Date of Award


Document Type

Master Thesis

Degree Name

Masters of Science (Research)


Applied Physics & Instrumentation

First Advisor

Dr. Guillaume Huyet


High-speed semiconductor quantum dot saturable absorbers have dramatically improved lasers to generate ultrafast optical pulses with a diverse range of applications. The carrier escape and relaxation dynamics of an InAs/GaAs quantum dot absorber waveguide were investigated using a heterodyne pump-probe spectroscopy technique. The measurements of the absorption recovery of the quantum dot waveguide were performed under applied reverse bias utilising both single-colour and two-colour pump probe spectroscopy. The study revealed differences in the intradot relaxation dynamics related to the initial population of the ground state or the excited state of the quantum dots. It was concluded that phonon mediated recovery dominates if the ground state is initially populated and that Auger-mediated recovery dominates if the excited state is initially populated.

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