Density-matrix theory of the optical dynamics and transport in quantum cascade structures: The role of coherence

Weber, Carsten; Wacker, Andreas; Knorr, A. (2009). Density-matrix theory of the optical dynamics and transport in quantum cascade structures: The role of coherence. Physical Review B (Condensed Matter and Materials Physics), 79, (16)
Download:
DOI:
| Published | English
Authors:
Weber, Carsten ; Wacker, Andreas ; Knorr, A.
Department:
Mathematical Physics
Linne Center for Nanoscience and Quantum Engineering-lup-obsolete
Research Group:
Linne Center for Nanoscience and Quantum Engineering-lup-obsolete
Abstract:
The impact of coherence on the nonlinear optical response and stationary transport is studied in quantum cascade laser structures. Nonequilibrium effects such as the pump-probe signals, the spatiotemporally resolved electron density evolution, and the subband population dynamics (Rabi flopping) as well as the stationary current characteristics are investigated within a microscopic density-matrix approach. Focusing on the stationary current and the recently observed gain oscillations, it is found that the inclusion of coherence leads to observable coherent effects in opposite parameter regimes regarding the relation between the level broadening and the tunnel coupling across the main injection barrier. This shows that coherence plays a complementary role in stationary transport and nonlinear optical dynamics in the sense that it leads to measurable effects in opposite regimes. For this reason, a fully coherent consideration of such nonequilibrium structures is necessary to describe the combined optical and transport properties.
Keywords:
quantum cascade lasers ; nonlinear optics ; optical pumping
ISSN:
1098-0121
LUP-ID:
ae66f4a6-ce41-4d7d-889f-08e54f160b7b | Link: https://lup.lub.lu.se/record/ae66f4a6-ce41-4d7d-889f-08e54f160b7b | Statistics

Cite this