LASER-INDUCED LONG-LIFETIME ELECTRON-TUNNELING IN BIASED ASYMMETRIC DOUBLE-QUANTUM-WELL

Laser (cw)-induced tunnelling dynamics of an electronic wavepacket in a biased asymmetric double quantum well (DWQ) structure is studied num erically, varying the quantum level alignment in the DQW. The Markoff master equation is used to determine the time evolution of the wavepac ket that is initially created by a pump pulse. Laser-induced long-life time (practically equal to the population relaxation time) electron tu nnelling is observed when the Rabi frequency is smaller in magnitude t han the dephasing rate. It is shown that this laser-induced effect can be eradicated by adjusting the bias voltage to align the upper two el ectronic states in the narrow and wide wells. (C) 1998 Academic Press Limited.