Application of high power terahertz sources to nonlinear spectroscopy of direct bandgap semiconductors

Nonlinear dynamics of free-carriers in direct bandgap semiconductors at terahertz (THz) frequencies is studied using high power, few-cycle pulses. Techniques as Z-scan and THz-pump / THz-probe are employed to explore nonlinear interactions in both n-doped and photoexcited systems. The physical mechanism that gives rise to such interactions will be discussed in details.