Tesla-class single-cycle terahertz magnetic field pulses generated with a spiral-shaped metal microstructure

We study the terahertz (THz) magnetic field pulse enhanced by a spiral-shaped antenna resonator (SAR). We deposit the SAR on the surface of a terbium-gallium-garnet crystal, which has a large Verdet constant, and measure the Faraday rotation angle for strong THz pulse excitation by magneto-optical sampling (MOS) with NIR light. The determined magnetic field strength and field-enhancement spectrum are consistent with the theoretical predictions. This first report of the detection of a Tesla-class picosecond magnetic field pulse by MOS is expected to be useful in research on the control of magnetization in spintronic devices.