Final Report Summary - UDENOP (Ultrafast Dynamics, Energy Exchanges, and Non-linear Optical Properties of Resonant Nanostructures)
This project was conducted in the broader context of nanoscience and nanotechnology with the particular aim at gaining an understanding on how light interacts with matter at the nanoscale in order to controllably and rationally design nonlinear optical functional nanodevices such as switches and modulators. The focus of the research has been on plasmonic materials for their resonant properties enable nanoscale confinement of electromagnetic energy and allow triggering nonlinear effects under low-power stimuli. This area of research has been increasingly active worldwide, especially since the late 2000’, and has shown the potential to be transformational from an academic prospective as demonstrated by the increasing quality and breadth of the work it generates. From a practical standpoint, this research is expected to provide a pathway to impact society as a whole with the development of applications in areas ranging from healthcare diagnostics and therapy, energy production and management, and especially information technology. For the latter, the ability to control and manipulate light on the nanoscale via plasmon modes offers the possibility of constructing compact optical components for use in areas such as energy collection, transformation, storage, transfer, and processing. The research implemented here is therefore very much at the forefront and was implemented through three main components, including the development of experimental facilities allowing for the study of both coherent (e.g. SHG, THG, FWM) and incoherent (self-modulation, non-degenerate ultrafast pump probe spectroscopies) nonlinear optical processes, as well as the development of numerical and analytical theoretical tools to address the same. These tools were used successfully to (1) demonstrate unidirectional excitation of guided modes via near-field dipole interferences, an effect key at coupling subwavelength sources to passive components in an addressable way; (2) demonstrate all-optical ultrafast switching in plasmonic systems with the description of two new switching mechanisms. The first of which is based on a Fano-resonator and can be implemented in deep-subwavelengths devices, while the second operates by optically controlling the hybridization between hyperbolic and elliptic modes in coupled plasmonic/photonic waveguides; (3) successfully implement numerical tools to describe both coherent and incoherent nonlinear effects in nanostructured materials. These achievements have helped further the state of the art in the field as demonstrated by their publication in top-tier journals (15), presentations at (26) international/national conferences (13 invited), as well as outreach presentations (4), and patent filing (3). It also seeded new innovative sponsored research, providing a sustainable research activity for the continuous training of students and professional researchers in their aim at leading the field forward in the future. The was done under the leadership of the Fellow who benefited from the grant to integrate this new research activity of nonlinear and ultrafast optical spectroscopy in the hosting group at KCL. During this 4-year project the Fellow has been promoted twice at King’s and has recently accepted a tenured position as an Associate Professor of Physics at the University of North Florida (USA). He also holds a Visiting Research position at King’s College London, enabling an ongoing collaboration with the hosting group.