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半绝缘6H型碳化硅(6H-SiC)具有高电阻率性质,在可见光照射下进行光电导测量时,通常光生电流很小;然而经过飞秒激光辐照改性之后,发现在可见光波段的光电导有明显的增益.本文利用紫外-可见-近红外吸收谱、X射线光电子能谱和发光光谱测量分析了激光改性之后碳化硅样品的光谱吸收、发射和晶体元素比例变化情况.分析认为碳化硅光电导增益的原因是飞秒激光辐照过程改变了碳化硅表面的硅碳元素的原子浓度比,形成新的物质结构形式,从而导致了表面光电导性能的提高. 相似文献
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The femtosecond temporal speckle field of a random medium is
studied theoretically and experimentally. Femtosecond temporal
speckle arises from the interference of multiple randomly scattered
electric fields. The femtosecond temporal speckle field is measured with
a cross-correlation frequency-resolved optical gating method. The
spatial average of the speckle field yields a smooth transmitted
profile. The speckle field is a circular complex Gaussian variable
because the scattered light beams from different trajectories have
no correlation with each other. The field and the intensity profiles
of individual speckle spots fluctuate randomly in time. The ensemble
average of the temporal intensity profiles converges, thereby
yielding the photon travel time probability distribution
function. 相似文献
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This paper investigates the generation of self-organized
surface structures on amorphous alloys by vortex femtosecond laser
pulses. The scanning electron microscope characterizations show that
the as-formed structures are periodic ripples, aperiodic ripples,
and `coral-like' structures. Optimal conditions for forming these
surface structures are determined in terms of pulses number at a
given pulse energy. The applicable mechanism is suggested to
interpret the formation and evolution of the `coral-like'
structures. 相似文献
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使用532nm,8ns激光脉冲研究了两种新型的基于富勒烯C60结构体系的金纳米粒子合成物的光学非线性.Z-scan实验结果和理论分析的比较表明,材料的非线性吸收强烈地依赖于材料中的配合体,而非线性折射主要来自金纳米粒子的贡献.而且与熟知的C60甲苯溶液光限幅特性作了比较,分析了光限幅机理.
关键词:
60结构体系')" href="#">基于富勒烯C60结构体系
金纳米粒子
等离子体
光限幅 相似文献
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The effects of heat treatment on microfluidic devices fabricated in silica glass by femtosecond lasers 下载免费PDF全文
We fabricated complex microfluidic devices in silica glass by water-assisted femtosecond laser ablation and subsequent heat treatment.The experimental results show that after heat treatment,the diameter of the microchannels is significantly reduced and the internal surface roughness is improved.The diameters of the fabricated microchannels can be modulated by changing the annealing temperature and the annealing time.During annealing,the temperature affects the diameter and shape of the protrusions in microfluidic devices very strongly,and these changes are mainly caused by uniform expansion and the action of surface tension. 相似文献
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Optical limitation(OL) performances of the gold nanoclusters protected by C60-tpy have been investigated with 8 ns pulses at 532nm.The experimental results show that the nanocomposite possesses OL effects superior to C60 in toluene.The main mechanism of OL is attributed to the nonlinear absorption and subsequently induced nonlinear scattering during excitation of the pulse.Ageing of the nanocomposite chloroform solution in air lowers the OL performances by a factor of 2.4,which can be due to the formation of aggregates of large gold particles. 相似文献
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激光诱导玻璃内部金纳米颗粒的析出及光谱 总被引:4,自引:0,他引:4
使用钛宝石飞秒激光引发和热处理相结合,实现了在含有金离子的硅酸盐玻璃内部,有空间选择性地析出金纳米颗粒。对吸收光谱的研究表明,随着热处理温度的升高,吸收峰强度增大且红移;随着激光功率密度的增大,金纳米颗粒也增大。在特定的激光和热处理条件作用下,可以在玻璃内部有空间选择性的使金离子还原后聚集,形成金纳米颗粒,具有量子尺寸效应。改变激光功率和热处理温度可以控制所析出的金属纳米粒子的尺寸,从而实现多色显示,飞秒激光诱导金纳米颗粒具有稳定性,颜色具有持久性。 相似文献