Browsing by Author "Belyanin, Alexey A."

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    Fermi-edge superfluorescence from a quantum-degenerate electron-hole gas
    (Nature Publishing Group, 2013) Kim, Ji-Hee; Noe, G. Timothy II; McGill, Stephen A.; Wang, Yongrui; Wojcik, Aleksander K.; Belyanin, Alexey A.; Kono, Junichiro
    Nonequilibrium can be a source of order. This rather counterintuitive statement has been proven to be true through a variety of fluctuation-driven, self-organization behaviors exhibited by out-of-equilibrium, many-body systems in nature (physical, chemical, and biological), resulting in the spontaneous appearance of macroscopic coherence. Here, we report on the observation of spontaneous bursts of coherent radiation from a quantum-degenerate gas of nonequilibrium electron-hole pairs in semiconductor quantum wells. Unlike typical spontaneous emission from semiconductors, which occurs at the band edge, the observed emission occurs at the quasi-Fermi edge of the carrier distribution. As the carriers are consumed by recombination, the quasi-Fermi energy goes down toward the band edge, and we observe a continuously red-shifting streak. We interpret this emission as cooperative spontaneous recombination of electron-hole pairs, or superfluorescence (SF), which is enhanced by Coulomb interactions near the Fermi edge. This novel many-body enhancement allows the magnitude of the spontaneously developed macroscopic polarization to exceed the maximum value for ordinary SF, making electron-hole SF even more ﾑﾑsuperﾒﾒ than atomic SF.
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    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.