Coherent Control of Bloch Oscillations by Means of Optical Pulse Shaping

We create excitonic wavepackets in biased semiconductor superlattices (SLs) with spectrally-shaped ultrashort optical pulses. We tailor the shape and phase of the pulse spectrum in order to control the coherent dynamics of the excitonic wavepackets formed from a superposition of three excitonic states. The wavepacket evolution is monitored using spectrally-resolved four wave mixing. This ability to control the BOs provides a way to control the emitted THz radiation.