Power dissipation spectra and terahertz intervalley transfer gain in bulk GaAs under high electric fields
Power dissipation spectra and terahertz intervalley transfer gain in bulk GaAs under high electric fields
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DOI：
10.1063/1.3039069
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发表时间：
2008-12
影响因子：
4
通讯作者：
Y. M. Zhu;T. Unuma;K. Shibata;K. Hirakawa;Y. Ino;M. Kuwata-Gonokami
中科院分区：
文献类型：
--
作者：
Y. M. Zhu;T. Unuma;K. Shibata;K. Hirakawa;Y. Ino;M. Kuwata-Gonokami
我们研究了在强偏压电场作用下，飞秒激光脉冲在块体GaAs体中光激发电子时产生的太赫兹辐射。通过计算太赫兹迹的傅里叶谱，得到了类阶跃函数输入电场下电子的功率耗散谱。研究发现，谷间转移引起的负功率耗散(即增益)的截止频率νc随电场的增加而逐渐增大，在300K时，在∼1太赫兹高于50 kV/cm时达到饱和。从νc与温度的关系发现，νc受光学声子发射的控制。
We have investigated terahertz radiation emitted from electrons photoexcited by femtosecond laser pulses in bulk GaAs under strong bias electric fields. Power dissipation spectra of electrons for step-function-like input electric fields have been obtained by calculating Fourier spectra of the measured terahertz traces. The cutoff frequency νc for negative power dissipation (i.e., gain) due to intervalley transfer is found to gradually increase with increasing electric fields below 50 kV/cm and saturate at ∼1 THz above 50 kV/cm at 300 K. From the temperature dependence of νc, it is found that νc is governed by the emission of optical phonons.