Terahertz Kerr microscopy using a SrTiO3 sensor

We report on the combination of a high-field terahertz source and two-dimensional near-field imaging capability using SrTiO
3
(STO) crystal. Specifically, we show that the surface of STO allows sub-picosecond Kerr-effect switching and multi-ps THz intensity recording. The sensitivity and spatial resolution achieved by the STO sensor outperform current near-field THz sensors based on the Pockel effect, and more importantly, its ability to remain polarized for several picoseconds may open the door to a new strategy for building an ultrafast two-dimensional space-time THz memory.