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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.
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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
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Rice WD, Kono J, Zybell S, Winnerl S, Bhattacharyya J, Schneider H, Helm M, Ewers B, Chernikov A, Koch M, Chatterjee S, Khitrova G, Gibbs HM, Schneebeli L, Breddermann B, Kira M, Koch SW. Observation of forbidden exciton transitions mediated by Coulomb interactions in photoexcited semiconductor quantum wells. PHYSICAL REVIEW LETTERS 2013; 110:137404. [PMID: 23581371 DOI: 10.1103/physrevlett.110.137404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 11/27/2012] [Indexed: 06/02/2023]
Abstract
We use terahertz pulses to induce resonant transitions between the eigenstates of optically generated exciton populations in a high-quality semiconductor quantum well sample. Monitoring the excitonic photoluminescence, we observe transient quenching of the 1s exciton emission, which we attribute to the terahertz-induced 1s-to-2p excitation. Simultaneously, a pronounced enhancement of the 2s exciton emission is observed, despite the 1s-to-2s transition being dipole forbidden. A microscopic many-body theory explains the experimental observations as a Coulomb-scattering mixing of the 2s and 2p states, yielding an effective terahertz transition between the 1s and 2s populations.
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Affiliation(s)
- W D Rice
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
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Smith RP, Wahlstrand JK, Funk AC, Mirin RP, Cundiff ST, Steiner JT, Schafer M, Kira M, Koch SW. Extraction of many-body configurations from nonlinear absorption in semiconductor quantum wells. PHYSICAL REVIEW LETTERS 2010; 104:247401. [PMID: 20867334 DOI: 10.1103/physrevlett.104.247401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Indexed: 05/29/2023]
Abstract
Detailed electronic many-body configurations are extracted from quantitatively measured time-resolved nonlinear absorption spectra of resonantly excited GaAs quantum wells. The microscopic theory assigns the observed spectral changes to a unique mixture of electron-hole plasma, exciton, and polarization effects. Strong transient gain is observed only under cocircular pump-probe conditions and is attributed to the transfer of pump-induced coherences to the probe.
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Affiliation(s)
- R P Smith
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
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Leinß S, Kampfrath T, Volkmann KV, Schmid BA, Fröhlich D, Wolf M, Kaindl RA, Leitenstorfer A, Huber R. THz quantum optics with dark excitons in Cu2O: from stimulated emission to nonlinear population control. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/pssc.200879859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Koch SW, Kira M, Khitrova G, Gibbs HM. Semiconductor excitons in new light. NATURE MATERIALS 2006; 5:523-31. [PMID: 16819475 DOI: 10.1038/nmat1658] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Accepted: 04/18/2006] [Indexed: 05/10/2023]
Abstract
Excitons are quasi-particles that form when Coulomb-interacting electrons and holes in semiconductors are bound into pair states. They have many features analogous to those of atomic hydrogen. Because of this, researchers are interested in exploring excitonic phenomena, from optical, quantum-optical and thermodynamic transitions to the possible condensation of excitons into a quantum-degenerate state. Excitonic signatures commonly appear in the optical absorption and emission of direct-gap semiconductor systems. However, the precise properties of incoherent exciton populations in such systems are difficult to determine and are the subject of intense debate. We review recent contributions to this discussion, and argue that to obtain detailed information about exciton populations, conventional experimental techniques should be supplemented by direct quasi-particle spectroscopy using the relatively newly available terahertz light sources. Finally, we propose a scheme of quantum-optical excitation to generate quantum-degenerate exciton states directly.
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Affiliation(s)
- S W Koch
- Department of Physics and Material Sciences Centre, Philipps-Universität, Renthof 5, D-35032 Marburg, Germany.
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Dai J, Raikh ME, Shahbazyan TV. Two-electron linear intersubband light absorption in a biased quantum well. PHYSICAL REVIEW LETTERS 2006; 96:066803. [PMID: 16606029 DOI: 10.1103/physrevlett.96.066803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Indexed: 05/08/2023]
Abstract
We point out a novel manifestation of many-body correlations in the linear optical response of electrons confined in a quantum well. Namely, we demonstrate that along with the conventional absorption peak at a frequency omega close to the intersubband energy delta, there exists an additional peak at frequency h omega approximately = 2delta. This new peak is solely due to electron-electron interactions, and can be understood as excitation of two electrons by a single photon. The actual peak line shape is comprised of a sharp feature, due to excitation of pairs of intersubband plasmons, on top of a broader band due to absorption by two single-particle excitations. The two-plasmon contribution allows us to infer intersubband plasmon dispersion from linear absorption experiments.
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Affiliation(s)
- J Dai
- Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA
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Huber R, Schmid BA, Shen YR, Chemla DS, Kaindl RA. Stimulated terahertz emission from intraexcitonic transitions in Cu2O. PHYSICAL REVIEW LETTERS 2006; 96:017402. [PMID: 16486513 DOI: 10.1103/physrevlett.96.017402] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2005] [Indexed: 05/06/2023]
Abstract
We report the first observation of stimulated emission of terahertz radiation from internal transitions of excitons. The far-infrared electromagnetic response of Cu2O is monitored via broadband terahertz pulses after ultrafast resonant excitation of three-dimensional 3p excitons. Stimulated emission from the 3p to the energetically lower 2s bound level occurs at a photon energy of 6.6 meV, with a cross section of approximately 10(-14) cm2. Simultaneous excitation of both exciton levels, in turn, drives quantum beats, which lead to efficient terahertz emission sharply peaked at the difference frequency.
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Affiliation(s)
- Rupert Huber
- Department of Physics, University of California at Berkeley, and Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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