Optical reflection from long-period multiple quantum wells: effects of dielectric constant mismatch

The theory of resonant optical reflection from long-period multiple quantum-well structures has been extended to take into account the difference between the dielectric constant of the barrier, epsilon(b), and the nonresonant contribution, epsilon(a), to the dielectric function in the wells. The reflection spectra taken from CdTe/CdMgTe quasi-Bragg quantum wells reveal, in addition to sharp excitonic features, smooth interference fringes determined by the mismatch epsilon(a) not equal epsilon(b). Implications arising due to the dielectric constant mismatch as well as due to detuning from the resonant Bragg condition are analyzed and discussed. (C) 1998 Elsevier Science B.V. All rights reserved.