Topological materials as promising candidates for tuneable helicity-dependent terahertz emitters
Topological materials as promising candidates for tuneable helicity-dependent terahertz emitters
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DOI：
10.1117/12.2681745
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发表时间：
2023-10
影响因子：
1.9
通讯作者：
J. Boland;D. Damry;Chelsea Q. Xia;Y. Saboon;A. Mannan;Piet Schoenherr;D. Prabhakaran;Laura M. Herz;T. Hesjedal;Michael B. Johnston
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文献类型：
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作者：
J. Boland;D. Damry;Chelsea Q. Xia;Y. Saboon;A. Mannan;Piet Schoenherr;D. Prabhakaran;Laura M. Herz;T. Hesjedal;Michael B. Johnston
拓扑材料作为相干、可控太赫兹发射器的竞争者，已迅速引起人们的兴趣。它们在表面或内部都有Weyl节点，承载自旋极化、螺旋相关的电流，通过改变产生辐射的光脉冲的偏振，可以控制发射的太赫兹脉冲。在这里，我们证明了在斜入射近红外激发下，砷化镉体晶体和纳米线系综产生了多周期脉冲，带宽为0.4太赫兹。通过改变光子的螺旋度和光激发光的入射角，可以调节产生的太赫兹辐射的带宽和峰值发射频率。
Topological materials have rapidly gained interest as contenders for development of coherent, controllable terahertz emitters. Possessing Weyl nodes either at the surface or within the bulk, they host spin-polarised, helicity-dependent currents that offer possibility to control the emitted THz pulse by changing the polarization of the optical pulses generating the radiation. Here, we show that upon near-infrared excitation at oblique incidence, multi-cycle pulses are generated with a narrow bandwidth of ∼0.4 THz for cadmium arsenide bulk crystals and nanowire ensembles. Both the bandwidth and peak emission frequency of the generated THz radiation can be tuned by respectively varying the photon helicity and angle of incidence of the photoexcitation light.