Resonant saturation laser spectroscopy of a single self-assembled quantum dot

• Published in: Physica. E, Low-dimensional systems & nanostructures Vol. 40; no. 6; pp. 1994 - 1996
• Main Authors: Kroner, M., Rémi, S., Högele, A., Seidl, S., Holleitner, A.W., Warburton, R.J., Gerardot, B.D., Petroff, P.M., Karrai, K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2008; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Laser spectroscopy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Power broadening; Quantum dot; Quantum dots; Saturation spectroscopy; Two-level system; 71.63.Hk; Saturation spectroscopy; Quantum dot; Power broadening; 74.40.Xy; Laser spectroscopy; Two-level system; 74.40.Xy; 71.63.Hk; Quantum dot; Power broadening; Laser spectroscopy; Two-level system; Saturation spectroscopy; Fluctuations; Excitons; Ground states; Quantum dots; Two-level systems; Line widths; Self-assembled layers; Absorption spectra; Radiative lifetimes
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2007.09.150

We performed high resolution resonant laser spectroscopy on a single self-assembled quantum dot (QD) at liquid He temperatures. We explore the two-level nature of the QD excitonic transition through the investigation of its behavior as a function of the laser power. The quantum ground state exciton absorption peak size diminishes with increasing power while its width increases. Fitting these dependencies to the predictions of a two-level atom model we extract unambiguously a radiative lifetime of 660 ps, a residual collisional broadening about 0.18 μ eV as well as the spectral fluctuation 1.3 μ eV . We find that at high power the line width of the exciton absorption is essentially given by the Rabi frequency.