Maria Papaioannou

Two-dimensional control of light with light on metasurfaces

The ability to control the wavefront of light is fundamental to focusing and redistribution of light, enabling many applications from imaging to spectroscopy. Wave interaction on highly nonlinear photorefractive materials is essentially the only established technology allowing the dynamic control of the wavefront of a light beam with another beam of light, but it is slow and requires large optical power. Here we report a proof-of-principle demonstration of a new technology for two-dimensional (2D) control of light with light based on the coherent interaction of optical beams on highly absorbing plasmonic metasurfaces. We illustrate this by performing 2D all-optical logical operations (AND, XOR and OR) and image processing. Our approach offers diffraction-limited resolution, potentially at arbitrarily-low intensity levels and with 100 THz bandwidth, thus promising new applications in space-division multiplexing, adaptive optics, image correction, processing and recognition, 2D binary optical data processing and reconfigurable optical devices.

All-optical multichannel logic based on coherent perfect absorption in a plasmonic metamaterial

The exponential growth of telecommunications bandwidth will require next generation optical networks, where multiple spatial information channels will be transmitted in parallel. To realise the full potential of parallel optical data channels, fast and scalable multichannel solutions for processing of optical data are of paramount importance. Established solutions based on the nonlinear wave interaction in photorefractive materials are slow. Here we experimentally demonstrate all-optical logical operations between pairs of simulated spatially multiplexed information channels using the coherent interaction of light with light on a plasmonic metamaterial. The approach is suitable for fiber implementation and—in principle—operates with diffraction-limited spatial resolution, 100 THz bandwidth, and arbitrarily low intensities, thus promising ultrafast, low-power solutions for all-optical parallel data processing.

All-optical dynamic focusing of light via coherent absorption in a plasmonic metasurface

Vision, microscopy, imaging, optical data projection and storage all depend on focusing of light. Dynamic focusing is conventionally achieved with mechanically reconfigurable lenses, spatial light modulators or microfluidics. Here we demonstrate that dynamic control of focusing can be achieved through coherent interaction of optical waves on a thin beam splitter. We use a nanostructured plasmonic metasurface of subwavelength thickness as the beam splitter, allowing operation in the regimes of coherent absorption and coherent transparency. Focusing of light resulting from illumination of the plasmonic metasurface with a Fresnel zone pattern is controlled by another patterned beam projected on the same metasurface. By altering the control pattern, its phase, or its intensity, we switch the lens function on and off, and alter the focal spot’s depth, diameter and intensity. Switching occurs as fast as the control beam is modulated and therefore tens of gigahertz modulation bandwidth is possible with electro-optical modulators, which is orders of magnitude faster than conventional dynamic focusing technologies.

Research data: All-optical multichannel logic based on coherent perfect absorption in a plasmonic metamaterial

Research data forPapaioannou, Maria, Plum, Eric, Valente, Joao, Rogers, Edward and Zheludev, Nikolay (2016) All-optical multichannel logic based on coherent perfect absorption in a plasmonic metamaterial. APL Photonics, 1, 090801.This research data description should be read and understood in the context of the corresponding manuscript. The figure numbers correspond to the figure numbers of the manuscript.