arXiv subjects

Kalun Bedingfield

Publications and source records attributed to Kalun Bedingfield.

3 recordsLinked to original sources

arXiv2023

Subradiant entanglement in plasmonic nanocavities

Plasmonic nanocavities are known for their extreme field enhancement and sub-wavelength light confinement in gaps of just a few nanometers. Pairing this with the ability to host quantum emitters, they form highly promising platforms to control or engineer quantum states at room temperature. Here, we use the lossy nature of plasmonic nanocavities to form sub-radiant entangled states between two or more quantum emitters, that persist for $\sim 100$ times longer than the plasmonic excitation. We develop a theoretical description that directly links quantum variables to experimentally measurable quantities, such as the extinction cross-section, and unlike previous studies includes plasmonic excitations necessary to resonantly form subradiant states. This work paves the way towards engineering quantum entangled states in ambient conditions with plasmonic nanocavities, for potential applications such as rapid quantum memories, quantum communications and sensors.

quant-ph↗

arXiv2022

Multi-faceted plasmonic nanocavities

Plasmonic nanocavities form very robust sub-nanometer gaps between nanometallic structures and confine light in deep subwavelength volumes to enable unprecedented control on light-matter interactions. However, spherical nanoparticles acquire various polyhedral shapes during their synthesis, which has defining impact on controlling many light-matter interactions, such as photocatalytic reactions. Here, we focus on nanocavities made of three polyhedral nanoparticles (cuboctahedron, rhombicuboctahedron, decahedron) that commonly occur during the synthesis of spherical nanoparticles. Their photonic modes have a very intricate and rich optical behaviour, both in the near- and far-field. Through a recombination technique, we obtain the total far-field produced by a molecule placed within these nanocavities, to reveal how energy couples in and out of the system. This work paves the way towards understanding and controlling light-matter interactions, such as photocatalytic reactions and non-linear vibrational pumping, in such extreme environments.

physics.optics↗

arXiv2022

On the Excitation and Radiative Decay Rates of Plasmonic Nanoantennas

Plasmonic nanoantennas have the ability to confine and enhance incident electromagnetic fields into very sub-wavelength volumes, while at the same time efficiently radiating energy to the far-field. These properties have allowed plasmonic nanoantennas to be extensively used for exciting quantum emitters-such as molecules and quantum dots-and also for the extraction of photons from them for measurements in the far-field. Due to electromagnetic reciprocity, it is expected that plasmonic nanoantennas radiate energy as efficiently as an external source can couple energy to them. In this paper, we adopt a multipole expansion (Mie theory) and numerical simulations to show that although reciprocity holds, certain plasmonic antennas radiate energy much more efficiently than one can couple energy into them. This work paves the way towards designing plasmonic antennas with specific properties for applications where the near-to-far-field relationship is of high significance, such as: surface-enhanced Raman spectroscopy, strong coupling at room temperature, and the engineering of quantum states in nanoplasmonic devices.

physics.optics↗