Xinhou Chen Hangtian Wang Chun Wang Chen Ouyang Gaoshuai Wei Prof. Tianxiao Nie Prof. Weisheng Zhao Prof. Jungang Miao Prof. Yutong Li Prof. Li Wang Prof. Xiaojun Wu,
https://onlinelibrary.wiley.com/doi/abs/10.1002/adpr.202000099
Polarization arbitrary manipulated terahertz (THz) pulses with a prescribed amplitude temporal evolution and deposited electric‐field vectors can promote many disruptive technologies and enable enormous applications in polarization‐sensitive THz spectroscopy and imaging, ultrafast THz opto‐spintronics, information encryption, and space exploration. However, the severe shortage of dynamically tunable THz polarization devices has impeded the proliferation of THz science and technology. Here we propose and demonstrate a method of efficient generation and arbitrary manipulation of chiral THz waves in the topological insulator (TI)‐iron (Fe) heterostructures through delicately engineering the linear photogalvanic effect (LPGE) and spin‐to‐charge conversion (SCC) effect induced by femtosecond laser pulses. Utilizing the intrinsic merits of optical controlled LPGE and magnetic field direction adjusted SCC effect, the TI‐Fe can radiate chiral THz waves with arbitrarily tailored chirality and ellipticity. To verify the capability of such a novel chiral THz source, helical substructure associated THz circular dichroism spectroscopy was implemented on several (bio)materials, exemplified by the beetle exoskeletons. Furthermore, ultrafast switching between two THz chirality states can be realized by a double‐pulse excitation scheme. Such versatile chiral THz emitters with high efficiency and easy integration may have some disruptive applications.
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