GENERATION OF TERAHERTZ ELECTROMAGNETIC PULSES FROM QUANTUM-WELL STRUCTURES

Terahertz generation from semiconductor quantum-well structures pumped by a femtosecond optical pulse is studied. We propose a three-level m odel for the electrons and holes in the quantum wells. We then solve t he coupled optical Bloch equations directly using a Runge-Kutta method and calculate the terahertz radiation field. We study optical rectifi cation and quantum beats caused by charge oscillations in 1) a coupled quantum well in which quantum beats occur between two electron states of the coupled system and 2) a single-quantum-well structure in which quantum beats occur between light-hole and heavy-hole excitons Our th eoretical results agree very well with the experimentally measured ter ahertz data.