Abstract
Ultrafast terahertz spectroscopy can be used to probe charge and spin dynamics in semiconductors. We have studied THz emission from bulk InAs and GaAs and from GaAs/AlGaAs quantum wells as a function of magnetic field. Ultrashort pulses of THz radiation were produced at semiconductor surfaces by photoexcitation with a femtosecond Ti-Sapphire laser, and we recorded the THz emission spectrum and the integrated THz power as a function of magnetic field and temperature. In bulk samples the emitted radiation is produced by coupled cyclotron-plasma oscillations: we model THz emission from n-GaAs as magneto-plasma oscillations in a 3-D electron gas. THz emission from a modulation-doped parabolic quantum well is described in terms of coupled intersubband-cyclotron motion. A model including both 3-D plasma oscillations and a 2-D electron gas in a surface accumulation layer is required to describe THz emission from InAs in a magnetic field.
Original language | English (US) |
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Title of host publication | Proceedings of SPIE - The International Society for Optical Engineering |
Editors | K.T. Tsen, J.-J. Song |
Pages | 12-18 |
Number of pages | 7 |
Volume | 4643 |
DOIs | |
State | Published - 2002 |
Event | Ultrafast Phenomena in Semiconductors VI - San Jose, CA, United States Duration: Jan 21 2002 → Jan 25 2002 |
Other
Other | Ultrafast Phenomena in Semiconductors VI |
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Country/Territory | United States |
City | San Jose, CA |
Period | 1/21/02 → 1/25/02 |
Keywords
- GaAs
- InAs
- Magnetic
- Parabolic quantum well
- Plasmon
- Terahertz
- Ultrafast