共查询到16条相似文献,搜索用时 140 毫秒
1.
分析了受激布里渊散射介质CCl4对纳秒激光脉冲的传输特性及功率限幅特性. 结果表明:透射脉冲波形随抽运光能量增加而压缩变形,脉冲前沿保持高斯型,后沿被压缩成功率“平台”,功率“平台”随抽运脉冲能量增加而逐渐变宽,但功率水平不变,表明该光学系统具有的功率限幅特性. 详细分析了功率限幅特性随抽运能量的变化规律和时间响应特性规律,采用脉宽为10ns、波长为1.06μm的Nd:YAG激光脉冲进行实验验证,理论与实验结论相符合.
关键词:
受激布里渊散射
功率限幅 相似文献
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采用布里渊噪声起源模型,数值研究了非聚焦条件下CS2液体介质中脉冲传输的能量与功率特性.结果表明,在非聚焦条件下,透射光的功率波形仍然表现出光限幅特性,而透射能量随入射能量线性变化,不具有限幅特性,这一点与聚焦条件下的结果不同.以波长1053nm、脉宽20 ns的Nd:YLF激光器为光源,采用3∶1的缩束系统,通过衰减片调整入射光能量在2mJ—92mJ变化,获得了透射光能量和功率波形随入射能量变化的规律,并与聚焦条件下的结果进行了比较.实验结果与理论模拟相符合.由于聚焦条件下当入射能
关键词:
非线性光学
受激布里渊散射
光限幅
非聚焦 相似文献
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采用受激布里渊散射(SBS)噪声起源理论模型,数值模拟了透镜焦距对SBS光限幅功率特性和能量特性的影响.结果表明,改变透镜焦距就可以方便的控制SBS光限幅的功率波形和输出能量.当采用焦距适中的透镜(f=15cm)时,可以得到较低的限幅输出能量;当采用短焦距的透镜(f=5cm)时,可以得到较理想的限幅功率波形.在实验上将波长1064nm、脉宽8ns、能量16mJ的Nd:YAG激光脉冲聚焦到CCl4介质中,研究了限幅功率波形和限幅输出能量随透镜焦距的变化规律,实验结果与理论模拟相符合.
关键词:
受激布里渊散射
光限幅
数值模拟 相似文献
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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)系统中,具有一定带宽的抽运激光中会含有一定比例的Stokes散射光成分,此Stokes散射光成分经SBS介质后表面反射后,将形成种子光与抽运光联合入射,构成自种子光式SBS放大器.通过数值求解此SBS放大器型耦合波方程组,探讨了抽运光脉冲中所含Stokes散射光成分的比例、抽运激光波长、抽运光能量大小、入射的聚焦高斯光脉冲脉宽、相互作用时间等激光参数对SBS特征参数(Stokes散射光脉冲波形、材料内部最大应力的时间演化及空间分布、脉宽压缩效果、能量提取效率及Stokes散射光的共轭保真度)的影响.同时发现,SBS过程中产生的超声应力不仅会对SBS介质前表面造成破坏,还可能对焦点附近造成破坏;调整各激光参数还会使焦点附近优于前表面先破坏.数值模拟中采用的抽运光是聚焦高斯光束.
关键词:
受激布里渊散射
斯托克斯散射光
冲击应力
能量反射率 相似文献
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采用布里渊噪声起源模型,数值研究了非聚焦条件下CS2液体介质中脉冲传输的能量与功率特性.结果表明,在非聚焦条件下,透射光的功率波形仍然表现出光限幅特性,而透射能量随入射能量线性变化,不具有限幅特性,这一点与聚焦条件下的结果不同.以波长1053 nm、脉宽20 ns的Nd:YLF激光器为光源,采用3∶1的缩束系统,通过衰减片调整入射光能量在2 mJ-92 mJ变化,获得了透射光能量和功率波形随入射能量变化的规律,并与聚焦条件下的结果进行了比较.实验结果与理论模拟相符合.由于聚焦条件下当入射能量较高时容易出现介质光学击穿,所以采用缩束结构的功率限幅更适用于高功率大能量的情况. 相似文献
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The optical limiting effect based on stimulated Brillouin scattering (SBS) in a nonlinear medium was investigated. We numerically treated the nonlinear propagation process with a theoretical model, which includes the spontaneous nature of the initiation of SBS, and obtained optical limiting effect in the process. Energy limiting, pulse reshaping and stabilization have been demonstrated on SBS mechanism with the nonlinear medium CCl_4. The input optical signals were Nd:YAG nanosecond laser pulses with width varying from 16ns to 7ns then to 2ns, the relationship between the transmitted signal and launched pump signal was shown. In the experimental regime, the most stable pulse and a superior energy stabilization of the transmitted pulse were obtained when the laser pulse-width became as short as 2ns. For the energy variation of laser pulses in a wide range of 14-88mJ, the output energy was limited in a quite narrow range 4.5-5.5mJ. 相似文献
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W. L. J. Hasi Z. W. Lu M. L. Fu H. H. Lu S. Gong D. Y. Lin W. M. He 《Applied physics. B, Lasers and optics》2009,95(4):711-714
In order to improve the optical limiting performance based on stimulated Brillouin scattering (SBS), a method based on double
SBS is proposed in this paper. The dependence of the output energy of optical limiting based on double SBS on the pump energy
is numerically simulated, and experimentally validated with an Nd:YAG seed-injected laser. The results indicate that only
the first SBS optical limiting works in the case of low pump energy. However, as the pump energy increases, the second SBS
process can be activated if the transmitted power of the first SBS is still above the SBS threshold. Therefore, the output
energy characteristic of optical limiting based on double SBS is much better than that based on single SBS. Owing to the sub-nanosecond
response time and a high power threshold, the SBS optical limiting can provide protection in high power laser systems. 相似文献
13.
Measurement of stimulated Brillouin scattering (SBS) threshold based on waveform variation of SBS optical limiting 下载免费PDF全文
This paper proposes a method for measuring the stimulated
Brillouin scattering (SBS) threshold based on waveform variation of
SBS optical limiting. The output waveforms for different pump power
densities are numerically simulated, and validated in the Nd:YAG
seed-injected laser system. The results indicate that SBS does not
take place in the case of a low pump power density and thus the
output power scales up linearly with pump power. Once the pump power
density exceeds the SBS threshold, SBS takes place and thereby the
energies are transferred from pump to Stokes. As a result, a small
shoulder appears in the trailing edge of the output waveform, which
provides another method to determine the SBS threshold. 相似文献
14.
W. L. J. Hasi Z. W. Lu S. Gong D. Y. Lin W. M. He R. Q. Fan 《Applied physics. B, Lasers and optics》2008,92(4):599-602
Stimulated Brillouin scattering (SBS) featuring sub-nanosecond response time takes place at a high power threshold, which
enables its application at a high power density. When the intensity of input light excesses the SBS threshold, strong SBS
process takes place through SBS medium, leading to a quick energy transfer from pump to the Stokes and thereby an optical
limiting characteristic in the output energy. In this paper, the correlation between SBS output energy and input power density
is numerically simulated and validated in the Nd: YAG Q-switch laser system. The results indicate that not only the output
energy exhibits an optical limiting characteristic, but also the clamped value of output energy can be controlled by changing
the medium or the focal length. 相似文献
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为了使受激布里渊散射(SBS)光限幅器的输出能量更"平",提出了一种基于SBS光限幅和金属酞菁光限幅相结合的复合型光限幅器的方案,即SBS光限幅后边放置金属酞菁光限幅,在两种光限幅器的共同限幅作用下,使复合型光限幅器的输出光能量更"平". 数值模拟了该复合型光限幅器的输出光能量随入射光强度的变化曲线,并在Countinuum's Nd: YAG种子注入式激光器中进行了实验验证. 理论和实验结果均表明,复合型光限幅器的输出光能量比单独SBS光限幅器更"平".
关键词:
复合型光限幅器
SBS光限幅
金属酞菁限幅 相似文献
16.
分析了利用光纤中的受激布里渊散射(stimulated Brillouin scattering,SBS)相位共轭效应进行激光腔内调Q,产生ns量级脉冲激光的原理,并对利用该效应产生的激光脉冲波形和脉冲形成过程进行了数值模拟,得到的脉冲波形与SBS相位共轭反射率随时间变化曲线基本一致,表明利用光纤中的SBS相位共轭作用调Q具有可行性.据此,对采用单模光纤(single-mode fiber,SMF)作为SBS池的Er3+掺杂调Q光纤激光器进行实验研究.当单模光纤长度为1.5 m时,在45 mW的光抽运功率下得到脉宽约2.6ns,脉冲周期58.23ns,平均功率7.35mW的激光脉冲.进一步的研究表明:激光器中相位共轭镜的形成与SBS介质长度有关,SBS介质过长,斯托克斯线之间无固定的相位关系,不能形成相干叠加,SBS相位共轭腔不能形成;SBS介质过短,腔内正交偏振模光子寿命的改变使脉冲出现双峰现象.脉冲形成后其属性只与SBS动态属性有关. 相似文献