Polarization Effects of Electro-optic Sampling and Over-rotation for High Field THz Detection

With ever increasing availability of terahertz fields, it is important to find suitable detection techniques without compromising the measured dynamic range. Electro-optic terahertz sampling techniques, which are commonly used to detect terahertz fields, exhibit over-rotation at high fields that limit the detection accuracy. Here we discuss a method to correct for over-rotation that put no limits on measured terahertz field strengths, while preserving the low field sensitivity. We further evaluate the induced polarizations at high terahertz fields and show how over-rotation can be corrected by simultaneously measuring the polarizations before and after the quarter wave plate.