Generation of coherent LO phonons in optically driven biased quantum wells

Titelangaben

Papenkort, Thomas ; Kuhn, Tilmann ; Axt, Vollrath Martin:
Generation of coherent LO phonons in optically driven biased quantum wells.
In: Physica Status Solidi C. Bd. 8 (2011) Heft 4 . - S. 1121-1124.
ISSN 1610-1642
DOI: https://doi.org/10.1002/pssc.201000823

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Abstract

We present a theoretical analysis and numerical simulations of the resonant generation of coherent LO phonons in an electrically biased quantum well. The system is driven by a laser pulse short enough to simultaneously excite two transitions, which leads to a quantum beat that can resonantly create coherent phonons. The generation of incoherent phonons is also calculated on a quantum kinetic level and found to be dominant in terms of the energy transferred to the lattice.The simulations successfully reproduce the main features found in recent experiments Mizoguchi et al., Appl. Phys. Lett. 94, 171105 (2009). Depending on the excitation conditions different generation mechanisms can be discerned. We discuss their characteristics and their relative efficiency in the special case of the quantum well model under consideration.