Spintronic terahertz emission with manipulated polarization (STEMP)

Abstract

Highly efficient generation and arbitrary manipulation of spin-polarized terahertz (THz) radiation will enable chiral lightwave driven quantum nonequilibrium state regulation, induce new electronic structures, consequently provide a powerful experimental tool for investigation of nonlinear THz optics and extreme THz science and applications. THz circular dichromic spectroscopy, ultrafast electron bunch manipulation, as well as THz imaging, sensing, and telecommunication, also need chiral THz waves. Here we review optical generation of circularly-polarized THz radiation but focus on recently emerged polarization tunable spintronic THz emission techniques, which possess many advantages of ultra-broadband, high efficiency, low cost, easy for integration and so on. We believe that chiral THz sources based on the combination of electron spin, ultrafast optical techniques and material structure engineering will accelerate the development of THz science and applications.

Graphical abstract

Keywords

Terahertz (THz) emission / Femtosecond laser / Spintronics / Polarization manipulation

References

[1] Li, Q. , Stoica, V.A. , Paściak, M. , Zhu, Y. , Yuan, Y. , Yang, T. , McCarter, M.R. , Das, S. , Yadav, A.K. , Park, S. , Dai, C. , Lee, H.J. , Ahn, Y. , Marks, S.D. , Yu, S. , Kadlec, C. , Sato, T. , Hoffmann, M.C. , Chollet, M. , Kozina, M.E. , Nelson, S. , Zhu, D. , Walko, D.A. , Lindenberg, A.M. , Evans, P.G. , Chen, L.Q. , Ramesh, R. , Martin, L.W. , Gopalan, V. , Freeland, J.W. , Hlinka, J. , Wen, H. : Subterahertz collective dynamics of polar vortices. Nature 592 (7854), 376- 380 (2021)

[2] Samizadeh Nikoo, M. , Jafari, A. , Perera, N. , Zhu, M. , Santoruvo, G. , Matioli, E. : Nanoplasma-enabled picosecond switches for ultrafast electronics. Nature 579 (7800), 534- 539 (2020)

[3] Peng, K. , Jevtics, D. , Zhang, F. , Sterzl, S. , Damry, D.A. , Rothmann, M.U. , Guilhabert, B. , Strain, M.J. , Tan, H.H. , Herz, L.M. , Fu, L. , Dawson, M.D. , Hurtado, A. , Jagadish, C. , Johnston, M.B. : Three-dimensional cross-nanowire networks recover full terahertz state. Science 368 (6490), 510- 513 (2020)

[4] Hafez, H.A. , Kovalev, S. , Deinert, J.C. , Mics, Z. , Green, B. , Awari, N. , Chen, M. , Germanskiy, S. , Lehnert, U. , Teichert, J. , Wang, Z. , Tielrooij, K.J. , Liu, Z. , Chen, Z. , Narita, A. , Müllen, K. , Bonn, M. , Gensch, M. , Turchinovich, D. : Extremely efficient terahertz high-harmonic generation in graphene by hot Dirac fermions. Nature 561 (7724), 507- 511 (2018)

[5] Cocker, T.L. , Jelic, V. , Hillenbrand, R. , Hegmann, F.A. : Nanoscale terahertz scanning probe microscopy. Nat. Photonics 15 (8), 558- 569 (2021)

[6] Plankl, M. , Faria Junior, P.E. , Mooshammer, F. , Siday, T. , Zizlsperger, M. , Sandner, F. , Schiegl, F. , Maier, S. , Huber, M.A. , Gmitra, M. , Fabian, J. , Boland, J.L. , Cocker, T.L. , Huber, R. : Subcycle contact-free nanoscopy of ultrafast interlayer transport in atomically thin heterostructures. Nat. Photonics 15 (8), 594- 600 (2021)

[7] Choi, W.J. , Cheng, G. , Huang, Z. , Zhang, S. , Norris, T.B. , Kotov, N.A. : Terahertz circular dichroism spectroscopy of biomaterials enabled by kirigami polarization modulators. Nat. Mater. 18 (8), 820- 826 (2019)

[8] Kovalev, S. , Hafez, H.A. , Tielrooij, K.J. , Deinert, J.C. , Ilyakov, I. , Awari, N. , Alcaraz, D. , Soundarapandian, K. , Saleta, D. , Germanskiy, S. , Chen, M. , Bawatna, M. , Green, B. , Koppens, F.H.L. , Mittendorff, M. , Bonn, M. , Gensch, M. , Turchinovich, D. : Electrical tunability of terahertz nonlinearity in graphene. Sci. Adv. 7 (15), 9809- 9818 (2021)

[9] Jelic, V. , Iwaszczuk, K. , Nguyen, P.H. , Rathje, C. , Hornig, G.J. , Sharum, H.M. , Hoffman, J.R. , Freeman, M.R. , Hegmann, F.A. : Ultrafast terahertz control of extreme tunnel currents through single atoms on a silicon surface. Nat. Phys. 13 (6), 591- 598 (2017)

[10] Pistore, V. , Nong, H. , Vigneron, P.B. , Garrasi, K. , Houver, S. , Li, L. , Giles Davies, A. , Linfield, E.H. , Tignon, J. , Mangeney, J. , Colombelli, R. , Vitiello, M.S. , Dhillon, S.S. : Millimeter wave photonics with terahertz semiconductor lasers. Nat. Commun. 12 (1), 1427- 1434 (2021)

[11] Xu, H. , Yan, L. , Du, Y. , Huang, W. , Tian, Q. , Li, R. , Liang, Y. , Gu, S. , Shi, J. , Tang, C. : Cascaded high-gradient terahertz-driven acceleration of relativistic electron beams. Nat. Photonics 15 (6), 426- 430 (2021)

[12] Kealhofer, C. , Schneider, W. , Ehberger, D. , Ryabov, A. , Krausz, F. , Baum, P. : All-optical control and metrology of electron pulses. Science 352 (6284), 429- 433 (2016)

[13] Hibberd, M.T. , Healy, A.L. , Lake, D.S. , Georgiadis, V. , Smith, E.J.H. , Finlay, O.J. , Pacey, T.H. , Jones, J.K. , Saveliev, Y. , Walsh, D.A. , Snedden, E.W. , Appleby, R.B. , Burt, G. , Graham, D.M. , Jamison, S.P. : Acceleration of relativistic beams using laser-generated terahertz pulses. Nat. Photonics 14 (12), 755- 759 (2020)

[14] Zhang, D. , Fallahi, A. , Hemmer, M. , Wu, X. , Fakhari, M. , Hua, Y. , Cankaya, H. , Calendron, A.L. , Zapata, L.E. , Matlis, N.H. , Kärtner, F.X. : Segmented terahertz electron accelerator and manipulator (STEAM). Nat. Photonics 12 (6), 336- 342 (2018)

[15] Tang, H. , Zhao, L. , Zhu, P. , Zou, X. , Qi, J. , Cheng, Y. , Qiu, J. , Hu, X. , Song, W. , Xiang, D. , Zhang, J. : Stable and scalable multistage terahertz-driven particle accelerator. Phys. Rev. Lett. 127 (7), 074801- 074807 (2021)

[16] Zhang, D. , Fakhari, M. , Cankaya, H. , Calendron, A.L. , Matlis, N.H. , Kärtner, F.X. : Cascaded multicycle terahertz-driven ultrafast electron acceleration and manipulation. Phys. Rev. X 10 (1), 011067- 011076 (2020)

[17] Zhao, L. , Wang, Z. , Tang, H. , Wang, R. , Cheng, Y. , Lu, C. , Jiang, T. , Zhu, P. , Hu, L. , Song, W. , Wang, H. , Qiu, J. , Kostin, R. , Jing, C. , Antipov, S. , Wang, P. , Qi, J. , Cheng, Y. , Xiang, D. , Zhang, J. : Terahertz oscilloscope for recording time information of ultrashort electron beams. Phys. Rev. Lett. 122 (14), 144801- 144802 (2019)

[18] Zhang, D. , Fallahi, A. , Hemmer, M. , Ye, H. , Fakhari, M. , Hua, Y. , Cankaya, H. , Calendron, A.L. , Zapata, L.E. , Matlis, N.H. , Kärtner, F.X. : Femtosecond phase control in high-field terahertzdriven ultrafast electron sources. Optica 6 (7), 872- 877 (2019)

[19] Curry, E. , Fabbri, S. , Maxson, J. , Musumeci, P. , Gover, A. : Meter-scale terahertz-driven acceleration of a relativistic beam. Phys. Rev. Lett. 120 (9), 094801- 094807 (2018)

[20] Ronny Huang, W. , Fallahi, A. , Wu, X. , Cankaya, H. , Calendron, A.L. , Ravi, K. , Zhang, D. , Nanni, E.A. , Hong, K.H. , Kärtner, F.X. : Terahertz-driven all-optical electron gun. Optica 3 (11), 1209- 1212 (2016)

[21] Nanni, E.A. , Huang, W.R. , Hong, K.H. , Ravi, K. , Fallahi, A. , Moriena, G. , Miller, R.J. , Kärtner, F.X. : Terahertz-driven linear electron acceleration. Nat. Commun. 6 (1), 8486- 8494 (2015)

[22] Nova, T.F. , Disa, A.S. , Fechner, M. , Cavalleri, A. : Metastable ferroelectricity in optically strained SrTiO₃. Science 364 (6445), 1075- 1079 (2019)

[23] Sekiguchi, F. , Hirori, H. , Yumoto, G. , Shimazaki, A. , Nakamura, T. , Wakamiya, A. , Kanemitsu, Y. : Enhancing the hot-phonon bottleneck effect in a metal halide perovskite by terahertz phonon excitation. Phys. Rev. Lett. 126 (7), 077401- 077407 (2021)

[24] Schmid, C.P. , Weigl, L. , Grössing, P. , Junk, V. , Gorini, C. , Schlauderer, S. , Ito, S. , Meierhofer, M. , Hofmann, N. , Afanasiev, D. , Crewse, J. , Kokh, K.A. , Tereshchenko, O.E. , Güdde, J. , Evers, F. , Wilhelm, J. , Richter, K. , Höfer, U. , Huber, R. : Tunable non-integer high-harmonic generation in a topological insulator. Nature 593 (7859), 385- 390 (2021)

[25] Keren-Zur, S. , Tal, M. , Fleischer, S. , Mittleman, D.M. , Ellenbogen, T. : Generation of spatiotemporally tailored terahertz wavepackets by nonlinear metasurfaces. Nat. Commun. 10 (1), 1778- 1784 (2019)

[26] Peller, D. , Kastner, L.Z. , Buchner, T. , Roelcke, C. , Albrecht, F. , Moll, N. , Huber, R. , Repp, J. : Sub-cycle atomic-scale forces coherently control a single-molecule switch. Nature 585 (7823), 58- 62 (2020)

[27] Li, X. , Qiu, T. , Zhang, J. , Baldini, E. , Lu, J. , Rappe, A.M. , Nelson, K.A. : Terahertz field-induced ferroelectricity in quantum paraelectric SrTiO₃. Science 364 (6445), 1079- 1082 (2019)

[28] Luo, L. , Cheng, D. , Song, B. , Wang, L.L. , Vaswani, C. , Lozano, P.M. , Gu, G. , Huang, C. , Kim, R.H.J. , Liu, Z. , Park, J.M. , Yao, Y. , Ho, K. , Perakis, I.E. , Li, Q. , Wang, J. : A light-induced phononic symmetry switch and giant dissipationless topological photocurrent in ZrTe₅. Nat. Mater. 20 (3), 329- 334 (2021)

[29] Reimann, J. , Schlauderer, S. , Schmid, C.P. , Langer, F. , Baierl, S. , Kokh, K.A. , Tereshchenko, O.E. , Kimura, A. , Lange, C. , Güdde, J. , Höfer, U. , Huber, R. : Subcycle observation of lightwave-driven Dirac currents in a topological surface band. Nature 562 (7727), 396- 400 (2018)

[30] Wu, X. , Quan, B. , Pan, X. , Xu, X. , Lu, X. , Gu, C. , Wang, L. : Alkanethiol-functionalized terahertz metamaterial as labelfree, highly-sensitive and specificbiosensor. Biosens. Bioelectron. 42, 626- 631 (2013)

[31] Xiong, H. , Cai, J. , Zhang, W. , Hu, J. , Deng, Y. , Miao, J. , Tan, Z. , Li, H. , Cao, J. , Wu, X. : Deep learning enhanced terahertz imaging of silkworm eggs development. iScience 24 (11), 103316- 103329 (2021)

[32] Pitchappa, P. , Kumar, A. , Prakash, S. , Jani, H. , Venkatesan, T. , Singh, R. : Chalcogenide phase change material for active terahertz photonics. Adv. Mater. 31 (12), 1808157- 1808164 (2019)

[33] Vaswani, C. , Mootz, M. , Sundahl, C. , Mudiyanselage, D.H. , Kang, J.H. , Yang, X. , Cheng, D. , Huang, C. , Kim, R.H.J. , Liu, Z. , Luo, L. , Perakis, I.E. , Eom, C.B. , Wang, J. : Terahertz secondharmonic generation from lightwave acceleration of symmetrybreaking nonlinear supercurrents. Phys. Rev. Lett. 124 (20), 207003- 207009 (2020)

[34] Kang, T. , Kim, R.H.J. , Choi, G. , Lee, J. , Park, H. , Jeon, H. , Park, C.H. , Kim, D.S. : Terahertz rectification in ring-shaped quantum barriers. Nat. Commun. 9 (1), 4914- 4922 (2018)

[35] Dong, T. , Li, S. , Manjappa, M. , Yang, P. , Zhou, J. , Kong, D. , Quan, B. , Chen, X. , Ouyang, C. , Dai, F. , Han, J. , Ouyang, C. , Zhang, X. , Li, J. , Li, Y. , Miao, J. , Li, Y. , Wang, L. , Singh, R. , Zhang, W. , Wu, X. : Nonlinear THz-nano metasurfaces. Adv. Funct. Mater. 31 (24), 2100463- 2100472 (2021)

[36] Zhang, B. , Ma, Z. , Ma, J. , Wu, X. , Ouyang, C. , Kong, D. , Hong, T. , Wang, X. , Yang, P. , Chen, L. , Li, Y. , Zhang, J. : 1. 4-mJ high energy terahertz radiation from lithium niobates. Laser Photonics Rev 15 (3), 2000295- 2000306 (2021)

[37] Li, Y. , Chang, C. , Zhu, Z. , Sun, L. , Fan, C. : Terahertz wave enhances permeability of the voltage-gated calcium channel. J. Am. Chem. Soc. 143 (11), 4311- 4318 (2021)

[38] Tachizaki, T. , Sakaguchi, R. , Terada, S. , Kamei, K.I. , Hirori, H. : Terahertz pulse-altered gene networks in human induced pluripotent stem cells. Opt. Lett. 45 (21), 6078- 6081 (2020)

[39] Liu, X. , Qiao, Z. , Chai, Y. , Zhu, Z. , Wu, K. , Ji, W. , Li, D. , Xiao, Y. , Mao, L. , Chang, C. , Wen, Q. , Song, B. , Shu, Y. : Nonthermal and reversible control of neuronal signaling and behavior by midinfrared stimulation. Proc. Natl. Acad. Sci. U.S.A. 118 (10), 1073- 1082 (2021)

[40] Pein, B.C. , Chang, W. , Hwang, H.Y. , Scherer, J. , Coropceanu, I. , Zhao, X. , Zhang, X. , Bulović, V. , Bawendi, M. , Nelson, K.A. : Terahertz-driven luminescence and colossal stark effect in CdSe-CdS colloidal quantum dots. Nano Lett. 17 (9), 5375- 5380 (2017)

[41] Lu, Y. , Zhang, Q. , Wu, Q. , Chen, Z. , Liu, X. , Xu, J. : Giant enhancement of THz-frequency optical nonlinearity by phonon polariton in ionic crystals. Nat. Commun. 12 (1), 3183- 3191 (2021)

[42] Kozina, M. , Fechner, M. , Marsik, P. , van Driel, T. , Glownia, J.M. , Bernhard, C. , Radovic, M. , Zhu, D. , Bonetti, S. , Staub, U. , Hoffmann, M.C. : Terahertz-driven phonon upconversion in SrTiO₃. Nat. Phys. 15 (4), 387- 392 (2019)

[43] von Hoegen, A. , Mankowsky, R. , Fechner, M. , Först, M. , Cavalleri, A. : Probing the interatomic potential of solids with strongfield nonlinear phononics. Nature 555 (7694), 79- 82 (2018)

[44] Wu, L. , Salehi, M. , Koirala, N. , Moon, J. , Oh, S. , Armitage, N.P. : Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator. Science 354 (6316), 1124- 1127 (2016)

[45] Afanasiev, D. , Hortensius, J.R. , Ivanov, B.A. , Sasani, A. , Bousquet, E. , Blanter, Y.M. , Mikhaylovskiy, R.V. , Kimel, A.V. , Caviglia, A.D. : Ultrafast control of magnetic interactions via lightdriven phonons. Nat. Mater. 20 (5), 607- 611 (2021)

[46] Matsuda, T. , Kanda, N. , Higo, T. , Armitage, N.P. , Nakatsuji, S. , Matsunaga, R. : Room-temperature terahertz anomalous Hall effect in Weyl antiferromagnet Mn₃Sn thin films. Nat. Commun. 11 (1), 909- 917 (2020)

[47] Vaidya, P. , Morley, S.A. , van Tol, J. , Liu, Y. , Cheng, R. , Brataas, A. , Lederman, D. , Del Barco, E. : Subterahertz spin pumping from an insulating antiferromagnet. Science 368 (6487), 160- 165 (2020)

[48] Siegrist, F. , Gessner, J.A. , Ossiander, M. , Denker, C. , Chang, Y.P. , Schröder, M.C. , Guggenmos, A. , Cui, Y. , Walowski, J. , Martens, U. , Dewhurst, J.K. , Kleineberg, U. , Münzenberg, M. , Sharma, S. , Schultze, M. : Light-wave dynamic control of magnetism. Nature 571 (7764), 240- 244 (2019)

[49] Kampfrath, T. , Tanaka, K. , Nelson, K.A. : Resonant and nonresonant control over matter and light by intense terahertz transients. Nat. Photonics 7 (9), 680- 690 (2013)

[50] Ma, J. , Shrestha, R. , Adelberg, J. , Yeh, C.Y. , Hossain, Z. , Knightly, E. , Jornet, J.M. , Mittleman, D.M. : Security and eavesdropping in terahertz wireless links. Nature 563 (7729), 89- 93 (2018)

[51] Sengupta, K. , Nagatsuma, T. , Mittleman, D.M. : Terahertz integrated electronic and hybrid electronic-photonic systems. Nat. Electron. 1 (12), 622- 635 (2018)

[52] Ummethala, S. , Harter, T. , Koehnle, K. , Li, Z. , Muehlbrandt, S. , Kutuvantavida, Y. , Kemal, J. , Marin-Palomo, P. , Schaefer, J. , Tessmann, A. , Garlapati, S.K. , Bacher, A. , Hahn, L. , Walther, M. , Zwick, T. , Randel, S. , Freude, W. , Koos, C. : THz-to-optical conversion in wireless communications using an ultra-broadband plasmonic modulator. Nat. Photonics 13 (8), 519- 524 (2019)

[53] Yang, Y. , Yamagami, Y. , Yu, X. , Pitchappa, P. , Webber, J. , Zhang, B. , Fujita, M. , Nagatsuma, T. , Singh, R. : Terahertz topological photonics for on-chip communication. Nat. Photonics 14 (7), 446- 451 (2020)

[54] Liebermeister, L. , Nellen, S. , Kohlhaas, R.B. , Lauck, S. , Deumer, M. , Breuer, S. , Schell, M. , Globisch, B. : Optoelectronic frequency-modulated continuous-wave terahertz spectroscopy with 4 THz bandwidth. Nat. Commun. 12 (1), 1071- 1081 (2021)

[55] Khalatpour, A. , Paulsen, A.K. , Deimert, C. , Wasilewski, Z.R. , Hu, Q. : High-power portable terahertz laser systems. Nat. Photonics 15 (1), 16- 20 (2021)

[56] Chen, X. , Wang, H. , Wang, C. , Ouyang, C. , Wei, G. , Nie, T. , Zhao, W. , Miao, J. , Li, Y. , Wang, L. , Wu, X. : Efficient generationand arbitrary manipulation of chiral terahertz waves emitted from Bi₂Te₃-Fe heterostructures. Adv. Photonics Res. 2 (4), 2000099- 2000109 (2021)

[57] Strecker, K.E. , Partridge, G.B. , Truscott, A.G. , Hulet, R.G. : Formation and propagation of matter-wave soliton trains. Nature 417 (6885), 150- 153 (2002)

[58] Kimel, A.V. , Kirilyuk, A. , Usachev, P.A. , Pisarev, R.V. , Balbashov, A.M. , Rasing, T. : Ultrafast non-thermal control of magnetization by instantaneous photomagnetic pulses. Nature 435 (7042), 655- 657 (2005)

[59] Taguchi, K. , Tatara, G. : Theory of inverse Faraday effect in a disordered metal in the terahertz regime. Phys. Rev. B Condens. Matter Mater. Phys. 84 (17), 4433- 4438 (2011)

[60] Masson, J.B. , Gallot, G. : Terahertz achromatic quarter-wave plate. Opt. Lett. 31 (2), 265- 267 (2006)

[61] Jia, M. , Wang, Z. , Li, H. , Wang, X. , Luo, W. , Sun, S. , Zhang, Y. , He, Q. , Zhou, L. : Efficient manipulations of circularly polarized terahertz waves with transmissive metasurfaces. Light Sci. Appl. 8 (1), 16- 25 (2019)

[62] Chen, K. , Feng, Y. , Monticone, F. , Zhao, J. , Zhu, B. , Jiang, T. , Zhang, L. , Kim, Y. , Ding, X. , Zhang, S. , Alù, A. , Qiu, C.W. : A reconfigurable active Huygens’ metalens. Adv. Mater. 29 (17), 1606422- 1606427 (2017)

[63] Knyazev, B.A. , Choporova, Y.Y. , Mitkov, M.S. , Pavelyev, V.S. , Volodkin, B.O. : Generation of terahertz surface plasmon polaritons using nondiffractive bessel beams with orbital angular momentum. Phys. Rev. Lett. 115 (16), 163901- 163906 (2015)

[64] Chang, C.C. , Zhao, Z. , Li, D. , Taylor, A.J. , Fan, S. , Chen, H.T. : Broadband linear-to-circular polarization conversion enabled by birefringent off-resonance reflective metasurfaces. Phys. Rev. Lett. 123 (23), 237401- 237407 (2019)

[65] Xie, Z. , He, J. , Wang, X. , Feng, S. , Zhang, Y. : Generation of terahertz vector beams with a concentric ring metal grating and photo-generated carriers. Opt. Lett. 40 (3), 359- 362 (2015)

[66] Zhao, H. , Chen, X. , Ouyang, C. , Wang, H. , Kong, D. , Yang, P. , Zhang, B. , Wang, C. , Wei, G. , Nie, T. , Zhao, W. , Miao, J. , Li, Y. , Wang, L. , Wu, X. : Generation and manipulation of chiral terahertz waves in the three-dimensional topological insulator Bi₂Te₃. Adv. Photonics 2 (6), 6003- 6004 (2020)

[67] Sarukura, N. , Ohtake, H. , Izumida, S. , Liu, Z. : High averagepower THz radiation from femtosecond laser-irradiated InAs in a magnetic field and its elliptical polarization characteristics. J. Appl. Phys. 84 (1), 654- 656 (1998)

[68] Lu, X. , Zhang, X.C. : Generation of elliptically polarized terahertz waves from laser-induced plasma with double helix electrodes. Phys. Rev. Lett. 108 (12), 123903- 123908 (2012)

[69] Zhang, Z. , Chen, Y. , Cui, S. , He, F. , Chen, M. , Zhang, Z. , Yu, J. , Chen, L. , Sheng, Z. , Zhang, J. : Manipulation of polarizations for broadband terahertz waves emitted from laser plasma filaments. Nat. Photonics 12 (9), 554- 559 (2018)

[70] Wang, W.M. , Gibbon, P. , Sheng, Z.M. , Li, Y.T. : Tunable circularly polarized terahertz radiation from magnetized gas plasma. Phys. Rev. Lett. 114 (25), 253901- 253906 (2015)

[71] You, Y.S. , Oh, T.I. , Kim, K.Y. : Mechanism of elliptically polarized terahertz generation in two-color laser filamentation. Opt. Lett. 38 (7), 1034- 1036 (2013)

[72] Sato, M. , Higuchi, T. , Kanda, N. , Konishi, K. , Yoshioka, K. , Suzuki, T. , Misawa, K. , Kuwata-Gonokami, M. : Terahertz polarization pulse shaping with arbitrary field control. Nat. Photonics 7 (9), 724- 731 (2013)

[73] Kanda, N. , Higuchi, T. , Shimizu, H. , Konishi, K. , Yoshioka, K. , Kuwata-Gonokami, M. : The vectorial control of magnetization by light. Nat. Commun. 2 (1), 362- 367 (2011)

[74] McDonnell, C. , Deng, J. , Sideris, S. , Ellenbogen, T. , Li, G. : Functional THz emitters based on Pancharatnam-Berry phase nonlinear metasurfaces. Nat. Commun. 12 (1), 30- 38 (2021)

[75] Seifert, T.S. , Jaiswal, S. , Barker, J. , Weber, S.T. , Razdolski, I. , Cramer, J. , Gueckstock, O. , Maehrlein, S.F. , Nadvornik, L. , Watanabe, S. , Ciccarelli, C. , Melnikov, A. , Jakob, G. , Münzenberg, M. , Goennenwein, S.T.B. , Woltersdorf, G. , Rethfeld, B. , Brouwer, P.W. , Wolf, M. , Kläui, M. , Kampfrath, T. : Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy. Nat. Commun. 9 (1), 2899- 2910 (2018)

[76] Zhou, C. , Liu, Y.P. , Wang, Z. , Ma, S.J. , Jia, M.W. , Wu, R.Q. , Zhou, L. , Zhang, W. , Liu, M.K. , Wu, Y.Z. , Qi, J. : Broadband terahertz generation via the interface inverse Rashba-Edelstein effect. Phys. Rev. Lett. 121 (8), 086801- 086807 (2018)

[77] Jungfleisch, M.B. , Zhang, Q. , Zhang, W. , Pearson, J.E. , Schaller, R.D. , Wen, H. , Hoffmann, A. : Control of terahertz emission by ultrafast spin-charge current conversion at Rashba interfaces. Phys. Rev. Lett. 120 (20), 207207- 207213 (2018)

[78] Cheng, L. , Wang, X. , Yang, W. , Chai, J. , Yang, M. , Chen, M. , Wu, Y. , Chen, X. , Chi, D. , Goh, K.E.J. , Zhu, J.X. , Sun, H. , Wang, S. , Song, J.C.W. , Battiato, M. , Yang, H. , Chia, E.E.M. : Far outof-equilibrium spin populations trigger giant spin injection into atomically thin MoS₂. Nat. Phys. 15 (4), 347- 351 (2019)

[79] Zhou, X. , Song, B. , Chen, X. , You, Y. , Ruan, S. , Bai, H. , Zhang, W. , Ma, G. , Yao, J. , Pan, F. , Jin, Z. , Song, C. : Orientation-dependent THz emission in non-collinear antiferromagnetic Mn₃Sn and Mn₃Sn-based heterostructures. Appl. Phys. Lett. 115 (18), 2402- 2407 (2019)

[80] Gao, Y. , Kaushik, S. , Philip, E.J. , Li, Z. , Qin, Y. , Liu, Y.P. , Zhang, W.L. , Su, Y.L. , Chen, X. , Weng, H. , Kharzeev, D.E. , Liu, M.K. , Qi, J. : Chiral terahertz wave emission from the Weyl semimetal TaAs. Nat. Commun. 11 (1), 720- 730 (2020)

[81] Kong, D. , Wu, X. , Wang, B. , Nie, T. , Xiao, M. , Pandey, C. , Gao, Y. , Wen, L. , Zhao, W. , Ruan, C. , Miao, J. , Li, Y. , Wang, L. : Broadband spintronic terahertz emitter with magnetic-field manipulated polarizations. Adv. Opt. Mater. 7 (20), 487- 496 (2019)

[82] Chen, X. , Wu, X. , Shan, S. , Guo, F. , Kong, D. , Wang, C. , Nie, T. , Pandey, C. , Wen, L. , Zhao, W. , Ruan, C. , Miao, J. , Li, Y. , Wang, L. : Generation and manipulation of chiral broadband terahertz waves from cascade spintronic terahertz emitters. Appl. Phys. Lett. 115 (22), 1104- 1109 (2019)

[83] Fang, Z. , Wang, H. , Wu, X. , Shan, S. , Wang, C. , Zhao, H. , Xia, C. , Nie, T. , Miao, J. , Zhang, C. , Zhao, W. , Wang, L. : Nonlinear terahertz emission in the three-dimensional topological insulator Bi₂Te₃ by terahertz emission spectroscopy. Appl. Phys. Lett. 115 (19), 1102- 1107 (2019)

[84] Wang, B. , Shan, S. , Wu, X. , Wang, C. , Pandey, C. , Nie, T. , Zhao, W. , Li, Y. , Miao, J. , Wang, L. : Picosecond nonlinear spintronic dynamics investigated by terahertz emission spectroscopy. Appl. Phys. Lett. 115 (12), 1104- 1109 (2019)

[85] Guo, F. , Pandey, C. , Wang, C. , Nie, T. , Wen, L. , Zhao, W. , Miao, J. , Wang, L. , Wu, X. : Generation of highly efficient terahertz radiation in ferromagnetic heterostructures and its application in spintronic terahertz emission microscopy (STEM). OSA Continuum 3 (4), 893- 902 (2020)

[86] Beaurepaire, E. , Turner, G.M. , Harrel, S.M. , Beard, M.C. , Bigot, J.Y. , Schmuttenmaer, C.A. : Coherent terahertz emission from ferromagnetic films excited by femtosecond laser pulses. Appl. Phys. Lett. 84 (18), 3465- 3467 (2004)

[87] Battiato, M. , Carva, K. , Oppeneer, P.M. : Superdiffusive spin transport as a mechanism of ultrafast demagnetization. Phys. Rev. Lett. 105 (2), 027203- 027207 (2010)

[88] Kampfrath, T. , Battiato, M. , Maldonado, P. , Eilers, G. , Nötzold, J. , Mährlein, S. , Zbarsky, V. , Freimuth, F. , Mokrousov, Y. , Blügel, S. , Wolf, M. , Radu, I. , Oppeneer, P.M. , Münzenberg, M. : Terahertz spin current pulses controlled by magnetic heterostructures. Nat. Nanotechnol. 8 (4), 256- 260 (2013)

[89] Seifert, T. , Jaiswal, S. , Martens, U. , Hannegan, J. , Braun, L. , Maldonado, P. , Freimuth, F. , Kronenberg, A. , Henrizi, J. , Radu, I. , Beaurepaire, E. , Mokrousov, Y. , Oppeneer, P.M. , Jourdan, M. , Jakob, G. , Turchinovich, D. , Hayden, L.M. , Wolf, M. , Münzenberg, M. , Kläui, M. , Kampfrath, T. : Efficient metallic spintronic emitters of ultrabroadband terahertz radiation. Nat. Photonics 10 (7), 483- 488 (2016)

[90] Huisman, T.J. , Mikhaylovskiy, R.V. , Costa, J.D. , Freimuth, F. , Paz, E. , Ventura, J. , Freitas, P.P. , Blügel, S. , Mokrousov, Y. , Rasing, T. , Kimel, A.V. : Femtosecond control of electric currents in metallic ferromagnetic heterostructures. Nat. Nanotechnol. 11 (5), 455- 458 (2016)

[91] Walowski, J. , Münzenberg, M. : Perspective: ultrafast magnetism and THz spintronics. J. Appl. Phys. 120 (14), 901- 917 (2016)

[92] Wu, Y. , Elyasi, M. , Qiu, X. , Chen, M. , Liu, Y. , Ke, L. , Yang, H. : High-performance THz emitters based on ferromagnetic/ nonmagnetic heterostructures. Adv. Mater. 29 (4), 1603031- 1603038 (2017)

[93] Seifert, T. , Jaiswal, S. , Sajadi, M. , Jakob, G. , Winnerl, S. , Wolf, M. , Kläui, M. , Kampfrath, T. : Ultrabroadband single-cycle terahertz pulses with peak fields of 300 kV⋅cm−1 from a metallic spintronic emitter. Appl. Phys. Lett. 110 (25), 2402- 2407 (2017)

[94] Zhang, S. , Jin, Z. , Liu, X. , Zhao, W. , Lin, X. , Jing, C. , Ma, G. : Photoinduced terahertz radiation and negative conductivity dynamics in Heusler alloy Co₂MnSn film. Opt. Lett. 42 (16), 3080- 3083 (2017)

[95] Wang, X. , Cheng, L. , Zhu, D. , Wu, Y. , Chen, M. , Wang, Y. , Zhao, D. , Boothroyd, C.B. , Lam, Y.M. , Zhu, J.X. , Battiato, M. , Song, J.C.W. , Yang, H. , Chia, E.E.M. : Ultrafast spin-to-charge conversion at the surface of topological insulator thin films. Adv. Mater. 30 (52), 1802356- 1802364 (2018)

[96] Feng, Z. , Yu, R. , Zhou, Y. , Lu, H. , Tan, W. , Deng, H. , Liu, Q. , Zhai, Z. , Zhu, L. , Cai, J. , Miao, B. , Ding, H. : Highly efficient spintronic terahertz emitter enabled by metal-dielectric photonic crystal. Adv. Opt. Mater. 6 (23), 1800965- 1800971 (2018)

[97] Liu, C. , Wang, S. , Zhang, S. , Cai, Q. , Wang, P. , Tian, C. , Zhou, L. , Wu, Y. , Tao, Z. : Active spintronic-metasurface terahertz emitters with tunable chirality. Adv. Photonics 3 (5), 56002- 56012 (2021)

[98] Niwa, H. , Yoshikawa, N. , Kawaguchi, M. , Hayashi, M. , Shimano, R. : Switchable generation of azimuthally- and radially-polarized terahertz beams from a spintronic terahertz emitter. Opt. Express 29 (9), 13331- 13343 (2021)

[99] Hibberd, M.T. , Lake, D.S. , Johansson, N.A.B. , Thomson, T. , Jamison, S.P. , Graham, D.M. : Magnetic-field tailoring of the terahertz polarization emitted from a spintronic source. Appl. Phys. Lett. 114 (3), 1101- 1106 (2019)

[100] Yang, D. , Liang, J. , Zhou, C. , Sun, L. , Zheng, R. , Luo, S. , Wu, Y. , Qi, J. : Powerful and tunable THz emitters based on the Fe/ Pt magnetic heterostructure. Adv. Opt. Mater. 4 (12), 1944- 1949 (2016)

[101] Zhang, L. , Huang, Y. , Zhu, L. , Yao, Z. , Zhao, Q. , Du, W. , He, Y. , Xu, X. : Polarized THz emission from in-plane dipoles in monolayer tungsten disulfide by linear and circular optical rectification. Adv. Opt. Mater. 7 (6), 1801314- 1801322 (2019)

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