Spatio-temporal light shaping for metamaterials
File(s)
Author(s)
Cielecki, Dimitrie-Calin
Type
Thesis
Abstract
In this thesis, we present new ways to control light for novel integrated technologies via complex light shaping. We first study the single-photon emission from quantum dots for novel quantum technologies at room temperature. In this context, we proposed new ways to integrate the emitters on a chip in order to accelerate the development of nano-optical devices with enhanced capabilities, such as the fabrication of a single-photon emitting array and a network of nanofibres transporting photons. The photodynamics of single-photon emission from quantum dots was characterised in order to understand the nature of light emission, its temporal and spectral properties. Then, we aimed at generating new frequencies of light from programmable space-time optical diffraction at a time-varying metamaterial. We built a 2D spatio-temporal pulse-shaper using a spatial-light modulator that imprints a phase on the spectrum of ultra-fast laser pulses. The pulse-shaper was used to tilt the pulse-front and generate synthetic motion at a surface with an optical response. The nonlinear properties of gallium phosphide were used to characterise the programmable synthetic velocity. Finally, the shaped pulses were used to generate moving transient mirrors on the surface of indium tin oxide, exploiting the time-varying properties of the material. The moving aperture with controllable velocity diffracts light in space-time, generating new frequencies propagating at different angles. This demonstration of a fabrication-less programmable space-time metamaterial opens a path towards spatio-temporal devices at optical frequencies and all-optical control.
Version
Open Access
Date Issued
2025-08-15
Date Awarded
2026-06-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Sapienza, Riccardo
Publisher Department
Department of Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)