%0 Journal Article
%T Visualization of ferroelectric domains in boracite using emission of terahertz radiation
%A Y. Kinoshita
%A N. Kida
%A M. Sotome
%A R. Takeda
%A N. Abe
%A M. Saito
%A T. Arima
%A H. Okamoto
%J Physics
%D 2014
%I arXiv
%R 10.7567/JJAP.53.09PD08
%X We report on the emission of terahertz radiation by irradiation of femtosecond laser pulses in non-centrosymmetric paraelectric and ferroelectric phases of Co$_3$B$_7$O$_{13}$I boracite. The Generation of the terahertz waves in both phases is caused by optical rectification via a second-order nonlinear optical effect. In the ferroelectric phase, we successfully visualized ferroelectric domains by analyzing the polarization state of the terahertz wave radiated from the crystal. In a large area of the crystal ($\sim$ 500 $\times$ 500 $\mu$m$^2$), the observed polarization vector of the radiated terahertz wave was tilted from directions of spontaneous polarization, i.e., [100]$_{\rm cub}$, [010]$_{\rm cub}$, and [001]$_{\rm cub}$ in cubic setting, which can be explained by the presence of a ferroelectric 90$^\circ$ domain wall of the (101)$_{\rm cub}$ plane.
%U http://arxiv.org/abs/1409.2960v1