Two-dimensional space–time terahertz memory in bulk SrTiO₃

Ferroelectric materials offer unprecedented ultrafast responses and are of great interest for the development new polarizable media under influence an electromagnetic field. Recent research efforts have demonstrated role optical excitation intense terahertz (THz) pulses in inducing a polar order revealing hidden phase transition SrTiO3 (STO), respectively. Here we show that surface STO crystals at room temperature act as sensors enable sub-picosecond switching through Kerr effect multi-ps recording THz intensity with spatial resolution below diffraction limit dipole alignment relaxation. The contrast sensitivity achieved by sensor significantly superior to those present-day near-field based on linear Pockels effect, more importantly, its ability remain polarized several picoseconds opens door strategy building space-time memory.