Picosecond time-resolved cyclotron resonance of non-equilibrium carriers in semiconductors

We have investigated the intraband dynamics of non-equilibrium carriers in semiconductors, using a picosecond far-infrared (FIR) free-electron laser s ynchronized with a femtosecond near-infrared (NIR) Ti : sapphire laser. An intense NIR pulse creates carriers, which interact with a delayed FIR pulse . We detect time-resolved cyclotron resonance by monitoring the intensity o f the transmitted and reflected FIR pulse as functions of magnetic held and time delay between the NIR and FIR pulses. Results reveal a variety of int raband dynamical phenomena over time scales much shorter than the interband lifetime. (C) 1999 Published by Elsevier Science B.V. All rights reserved.