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MA: Fachverband Magnetismus

MA 24: Terahertz Spintronics I

MA 24.10: Talk

Wednesday, March 20, 2024, 12:00–12:15, EB 202

Broadband spintronic sampling of true terahertz electric fields — •Alexander Chekhov¹, Yannic Behovits¹, Julius Heitz¹, Maria-Andromachi Syskaki², Bruno Rosinus Serrano¹, Amon Ruge¹, Jana Kredl³, Markus Münzenberg³, Gerhard Jakob², Mathias Kläui², Tom Seifert¹, and Tobias Kampfrath¹ — ¹Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany — ²Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany — ³Institut für Physik, Universität Greifswald, 17489 Greifswald, Germany

The increasing bandwidth of intense terahertz (THz) sources demands the development of new methods for the sampling of broadband THz electromagnetic pulses. Here, we demonstrate a spintronic approach to THz-electric-field detection based on measuring the THz spin accumulation that is induced at a ferromagnet/heavy-metal (FM/HM) interface by a THz electric field. To put this scheme to the test, we apply ultrabroadband THz pulses from a spintronic THz emitter to FM|HM stacks and probe the transient optical birefringence. We find that the measured signal has the same shape as the driving THz field without any distortions over the full range of 0.1-12 THz. By studying various FM|HM stacks, we reveal the mechanism behind the observed signals and maximize the detector efficiency. Our work not only provides new opportunities in THz photonics but also new insights into THz spin dynamics at interfaces.

Keywords: Terahertz detection; Spin accumulation; Spintronic terahertz emitter; Interface physics