title: Terahertz beat oscillation of plasmonic electrons interacting with femtosecond light pulses.
abstract: Plasmon resonance in nanostructured metals is in essence collective oscillation of free electrons, which is driven by optical electric fields and oscillates at nearly the same frequency as the excitation photons. This is the basic physics for the currently extensively interested topics in optical metamaterials, optical switching, and logic optical "circuits" with potential applications in optical communication and optical computation. We present here an interference effect between photons and plasmon electrons, which is observed as multi-cycle beat-oscillation. The beat frequency is in the range of 3~4 THz, which is equal to the difference between optical frequency of the photons and oscillation frequency of the plasmon electrons. Such beat oscillation evolves in a time scale of more than 1 ps, which is much longer than the optical pulse length, implying interaction between photons and pure damping plasmon-electrons. The discovered mechanisms might be important for exploring new approaches for THz generation.
authors.affiliation: Institute of Information Photonics Technology and College of Applied Sciences, Beijing University of Technology, Beijing 100124, P. R. China.
authors.forename: Xinping
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Information Photonics Technology and College of Applied Sciences, Beijing University of Technology, Beijing 100124, P. R. China.
authors.forename: Jianfang
authors.initials: J
authors.lastname: He
authors.affiliation: Institute of Information Photonics Technology and College of Applied Sciences, Beijing University of Technology, Beijing 100124, P. R. China.
authors.forename: Yimeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Information Photonics Technology and College of Applied Sciences, Beijing University of Technology, Beijing 100124, P. R. China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Liu