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MA: Fachverband Magnetismus
MA 24: Terahertz Spintronics I
MA 24.8: Talk
Wednesday, March 20, 2024, 11:30–11:45, EB 202
Rotating spintronic THz emitter for high-power and field-driven applications at MHz repetition rates — •Alkisti Vaitsi1, Vivien Sleziona1, Luis E. Parra Lopéz1, Yannic Behovits2, Fabian Schulz3, Natalia Martín Sabanés4, Tobias Kampfrath2, Martin Wolf1, Tom S. Seifert2, and Melanie Müller1 — 1Fritz Haber Institute, Berlin, Germany — 2Freie Universität Berlin, Berlin, Germany — 3CIC nanoGUNE, San Sebastian, Spain — 4IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, Madrid, Spain
We demonstrate high-power operation of a broadband spintronic terahertz emitter (STE) excited with up to 18 W pump power at MHz repetition rates for THz-field-driven applications. By rotating the STE at angular speed on the order of 100 Hz, we achieve optimal power conversion efficiency at fluences of ∼1 mJ/cm2 at average power densities of ∼350 W/cm2, well above the laser damage threshold of thin metallic films. The rotating STE design is scalable and eliminates material degradation due to thermal heating. Optimizing further the THz propagation from the rotating STE, we achieve peak THz fields of up to 10 and 6 kV/cm incident on the junction of a THz scanning tunneling microscope at 1 and 2 MHz repetition rate, resulting in ∼5 V and 8 V THz bias voltages inside the STM. We discuss performance limiting saturation mechanisms and present an optimal setup design for application of the STE in THz-STM and other field-driven applications.
Keywords: Spintronic terahertz emitter; Terahertz scanning tunneling microscopy; THz-field-driven applications; Terahertz propagation