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无序介质激光是由该介质的非周期-类结构与相匹配的泵浦光场相互作用时其整体多重散射的干涉效应产生的.因此其局域模不仅与无序介质被泵浦的功率、面积有关,而且与方向有关.本文以ZnO粉末激光为例,运用传输矩阵的方法计算模拟了其局域模谱的方向效应. 相似文献
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基于具有局域-非周期-类结构的活性无序介质中的复杂局域模与合适泵浦光的相互作用模型,研究活性无序介质中泵浦功率对局域模发射的影响,定性解释了泵浦功率对局域模发射的影响.结果表明,局域-非周期-类结构的无序介质的透射谱只与介质的结构有关,而与介质的损耗和增益无关,不同的激发模具有不同的泵浦功率阈值. 相似文献
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基于相干反馈无序激光理论,以ZnO粉末激光器为例,模拟了光子在无序介质中的行为.发现只有密度达到临界值时才能出射激光;另外,当ZnO散射体密度不断增加时,系统的增益与损耗之比不断变大.系统激射激光变得更容易,以及满足激光激射所需的临界增益系数要求也越来越低,这与实验结果是相符的. 相似文献
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本文通过数值仿真分析了无序正方晶格光子晶体中类狄拉克点的光子传输特性. 结构中的无序是通过随机移动氧化铝介质柱的位置来实现. 研究发现, 由于纵模被激发出来, 在类狄拉克点及其附近无序对结构透射率的影响是不同的. 在类狄拉克点, 由于纵模的干扰, 透射率随着无序的增加而减小, 与通带的行为类似. 在不受纵模干扰的类狄拉克点附近, 透射率几乎不受无序的影响, 这主要是由于结构可以等效为近零折射率材料, 等效的波长非常大. 本文的研究结果有助于人们进一步理解光学纵模和零折射率材料. 相似文献
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实验发现当一束较强的抽运激光(526nm)与一束较弱的探测激光(6328nm)相交通过非线性 介质薄膜(聚吡咯甲烯/聚乙烯醇薄膜)时,在探测光束的远场产生了中心为亮斑,近场中心 为暗斑的多个同心衍射环.从菲涅耳-基尔霍夫衍射积分公式出发,理论分析了产生这种现象 的原因是抽运光在非线性介质中诱导的相位孔对探测光的衍射效应.通过数值积分,计算结 果与实验结果符合.
关键词:
聚合物非线性光学薄膜
抽运-探测
激光诱导衍射 相似文献
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Lasing was achieved in a new type of random laser: the planar random microcavity laser. The laser consists of a planar microcavity with a random gain layer. Optical confinement by the two-dimensional random cavity and the one-dimensional planar microcavity drastically reduces the number of resonant modes. As a result, the laser output is highly directional (the divergence angle is 1.68 degrees) with an extremely narrow-linewidth and ultralow threshold. All these phenomena are explained in terms of the coupling of random cavity modes and planar microcavity modes. The results demonstrate an important step towards applications of random lasers. 相似文献
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V. P. Bykov 《Journal of Russian Laser Research》1997,18(3):260-275
Modern high-stability lasers are extremely precise measuring instruments. It is not surprising that laser investigations often deal with the most essential problems of quantum theory. In the present paper, two close questions are discussed concerning laser physics: the reason for random photocounts in photodetectors under the action of high-coherence light and the reason for the smallness of quantum-mechanical wave packets of macroscopic bodies. Conventionally, these phenomena are explained on the basis ofa priori statistical (stochastic) approaches. The paper shows that such an explanation is internally contradictory in the context of modern laser measurements. It is also shown that these phenomena have natural explanations in terms of physics—the first, on the basis of the instability and stochastic character of electron plasma in electronic devices, and the second, on the basis of the gravitational self-focusing of wave packets for macroscopic bodies. Thus, it is shown thata priori statistical explanation of some phenomena is not physically justified, and by abandoning it one can get deep insight into them. 相似文献
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We study the nonlinear dynamics of a multimode random laser using the methods of statistical physics of disordered systems. A replica-symmetry breaking phase transition is predicted as a function of the pump intensity. We thus show that light propagating in a random nonlinear medium displays glassy behavior; i.e., the photon gas has a multitude of metastable states and a nonvanishing complexity, corresponding to mode-locking processes in random lasers. The present work reveals the existence of new physical phenomena, and demonstrates how nonlinear optics and random lasers can be a benchmark for the modern theory of complex systems and glasses. 相似文献
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A. A. Berezin A. R. Karimov S. A. Reshetnyak V. A. Shcheglov 《Journal of Russian Laser Research》2002,23(4):381-393
It is shown in numerical study that the simultaneous influence of discrete and continuous random processes on the Fermi–Pasta–Ulam (FPU) recurrence dynamics in chains of vibrators having both fixed and open ends leads to a widening of the FPU spectrum and to its permanent evolution. These phenomena are much more markedly manifested in the chain with open ends. Taking into account that the FPU recurrence takes place in distributed oscillatory systems one of which is a laser, the present research can be promising in developing multimode lasers exhibiting the recurrence phenomena. 相似文献
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The statistical distribution of natural phenomena is of great significance in studying the laws of nature. In order to study the statistical characteristics of a random pulse signal, a random process model is proposed theoretically for better studying of the random law of measured results. Moreover, a simple random pulse signal generation and testing system is designed for studying the counting distributions of three typical objects including particles suspended in the air, standard particles, and background noise. Both normal and lognormal distribution fittings are used for analyzing the experimental results and testified by chi-square distribution fit test and correlation coefficient for comparison. In addition, the statistical laws of three typical objects and the relations between them are discussed in detail. The relation is also the non-integral dimension fractal relation of statistical distributions of different random laser scattering pulse signal groups. 相似文献
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基于混沌激光实现全光物理随机数发生器的物理基础是完成对混沌光信号的高速实时全光采样. 本文利用偏振无关的SOA构建出TOAD全光采样门, 以光反馈半导体激光器产生混沌激光, 对混沌激光的全光采样可行性进行了原理性实验论证, 实现了对光反馈半导体激光器产生的6.4 GHz带宽的混沌激光5 GSa/s的实时、高保真全光采样. 进一步研究显示, 光采样周期与外腔反馈时间成比例与否对混沌信号弱周期性的抑制水平影响显著. 当两者不成比例时, 可有效消除原始混沌信号的弱周期性, 有利于高质量物理随机数的产生. 相似文献
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Jiangying Xia Jijun He Kang Xie Xiaojuan Zhang Lei Hu Yaxin Li Xianxian Chen Jiajun Ma Jianxiang Wen Jingjing Chen Qiaosheng Pan Junxi Zhang Ilya D. Vatnik Dmitry Churkin Zhijia Hu 《Annalen der Physik》2019,531(9)
Spin‐glass theory has been widely introduced to describe the statistical behaviors in complex physical systems. By analogy between disorder photonics and other complex systems, the glassy behavior, especially the replica symmetry breaking (RSB) phenomenon, has been observed in random lasers. However, previous studies only analyzed the statistical properties of the random laser systems with single gain material. Here, the first experimental evidence of the glassy behavior in a random laser with complex energy level structure is reported. This novel random laser is demonstrated based on the electrospun polymer fibers with the assistance of Förster resonance energy transfer (FRET). The electrospinning technology employed in the experiment herein promises high‐volume production of random laser devices with multiple energy levels, enabling the comprehensive investigation of lasing properties in multi‐energy level random laser system. Clear paramagnetic phase and spin‐glass phase are observed in the FRET‐assisted random laser under different pump energies. The RSB phase transition is verified to occur at the laser threshold, which is robust among the random lasers with different donor–acceptor ratio. The finding of RSB in FRET‐assisted random laser provides a new statistical analysis method toward the laser system with complex energy level, for example, quantum cascade laser. 相似文献
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利用连续波段内激光对两批光伏型碲镉汞探测器进行了激光辐照实验, 发现了两种不同的过饱和现象. 实验表明, 光伏型碲镉汞探测器在强光辐照下都会出现开路电压随光强增强而减小的过饱和现象, 明晰了PV型探测器在强光辐照下的一般规律性现象和由探测器个体差异导致的特殊现象. 从等效电路模型出发, 剖析了两种过饱和现象的发生条件, 建立了数值计算的理论模型, 对两种过饱和现象进行了数值模拟, 计算结果与实验结果符合得较好. 研究表明, 光伏型碲镉汞探测器在波段内强光辐照下引起的过饱和现象有两种产生机理, 一种是热效应引起的暗电流增大机理; 另一种是探测器材料中缺陷引起的漏电流增大机理.
关键词:
波段内连续激光
光伏型碲镉汞探测器
过饱和现象 相似文献