Nonlinear intersubband dynamics in quantum wells driven by intense few-cycle terahertz pulses

In this contribution, we demonstrate the direct observation of non-equilibrium intersubband dynamics in a modulation-doped quantum well sample induced by intense, broadband terahertz pulses. The THz field dependent transmission of the intersubband system is probed using a depletion-modulation technique, which allows to selectively measure the nonlinear interaction of the THz pulses and the electrons in the quantum well.