Near-Field Analysis of Terahertz Pulse Generation From Photo-Excited Charge Density Gradients
Near-Field Analysis of Terahertz Pulse Generation From Photo-Excited Charge Density Gradients
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DOI：
10.1109/tthz.2015.2395389
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发表时间：
2015-03-01
影响因子：
3.2
通讯作者：
Mitrofanov, Oleg
中科院分区：
文献类型：
--
作者：
Mueckstein, Raimund;Natrella, Michele;Mitrofanov, Oleg
用亚皮秒光脉冲激发半导体表面的瞬时光电流，产生太赫兹（THz）频率辐射的电磁脉冲。为了将太赫兹辐射与光激发电荷密度分布和光电流方向联系起来，我们绘制了GaAs和掺铁InGaAs表面产生的太赫兹波的近场和远场分布。实验结果表明，表面平面上的电荷动力学比表面垂直方向上的电荷动力学能辐射出更强的太赫兹脉冲，这通常被认为是发射的主要来源。
Excitation of photo-current transients at semiconductor surfaces by subpicosecond optical pulses gives rise to emission of electromagnetic pulses of terahertz (THz) frequency radiation. To correlate the THz emission with the photo-excited charge density distribution and the photo-current direction, we mapped near-field and far-field distributions of the generated THz waves from GaAs and Fe-doped InGaAs surfaces. The experimental results show that the charge dynamics in the plane of the surface can radiate substantially stronger THz pulses than the charge dynamics in the direction normal to the surface, which is generally regarded as the dominant origin of the emission.