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91.
92.
Diffractive optical elements have a large number of industrial applications, such as beam shaping and optical filtering. Traditionally, these elements modulate the phase of the incoming light or its amplitude, but not both. To overcome this limitation, full complex-amplitude modulation diffractive optical elements were developed. Well-established integrated circuit fabrication steps were employed to fabricate the devices with high precision. Using this approach, the new element‘s optical performances are improved also for near field operations. With this device it is possible to obtain 100% efficient spatial filtering and low noise reconstructed images. 相似文献
93.
研究了用真空蒸发法在玻璃衬底上制备稀土掺杂纳米ZnO薄膜结构、导电性及光透射性能。结果显示 ,在 5 0 0℃氧化、热处理稀土元素Nd掺杂后能够明显改善纳米ZnO薄膜的结构特性 ,薄膜的晶粒尺寸随掺杂含量的增加而减小。掺Nd使ZnO薄膜的电性能有所改善但使纳米ZnO薄膜的光透射性有所降低。 相似文献
94.
本文从应用出发,选择光学石英为衬底,采用热丝辅助射频化学气相沉积的方法沉积BPxN1—x薄膜,对样品进行了X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外—可见等测试。XRD、SEM结果显示薄膜多晶态,表面形貌随时间变化,最终为胞状;紫外—可见光光谱结果显示BPxN1—x薄膜的紫外吸收边随沉积时间的加长、PH3流量的增加而向长波长方向移动。因此,该材料的光学能隙可以通过生长工艺适当调整。另外,BPxN1—x薄膜与液晶层能较好匹配等特性更使其适用于紫外空间光调制器。 相似文献
95.
Waveband switching (WBS) is a promising technique to reduce the switching and transmission costs in the optical domain of a wavelength-division multiplexing (WDM) network. This paper considers the problem of provisioning dynamic traffic using WBS in a WDM mesh network. The network of interest is a homogeneous WBS network, where each node has the functionality of WBS. The problem is called the dynamic WBS problem, which involves searching waveband-routes or wavelength-routes for the dynamically arriving traffic requests. The objective is to minimize the total switching and transmission costs in the optical domain. To solve the dynamic WBS problem, an auxiliary graph model capturing the network state is proposed. Based on the auxiliary graph, two heuristic on-line WBS algorithms with different waveband grouping policies are proposed, namely the wavelength-first WBS algorithm based on the auxiliary graph (WFAUG) and the waveband-first WBS algorithm based on the auxiliary graph (BFAUG). Simulation results indicate that WBS is an attractive technique which reduces the overall switching and transmission costs by up to 30% in the network. The results also show that the WFAUG algorithm outperforms the BFAUG algorithm in terms of port savings and cost savings. 相似文献
96.
In this paper, we examine, both experimentally and theoretically, the kinetics of formation and microstructure of product
phases in thin film reactions, using the Nb/Al and Ti/Al systems as our prototypes. The results of calorimetry and microscopy
studies are interpreted using simple kinetic and morphology models. In particular, the kinetic models employed here focus
on the nucleation and growth components of the phase formation process and the morphology models provide a starting point
for the classification of product grain structures.
An erratum to this article is available at . 相似文献
97.
A vibrating Kelvin probe in form of a platinum wire loop is used to measure the surface potential Us on electron-irradiated free-floating metal and insulator specimens as a function of electron energy E. This allows an accurate measurement of the critical electron energy E2 for no charging. At energies below E2, the positive charging increases with decreasing energy to Us=2–5 eV at E=0.5 keV and switching off the collector bias of the Everhart-Thornley detector. A two-to threefold increase of Us is observed when the bias is switched on. For E > E2, the strong increase of a negative surface potential can be measured. Insulating films free-supported on a conductive substrate show a steep decrease to small positive and negative Us when the film thickness becomes lower than the electron range at a critical energy E3 > E2. At insulating specimen the temporal decrease of charging can be measured when the electron beam is switched off. 相似文献
98.
99.
100.
运用不共轴光学系统的光路计算和象质评价理论,通过共轴光学系统中光学表面,光学元件,部件的小位移和微倾斜,对切比雪夫综合象质函数计算相应的有关限差分,以掌握各种离轴性误差对象质的危害程度,再按多元函数的极值理论和适应度性优化技术自动妥共轴光学系统中各种轴性公差,并进行反馈和非线性处理;达到公差的最优化分配。 相似文献