Theoretical studies of submillimeter radiation and near-infrared emission due to excitonic recombination in an asymmetric coupled-quantum-well structure

Abstract

In this paper the delocalized behaviours of an asymmetric coupled-quantum-well structure (a-CQWS) have been studied and the transfer process of the electrons between the two wells has been analyzed theoretically based on V-type system. We show that an electronic packet of coherent oscillation created by an ultrashort pulse can be viewed as a classical electronic dipole damping oscillator, whose lifetime depends strongly on both the electronic-tunneling transfer time and the carrier-longitudinal optial scattering time.The submillimeter radiative lifetime created by coherent oscillation of an electronic wave packet is related to the oscillation damping rate between the two wells but not to the exitonic recombination rate; the intensity in frequency domain has the Lorentzs profile.It is shown that the transiton frequency of near-infrared radiation generated by the excitonic recombination has a tunable characteristic.This result implys that the high-speed modulator and the tunable source in the near infrared-radiation region can be obtained from the asymmetric double-quantum well structure in the future optical communication.