Transient and steady-state properties of asymmetric semiconductor quantum wells at Telecom wavelength bands
H. R. Hamedi
Institute of Theoretical Physics and Astronomy, Vilnius University,
LT-01108 Vilnius, Lithuania
Abstract
Transient and steady-state dispersion and absorption properties of a three-subband asymmetric
semiconductor quantum well system are investigated. In the steady-state regime, it is shown that
by increasing the strength of Fano-interference as well as enhancement of energy splitting of two
excited states the slope of dispersion changes from negative to positive which is corresponding to
a switch between superluminal to subluminal light propagation. At the same time, the probe
absorption reduces at telecommunication wavelength λ=1550 nm. The influence of incoherent
pumping fields on time-dependent susceptibility is then discussed. It is found that due to more
transfer of population to the upper levels, increasing the rate of incoherent pump field leads to
the reduction of probe absorption. In addition, it is realized that incoherent pumping has a major
role in converting fast to slow propagation of light at long wavelength. We also introduce an
extra controllability for the light pulse to be slow downed at Telecom wavelength just through
the quantum interference arising from incoherent pumping fields. The obtained results may be
practical in telecommunication applications.