Browsing by Author "Arikawa, Takashi"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Giant tunable Faraday effect in a semiconductor magneto-plasma for broadband terahertz polarization optics
    (Optical Society of America, 2012) Arikawa, Takashi; Wang, Xiangfeng; Belyanin, Alexey A.; Kono, Junichiro
    We report on a giant Faraday effect in an electron plasma in n- InSb probed via polarization-resolved terahertz (THz) time-domain spectroscopy. Polarization rotation angles and ellipticities reach as large as π/2 and 1, respectively, over a wide frequency range (0.3-2.5 THz) at magnetic fields of a few Tesla. The experimental results together with theoretical simulations show its promising ability to construct broadband and tunable THz polarization optics, such as a circular polarizer, half-wave plate, and polarization modulators.
  • Thumbnail Image
    Item
    Superradiant Decay of Cyclotron Resonance of Two-Dimensional Electron Gases
    (American Physical Society, 2014) Zhang, Qi; Arikawa, Takashi; Kato, Eiji; Reno, John L.; Pan, Wei; Watson, John D.; Manfra, Michael J.; Zudov, Michael A.; Tokman, Mikhail; Erukhimova, Maria; Belyanin, Alexey; Kono, Junichiro
    We report on the observation of collective radiative decay, or superradiance, of cyclotron resonance (CR) in high-mobility two-dimensional electron gases in GaAs quantum wells using time-domain terahertz magnetospectroscopy. The decay rate of coherent CR oscillations increases linearly with the electron density in a wide range, which is a hallmark of superradiant damping. Our fully quantum mechanical theory provides a universal formula for the decay rate, which reproduces our experimental data without any adjustable parameter. These results firmly establish the many-body nature of CR decoherence in this system, despite the fact that the CR frequency is immune to electron-electron interactions due to Kohnﾒs theorem.