Ultrabroadband single-cycle terahertz pulses with peak fields of 300 kV cm−1 from a metallic spintronic emitter

By T. Seifert, S. Jaiswal, M. Sajadi, Gerhard Jakob, S. Winnerl, Martin Wolf, Mathias Kläui, T. Kampfrath. 2017

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We explore the capabilities of metallic spintronic thin-film stacks as a source of intense and broadband terahertz electromagnetic fields. For this purpose, we excite a W/CoFeB/Pt trilayer (thickness of 5.6 nm) on a large-area glass substrate (diameter of 7.5 cm) by a femtosecond laser pulse (energy 5.5 mJ, duration 40 fs, and wavelength 800 nm). After focusing, the emitted terahertz pulse is measured to have a duration of 230 fs, a peak field of 300 kV cm−1, and an energy of 5 nJ. In particular, the waveform exhibits a gapless spectrum extending from 1 to 10 THz at 10% of its amplitude maximum, thereby facilitating nonlinear control over matter in this difficult-to-reach frequency range on the sub-picosecond time scale.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/9fa5640385aacb167ccebf80a03c995357afdcfd