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S. Schmitt-Rink, D. S. Chemla and
D. A. B. Miller, "Theory of Transient Excitonic Optical Nonlinearities
in Semiconductor Quantum-Well Structures," Phys. Rev. B32, 6601-6609 (1985). The
authors present theoretical results for the effects of an exciton gas and an electron-hole
plasma on the excitonic optical absorption in a two-dimensional semiconductor and compare
these with recent experimental results on absorption saturation in single- and
multiple-quantum-well structures. A simple theoretical description of the nonlinear
optical properties of these microstructures is developed for the case of low-density
optical excitation near and above the band edge. They argue that the effects of Coulomb
screening of excitons by the plasma are relatively weak in these structures but that the
consequences of phase-space filling and exchange are significant in each case. The authors
are able to explain the recent unexpected experimental result that 'cold' excitons are
more effective than 'hot' carriers in saturating the excitonic absorption. Good agreement
with the experimental data is obtained without adjustable parameters
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