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Carrier shock and frequency conversion of a few—cycle pulse laser propagating in a non—resonant two—level atom medium 下载免费PDF全文
We have studied the spectral behaviour of few-cycle soliton pulses in a non-resonant two-level atom medium by solving the full Maxwell-Bloch equations. It is demonstrated further that the carrier effects play an important role in the propagation of the few-cycle pulse laser. When the frequency detuning is not very large, both the population distribution and the refractive index of the medium follow the oscillatory carrier field instantaneously; in this case, carrier-wave compression or carrier shock occurs, and a supercontinuum broader than that in the resonant medium may be generated. When the frequency detuning is large, the carrier shock is weak and the spectrum is not continuous, only showing an odd harmonic radiation. 相似文献
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The spectrum evolution of a few-cycle optical pulse in a resonant two-level atom medium is studied theoretically by using the full Maxwell--Bloch equations. On the propagating pulse, significantly much faster oscillation components separated with the main pulse appear due to strong self-phase modulation and pulse reshaping. In this case, ideal self-induced transparency cannot occur for a 2π pulse. The spectrum of the 4π pulse shows an evident oscillatory feature because of the continuum interference of the separate pulses. For larger pulse areas, continuum generation from near ultraviolet to infrared occurs. 相似文献
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研究了光电导天线产生太赫兹波的辐射特性,采用时域有限差分方法(FDTD)来模拟计算光电导偶极天线的辐射特性,并在计算机上以伪彩色图进行了图形显示。采用电偶极子天线模型,以0.1THz电磁波为例计算了天线辐射的特性参数,得到天线的辐射电阻为790Ω,方向性系数为1.5。结果表明,光电导天线可以采用偶极天线的理论进行计算,可以通过提高电长度来增大辐射电阻,从而提高太赫兹的辐射功率。 相似文献
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The phase-dependent feature of few-cycle pulsed laser propagation in a resonant two-level atom medium in demonstrated by solving the full Maxwell-Bloch equations.Even in the perturbative region,the propagating carrier field and the corresponding spectra of the few-cycle pulsed laser are sensitive to the initial phase due to self-phase modulation.For the larger pulse area,the fact that the carrier-wave reshaping comes from the carrierwave Rabi flopping is also responsible for this sensitivity,and the phase-dependent feature is more evident. 相似文献
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描述了我国公民科学素质的现状,研究了多种测评抽样方案,根据国务院颁布实施的《全民科学素质行动计划纲要》(2006-2010-2020年)提出的要求,研究制定了测评我国公民科学素质水平的评价指标体系. 相似文献
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