|
1
|
Li X, Yoshioka K, Zhang Q, Peraca NM, Katsutani F, Gao W, Noe GT, Watson JD, Manfra MJ, Katayama I, Takeda J, Kono J. Observation of Photoinduced Terahertz Gain in GaAs Quantum Wells: Evidence for Radiative Two-Exciton-to-Biexciton Scattering. PHYSICAL REVIEW LETTERS 2020; 125:167401. [PMID: 33124876 DOI: 10.1103/physrevlett.125.167401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 06/19/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
We have observed photoinduced negative optical conductivity, or gain, in the terahertz frequency range in a GaAs multiple-quantum-well structure in a strong perpendicular magnetic field at low temperatures. The gain is narrow band: it appears as a sharp peak (linewidth <0.45 meV) whose frequency shifts with applied magnetic field. The gain has a circular-polarization selection rule: a strong line is observed for hole-cyclotron-resonance-active polarization. Furthermore, the gain appears only when the exciton 1s state is populated, which rules out intraexcitonic transitions to be its origin. Based on these observations, we propose a possible process in which the stimulated emission of a terahertz photon occurs while two free excitons scatter into one biexciton in an energy and angular-momentum conserving manner.
Collapse
Affiliation(s)
- Xinwei Li
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
| | - Katsumasa Yoshioka
- Department of Physics, Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan
| | - Qi Zhang
- School of Physics, Nanjing University, Nanjing 210093, China
| | | | - Fumiya Katsutani
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
| | - Weilu Gao
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
| | - G Timothy Noe
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
| | - John D Watson
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Michael J Manfra
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Ikufumi Katayama
- Department of Physics, Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan
| | - Jun Takeda
- Department of Physics, Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan
| | - Junichiro Kono
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Department of Material Science and NanoEngineering, Rice University, Houston, Texas 77005, USA
| |
Collapse
|