High-Field Terahertz Bulk Photovoltaic Effect in Lithium Niobate

作者：Carmine Somma, Klaus Reimann, Christos Flytzanis, Thomas Elsaesser, Michael Woerner · 发表于：Physical Review Letters · 年份：2014 · DOI：10.1103/physrevlett.112.146602 · 被引用次数：82 · 研究领域：Terahertz technology and applications、Photorefractive and Nonlinear Optics、Photonic and Optical Devices

The terahertz (THz) response of the ferroelectric prototype material lithium niobate (LiNbO3) is studied in the nonperturbative regime of light-matter interaction. Applying two-dimensional THz spectroscopy with few-cycle pulses of an amplitude E≈100 kV/cm and a center frequency of 2 THz, we dissect the overall nonlinear response into different orders in the electric field. The underlying nonlinear current is of interband character and consists of a strong low-frequency shift current (SC) and higher harmonics of the THz fundamental. The SC component originates from the lack of inversion symmetry and the strong interband decoherence for long electron trajectories in k space as shown by theoretical calculations.