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光纤中受激拉曼散射连续谱研究 总被引:1,自引:1,他引:0
我们在实验中研究了自相位调制效应和受激四光子混频效应对受激拉曼散射光谱的影响。在较强的泵浦光和适当的入射条件下,得到九阶受激拉曼散射的级联 Stokes 连续平滑谱带,带宽3500cm~(-1),其强度可与530nm 泵浦光强相比拟。 相似文献
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从理论上分析了激光被聚焦到高压气体内可能发生各种非线性现象的规律及其相互作用和相互干扰.在实验中把Nd:YAG四倍频激光聚焦到充有甲烷的拉曼管内,测各阶斯特克斯光输出能量与气压pa、透镜焦距f和输入能量Ep之间的关系.实验结果与理论分析定性地相符合,这就为我们优化和利用受激拉曼过程提供了理论和实验依据.
关键词:
非线性过程
受激拉曼散射
四波混频
激光诱导离解 相似文献
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详细比较了磷酸二氢钾(KDP)晶体的自发拉曼散射和受激拉曼散射光谱,在受激拉曼散射(SRS)中观察到了自发拉曼散射中最强的振动模的三阶Stokes光(559.43,589.74,623.50nm),由于其他振动模的受激拉曼散射增益系数较小,其SRS光谱未观察到。另外,比较了传统生长的未退火和退火后的KDP晶体及快速生长的锥区和柱区KDP晶体的受激拉曼散射增益系数,结果表明生长方法和热退火对KDP晶体的受激拉曼散射增益系数无明显影响。 相似文献
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基于大规模光通信中频分复用的需求,本文以热原子的简并四波混频为模型,研究了具有双频段特性的双信道增益光谱.一束缀饰场诱导激发态能级发生分裂,由于量子干涉效应,四波混频信号的增益在双光子共振处被抑制,从而使增益谱线的包络由单频段转变为"M"型的双频段结构.同时,缀饰场还提高了相干基态的原子布居,进一步增强了四波混频信号的强度.最终实验上在铯原子气室内获得了一对具备双频段的双信道高增益光谱,并通过调节缀饰场的强度和频率失谐,实现了对双增益峰频率间隔的有效操控. 相似文献
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提出了一个由两个弱探测场和两个强耦合场驱动的四能级双V型原子系统, 研究发现在四波混频共振条件下, 两探测场均可被放大而无须粒子数反转. 值得注意的是, 由于所选择的激发态为超精细结构的两个近能级, 这里必须考虑自发辐射相干效应的影响. 与不考虑自发辐射相干相比, 同样参数条件下探测场的增益得到大幅度提高.而且, 探测场增益对相位非常敏感, 即增益-吸收线型受相位周期性调制, 同时也受两个偶极矩之间夹角θ制约. 此外还分析了相干抽运场 (强耦合场)的失谐对增益谱线产生的影响.
关键词:
无粒子数反转激光
四波混频
自发辐射相干 相似文献
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当酒精的弱增益拉曼模式处于罗丹明640染料分子的激光增益范围时,在由悬垂液滴构成的圆形谐振腔中,观察到乙醇分子C—H伸缩系列模中多个弱增益拉曼模式的受激拉曼散射(SRS)光谱.随着抽运光的增强,迅速增长的强增益拉曼模式的受激辐射抑制了其他弱增益模式的SRS,并导致染料激光的完全淬灭.通过分析圆形腔腔模的光子速率方程和激光染料分子的三能级粒子数速率方程,解释了观察到的实验现象.
关键词:
受激拉曼散射
悬垂液滴
弱拉曼增益模式
激光增益 相似文献
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The kinematics of pre-Maxwell electrodynamics is examined and interpretations of these fields is found through an examination of the associated Lorentz force and the structure of the energy-momentum tensor. 相似文献
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We define an operator-valued distribution on the circle with the expected properties (correlation functions, Hermiticity, etc.) of the logarithmic boson field in the cylinder compact picture. This is done starting from the known Krein space realization of the right and left movers on the light cone and considering its relation with the U(1)-current algebra. The relevance of this construction fortwo-dimensional conformal quantum field theory is discussed. 相似文献
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分析了静电放电(ESD)辐射场的偶极子模型。用高采样速率数字示波器和定做的宽带电磁与磁场探头测量了计算机操作中人体静电放电产生的瞬态电场与磁场。用FFT分析了静电放电辐射场的频谱。研究了静民放电辐射场对某电路高频信号的影响。研究结果表明,即使是很低电压(2kV)的静电放电,其辐射近场的电场达几百V/m,磁场可达几十A/m静电放电辐射场的频谱极宽,从数兆赫到数千兆赫。静电放电对高频电路的试验结果表明,若不采取有效的防护措施,人体静电放电辐射电磁场会对电路造成一定的影响,如对集成电路与元器件造成“潜在效应”的损害,对电路造成电磁干扰,甚至损坏电子器件。 相似文献
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Using Noether's procedure we directly construct a complete cubic selfinteraction for the case of spin s=4 in a flat background and discuss the cubic selfinteraction for general spin s with s derivatives in the same background. The leading term of the latter interaction together with the leading gauge transformation of first field order are presented. 相似文献
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The non-thermal effects of external electric and electromagnetic fields in the microwave to far-infrared frequency range and at (r.m.s.) electric field intensities of 10?3 to 0.25?V/År.m.s. on neat salts of 1,3-dimethyl-imidazolium hexafluorophosphate ([dmim][PF6]) and 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6]) have been investigated by means of non-equilibrium molecular dynamics simulation. Significant alterations in molecular mobility were found vis-à-vis zero-field conditions. Using Green–Kubo and transient time correlation function analysis, the electrical conductivity of these ionic liquids has been estimated. The results indicate that ionic liquids respond most significantly to frequencies much lower than those of smaller polar solvents such as water, although the mechanism of the field response is almost exclusively translational. 相似文献
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Unruh’s technique of replacing collapse by boundary conditions on the past horizon (theξ-quantisation scheme) for the derivation of the well-known Hawking radiation is extended to the Kerr black hole for the scalar
and especially for the spin half field. The expectation value of the energy momentum tensor is evaluated asymptotically in
theξ-vacuum state yielding explicitly the net Hawking flux of scalar and spin half quanta. The appropriate statistical distribution
that emerges naturally for Dirac quanta validates the ξ-scheme for fermions and confirms the association of temperature with
a Kerr black hole. 相似文献
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Roy Maartens 《Pramana》2000,55(4):575-583
Magnetic fields are observed not only in stars, but in galaxies, clusters, and even high redshift Lyman-α systems. In principle, these fields could play an important role in structure formation and also affect the anisotropies in the cosmic microwave background radiation (CMB). The study of cosmological magnetic fields aims not only to quantify these effects on large-scale structure and the CMB, but also to answer one of the outstanding puzzles of modern cosmology: when and how do magnetic fields originate? They are either primoridial, i.e. created before the onset of structure formation, or they are generated during the process of structure formation itself. 相似文献