Efficient Terahertz Harmonic Generation with Coherent Acceleration of Electrons in the Dirac Semimetal Cd3As2
Efficient Terahertz Harmonic Generation with Coherent Acceleration of Electrons in the Dirac Semimetal Cd3As2
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DOI：
10.1103/physrevlett.124.117402
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发表时间：
2020-03-19
影响因子：
8.6
通讯作者：
Matsunaga, Ryusuke
中科院分区：
文献类型：
--
作者：
Cheng, Bing;Kanda, Natsuki;Matsunaga, Ryusuke
我们报道了三维狄拉克半金属Cd3As2薄膜在室温下产生的强太赫兹（类似于10(12)Hz）高谐波。第三次谐波可以用桌面光源检测到，通过在薄膜内部施加6.5 kV/cm的基场，可以达到100 V/cm的强度，显示出前所未有的太赫兹频率转换效率。我们的时间分辨太赫兹光谱和计算也阐明了狄拉克电子在动量空间中相干加速产生的非线性的微观机制。我们的研究结果为太赫兹场在散射影响下驱动狄拉克电子的非线性电流提供了清晰的见解，为基于拓扑半金属的高速电子和光子学的新型器件铺平了道路。
We report strong terahertz (similar to 10(12) Hz) high harmonic generation at room temperature in thin films of Cd3As2, a three-dimensional Dirac semimetal. Third harmonics are detectable with a tabletop light source and can be as strong as 100 V/cm by applying a fundamental field of 6.5 kV/cm inside the film, demonstrating an unprecedented efficiency for terahertz frequency conversion. Our time-resolved terahertz spectroscopy and calculations also clarify the microscopic mechanism of the nonlinearity originating in the coherent acceleration of Dirac electrons in momentum space. Our results provide clear insights for nonlinear currents of Dirac electrons driven by the terahertz field under the influence of scattering, paving the way toward novel devices for high-speed electronics and photonics based on topological semimetals.