半球形固体浸没透镜显微系统的透射光场研究

应用高数值孔径系统的矢量衍射理论研究了半球形固体浸没透镜(SIL)球面表面的反射对SIL系统透射场的影响.研究结果表明,半球形SIL球面表面的反射对SIL显微系统的透射光强产生很大的影响.然而,这种反射不改变半球形SIL显微系统的分辨率.SIL球面介质界面材料的折射率失配越大,透射光强减小越多.在SIL的球面表面涂上减反膜或者在物镜和SIL之间填充折射率较大（但比SIL的折射率小）的介质可以提高系统的透射光强.     

FDTD方法对固体浸没透镜的光场分析

采用二维时域有限差分(2D-FDTD)方法研究了高斯光束通过固体浸没透镜(SIL)的光场分布特性.模拟结果表明,SIL的折射率越大,底面出射的光斑越小,但随离底面距离的增大光束很快展宽;当只有入射角大于全反射临界角、具有高空间频率的部分高斯光束聚焦到SIL底面金属膜中心的微孔时,针对不同直径的微孔,模拟了出射光场的分布,发现微孔直径在某一特定值时,出射光斑半径在距SIL底面近半个波长范围内无明显改变,该结果为增大SIL和存储介质间距的方案提供了理论依据.     

The validity of high-pass angular spectrum filter in solid immersion lens system

应用矢量方法计算了具有高通角谱滤波器的固体浸没透镜（SIL）系统的焦场分布。数值结果显示，对于径向（角向）偏振输入光，高通角谱滤波器可以减小SIL系统的光斑（暗斑）大小。然而，对于线性偏振输入光，简单的高通角谱滤波器不能够优化SIL系统的光场分布，也不能够改进系统的光存储密度。     

用于双层存储的SIL近场分析

固体浸没透镜 (SIL)用于光存储光学系统增大了光学头物镜的数值孔径 ,利用近场倏逝波读写 ,减小了光斑的直径 ,提高了存储密度。文中建议 :(1)将半球SIL分割成两部分 ,其中一部分由存储媒质的保护层充当 ,避免直接污染记录层 ;(2 )在半球SIL单层读写的基础上 ,再将第一层记录媒质作为SIL的一部分形成超半球齐明SIL ,以实现双层存储。并对此时的近场进行了解析分折     

信息光学 光学记录、存储与器件

O438 2005021197 FDTD方法对固体浸没透镜的光场分析=Analysis of the optical field of solid immersion lens by FDTD[刊,中]／张 东玲(河南大学物理与信息光电子学院．河南,开封 (475001)),白永林…//光子学报．-2004,33(7).-884- 888 采用二维时域有限差分(2D-FDTD)方法研究了高斯 光束通过固体浸没透镜(SIL)的光场分布特性。模拟结果     

近场高密度光存储

文章综述了近场高密度光存储领域的研究进展情况，着重介绍了固体浸没透镜（solid immersion lens,SIL)存储方案和近场超分辨结构（super resolution near-field,SuperRENS)的原理、研究进展及问题。     

用两区π-相位滤波器改善超半球形固体浸没透镜显微系统的成像特性

利用矢量衍射理论分析了π-相位滤波器在超半球形固体浸没透镜显微系统中的超分辨特性.结果显示,光斑的增益、Strehl率和边瓣强度随相位区域边界呈现出同步的、只一个周期的振荡性变化.从辐射场和速逝场的角度解释了这种变化的原因.对于近场显微,速逝场起决定性作用.π-相位滤波器的相位区域边界角大于临界角时,才能产生较大的超分辨作用.滤波器边界参量等于0.743（对应的角度大于临界角）的π-相位滤波器,可以使系统分辨率提高16%.     

微球透镜亚波长显微成像远场特性实验研究

利用低折射率的二氧化硅和高折射率的钛酸钡微球透镜对蓝光刻录光碟的亚波长表面结构进行了显微成像实验,观察了两类微球在空间上与样品表面分离时的成像特性.实验结果表明:在微球透镜与样品表面分离0～6μm的空间范围内,微球透镜对亚波长纳米结构仍具有分辨能力,且放大作用明显.通过实验比较,发现在浸没方式、放大率大小、成像尺度范围...     

固体浸没透镜出射光场偏振特性研究

在固体浸没透镜近场光存储中, 光的偏振对近场光场分布具有很大的影响. 采用三维时域有限差分法, 对聚焦线偏振高斯光束通过固体浸没透镜后焦平面上各分量场分布及距离焦平面不同位置光斑图样进行了模拟. 结果表明在焦平面上及距离焦平面较近的近场区域, 出射光场在与入射光偏振垂直方向出现显著的场增强现象, 从而使光斑图样呈近似椭圆分布; 而在距焦平面较远的远场区域光斑图样趋向圆形对称分布.     

固体浸没透镜飞行高度的气浮控制

采用固体浸没透镜的光存储方法是提高光存储密度的比较实用的近场光存储方法,而严格控制SIL下底面与光存储介质之间的亚波长级距离是此光存储系统正常工作的前提.本文采用电容法测量SIL的飞行高度,采用弹性悬臂将SIL加载在转盘表面上,转盘以不同速度转动时SIL将悬浮在不同的高度.计算机首先采集到SIL的飞行高度信息,再与设定的飞行高度作比较,根据比较结果调整转盘转速,从而达到调整SIL飞行高度的目的.采用此方法,可以动态地将SIL的下底面控制在距高速转动的转盘表面上150～600 nm范围内的一定高度上.     

Realization of a subwavelength focused spot without a longitudinal field component in a solid immersion lens-based system

In a solid immersion lens (SIL)-based system, we predict theoretically that, by using the illumination of an azimuthally polarized beam with helical phase (APH), the subwavelength focusing can be simultaneously realized both in SIL and the third medium in spite of the presence of an air gap between the SIL and the third medium, which is not easily achieved in the case of the illumination of linearly, circularly, and radially polarized beams. For the APH illumination, the field in the focal region of the multilayered medium has no longitudinal component, and the on-axis intensity of the focused spot is nonzero. The APH illumination extends the capacity of SIL in realizing a supersmall focused spot, which is useful in microscopy, near-field optics, recording optics, and lithographic optics.     

Dispersion effect in optical microscopy systems with a supersphere solid immersion lens

This paper studies the dispersion effect of the supersphere solid immersion lens (SIL) on a near field optical microscopy system by using the vector diffraction theory. Results show that when a real non-monochromatic beam illuminates a supersphere SIL microscopy, the dispersion effect of the SIL has an important influence on the image quality. As the wavelength bandwidth of the non-monochromatic beam increases, the size of the focused spot increases and its intensity decreases in near-field microscopy systems with a supersphere SIL.     

Optimizing the optical field distribution of solid immersion lens system by a continuous phase filter

In solid immersion lens (SIL) microscopy systems with high numerical aperture (NA), there always exists the aberration produced by Fresnel effects at the interface between SIL and the sample. This aberration may cause the degradation of the image of sample. We design a continuous phase filter and optimize the optical field distribution of SIL system. The numerical results show that when the continuous phase filter is used, the field distribution of SIL system can be optimized, and the focal depth and intensity of transmitted light can be increased. At the same time, the intensity of side-lobe and the resolution are kept almost unchanged.     

Three-zone phase-only filter increasing the focal depth of optical storage systems with a solid immersion lens

The field distribution of a Weierstrass solid immersion lens (SIL) is presented, which shows that its focal depth is only in nanoscale. A novel filter design based on a three-zone binary phase pupil function is introduced for increasing the focal depth of a near-field Weierstrass SIL system and a procedure for designing a rotationally symmetric binary phase filter is presented. Numerical results show that an appropriate three-zone phase-only filter not only can evidently increase the focal depth of the SIL system, but also can effectively lower the spreading of the spot size with distance and suppress the side-lobe intensity. PACS 42.79.Ci; 42.40.Lx; 42.79.Vb; 42.25.-p     

厚靶轫致辐射特性的数值模拟研究

X光机正朝高能强流方向发展.这些装置中普遍采用mm厚度的重金属厚靶,其辐射特性和各种参数间的规律受到关注.本文采用基于蒙特卡罗法的EGS4程序比较全面的研究了高能X光机中所关心的靶厚度的选择、轫致辐射场的角分布和X射线能谱的规律.同时还专门就X光强度和束流发射度、打靶焦斑尺寸三者的依赖关系进行分析,结论表明针对现有的X光机参数,不用担心因追求小焦斑而带来X光照射量的损失。文中还分析了强束流条件下单粒子蒙特卡罗模拟程序的适用性.文中结论和已有实验结果吻合,对实际工作具有意义.     

Near-field radiation from a ridge waveguide transducer in the vicinity of a solid immersion lens

A near-field optical system is investigated to improve the transmission efficiency of near-field transducers. A ridge waveguide is placed adjacent to a solid immersion lens (SIL) but separated by a low-index dielectric layer. The incident electric field near the focus of the SIL is determined by the Richards-Wolf vector field equations. The finite element method is used to solve Maxwell's equations. A spot size of 31 nm is obtained. The maximum value of the absorbed optical power density in the recording medium is 7.51 x 10(-4) mW/nm3 for a 100 mW input power.     

高通量微区扫描EDXRF仪器设计

用多毛细管X射线透镜做光源的微区扫描型EDXRF仪器,围绕出射焦斑对称放置4～6个SDD探测器,设计软件控制X射线管、多个探测器、高精度移动平台,同时进行数据采集、信号同步和结果分析,从而开发完成NX-mapping高通量微区扫描型EDXRF仪器。由于多探测器的采用,该仪器的信号强度得到数倍的提升,且稳定性没有因为器件间的差异而变差,同等条件,同等用时的情况下,测试标准偏差降为单探测器时的不足40%。均匀样品2 mm×2 mm面扫描时,400个点的测试标准偏差与定点测试无差异,说明运动机构和控制算法表现优异,不会对测试结果产生影响。对于微区扫描仪器的焦斑尺寸,用“荧光刀口实验”的方法,对Fe,Ni和Mo元素进行了测试,测得三种元素的有效焦斑尺寸最小值分别为52.4,49.3和39.03 μm,各元素有效焦斑尺寸随原子序数的增加而减小,这与多毛细管X射线透镜的设计原理相符;实验还发现了各元素焦斑有效尺寸在极小值处对高度变化较为敏感的规律,因此建议为了得到统一清晰的扫描图像,要保持样品表面的平整。最后用NX-mapping仪器对某单晶高温合金样品的Ni,Ta,W和Re元素进行扫描和分布分析,图像清晰,枝晶结构明显可辨,并且其中Ni∶Ka特征线强度高达220 kcps,明显高于普通的XRF测试。在NX-mapping微区扫描型EDXRF仪器中,由于多探测器的采用,信号强度高,测试精密度好,随之测试时间可以缩短,因此可以满足高通量测试的需求。     

Enhancing near-field photolithography by surface plasmon polaritons excited from negative-refractive-index nanofilms

We report a novel method for enhancing near-field nanophotolithography using negative-refractive-index slabs. In our method, a negative-refractive-index-metal film (NIF) is attached to the plane surface of an aplanatic solid immersion lens (SIL), and the polymer layer is coated on the negative-refractive-index film. The intensity of the transmitted light is enhanced by the surface plasmon polaritons excited in the NIF-polymer composite layer. The numerical results based on the vector diffraction theory show that under the illumination of the SIL-NIF-polymer composite by a sharp focused radially polarized beam, the composite configuration under investigation can substantially increase the spot intensity, suppress the spot expansion along the distance from the interface, and improve the depth of focus, in comparison with conventional focusing systems using bare SILs. In the case where a photoresist film is placed near the composite configuration, a subtle deep-etching pattern with high resolution can be achieved.     

Multiple reflection effect inside a hemispherical solid immersion lens

The reflection inside a hemispherical solid immersion lens (h-SIL) is analyzed by using the film-interference optics and the new unique characteristic of the h-SIL is presented. The image theory of SIL microscopy is developed. Numerical results show that the reflection inside the h-SIL, especially for large mismatch in refractive indices between the SIL and the medium, has an important influence on the resolution of SIL surface microscope and the collection efficiency from the emitter. Theoretical and experimental results are compared through three examples, the reflection-mode microscope, the transmission-mode microscope, and the collection of light from the emitters. The present theoretical values are quite consistent with the experimental values in SIL microscopy. It is of interest to note that owing to the interference in the SIL, the resolution and collection efficiency periodically oscillate with the radius of an h-SIL, which mean that the radius of an h-SIL has to be well-controlled to achieve enough high resolution and collection efficiency.