Final Report Summary - EL DORADO (electromagnetic Doppler reflection and refraction in artificially-dielectric objects)
During the project "el Dorado", Dr. Zeno Gaburro has invented a new kind of antenna, with a V-shape and adjustable parameters. Instead of working as a traditional receiving or transmitting antenna, the V-shaped antenna is a light scattering element with controllable amplitude, phase and polarization.
With these elements, Dr. Gaburro has designed an interface that modifies the laws of reflection and refractions, by engineering reflected and refracted beams with arbitrary propagation angles. Reflection and refraction are arguably among the most fundamental phenomena in optics. They have been observed and studied since the early days of the history of science. The laws that regulate them have been quantitatively known for about one thousand years. With his team at Harvard, led by Prof. Capasso, he has experimentally demonstrated the idea. The work has been published recently as a Research Article by Science magazine (N. Yu, P. Genevet, M. A. Kats, F. Aieta, J.-P. Tetienne, F. Capasso, and Z. Gaburro, "Light Propagation with Phase Discontinuities: Generalized Laws of Reflection and Refraction", Science 334, 333, 2011), and has deserved the cover of the issue in which it appeared a perspective commentary (N. Engheta, "Antenna-Guided Light", Science 334, 317, 2011). In November 2011, Physics Today has featured this work as cover story.
These antennas work as basic building blocks for phase engineering. In the metamaterial jargon, they can actually be thought as "meta-atoms", i.e. elemental constituents of "metasurfaces". The latter are a flexible enabling technology for wavefront engineering, which goes well beyond the manipulation of reflection and refraction of plane waves. For example, the team has experimentally demonstrated the generation of optical vortices with arbitrary topological charges (Science, cited).
On a complementary perspective, the functionality one of these antennas mimics very closely the behavior of a tiny high-frequency circuit: there is a signal-receiving mechanism, a processing mechanism (the phase shift, different in each antenna), and a signal-transmitting mechanism. These devices are similar to phased-array radioantennas. There is however a fundamental difference in terms of speed performance: our "circuits" work at frequencies that are at least 3 orders of magnitude faster than highest radio frequencies, and at room temperature.
With these elements, Dr. Gaburro has designed an interface that modifies the laws of reflection and refractions, by engineering reflected and refracted beams with arbitrary propagation angles. Reflection and refraction are arguably among the most fundamental phenomena in optics. They have been observed and studied since the early days of the history of science. The laws that regulate them have been quantitatively known for about one thousand years. With his team at Harvard, led by Prof. Capasso, he has experimentally demonstrated the idea. The work has been published recently as a Research Article by Science magazine (N. Yu, P. Genevet, M. A. Kats, F. Aieta, J.-P. Tetienne, F. Capasso, and Z. Gaburro, "Light Propagation with Phase Discontinuities: Generalized Laws of Reflection and Refraction", Science 334, 333, 2011), and has deserved the cover of the issue in which it appeared a perspective commentary (N. Engheta, "Antenna-Guided Light", Science 334, 317, 2011). In November 2011, Physics Today has featured this work as cover story.
These antennas work as basic building blocks for phase engineering. In the metamaterial jargon, they can actually be thought as "meta-atoms", i.e. elemental constituents of "metasurfaces". The latter are a flexible enabling technology for wavefront engineering, which goes well beyond the manipulation of reflection and refraction of plane waves. For example, the team has experimentally demonstrated the generation of optical vortices with arbitrary topological charges (Science, cited).
On a complementary perspective, the functionality one of these antennas mimics very closely the behavior of a tiny high-frequency circuit: there is a signal-receiving mechanism, a processing mechanism (the phase shift, different in each antenna), and a signal-transmitting mechanism. These devices are similar to phased-array radioantennas. There is however a fundamental difference in terms of speed performance: our "circuits" work at frequencies that are at least 3 orders of magnitude faster than highest radio frequencies, and at room temperature.