Abstract
We have studied terahertz (THz) emission from InAs and GaAs in a magnetic field, and find that the emitted radiation is produced by coupled cyclotron-plasma charge oscillations. Ultrashort pulses of THz radiation were produced at semiconductor surfaces by photoexcitation with a femtosecond Ti-sapphire laser. We recorded the integrated THz power and the THz emission spectrum as a function of magnetic field at fields up to 5.5 T, and as function of temperature for The maximum observed THz power is (12 μW average power) from at We compare our results to semiclassical models of magnetoplasma oscillations of bulk free carriers and damped motion of free carriers in a two-dimensional electron gas. The bulk model describes THz emission from at all magnetic fields, and InAs at It fails to describe THz emission from InAs at nonzero magnetic fields. We show that a model including both bulk plasma oscillations and THz emission from a surface accumulation layer describes THz emission from InAs in a moderate magnetic field, but this model does not completely describe emission at fields
- Received 22 February 2001
DOI:https://doi.org/10.1103/PhysRevB.64.085202
©2001 American Physical Society