超分辨近场结构之纳米光刻技术

超分辨近场结构(Super-RENS)是在传统的超分辨光盘技术和近场光学的基础上发展起来的新技术.介绍了超分辨近场结构的基本原理及其在纳米光刻方面的应用,拓展了超分辨近场结构的外延:在近场范围内,能实现超过衍射极限的纳米多层膜结构.局域表面等离子体效应在高密光存储、纳米光刻等纳米光子学研究领域具有重要的科学意义和应用价值.     

超分辨近场结构光盘的研究进展

超分辨近场结构(Super-RENS)光数据存储方案在近场超高密度光数据存储方面具有巨大的发展潜力和广阔的发展前景。在此方案中,超分辨结构的非线性层起着至关重要的作用。本文简述了Super-RENS光盘中两种类型光盘的结构及优点,并着重介绍了其工作机理的研究进展。     

散射中心型超分辨近场结构的非线性光学特性研究进展

超分辨近场结构(Super-RENS)技术是近年来发展起来的一种新型近场光存储技术，是目前最有实用化前景的纳米尺度近场超分辨技术之一。初步研究表明，其近场超分辨特性与非线性响应密切相关，研究其非线性光学特性对阐明物理机制、发展新的掩模材料和非线性光学应用都具有重要意义。对散射中心型超分辨近场结构非线性光学特性的最新研究进展进行了介绍和分析。     

磁光盘存储技术综述

文中对下一代磁光盘可能采用的技术：短波长记录读出技术、短波长磁超分辨技术（MSR）、磁畴放大读出技术（MAMMOS）、畴壁移动检测技术（DWDD）和超分辨近场结构型（Super-RENS)光存储技术的原理进行了介绍，并对上述磁光盘记录技术的现状及发展趋势进行了综述。     

近场光学存储器

近场光学存储器采用了纳米高新制作技术,具有极高的读出速度和极高的存储密度。本文介绍了近场光学“头”、近场光学记录方法、记录机理和处理方法以及T比特光盘的制造技术和结构。     

超分辨近场结构光刻技术

介绍了一种新的近场光刻技术的基本原理及其在光刻方面的应用研究的最新进展。新技术的基本原理是;光远场照射,通过超分辨掩模产生光刻所需的超过衍射极限的近场光,利用夹在掩模和光刻胶中闯的电介质保护层实现了近场光的最佳耦合,减小了线宽并大大提高了光刻速度。这种膜层结构叫超分辨近场结构(Super-RENS),是近年来发展起来的一种新的近场光学技术。     

Radiation effects in near-field microwave diagnostics

Radiation effects in the near-field diagnostics of weakly absorbing dielectrics are studied theoretically and experimentally. Calculations are performed on the basis of the developed theory of the near-field radar of a plane-layered medium, which is used for calculation of the complex impedance of a probe situated above the interface of a homogeneous medium and an inhomogeneous medium. It is found that the height dependence of the active part of impedance is characterized by “wave” spatial scale h _w, whereas the reactive part has quasistatic scale h _qs, where h _qs ? h _w. It is revealed that the response of a near-field radar contains a parameter sensitive to the radiation fields of the probe. It is shown that recording of this parameter can substantially extend the sensing volume of near-field radar.     

基于近场光学理论光镊的研究进展

近场光镊是基于近场光学理论建立起来的可以对微粒实现稳定捕获和操作的新技术,相较基于单光束梯度力的传统远场光镊,近场光镊克服了光学分辨率衍射极限和热效应等众多因素的限制,可以实现对纳米量级微小粒子的捕获和操控,在物理学、细胞工程、生物医学等领域备受关注.首先阐述了基于倏逝场近场光镊的模型和捕获的基本原理,详述了棱镜全反射光镊、探针型光镊、纳米孔径光镊、聚焦倏逝场光镊、微纳光纤光镊、以及微谐振腔耦合结构型近场光镊的研究进展.最后,重点介绍了光镊在生物医学领域的应用.     

FFT applications to plane-polar near-field antenna measurements

The four-point bivariate Lagrange interpolation algorithm was applied to near-field antenna data measured in a plane-polar facility. The results were sufficiently accurate to permit the use of the FFT (fast Fourier transform) algorithm to calculate the far-field patterns of the antenna. Good agreement was obtained between the far-field patterns as calculated by the Jacobi-Bessel and the FFT algorithms. The significant advantage in using the FFT is in the calculation of the principal plane cuts, which may be made very quickly. Also, the application of the FFT algorithm directly to the near-field data was used to perform surface holographic diagnosis of a reflector antenna. The effects due to the focusing of the emergent beam from the reflector, as well as the effects of the information in the wide-angle regions, are shown. The use of the plane-polar near-field antenna test range has therefore been expanded to include these useful FFT applications     

Nanoscale modification of phase change materials with near-field light

Scanning near-field optical microscope (SNOM) was applied to the formation of ultrasmall phase change domains to investigate the feasibility of ultrahigh density data storage. Phase change domains ranging 60 – 100 nm in diameter, which is far beyond the diffraction limit, could be successfully written in amorphous GeSbTe recording film by point heating with pulsed laser light (λ=785 nm, 7 mW, 0.5 ms) through the optical fiber probe whose aperture size was nearly 50 – 100 nm. The detected power in observation of these recorded domains is 10² – 10³ times as high as that in magneto-optical observation. It indicates that phase change recording with SNOM has a potential to achieve ultrahigh density data storage (more than 100 Gb/in²) with high signal detection efficiency.     

Three-dimensional near-field MIMO array imaging using range migration techniques

This paper presents a 3-D near-field imaging algorithm that is formulated for 2-D wideband multiple-input-multiple-output (MIMO) imaging array topology. The proposed MIMO range migration technique performs the image reconstruction procedure in the frequency-wavenumber domain. The algorithm is able to completely compensate the curvature of the wavefront in the near-field through a specifically defined interpolation process and provides extremely high computational efficiency by the application of the fast Fourier transform. The implementation aspects of the algorithm and the sampling criteria of a MIMO aperture are discussed. The image reconstruction performance and computational efficiency of the algorithm are demonstrated both with numerical simulations and measurements using 2-D MIMO arrays. Real-time 3-D near-field imaging can be achieved with a real-aperture array by applying the proposed MIMO range migration techniques.     

The near-field polarization ellipse

The near-field polarization ellipse is described. The tip of the near electric-field vector traces out an ellipse lying in an arbitrary plane. The peak and rms values of the magnitude of the electric vector are determined, as well as the orientation of the ellipse. The results are related to near-field radiation hazard criteria.     

"时间窗"对天线时域平面近场测试结果的影响

天线时域近场测试技术是一种新兴的、测试宽带场和工作在窄脉冲激励下天线辐射场的高效的测试技术.因为它可以利用"时间窗"技术进行信号处理,使其相对频域测试具有独特的优势.本文在已建立的天线时域近场测试系统的基础上,从实验的角度,对"时间窗"参数在天线时域平面近场测试中的影响进行验证分析.举例了三个波段标准天线方向图的测试分析结果,并得出初步结论.     

Application of a six-port network to a near-field antenna measurement system

The configuration and calibration of a six-port network analyser for application in near-field antenna measurements is described. The suitability of the new measurement system is illustrated by experimental results.     

窗函数在相控阵天线平面近场测量中的应用

有限扫描面截断是影响天线平面近场测量精度的主要误差源之一，尤其是对于波束扫描的相控阵天线的平面近场测量更是如此。为了减小相控阵天线平面近场测量中的有限扫描面截断误差，介绍了余弦窗函数并将其应用到相控阵天线平面近场测量中。计算机模拟结果表明，通过对近场进行加余弦窗的数据处理能够有效地减小有限扫描面截断误差。提出了对近场数据进行加余弦窗处理的适用条件。     

Spherical near-field scanning at the Technical University ofDenmark

The early work (1969-79) on spherical near-field antenna measurements at the Technical University of Denmark (TUD) is outlined. A spherical near-field transmission formula is described and the first probe-corrected spherical near-field measurements are discussed. The TUD-ESA (European Space Agency) joint effort on spherical near-field testing is also described     

Numerical beam alignment procedure for planar near-field phaseretrieval

The authors demonstrate mathematically that the direction of an antenna beam (antenna pointing) can be determined by the centre-of-gravity of its beam intensity. The technique is validated using measurements on a 1.118 m 94 GHz Cassegrain reflector and is seen as pivotal in the future application of the phase retrieval technique for near-field/far-field prediction     

Error analysis techniques for planar near-field measurements

A combination of techniques is described for reliably estimating the magnitude of each error arising in planar near-field measurements. They include mathematical analysis, computer simulation, and measurement tests. There are three primary applications for these tests: in designing a measurement facility, the requirements of each part of the measurement system can be specified to meet a given level of accuracy; during actual measurements, the experimenter can identify, and reduce where necessary, potential sources of error in the measurement; and when a measurement has been completed, the estimated uncertainty in the measurement can be obtained with confidence and ease. The latter application has been used in many measurements to verify that the planar near-field technique produces high-accuracy results competitive with any other measurement technique     

An overview of near-field antenna measurements

After a brief history of near-field antenna measurements with and without probe correction, the theory of near-field antenna measurements is outlined beginning with ideal probes scanning on arbitrary surfaces and ending with arbitrary probes scanning on planar, cylindrical, and spherical surfaces. Probe correction is introduced for all three measurement geometries as a slight modification to the ideal probe expressions. Sampling theorems are applied to determine the required data-point spacing, and efficient computational methods along with their computer run times are discussed. The major sources of experimental error defining the accuracy of typical planar near-field measurement facilities are reviewed, and present limitations of planar, cylindrical, and spherical near-field scanning are identified.     

Fields of linear radiators in the near-field zone

The mutual effect of electric dipoles that are close to each other is analyzed in the near-field zone. The input impedances, currents and fields of the radiators are calculated. The method for the calculation of the system of two radiators is based on the theory of folded dipoles. The fields of application of the closely lying radiators are presented.