Author

Saba Arash

Date of Award

Fall 2021

Document Type

Open Access Dissertation

Department

Physics and Astronomy

First Advisor

Yanwen Wu

Abstract

Here we present all-optical investigations of two hybrid nanostructures. In the first hybrid system, we study Janus-type nanofibers consisting of two hemi-cylinders of ferroelectric barium titanate and ferrimagnetic cobalt ferrite. Using the magnetic field-dependent polarization-resolved second harmonic generation technique, we observe a strong magnetoelectric coupling between the two ferroic constituents at room temperature. Corroborating these results by X-ray diffraction, we can also extract repeatable memory-dependent behaviors in these biphasic nanofibers. In the second hybrid system, we study the interaction between the semiconductor indium/gallium arsenide quantum dots and surface plasmon supporting silver structures in the weak coupling regime. When quantum dots are excited above the gallium arsenide band gap energy, we observe polarization- and bias-dependent transitions between different exciton charge states. We also observe a polarization-dependent effect in the photoluminescence signal when exciting below this band gap energy. Both these behaviors are absent in dots away from plasmonic structures.

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Physics Commons

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