Electro-optic sampling of terahertz pulses using BaTiO3 in non-collinear Cherenkov phase-matching scheme

In this paper we report electro-optic (EO) sampling of THz pulses using ferroelectric crystal in the non-collinear Cherenkov phase-matching scheme, where an effective velocity matching is achieved in an EO crystal with a large refractive index in the THz frequency region. We demonstrate efficient THz EO sampling using LiNbO₃ and BaTiO₃ crystals in the Cherenkov- phase-matching scheme. It is shown that the efficiency of EO sampling with BaTiO3 is smaller than that with LiNbO₃, even though the EO coefficient (r₃₃) of BaTiO₃ is three times higher than that of LiNbO₃. The reason of the poor performance of BaTiO₃ is attributed to the strong absorption in the THz frequency region.