1School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China 2Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China 3Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Opto-electronics Information and Technical Science (Ministry of Education), Tianjin University, Tianjin 300072, China 4Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China 5University of Chinese Academy of Sciences, Beijing 100049, China
Abstract：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 ${5S_{1/2}}$ and ${5P_{3/2}}$ 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.
Goulielmakis E, Uiberacker M, Kienberger R, Baltuska A, Yakovlev V, Scrinzi A, Westerwalbesloh T, Kleineberg U, Heinzmann U, Drescher M and Krausz F 2004 Science305 1267
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Gaumnitz T, Jain A, Pertot Y, Huppert M, Jordan I, Ardana-Lamas F and Wörner H J 2017 Opt. Express25 27506
2021, Vol. 38 
