Terahertz emission from cubic semiconductor induced by a transient anisotropic photocurrent
Terahertz emission from cubic semiconductor induced by a transient anisotropic photocurrent
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DOI：
10.1063/1.4758181
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发表时间：
2012-10-01
影响因子：
3.2
通讯作者：
Malevich, Y. V.
中科院分区：
文献类型：
--
作者：
Malevich, V. L.;Ziaziulia, P. A.;Malevich, Y. V.
用瞬态带间光电导描述了飞秒激光脉冲激发窄禁带半导体表面的太赫兹辐射。已经发现，电子色散定律的非抛物线性以及光激发载流子动量的光学对准导致各向异性光电流，即使在具有立方对称性的半导体中也具有垂直于表面直流电场的分量。这种横向瞬态光电流分量在光激发后的前几百飞秒期间是最强的，并且导致太赫兹辐射脉冲的发射，其幅度取决于光场与晶轴之间的角度。在InAs的情况下，这个组件的贡献解释了实验结果的方位角各向异性的发射太赫兹脉冲的振幅和它的依赖于激发光子能量。(C)2012年美国物理学会。[http：//dx.doi.org/10.1063/1.4758181]
Terahertz emission from the surfaces of narrow-gap semiconductors excited by femtosecond laser pulses was described in terms of a transient interband photoconductivity. It has been found that the nonparabolicity of the electron dispersion law as well as the optical alignment of the photoexcited carrier momenta result in anisotropic photocurrent with a component perpendicular to the surface dc electric field even in semiconductors with a cubic symmetry. This lateral transient photocurrent component is the strongest during the first few hundreds of femtoseconds after the photoexcitation and causes the emission of terahertz radiation pulses with an amplitude dependent on the angle between the optical field and the crystallographic axes. In the case of InAs the contribution of this component explains experimental results of both the azimuthal anisotropy of the emitted terahertz pulse amplitude and its dependence on the exciting photon energy. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4758181]