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arXiv · 2306.09734

Broadband spintronic detection of the absolute field strength of terahertz electromagnetic pulses

A. L. Chekhov·Y. Behovits·U. Martens·B. R. Serrano·M. Wolf·T. S. Seifert·M. Muenzenberg·T. Kampfrath
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Abstract

We demonstrate detection of broadband intense terahertz electromagnetic pulses by Zeeman-torque sampling (ZTS). Our approach is based on magneto-optic probing of the Zeeman torque the terahertz magnetic field exerts on the magnetization of a ferromagnet. Using an 8 nm thick iron film as sensor, we detect pulses from a silicon-based spintronic terahertz emitter with bandwidth 0.1-11 THz and peak field >0.1 MV/cm. Static calibration provides access to absolute transient THz field strengths. We show relevant added values of ZTS compared to electro-optic sampling (EOS): an absolute and echo-free transfer function with simple frequency dependence, linearity even at high terahertz field amplitudes, the straightforward calibration of EOS response functions and the modulation of the polarization-sensitive direction by an external AC magnetic field. Consequently, ZTS has interesting applications even beyond the accurate characterization of broadband high-field terahertz pulses for nonlinear terahertz spectroscopy.

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A. L. Chekhov, Y. Behovits, U. Martens, B. R. Serrano, M. Wolf, T. S. Seifert, M. Muenzenberg, T. Kampfrath. 2023-06-16. Broadband spintronic detection of the absolute field strength of terahertz electromagnetic pulses. https://arxiv.org/abs/2306.09734

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