Berlin 2024 – scientific programme
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MA: Fachverband Magnetismus
MA 24: Terahertz Spintronics I
MA 24.7: Talk
Wednesday, March 20, 2024, 11:00–11:15, EB 202
Tunable ultrabroadband hybrid terahertz emitter combining a spintronic terahertz source and a GaSe crystal — •Afnan Alostaz1,2, Oliver Gueckstock1, Jungwei Tong1, Jana Kredl3, Chihun In1, Markus Münzenberg3, and Tom S. Seifert1 — 1Department of Physics, Freie Universität Berlin, Germany — 2Peter Grünberg Institut-6, Forschungszentrum Jülich GmbH, Jülich, Germany — 3Institut für Physik, Universität Greifswald, Greifswald, Germany
Linear terahertz time-domain spectroscopy (THz-TDS) is a sensitive probe for material characterization including thickness measurements of thin layers. To widen the impact of THz-TDS systems, the THz bandwidth should be maximized, ideally exceeding 15 THz
Here, we introduce a hybrid THz-emitter concept based on a spintronic THz emitter (STE) [1] that is deposited onto a thin freestanding GaSe nonlinear crystal. By tuning the parameters of this hybrid emitter and by superimposing the generated THz pulses from the STE and GaSe, we generate an ultrabroadband THz spectrum covering the full range from 1 to 40 THz without any gaps at high spectral amplitudes, resulting in ultrashort THz-pulse durations of only 32 fs.
Finally, we demonstrate a tunability of the carrier-envelope phase by the external magnetic field from unipolar or bipolar THz pulses with ultrashort duration that are well suited as ultrabroadband THz probe pulses.
[1] Seifert, T., Jaiswal, S., Martens, U. et al. Nature Photon. 10 (2016).
Keywords: Spintronics; Terahertz emitter; terahertz time-domain spectroscopy; ultrabroadband THz emission; optical rectification