arXiv subjects

Yuanyang Xie

Publications and source records attributed to Yuanyang Xie.

4 recordsLinked to original sources

arXiv2026

Electrically-driven chiral emission from plasmonic tunnel junctions

Chirality plays a crucial role in a broad range of processes including light-matter interactions in physics, chemistry and biology, which opens up new applications in nanophotonics, quantum technologies and photochemistry. Quantum tunnelling provides a promising mechanism for light generation at the nanoscale, however the realisation of chiral light emission has remained elusive. Here, by integrating tunnel junctions with chiral plasmonic nanohelicoids, we achieve nanoscale generation of chiral light at a single-particle level. The tunnelling-driven resonant excitation of chiral dipolar modes of the nanohelicoids results in emission of a vortex light beam possessing both spin angular momentum with handedness selectivity of over 0.8 and its orbital counterpart, equal in magnitude and opposite in sign. The developed approach offers a new means for sculpturing photon spin generation at the nanoscale, highlighting its potential for next-generation optical components in display and AR/VR applications, as well as quantum information processing and photochemistry.

physics.optics↗

arXiv2026

Dynamics of Transverse Spin and Longitudinal Fields of Cylindrical Vector Beams in Optically Active Media

Due to the inhomogeneous polarisation across the beam profile, cylindrical vector beams interact with optically active media in a complex manner. Here, we analyse evolution of polarisation of cylindrical vector beams propagating in an isotropic optically-active medium. After identifying polarisation normal modes of three-dimensional electromagnetic fields, we predict periodic inter-conversion between azimuthally- and radially-polarised modes of the beams accompanied by rotation of the transverse optical spin and pulsing field during the propagation. Theory and simulations are validated by experimental observations. The observed effects maybe important for imaging in biological chiral media, enhanced chiral sensing and enantioselective spectroscopy, nonlinear optics in chiral media, and generally enhanced spin-orbit coupling and nanoscale vector field engineering.

physics.optics↗

arXiv2025

Meso-chiral optical properties of plasmonic nanoparticles: uncovering hidden chirality

Molecular chirality plays an important role in chemistry and biology, allows control of biological interactions, affects drugs efficacy and safety, and promotes synthesis of new materials. In general, chirality manifests itself in optical activity (circular dichroism or circular birefringence). Chiral plasmonic nanoparticles have been recently developed for molecular enantiomer separation, chiral sensing and chiral photocatalysis. Here, we show that optical chirality of plasmonic nanoparticles exhibiting strong scattering can remain completely undetected using standard characterisation techniques, such as circular dichroism measurements. This phenomenon, which we term meso-chiral in analogy to meso-compounds in chemistry, is based on mutual cancellation of absorption and scattering chiral responses. As a prominent example, the meso-optical behaviour has been numerically demonstrated in multi-wound-SiO2/Au nanoparticles over the entire visible spectral range and in other prototypical chiral nanoparticles in narrower spectral ranges. The meso-chiral property has been experimentally verified by demonstrating chiral absorption of gold helicoid nanoparticles at the wavelength where conventional circular dichroism measurements show absence of chiral response (gext=0). These findings demonstrate a valuable link between microscopic to macroscopic manifestations of chirality and can provide insights for interpreting a wide range of experimental results and designing chiral properties of plasmonic nanoparticles.

physics.optics↗

arXiv2024

Unidirectional chiral scattering from single enantiomeric plasmonic nanoparticles

Controlling scattering and routing of chiral light at the nanoscale is important for optical information processing and imaging, quantum technologies as well as optical manipulation. Here, we introduce a concept of rotating chiral dipoles in order to achieve unidirectional chiral scattering. Implementing this concept by engineering multipole excitations in plasmonic helicoidal nanoparticles, we experimentally demonstrate enantio-sensitive and highly-directional forward scattering of circularly polarised light. The intensity of this highly-directional scattering is defined by the mutual relation between the handedness of the incident light and the chirality of the structure. The concept of rotating chiral dipoles opens up numerous possibilities for engineering of scattering from chiral nanostructures and optical nano-antennas for the design and application of chiral light-matter interaction.

physics.optics↗