共查询到20条相似文献,搜索用时 399 毫秒
1.
2.
3.
4.
假设石英光纤的Raman增益谱为线性谱,并给出了拟合直线.以此为基础,得到了前向N信道 受激Raman散射稳态耦合波方程的解析解.这个解析解是在考虑了N个信号光之间串话下得到 的,它适用于任意功率大小的信号光和任意信道间隔排列的情况.N个信号光在石英光纤中经 过受激Raman散射作用后,具有以下特点:在传输过程中,任意两信道的信号光光子通量的比 值随光纤的有效互作用长度、总的输入光子通量和两信道频率间隔按指数规律变化.解析解 与数值解进行了比较,两者取得了很好的一致.
关键词:
受激Raman散射
密集波分复用
石英光纤
Raman放大 相似文献
5.
6.
为提高液体介质中受激拉曼散射的输出能量,提出了通过温度调控来抑制受激布里渊散射的方法,设计了532 nm多纵模宽带脉冲激光泵浦的受激拉曼散射发生系统,测量了不同温度下水中前向受激拉曼散射及后向受激布里渊散射的输出能量,分析了水温、泵浦激光线宽及热散焦效应对受激拉曼散射输出能量影响的物理机制.实验结果表明:通过降低水温可实现对受激布里渊散射过程的有效抑制,同时减小热散焦效应带来的光束畸变,从而有效提高受激拉曼散射的输出能量.研究结果对液体介质中的受激拉曼散射多波长转换具有重要意义. 相似文献
7.
8.
电子俘获是激光尾波场加速电子的主要机理,增大电子的初速度可以使更多的电子被尾波场俘获.提出三角脉冲激发尾波加速电子的方案,三角脉冲平缓上升沿激发受激Raman散射,用以初步加速电子,三角脉冲陡峭下降沿激发尾波场,将更多的电子加速到接近光速.2D3V粒子模拟结果证实了这一点.同时表明:脉冲长度为几个等离子体波长的超强激光在稀薄等离子体中传播时,还激发侧向Raman散射.在侧向受激Raman散射中,静电波增长最快的波矢模式为kp=(2ωp/ω0
关键词:
有质动力
电子俘获
前向受激Raman散射
侧向受激Raman散射 相似文献
9.
带受激布里渊散射池的位相共轭激光器输出的空间特性 总被引:1,自引:1,他引:0
本文应用传输矩阵的方法对受激布里渊散射位相共轭腔输出的空间特性进行了分析及编程计算,给出了各种参数下受激布里渊散射-位相共轭腔的传输光束轮廓图,同时给出了实验结果与之相比较,提出了设计受激布里渊散射共轭腔时应注意的问题及几种实用的受激布里渊散射位相共轭腔的腔型。 相似文献
10.
11.
R. J. Heeman H. P. Godfried W. J. Witteman 《Applied physics. B, Lasers and optics》1995,60(5):479-484
High energy-conversion efficiencies in Stimulated Raman Scattering (SRS) are demonstrated both in experiments and by simulations for pump powers below SRS threshold. The scattering is induced by a short seed pulse at the Stokes frequency, the pulse width of which is much shorter than the pump pulse width and which is comparable with the medium's dephasing time. 相似文献
12.
A theory of real-time dependence of Raman scattering for a pulse-mode laser is developed within second-order perturbation theory and using the wavepacket terminology.We apply the theory to continuum Raman scattering for short and long pulses and varying pulse carrier frequency,For an initial ground virational state,it is shown that the rate of Raman emission as a funcition of time and pulse carrier frequency is structureless for all pulses,and for pulses that are longer than the dissociation time the rate also decays with the pulses.This is contrary to recently reported resonance fluorescence type structures at long times (M.Shapiro,J.Chem.Phys.99,2453(1993),We explain why such structures are unphysical for continuum Raman scattering. 相似文献
13.
V. P. Kochanov 《Journal of Experimental and Theoretical Physics》2009,109(6):913-923
We have developed a theory of the nonlinear ring interaction of three intense fields in the scheme of resonant Raman scattering
on the dipole-allowed transition from the ground state to the first excited state of a cascade three-level quantum system.
We show that the backward Stokes radiation generated by a pump resonant to the dipole-forbidden transition can be used in
remote laser sensing of metal vapors. 相似文献
14.
Surface enhanced Raman scattering (SERS) due to charge transfer interactions between the adsorbed molecule and the metal surface is analyzed using the semiempirical Wolfsberg-Helmholz method1 to relate the molecule-surface interactions and the resulting charge transfer states to the overlap integrals between the metal conduction-band orbitals and an acceptor or donor molecular orbital of the molecule. Calculations for the model system of ethylene adsorbed on silver (approximated as a simple cubic metal with tight binding wave functions constructed from Ag 5s valence orbitals), with charge-transfer excitation of an electron from the metal to the antibonding ethylene π orbital, show that charge-transfer Raman enhancements of the order of 10 to 1000 are possible if the charge-transfer band is partially resonant with the exciting radiation. The net enhancement is the product of the charge-transfer gain and the electrodynamic enhancement due to plasmon resonances at surface roughness elements. Symmetric vibrations usually will be enhanced substantially more than nonsymmetric ones by charge-transfer because, in contrast to non-resonant Raman scattering, the vibrational coupling is primarily Franck- Condon (due to differences in the equilibrium nuclear configurations of the ground and excited charge transfer states and the resulting nonorthogonality of different vibrational sublevels of these states) rather than Herzberg-Teller (due to vibrationally induced changes in the electronic wave functions). The charge-transfer mechanism is selective with the most enhanced vibrations involving those atoms which experience the greatest change in electron density between the ground and excited charge-transfer state. A recent report of SERS for benzene on platinum,2 strongly suggests charge-transfer enhancement because the electromagnetic-field-enhancing plasmon resonances are strongly damped in this metal.The complete paper will be published in the December 1, 1982 issue of the Journal of Chemical Physics. 相似文献
15.
Jin-Qi Wang 《中国物理 B》2022,31(9):90601-090601
Sideband cooling is a key technique for improving the performance of optical atomic clocks by preparing cold atoms and single ions into the ground vibrational state. In this work, we demonstrate detailed experimental research on pulsed Raman sideband cooling in a $^{171}$Yb optical lattice clock. A sequence comprised of interleaved 578 nm cooling pulses resonant on the 1st-order red sideband and 1388 nm repumping pulses is carried out to transfer atoms into the motional ground state. We successfully decrease the axial temperature of atoms in the lattice from 6.5 μK to less than 0.8 μK in the trap depth of 24 μK, corresponding to an average axial motional quantum number $\langle n_z\rangle<0.03$. Rabi oscillation spectroscopy is measured to evaluate the effect of sideband cooling on inhomogeneous excitation. The maximum excitation fraction is increased from 0.8 to 0.86, indicating an enhancement in the quantum coherence of the ensemble. Our work will contribute to improving the instability and uncertainty of Yb lattice clocks. 相似文献
16.
17.
Femtosecond stimulated Raman microscopy (FSRM) is an upcoming technique in nonlinear microscopy which facilitates rapid chemical mapping. It employs femtosecond white‐light pulses as probe pulses and intense picosecond pulses as pump pulses. Stimulated Raman scattering (SRS) occurs at the focus of a scanning microscope. Chemical constituents in the sample are identified via their Raman signatures. In this article, disturbing interference patterns in FSRM are reported. They are caused by a broadening of the pump pulse due to nonlinear interactions in the focal region of the microscope and reduce the signal‐to‐noise ratio. The properties of these modulations are explored, and the methods to suppress them are presented. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
18.
W. Schatz P. T. Lang T. Kass M. A. Heusinger K. F. Renk 《International Journal of Infrared and Millimeter Waves》1992,13(6):853-867
In this paper we report on the determination of the spectral width of Raman gain regions for different far infrared laser gases using a metal mesh Fabry Pérot interferometer. By use of broadband pump radiation emitted from a high pressure CO2 laser we generated far infrared radiation within the Raman gain regions via stimulated Raman scattering. The spectral width of the far infrared radiation was determined using a Fabry Pérot interferometer in high interference order. We applied the method to study stimulated Raman scattering in D2O and methylfluoride at different gas pressures. 相似文献
19.
Synchronously pumped Raman oscillators allow for an efficient frequency conversion of pump pulses whose power is well below the threshold for extracavity stimulated Raman scattering (SRS). Numerical simulations show that the cavity mismatch of pump laser and Raman oscillator is critical for maximum conversion efficiency and minimum pulse duration for transient and stationary SRS. At a certain mismatch the simulations predict a quasi-cw Raman oscillator output even at moderate cavity quality factors. Optimum operation conditions are discussed for pump pulse trains of finite lengths. The results of the numerical calculations are in qualitative agreement with a simple phenomenological model. PACS 42.55.Ye; 42.65.Dr; 42.55.Lt 相似文献
20.
根据参量放大和拉曼效应共同作用下的耦合波方程,在考虑高阶色散情况下,当输入泵浦波偏振方向同双折射轴成45时,通过引入拉曼增益的洛伦兹模型,研究了高双折射光纤中,参量放大和拉曼效应共同作用下的增益谱随相关参量的变化关系。结果表明:高双折射光纤中,在不同色散区,不同的输入参量(输入功率、群速度失配等)条件下,参量放大和拉曼效应共同作用下的增益谱受到高阶色散的影响,增益谱的结构、强度和谱宽产生了变化, 高阶色散对增益谱的影响不可忽略;可以利用增益谱在大群速度失配区域远离中心频率偏移的性质,提取T频率脉冲。 相似文献