Berlin 2024 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 24: Terahertz Spintronics I
MA 24.9: Vortrag
Mittwoch, 20. März 2024, 11:45–12:00, EB 202
Broadband spintronic terahertz source with peak electric fields exceeding 1.5 MV/cm — •Reza Rouzegar1,2, Alexander Chekhov1,2, Yannic Behovits1,2, Bruno Serrano1, Maria Syskaki3, Charles Lambert4, Dieter Engel5, Markus Münzenberg6, Gerhard Jakob3, Mathis Kläui3, Tom S. Seifert1, and Tobias Kampfrath1,2 — 1Freie Universität Berlin — 2Fritz-Haber-Institute of MPG — 3Johannes Gutenberg University Mainz — 4ETH Zürich — 5Max-Born-Institute in Berlin — 6Universität Greifswald
Spintronic terahertz emitters (STEs) allow one to generate ultrashort terahertz electromagnetic pulses by excitation with a femtosecond laser pulse. Here, we significantly improve the performance of an STE by a factor of up to 6 in field amplitude by optimizing the management of light and heat flow. Our new Si-based STE (Si-STE) design features almost 100% pump absorptance, enhanced terahertz outcoupling and maximized heat-transport into the substrate. Using high energy pump pulses (energy 5 mJ, duration 80 fs, wavelength 800 nm), we generate THz pulses with peak electric fields of 1.5 MV/cm, a fluence of the order of 1 mJ/cm2, with a gapless spectrum covering the range 1-11 THz. We compared our new Si-STE design to LiNbO3, which is the gold standard of table-top high-power terahertz sources. We find comparable peak fields and fluences. The optimized STE (Si-STE) still has all attractive features of the standard STE, e.g., straightforward rotation of the terahertz polarization plane by an external magnetic field, ease-of-use and independence of the pump wavelength.
Keywords: spintronic terahertz emitter; spin transport