Terahertz signatures of the exciton formation dynamics in non-resonantly excited semiconductors

A microscopic theory for the induced terahertz (THz) absorption of semiconductors is applied to study the time-dependent system response after non-resonant optical excitation. The formation of excitonic populations from an interacting electronhole plasma is analyzed and the characteristic THz signatures are computed. Good qualitative agreement with recent experiments is obtained. (C) 2003 Elsevier Ltd. All rights reserved.