ИСТИНА

Intense few cycle terahertz pulses may exhibit complex non-linear behavior under interaction with heavily n-doped Silicon. We show that a fast increase in the transmission of the 700 fs electromagnetic pulse (central frequency ~1.5 THz) through the 245-µm thick n-doped silicon sample with carrier concentration of 9x1016 cm-3 (low field transmission of ~0.02%) saturates at the field strength of ~5 MV/cm-1 at ~ 8% and then drops twofold at ~20 MV/cm-1. Electro-optical sampling measurements reveal formation of a single cycle terahertz pulse at highest field strengths due to an efficient cut-off of all field oscillations except for the first one by a thin layer ionized by this oscillation.