Electrooptical effect in silicon induced by a terahertz radiation pulse

This paper presents the experimental results of studying the nonlinear optical effect in crystalline silicon samples with various degrees and types of doping, induced by the electric field of an ultrashort terahertz radiation pulse in the intensity range from $4$ to $10$ MV/cm. The electrooptical coefficient is experimentally measured for silicon samples of different thicknesses and doping levels at a wavelength of $1240$ nm. Estimates are obtained for the real part of the third-order volume nonlinear susceptibility $\chi^{(3)}$, the Kerr constant, and the nonlinear refractive index $n_2$.