Tailoring Light-Matter Interaction via Advanced Nanophotonic Structures : From Passive to Dynamically Tunable Systems
Ghindani, Dipa (2023)
Tampere University
2023
Tekniikan ja luonnontieteiden tohtoriohjelma - Doctoral Programme in Engineering and Natural Sciences
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Väitöspäivä
2023-03-31
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-03-2810-8
https://urn.fi/URN:ISBN:978-952-03-2810-8
Tiivistelmä
Light-matter interaction is the fundamental principle of photonics that governs numerous disruptive applications. Dynamically tuning the light-matter interaction is key to designing advanced photonic devices with improved and enhanced functionalities. Specifically, having active control of the amplitude, wavelength, phase, and polarization of light is vital. It essentially addresses the key pillars of photonics, ranging from generating, guiding, manipulating, amplifying, and detecting light.
This thesis presents a framework and platform to model, tailor, and enhance the light-matter interactions in nanophotonic structures. Epsilon-near-zero (ENZ) materials, plasmonic nanostructures, and metal-insulator-metal (MIM) cavities were utilized as a light-matter interaction platform. First, the underlying mechanism of emission enhancement was unravelled by integrating fluorescent dye with the MIM cavity. This study suggests a pathway for engineering the emission properties of an emitter through both Purcell and excitation rate enhancement. Following this, dynamic emission tuning was achieved, whereby a fluorescent dye containing hydrogel integrated MIM cavity was utilized. The thickness of the insulator layer was tuned by changing the ambient humidity, which resulted in spectral tuning of cavity resonance, hence the active tuning of emission.
The coupling strength quantifies the light-matter interaction, so tuning the coupling strength is another way to tailor the light-matter interaction. By developing a novel electrical gating scheme, an active tuning of the coupling strength was demonstrated in a strongly coupled system comprised of ENZ materials that support ENZ mode and gold nanorods supporting the localized surface plasmon mode. Lastly, by harnessing the vanishing index of the ENZ material, less sensitivity of the spectral position of photonic resonance towards the geometrical perturbations was obtained through a polarization-independent plasmonic structure on an ENZ substrate.
Overall, this thesis shows broad opportunities for using nanophotonic systems to tailor light-matter interactions dynamically.
This thesis presents a framework and platform to model, tailor, and enhance the light-matter interactions in nanophotonic structures. Epsilon-near-zero (ENZ) materials, plasmonic nanostructures, and metal-insulator-metal (MIM) cavities were utilized as a light-matter interaction platform. First, the underlying mechanism of emission enhancement was unravelled by integrating fluorescent dye with the MIM cavity. This study suggests a pathway for engineering the emission properties of an emitter through both Purcell and excitation rate enhancement. Following this, dynamic emission tuning was achieved, whereby a fluorescent dye containing hydrogel integrated MIM cavity was utilized. The thickness of the insulator layer was tuned by changing the ambient humidity, which resulted in spectral tuning of cavity resonance, hence the active tuning of emission.
The coupling strength quantifies the light-matter interaction, so tuning the coupling strength is another way to tailor the light-matter interaction. By developing a novel electrical gating scheme, an active tuning of the coupling strength was demonstrated in a strongly coupled system comprised of ENZ materials that support ENZ mode and gold nanorods supporting the localized surface plasmon mode. Lastly, by harnessing the vanishing index of the ENZ material, less sensitivity of the spectral position of photonic resonance towards the geometrical perturbations was obtained through a polarization-independent plasmonic structure on an ENZ substrate.
Overall, this thesis shows broad opportunities for using nanophotonic systems to tailor light-matter interactions dynamically.
Kokoelmat
- Väitöskirjat [5269]