Abstract
In this thesis we investigate the optical response of nanohybrids, comprising a closely spaced quantum emitter (QE) and a spherical metal nanoparticle (MNP), interacting with light.
First, a system composed of a two-level semiconductor quantum dot (SQD) coupled to a gold MNP is considered. It is shown that the SQD-MNP coupling, characterized by a complex-valued parameter, gives rise to bistability of the hybrid’s optical response. The real and imaginary parts of the coupling parameter lead to two different mechanisms of bistability. We also address the time dependent response of the system, which is crucial to assess the potential usefulness of such systems as building blocks of real devices.
Next, we study a symmetric dimer (DIM) coupled to a silver MNP. The dimer consists of two molecules effectively representing an optical three-level ladder system. In addition to bistability, the DIM-MNP hybridization leads to a drastic enhancement of two-photon absorption. The linear absorption spectrum exhibits Fano-like line shapes which can be tailored by controlling the spectral and spatial separation of both constituents as well as by changing the input power.
Finally, we examine the nonlinear optical response of an SQD modelled as a ladder-like three-level system strongly coupled to an MNP. We show that, under certain conditions, the SQD-MNP hybrid may exhibit self-oscillations and quasi-chaotic behavior. The period of self-oscillations can be pushed down to the sub-picosecond regime. Thus, potentially an SQD-MNP heterodimer represents a tunable nanogenerator of ultrashort optical pulses trains that might be interesting from the viewpoint of practical applications in nanodevices.
First, a system composed of a two-level semiconductor quantum dot (SQD) coupled to a gold MNP is considered. It is shown that the SQD-MNP coupling, characterized by a complex-valued parameter, gives rise to bistability of the hybrid’s optical response. The real and imaginary parts of the coupling parameter lead to two different mechanisms of bistability. We also address the time dependent response of the system, which is crucial to assess the potential usefulness of such systems as building blocks of real devices.
Next, we study a symmetric dimer (DIM) coupled to a silver MNP. The dimer consists of two molecules effectively representing an optical three-level ladder system. In addition to bistability, the DIM-MNP hybridization leads to a drastic enhancement of two-photon absorption. The linear absorption spectrum exhibits Fano-like line shapes which can be tailored by controlling the spectral and spatial separation of both constituents as well as by changing the input power.
Finally, we examine the nonlinear optical response of an SQD modelled as a ladder-like three-level system strongly coupled to an MNP. We show that, under certain conditions, the SQD-MNP hybrid may exhibit self-oscillations and quasi-chaotic behavior. The period of self-oscillations can be pushed down to the sub-picosecond regime. Thus, potentially an SQD-MNP heterodimer represents a tunable nanogenerator of ultrashort optical pulses trains that might be interesting from the viewpoint of practical applications in nanodevices.
| Original language | English |
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| Qualification | Doctor of Philosophy |
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| Supervisors/Advisors |
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| Award date | 22-Nov-2016 |
| Place of Publication | [Groningen] |
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| Print ISBNs | 978-90-367-9293-6 |
| Electronic ISBNs | 978-90-367-9292-9 |
| Publication status | Published - 2016 |