arXiv subjects

Ali H. Alhulaymi

Publications and source records attributed to Ali H. Alhulaymi.

3 recordsLinked to original sources

arXiv2026

Coherent Control of Wave Scattering via Minimal-Parameter Tuning of Complex Spectra

We introduce and validate a theoretical framework for coherent control of multichannel linear scattering to route waves through complex geometries with multiple scattering. We show that steady-state perfect routing solutions are achievable at any frequency via tuning geometric parameters so that multiple complex eigenfrequencies coincide on the real axis. The relevant complex spectra describe critically constrained scattering processes (CCONs), where a specific number of generically accessible outgoing channels are inaccessible due to destructive interference. Focusing on electromagnetic waves, we demonstrate in simulations routing and demultiplexing with high discrimination of signals in a multiport chaotic cavity with a small number of tunable scatterers and free-space signal routing in a grating coupler with a similar number of tunable elements in its unit cell. The minimal number of tuning parameters required is predicted by codimension arguments and validated in simulations. A special class of perfect reflection processes are found to be enhanced in the presence of time-reversal symmetry. A similar approach can be used to implement other interesting functionalities, such as isolation, power division, mode conversion and filtering. The method can be applied to other classical waves and also to quantum matter waves.

physics.optics↗

arXiv2026

Plasmonic coated scatterers for tunable coherent perfect absorption

We derive, in closed-form, the surface conductivity required for coated subwavelength-scale spherical and cylindrical scatterers to perfectly absorb incident coherent light of fixed angular momentum. To address the challenge of synthesizing an incident wave of a fixed angular momentum, we analyze two geometries where this physics can be accessed from the far-field: a single coated sphere suspended above a good conducting surface, and an array of dipole-coupled coated cylindrical scatterers. We show that the required complex surface conductivities necessary for coherent perfect absorption over a large bandwidth in the terahertz may be easily achieved in moderately doped graphene.

physics.optics↗

arXiv2021

An optic to replace space and its application towards ultra-thin imaging systems

Centuries of effort to improve imaging has focused on perfecting and combining lenses to obtain better optical performance and new functionalities. The arrival of nanotechnology has brought to this effort engineered surfaces called metalenses, which promise to make imaging devices more compact. However, unaddressed by this promise is the space between the lenses, which is crucial for image formation but takes up by far the most room in imaging systems. Here, we address this issue by presenting the concept of and experimentally demonstrating an optical 'spaceplate', an optic that effectively propagates light for a distance that can be considerably longer than the plate thickness. Such an optic would shrink future imaging systems, opening the possibility for ultra-thin monolithic cameras. More broadly, a spaceplate can be applied to miniaturize important devices that implicitly manipulate the spatial profile of light, for example, solar concentrators, collimators for light sources, integrated optical components, and spectrometers.

physics.optics↗