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Title: Negative differential gain in quantum dot systems: Interplay of structural properties and many-body effects

The saturation behaviour of optical gain with increasing excitation density is an important factor for laser device performance. For active materials based on self-organized InGaAs/GaAs quantum dots, we study the interplay between structural properties of the quantum dots and many-body effects of excited carriers in the optical properties via a combination of tight-binding and quantum-kinetic calculations. We identify regimes where either phase-space filling or excitation-induced dephasing dominates the saturation behavior of the optical gain. The latter can lead to the emergence of a negative differential material gain.
Authors:
;  [1] ; ;  [2]
  1. Institute for Theoretical Physics, University of Bremen, Bremen 28359 (Germany)
  2. Bremen Center for Computational Materials Science BCCMS, University of Bremen, Bremen 28359 (Germany)
Publication Date:
OSTI Identifier:
22299895
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CARRIERS; EQUIPMENT; EXCITATION; GAIN; GALLIUM ARSENIDES; INDIUM ARSENIDES; LASERS; MANY-BODY PROBLEM; OPTICAL PROPERTIES; PHASE SPACE; QUANTUM DOTS; SATURATION