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用酞菁酮金属有机染料首次演示了基于反饱和吸收和自聚焦两种效应的光限幅器。实验和理论分析表明,这种限幅器的输入阈值功率由反饱和吸收决定,而自聚焦使限幅器的最大限幅输出功率降低,限幅效果显著增强。 相似文献
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萘酞菁铅化合物的光限幅特性研究 总被引:6,自引:0,他引:6
应用调Q倍频ns/ps Nd:YAG脉冲激光,在波长为532nm,脉冲宽度为8ns,重复频率为1Hz的条件下,研究了溶于二甲基亚砜(DMSO)中的萘酞菁铅溶液的反饱和吸收和光限幅特性。实验表明,萘酞菁铅具有良好的光限幅特性,它的有效激发态吸收截面与基态吸收截面的比值约为15.21,大于萘酞菁铜。研究结果表明,萘酞菁铅的光限幅特性优于C60,激发态吸收是其主要的光限幅机理。实验结果证实了重原子效应可以通过增强系际跃迁而使三重态的反饱和吸收增强,从而提高光限幅的能力。 相似文献
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碳纳米粒子悬浮液具有良好的光限幅性质,是一种优良的宽波段光限幅材料。通过热传导方程和米氏散射理论建立了微气泡半径与入射光能量、碳纳米粒子悬浮液散射系数和透过率的理论模型。采用Matlab数值模拟了散射系数随微气泡尺寸因子的变化关系,碳纳米粒子悬浮液光限幅性能随入射光能量的变化规律。研究了气泡尺寸因子、入射激光能量以及波长对碳纳米粒子悬浮液光限幅特性的影响。研究发现当激光能量达到一定值时,微气泡的半径保持恒定,不再随入射激光能量的增加而增加。微气泡尺寸的增大对碳纳米粒子悬浮液的透过率有着显著的影响。同时,碳纳米粒子悬浮液对不同入射光波长和光能表现出不同的光限幅性能。研究结果为实验研究提供了理论指导。 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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通过超声波降解法制备了多壁碳纳米管的水-表面活性剂悬浮液,测量了其对于1 064 nm,脉宽10 ns Nd:YAG调Q脉冲激光的光限幅曲线。实验发现:入射激光能量密度较低时,出射能量密度随入射能量密度的增加而线性增加;当入射能量密度为160 mJ/cm2时,出射能量不再线性增加并且逐渐趋近于光限幅器的嵌位输出值,约16 mJ,同时,对激光的透过率从71%下降到15%。通过Z扫描和探针光实验以及45°散射角下散射能量、散射率随入射激光能量变化曲线的测量,对碳纳米管悬浮液的光限幅机理进行了研究。结果表明:其限幅机理可能源于碳纳米管吸收激光能量后升华产生的膨胀的碳气泡对入射激光产生的非线性散射;另外,非线性折射对光限幅效果也有一定的作用。 相似文献
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酞菁掺杂复合体系光限幅性能的基质效应 总被引:1,自引:0,他引:1
采用Sol-gel法将四磺化酞菁镍(NiTSPc)、酞菁铅(PbPc)分别植入二氧化硅凝胶基质,制备出均匀掺杂的复合凝胶玻璃,并对光限幅性能进行了测试。研究结果表明基质的组成、结构和凝胶化过程将改变复合体系中掺杂酞菁存在的微化学环境,进而影响其激发态物理过程和由此决定的光限幅性能,表现出复合体系光限幅性能的基质效应。 相似文献
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近年来,实验发现碳纳米管在光限幅中表现出良好的性质,其光限幅带宽宽,响应时间短,限幅阈值较低,使其成为继C60后又一理想的光限幅材料。为了研究其光限幅机理,测量了碳纳米管悬浮液的散射和透射能量随入射激光能量的变化,限幅过程中散射光的角度分布以及探针光随时间的变化。 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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采用布里渊噪声起源模型,数值模拟了受激布里渊散射介质CCl4对波长1064nm的Nd:YAG纳秒激光脉冲的传输特性及光限幅特性。入射抽运脉冲能量较低时,非线性介质对纳秒激光脉冲呈光学透明。入射抽运脉冲能量高于受激布里渊散射产生阈值后,透射脉冲峰值受限,脉宽压缩,能量趋于饱和,说明该光学系统同时具有光功率限幅和能量限幅的光限幅特性。利用理论模型模拟了如下光限幅参量:透射脉冲峰值功率、透射能量、能量透射率、脉宽压缩率依赖抽运光能量的变化关系。相应的理论模拟计算结果由实验进行验证,实验结果与理论模拟相符合。 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
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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
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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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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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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