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Optical Non‐Linearities Related to Trions in Quantum Wells and Quantum Dots
Author(s) -
Puls J.,
Akimov I.A.,
Henneberger F.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200211)234:1<304::aid-pssb304>3.0.co;2-6
Subject(s) - trion , quantum dot , physics , electron , pauli exclusion principle , quantum well , exciton , atomic physics , electro absorption modulator , auger effect , condensed matter physics , quantum dot laser , quantum mechanics , laser
We study the non‐linear optical properties associated with negatively charged excitons (trions) in II–VI semiconductor quantum wells and single quantum dots. In n‐type doped quantum well structures, we observe optical gain and lasing at the trion resonance. The trion momentum distribution spreads out deeper in k ‐space, while the electrons are closer to the zone center. This results in optical gain at moderate injection levels without inversion in the total number of trions and electrons. The non‐linear response of single self‐assembled CdSe/ZnSe quantum dots charged with an electron is indeed atom‐like. We observe complete bleaching of linear trion absorption spectrum and appearance of induced absorption due to two‐pair excitations. The data embody clear signatures for Pauli blocking, few‐particle Coulomb correlation, as well as electron–hole exchange finestructure.