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Rabi Oscillations and Coherence Dynamics in Terahertz Streaking-Assisted Photoelectron Spectrum 下载免费PDF全文
We present an approach,a Terahertz streaking-assisted photoelectron spectrum(THz SAPS),to achieve direct observations of ultrafast coherence dynamics with timescales beyond the pulse duration.Using a 24 fs probe pulse,the THz SAPS enables us to well visualize Rabi oscillations of 11.76 fs and quantum beats of 2.62 fs between the 5S1/2 and 5P3/2 in rubidium atoms.The numerical results show that the THz SAPS can simultaneously achieve high resolution in both frequency and time domains without the limitation of Heisenberg uncertainty of the probe pulse.The long probe pulse promises sufficiently high frequency resolution in photoelectron spectroscopy allowing to observe Autler-Townes splittings,whereas the streaking THz field enhances temporal resolution for not only Rabi oscillations but also quantum beats between the ground and excited states.The THz SAPS demonstrates a potential applicability for observation and manipulation of ultrafast coherence processes in frequency and time domains. 相似文献
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太赫兹光谱成像,不但包括在二维图像空间的强度信息,同时可以得到太赫兹波段的光谱信息,构成了一个三维的数据矩阵。由于受到太赫兹成像系统内部硬件的限制和影响,太赫兹频域较高频段处信号存在能量弱、信噪比低的特点,导致所成的太赫兹图像普遍存在分辨率低、对比度低等问题。因此,利用三维数据矩阵,应用适合的算法,实现了提高太赫兹光谱成像空间分辨率、边缘细节可见度的目的。搭建了三维可移动式太赫兹时域光谱成像系统,实现了对标准高分辨率板的二维扫描。对该系统所采集到的信号分别进行时域、频域等多种方式成像对比,结合瑞利判据和分辨率标尺对成像系统的空间分辨率、景深进行标定,研究了提高太赫兹光谱成像的空间分辨率算法。然后,针对太赫兹频域高频区域信噪比低、对比度低、噪声原因复杂的特点,结合深度残差学习的图像去噪理论,提出了太赫兹图像深度去噪网络,在训练集中引入成像系统中真实的“太赫兹残差噪声”。最后,利用所训练出的模型对太赫兹频域高频区域图像进行盲去噪,并用重建图像分别与原始成像结果和传统太赫兹去噪算法结果进行比较,分别从主观和客观两个方面评价了不同算法对太赫兹频域高频图像的去噪效果。实验结果表明,通过该算法实现... 相似文献
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