Effect of inter-level relaxation and cavity length on double-state lasing performance of quantum dot lasers
Autor: | Bowei Xu, Zhong-Su Wang, Liwei Shi, Yuntang Chen, Z.G. Wang |
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Rok vydání: | 2007 |
Předmět: |
Materials science
Condensed matter physics Physics::Optics Rate equation Condensed Matter Physics Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Quantum dot laser Quantum dot Excited state Relaxation (physics) Atomic physics Ground state Lasing threshold Wetting layer |
Zdroj: | Physica E: Low-dimensional Systems and Nanostructures. 39:203-208 |
ISSN: | 1386-9477 |
Popis: | Double-state lasing phenomena are easily observed in self-assembled quantum dot (QD) lasers. The effect of inter-level relaxation rate and cavity length on the double-state lasing performance of QD lasers is investigated on the basis of a rate equation model. Calculated results show that, for a certain cavity length, the ground state (GS) lasing threshold current increases almost linearly with the inter-level relaxation lifetime. However, as the relaxation rate becomes slower, the ratio of excited state (ES) lasing threshold current over the GS one decreases, showing an evident exponential behavior. A relatively feasible method to estimate the inter-level relaxation lifetime, which is difficult to measure directly, is provided. In addition, fast inter-level relaxation is favorable for the GS single-mode lasing, and leads to lower wetting layer (WL) carrier occupation probability and higher QD GS capture efficiency and external differential quantum efficiency. Besides, the double-state lasing effect strongly depends on the cavity length. (c) 2007 Elsevier B.V. All rights reserved. |
Databáze: | OpenAIRE |
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