Ultrafast Terahertz Gating of the Polarization and Giant Nonlinear Optical Response in BiFeO3 Thin Films.

Chen, Frank; Goodfellow, John; Liu, Shi; Grinberg, Ilya; Hoffmann, Matthias C; Damodaran, Anoop R; Zhu, Yi; Zalden, Peter et al. · Adv Mater · 2015

basic_science · Level V

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Abstract

Terahertz pulses are applied as an all-optical bias to ferroelectric thin-film BiFeO3 while monitoring the time-dependent ferroelectric polarization through its nonlinear optical response. Modulations in the intensity of the second harmonic light generated by the film correspond to on-off ratios of 220× gateable on femtosecond timescales. Polarization modulations comparable to the built-in static polarization are observed.