Polaron signatures in the line shape of semiconductor intersubband transitions:: quantum kinetics of the electron-phonon interaction

We present a theory of the optical line shape of coherent intersubband transitions in a semiconductor quantum well, considering non-Markovian LO-phonon scattering as major broadening mechanism. We show that a quantum kinetic approach leads to additional polaron resonances and a resonance enhancement for gap energies close to the phonon energy. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.