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41.
A long optically controlled delay line enhanced by ring configuration is demonstrated by using the group-velocity control of signal pulses based on stimulated Brillouin scattering. In experiment, two optical fibre ring cavities are used: one is used as the Brillouin laser, providing single-mode Stokes wave as probe wave; the other is used as the Brillouin amplifier, working as slow light medium. We achieve a maximum time delay of 215ns using the ring Brillouin amplifier, five times larger than the input probe pulse width of 40ns. In the meantime, a considerable pulse broadening is observed, which agrees well with the theoretical prediction based on linear theory. 相似文献
42.
从实验和理论上研究了受激布里渊散射(SBS)光脉冲波形.在Nd∶YAG调Q激光器中实验研究了SBS光脉冲波形随抽运光参数、结构参数和介质参数的变化规律,并利用SBS理论模型进行了数值模拟,实验与数值模拟结果的变化趋势基本一致.结果表明,抽运光能量越小,透镜焦距越短,镜-池间距越长,介质声子寿命越长,SBS光脉冲波形就越不容易出现调制现象.分析和讨论了抽运光参数、结构参数和介质参数对SBS光脉冲波形的影响机理.
关键词:
受激布里渊散射
脉冲波形
抽运光参数
结构参数 相似文献
43.
理论研究了受激布里渊散射过程中功率限幅响应特性.采用高斯型入射脉冲,数值模拟了抽运参数(抽运峰值功率密度、抽运脉冲宽度),介质参数(增益系数、声子寿命)和结构参数(聚焦透镜焦距、介质池长)等物理参数影响限幅输出波形中剩余峰的特性规律.对如何控制剩余峰进行了理论分析.研究表明,声子寿命较小、增益系数大的布里渊介质光限幅响应较好,声子寿命较大、增益系数小的布里渊介质光限幅响应较差;无法单纯通过控制布里渊介质参数来完全消除剩余峰.实验上采用染料片吸收剩余峰,获得接近平顶的限幅输出波形. 相似文献
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受激布里渊散射(SBS)介质——全氟聚醚(PFPE)不仅具有低吸收高负载的SBS特性,还具有低的流点或高的沸点,可适合于较宽温度范围之内工作.通过分析PFPE的化学结构,对PFPE具有良好的SBS特性及独特物理化学特性进行了解释.在连续Nd:YAG种子注入激光系统中选用HT230,DET和HS260三种PFPE进行了不同温度下SBS特性研究.结果表明,PFPE不仅具有良好的SBS特性,还可以在低温或高温条件下工作,这为不同温度下研究SBS相位共轭镜打下了良好的基础. 相似文献
46.
The spontaneous emission decay dynamics of a tripod configuration four-level atom driven by a single laser field is studied.Under different initial conditions,we discuss the effects of quantum interference and detuning of external driving field on atomic spontaneous emission properties.For the larger detuning,the interesting phenomena of the spectral line narrowing are found which stem from the contribution of external driving field. 相似文献
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A method to measure the Brillouin frequency shift of the medium through Brillouin amplification ratio 下载免费PDF全文
In order to measure the Brillouin frequency shift (BFS) of the
medium, this paper proposes a method using mixtures in a two-cell
stimulated Brillouin scattering system, which uses a medium to be
measured as amplifier medium and a mixture medium as generator
medium. The seed light from the generator gains effective
amplification in the amplifier and the amplification ratio changes
with the mixing fraction. Only when the BFS of the mixture medium is
equal to that of the medium in the amplifier does the seed light
obtain the maximum amplification ratio. The method has the advantage
of independence of the wavelength of the incident light. 相似文献
49.
Investigation of stimulated rotational Raman scattering of the high-power broadband laser with applied angular dispersion 下载免费PDF全文
Smoothing by spectral dispersion (SSD) leads to considerable improvement on laser-irradiation uniformity in far field for fusion lasers. Phase modulation in time and spectral angular dispersion (SAD) across the beam introduced by SSD will affect the stimulated rotational Raman scattering (SRRS) gain in the near field. This paper focuses on the influence of SAD on SRRS gain under different laser conditions. Results show that the SAD will aggravate the generation of SRRS when the laser initial additional phase is constant. On the contrary, the SAD can reduce the SRRS gain if appropriate SSD parameters are adopted when the laser initial additional phase is variable. SSD has a certain application prospect in SRRS suppression. 相似文献
50.
为了抑制大口径光学元件中的受激Brillouin散射效应,并满足打靶过程中束匀滑的要求, 目前高能激光驱动器大都采用了正弦相位调制脉冲.然而,这类脉冲在复杂激光系统中传输时, 会出现明显的调频-调幅(FM-to-AM)效应.研究这种效应的来源,对提升激光系统的整体输出性能至关重要. 对复杂激光系统中一直被人们所忽视的平板光学元件带来的FM-to-AM效应进行了理论研究和数值模拟. 数值模拟结果表明,通过平板光学元件的次数越多调制深度越大,呈线性递增趋势,当通过次数为10次时, 调制深度高达22.2%;并且平板光学元件对各谱线的过滤也各不相同,当前端选用的中心波长为1054 nm时, 平板光学对各谱线的过滤作用非常小.提出通过改变中心波长来减小FM-to-AM效应, 这对于复杂激光系统的设计具有重要的指导意义. 相似文献