineering process, where the requirements to be met are clearly spelt out — and the design and the actual plant is tested against these requirements. In the context of batch processes — with the added complexity of time variance and some degree of flexibility — this becomes anything but trivial.

The approach described in this paper is an attempt to combine a consistent engineering approach for pharmaceutical plants with the models presented by SP88. The SP88 batch control standard provides an excellent platform for structuring this problem - not only from a control perspective, but from the perspective of the multi-disciplinary, complete specification and test of a plant. The following life-cycle models and terminology are therefore in no way control-specific, but cover the complete installation - including mechanical equipment and installations and manual functions.     

Near-field optical excitation as a dipole–dipole energy transfer process

The process of fluorescence excitation in the scanning near-field optical microscope (SNOM) is considered as a dipole–dipole resonance energy transfer process between a molecule under study and a SNOM aperture, which can be treated as a magnetic-type point dipole. It is shown that such an approach satisfactorily describes the conditions of the usual SNOM fluorescence experiments. Fluorescence excitation dependence on the polarization of the incident light and medium refraction index have been obtained. The equation to calculate the resonance dipole–dipole energy transfer radius (which is a natural unit of a SNOM's longitudinal resolution) is derived. Those cases where such a radius is of the order of the SNOM aperture, and thus single dipole, can strongly influence the radiation conditions are discussed briefly.     

A Dosimeter for On-line Dose Rate Monitoring Based on a Natural Diamond Detector

The structure and principle of operation of a dosimeter for on-line dose rate monitoring (DOM) are considered. The DOM provides real-time measurements of the absorbed -ray and electron dose rates, monitors relative distributions of radiation fields in radiotherapy facilities, and controls the radiation characteristics of radiotherapeutic equipment during its adjustment, certification, and service. The dosimeter can measure the dose absorbed in a certain period of time. Compared to conventional dosimeters based on air ionization chambers and silicon semiconductor detectors, the DOM has a number of advantages: dose-rate measurement linearity, energy independence of radiation detection in the range of 0.8–20 MeV for -rays and 8–20 MeV for electrons, high sensitivity compared to air ionization chambers, high radiation and thermal stability, and the small size of the device. The detecting element of the dosimeter is manufactured from a tissue equivalent to a biological material. The operating ranges of dose rate measurements are 10^–3–10 Gy/min and 10^–2–10² Gy/min. The DOM measurement error is <2%. Radiation therapy is the dosimeter field of application.     

Far-field emission of a tapered optical fibre tip: a theoretical analysis

The far-field transmission pattern of a tapered optical tip with small aperture (radius ∼ < 40 nm) is modelled by solving Maxwell's equations in the radiation zone with boundary conditions appropriate to the conical geometry. The model is able to reproduce the large differences between the S and P polarizations observed previously in the emission profile of such a tip [ Obermüller and Karrai. Appl. Phys. Lett . (1995) 67 , 3408 ].     

Comparison of methods for quantifying dental wear caused by erosion and abrasion

Various methods have been applied to evaluate the effect of erosion and abrasion. So, the aim of this study was to check the applicability of stylus profilometry (SP), surface hardness (SH) and focus‐variation 3D microscopy (FVM) to the analysis of human enamel and dentin subjected to erosion/abrasion. The samples were randomly allocated into four groups (n = 10): G1‐enamel/erosion, G2‐enamel/erosion plus abrasion, G3‐dentin/erosion, and G4‐dentin/erosion plus abrasion. The specimens were selected by their surface hardness, and they were subjected to cycles of demineralization (Coca‐Cola®‐60 s) and remineralization (artificial saliva‐60 min). For groups G2 and G4, the remineralization procedures were followed by toothbrushing (150 strokes). The above cycle was repeated 3×/day during 5 days. The samples were assessed using SH, SP, and FVM. For each substrate, the groups were compared using an unpaired t‐test, and Pearson correlation coefficients were calculated (α = 5%). For enamel, both profilometry technique showed greater surface loss when the erosion and abrasion processes were combined (P <0.05). The correlation analysis did not reveal any relationships among SH, SP, and FVM to G2 and G4. There were significant correlation coefficients (–0.70 and –0.67) for the comparisons between the FVM and SH methods in enamel and dentin, respectively, in G1 and G3. Choosing the ideal technique for the analysis of erosion depends on the type of dental substrate. SP was not sufficiently sensitive to measure the effects on dentin of erosion or erosion/abrasion. However, SP, FVM and SH were adequate for the detection of tissue loss and demineralization in enamel. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.     

四极杆离子光学和串联振荡电子学系统

四极杆和飞行时间质谱是液相色谱-质谱（LC/MS）、三重四极杆质谱（QQQ）和四极杆-飞行时间质谱（Q TOF）等质谱仪器中必备的核心部件,也是我国亟待研发的国产化仪器。目前,国内对质谱仪器的研制热情日益高涨,得到了国家相关部门的高度认可和广大研发人员的积极响应。本综述基于作者课题组多年的研制经验,从质谱仪器研发的角度介绍实现离子光学系统和电子学系统的技术原理。首先回顾四极杆的基本原理;然后着重讨论加工和装配精度对提高四极杆分辨率的重要性,以及四极杆尺寸选择对射频电压控制的影响;最后重点介绍四极杆串联振荡电子学系统以及在系统中起关键作用的阻抗匹配,希望能为质谱仪器研制提供参考。     

Surface plasmon micro- and nano-optics

We report the experimental realization of key elements of a two‐dimensional optics based on surface plasmon polaritons (SPPs). Local SPP sources, Bragg mirrors and beamsplitters were lithographically built from silver nanostructures. The SPP fields were imaged by detecting the fluorescence of molecules that act as local probes of the SPP near‐field intensity.