Open Access
Terahertz power dissipation spectra of electrons in bulk GaAs under high electric fields at low temperature
Author(s) -
Yiming Zhu,
Kaz Hirakawa,
Lin Cao,
Bo He,
Yuanshen Huang,
Jia Xiao-Xuan,
Dawei Zhang,
Zhuang Song-Lin
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.2692
Subject(s) - terahertz radiation , electric field , physics , dissipation , electron , atomic physics , spectral line , waveform , optics , electromagnetic radiation , cutoff frequency , materials science , voltage , astronomy , thermodynamics , quantum mechanics
By using the freespace terahertz THz electrooptic EO sampling technique, the THz electromagnetic wave waveforms emitted from intrinsic bulk GaAs photoexcited by femtosecond laser pulses under strong bias electric fields up to 300 kV/cm were recorded. From the experimental data, we can clearly see the THz electromagnetic wave emission waveforms, ETHzt, which are proportional to the acceleration/deceleration of electrons, have a bipolar feature. Power dissipation spectra of electrons for stepfunctionlike input electric fields have been obtained by calculating Fourier spectra of the measured THz traces. The cutoff frequency, νc, for negative power dissipation i.e., gain due to intervalley transfer is found to gradually increase with increasing bias electric fields, F0, for F0 < 50 kV/cm and saturate at 750 GHz above 50 kV/cm at 10 K.