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101.
S. M. Vuković N. B. Aleksić D. V. Timotijević 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(2):295-301
We studied electromagnetic beam reflection from layered
structures that include materials with negative refraction. Excitation of
leaky surface waves leads to the formation of anomalous lateral shifts in the reflected beams
with single or double peak structures. The presence of reasonable losses
within material with negative refraction, besides significant influence on
manifestation of the giant lateral shifts, can lead to their total
suppression and anomalously high absorption of the incident radiation. If,
in addition to the resonant excitation of leaky surface waves, radiation
inflow exactly compensates their irreversible damping, total absorption of the incoming
radiation can be achieved for moderately wide beams. 相似文献
102.
Entangled photon pairs must often be spatially separated for their subsequent manipulation in integrated quantum circuits. Separation that is both deterministic and universal can in principle be achieved through anti‐coalescent two‐photon quantum interference. However, such interference‐facilitated pair separation (IFPS) has not been extensively studied in the integrated setting, which has important implications on performance. This work provides a detailed review of IFPS and examines how integrated device dependencies such as dispersion impact separation fidelity and interference visibility. The analysis applies equally to both on‐chip and in‐fiber implementations. When coupler dispersion is present, the separation performance can depend on photon bandwidth, spectral entanglement and the dispersion. By design, reduction in the separation fidelity due to loss of non‐classical interference can be perfectly compensated for by classical wavelength demultiplexing effects. This work informs the design of devices for universal photon pair separation of states with tunable arbitrary properties.
103.
Synthesized 2,5-diphenylethynyl thiophene based bent bolaamphiphiles can self-organize into square honeycomb LC phases with p4mm symmetries in the presence of water. UV and PL measurements indicate fl uorescent properties making them potential candidates for application in fl uorescence sensor devices 相似文献
104.
Yu Qing Chen 《Journal of Combinatorial Theory, Series A》2011,118(8):2185-2206
Additive Hadamard cocycles are a natural generalization of presemifields. In this paper, we study divisible designs and semi-regular relative difference sets obtained from additive Hadamard cocycles. We show that the designs obtained from additive Hadamard cocycles are flag transitive. We introduce a new product construction of Hadamard cocycles. We also study additive Hadamard cocycles whose divisible designs admit a polarity in which all points are absolute. Our main results include generalizations of a theorem of Albert and a theorem of Hiramine from presemifields to additive Hadamard cocycles. At the end, we generalize Maiorana-McFarland?s construction of bent functions to additive Hadamard cocycles. 相似文献
105.
A theoretical analysis of nano-deep corrugated long-period waveguide gratings on a SU-8 polymer-based channel waveguide with NOA61 optical epoxy coated upper- and lower cladding is presented. The transmission spectra of the gratings show strong rejection bands both at visible (at wavelength region of 450?460 nm) and infra-red (at wavelength region of 1530?1540 nm) regions when a grating period of ?68 μm with optimized grating tooth height is considered. Phase-matching graphs are studied to find the relationship between resonance wavelength and grating period. These results show that the grating parameters significantly affect the characteristics of transmission spectra as well as the resonance wavelength of the grating. Long-period waveguide grating-based band pass filter made by use of same polymer materials are also designed and analyzed. These types of waveguide grating-based filters can widely be used for visible and infra-red wavelength sensing applications. 相似文献
106.
Juan de Torres Petru Ghenuche Satish Babu Moparthi Victor Grigoriev Jérôme Wenger 《Chemphyschem》2015,16(4):782-788
Zero‐mode waveguides (ZMWs) can confine light into attoliter volumes, which enables single molecule fluorescence experiments at physiological micromolar concentrations. Of the fluorescence spectroscopy techniques that can be enhanced by ZMWs, Förster resonance energy transfer (FRET) is one of the most widely used in life sciences. Combining zero‐mode waveguides with FRET provides new opportunities to investigate biochemical structures or follow interaction dynamics at micromolar concentrations with single‐molecule resolution. However, prior to any quantitative FRET analysis on biological samples, it is crucial to establish first the influence of the ZMW on the FRET process. Here, we quantify the FRET rates and efficiencies between individual donor–acceptor fluorophore pairs that diffuse into aluminum zero‐mode waveguides. Aluminum ZMWs are important structures thanks to their commercial availability and the large amount of literature that describe their use for single‐molecule fluorescence spectroscopy. We also compared the results between ZMWs milled in gold and aluminum, and found that although gold has a stronger influence on the decay rates, the lower losses of aluminum in the green spectral region provide larger fluorescence brightness enhancement factors. For both aluminum and gold ZMWs, we observed that the FRET rate scales linearly with the isolated donor decay rate and the local density of optical states. Detailed information about FRET in ZMWs unlocks their application as new devices for enhanced single‐molecule FRET at physiological concentrations. 相似文献
107.
提出了一种结构模型来分析由工艺引起的波导侧壁起伏对于聚合物波导光学梳状滤波器的滤波特性的影响。含氟聚酰亚胺高分子聚合物制备多级马赫一曾德尔串联型光学梳状滤波器件的工作参量为中心波长1550nm,波长间隔为0.8nm,40通道的波长交错分离。模拟计算:表明,对由高分子聚合物材料制备的多级马赫-曾德尔串联型光学梳状滤波器件,其主要影响是增大了信道之间的串扰,中心波长1550nm处的信道串扰由理想情况下的-40dB降为-12dB,极大地影响了器件的性能。在此基础上,提出一种改善光学梳状滤波器串扰性能的新结构,该结构由多级马赫-曾德尔耦合器和微环共振滤波器串接构成,40个通道的串扰改善为-0dB以下。 相似文献
108.
提出一种分析非平行波导间耦合的简明方法-耦合系数推广法.利用这种方法,导出一种新的非平行双波导的耦合方程,由此得到一组非平行波导耦合的完美的分析解,依据这些分析解可以优化非平行波导的传输距离、输入/输出端口波导间距和夹角. 相似文献
109.
Fogli Fabrizio Greco Nicola Bassi Paolo Bellanca Gaetano Aschieri Pierre Baldi Pascal 《Optical and Quantum Electronics》2001,33(4-5):485-498
A theoretical approach based on Bloch theorem and spatial harmonics has been used to investigate the propagation characteristics in planar periodic segmented waveguides. This analytical method allows to evaluate the field distribution, the effective index and the propagation losses of these structures, taking into account both the propagating and the counterpropagating field components, thus evidencing all the phenomena which can take place in: Bragg reflections, leaky waves, etc. Results for TE fields are presented and compared with those obtained using a paraxial 2D FD-BPM method and a Padé based one, showing that no more than (1, 1) order approximants are needed to provide good estimates of the device characteristics. 相似文献
110.