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Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


Physical Sciences and Mathematics

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This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in T. Piwonski et al., Appl. Phys. Lett. 99, 171103 (2009) and may be found at

The authors would like to thank Bryan Kelleher for proof reading the manuscript. This study has been supported by Science Foundation Ireland (SFI) under the contract number SFI 07/IN.1/I929, the INSPIRE Programme, funded by the Irish Government’s Programme for Research in Third Level Institutions, Cycle 4, National Development Plan 2007-2013, and the Institute of Technology Ireland’s Strand I Programme and the Tyndall National Access Program. In Belgium, support was provided by the Fond National de la Recherche Scientifique. T. Erneux was also supported by the Air Force Office of Scientific Research (AFOSR) grant FA8655-09-1-3068.


Multi-pulse heterodyne pump-probe measurements are used to investigate the reverse bias dynamics of InAs/GaAs quantum dots in a waveguide structure. Using a femtosecond pulse, we simultaneously populate high energy ground states and low energy excited states and measure the resulting gain and phase dynamics over the bandwidth of the pulse. We identify a ∼5 ps timescale in the phase dynamics which can be associated with low energy ground states outside the pulse bandwidth and may provide an explanation for the deterioration of monolithic mode locked laser performance at high reverse voltages.