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对含有反常色散材料和金属材料散射体无序介质的光子定域化行为进行了理论研究 .基于Mie散射理论研究发现 ,对于某些反常色散电介质球做散射体的无序介质 ,在较低浓度 (10 % )下 ,在中红外区可以实现一定的光子定域化 ,且频率位于各自的剩余射线带 .对金属散射体的无序光学介质的研究表明 ,各种金属在中红外区的各个频率点上的散射行为均极为相近 ,结果表明 ,在整个中红外区几乎不可能实现光子定域化 . 相似文献
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Helium is the second most abundant element in the universe, and together with silica, they are important components of giant planets. Exploring the reactivity and state of helium and silica under high pressure is crucial for understanding of the evolution and internal structure of giant planets. Here, using first-principles calculations and crystal structure predictions, we identify four stable phases of a helium-silica compound with seven/eight-coordinated silicon atoms at pressure of 600–4000 ... 相似文献
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An ultrabroadband supercontinuum (SC) is demonstrated in a pure silica photonic crystal fiber (PCF) pumped by quasi-continuous wave nanosecond-long pulses at 1,064 nm. The generated SC spectra extending from 450 to at least 2,400 nm have the salient feature of a short wavelength regime below the pump wavelength, which is much higher in intensity than the long-wavelength over the pump wavelength. The influence of pump power and repetition rates on SC generation (SCG) is explored. Results suggest that this pump source has both the advantages of short-pulse and continuous-wave pumps for SCG. 相似文献
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Ghost imaging functions achieved by means of the spatial correlations between two photons is a new modality in imaging systems. With a small number of photons, ghost imaging is usually realized based on the position correlation of photon pairs produced from the spontaneous parametric down-conversion process. Here we demonstrate a way to realize multi-path ghost imaging by introducing an additional time correlation. Different delays of paths will induce the shift of the coincidence peak, which carries the information about objects. By choosing the suitable coincidence window, we obtain images of three objects simultaneously, with a visibility of 87.2%.This method provides insights and techniques into multi-parameter ghost imaging. It can be applied to other correlated imaging systems, for example, quantum spiral imaging. 相似文献
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采用旋转甩膜法制备了主客体掺杂型的偶氮类聚合物薄膜.构成薄膜的光学活性生色团包括分散红1、分散橙25、分散黄7、分散红54,基体为聚甲基丙烯酸甲酯(PMMA)或聚碳酸酯(PC)。利用扫描电镜(SEM)、X射线衍射(XRD)、差示扫描量热计(DSC)、红外光谱法(IR)、紫外-可见吸收谱仪和显微硬度仪等对样品的表面、染料的结晶性、玻璃化转变温度、掺杂聚合物的结构、薄膜的吸收谱以及硬度进行了分析。并系统研究了工艺条件对偶氮类聚合物薄膜的全光极化特性的影响。实验表明,分散染料浓度越大光极化产生的二阶非线性效应越强,这与单位面积内聚合物薄膜中含有较高浓度的分散红有关。通过普通热处理的聚合物薄膜样品,在避光保存的条件下,产生的全光极化效果最明显。总之,偶氮类聚合物薄膜全光极化下的二次谐波强度与其制备过程中的参数有密切的关系。 相似文献
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作为光子重要自由度之一,轨道角动量(OAM)在光量子信息研究中占据着重要地位。将其与偏振等光子的其他自由度相结合,可实现多自由度光量子信息处理。此外,由于其具有天然的离散高维属性,故其是开展高维量子信息处理研究的最佳自由度之一。基于自发参量下转换非线性光学过程能够便捷地获得OAM纠缠源。近年来,光子OAM量子纠缠的研究受到了广泛关注,在多自由度、高维和多光子等多个方向都取得了重要进展。然而,该领域尚有诸多悬而未决的关键科学问题亟须深入研究,包括如何实现高效高质的OAM分离,如何实现更高维度的频率转换,如何提升多自由度纠缠源的品质,如何获得更多维度、更多光子的高维纠缠态以及如何构建可行的高维量子门等。从光子OAM最基本的二维操纵着手,综述了单光子OAM量子态调控、双光子及多光子OAM纠缠操纵。围绕多自由度、大角动量和高维等特性,从生成、调控、测量及应用等角度系统讨论了光子OAM量子纠缠。同时,探索了解决本方向关键科学问题的一些可能解决途径。 相似文献