Br. Hyun et al., COHERENT REFLECTED PULSES OF EXCITON POLARITONS IN MULTIPLE-QUANTUM WELLS AT BREWSTERS-ANGLE INCIDENCE, Physical review. B, Condensed matter, 56(20), 1997, pp. 12780-12783
A coherent emission of excitons in semiconductor multiple quantum well
s was investigated by using transient Brewster reflection spectroscopy
. The method reduced nonresonant background reflection greatly and all
owed us to observe the coherent dynamics of the excitons clearly. The
coherent signal showed not only the quantum beats of the heavy-and lig
ht-hole excitons but also the oscillatory modulation structures that r
esulted from the radiative coupling of exciton polaritons. In the line
ar regime, these observations were compared with results calculated fr
om the transfer-matrix method involving multiple-reflection effects, a
nd good agreement was obtained. As the excitation density of the incid
ent pulses was raised, the decay rate of the coherent signal increased
due to the exciton-exciton scattering.