Rigorous signal reconstruction in terahertz emission spectroscopy

Terahertz (THz) emission spectroscopy is a powerful method that allows one to measure the ultrafast dynamics of polarization, current, or magnetization in a material based on THz emission from the material. However, the practical implementation of this method can be challenging, and can result in significant errors in the reconstruction of the quantity of interest. Here, we experimentally and theoretically demonstrate a rigorous method of signal reconstruction in THz emission spectroscopy, and describe the main experimental and theoretical sources of reconstruction error. We identify the linear line-of-sight geometry of the THz emission spectrometer as the optimal configuration for accurate, fully calibrated THz signal reconstruction. As an example, we apply our reconstruction method to ultrafast THz magnetometry experiment, where we recover the ultrafast magnetization dynamics in a photoexcited iron film, including both its temporal shape and absolute magnitude. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

Terahertz emission spectroscopy is a powerful method for measuring ultrafast dynamics in materials, but practical implementation can be challenging and lead to significant errors. A rigorous signal reconstruction method is proposed in this study, with the linear line-of-sight geometry of the THz emission spectrometer identified as the optimal configuration. This method was successfully applied to ultrafast THz magnetometry experiments, showcasing its ability to recover dynamics accurately.