New nanoscale metamaterials for future ultra-high-speed computing

Tel Aviv University (TAU) researchers have discovered novel nanoscale “metamaterials” which could serve as future ultra-high-speed computing units.

The new optical materials could serve as the nuts and bolts of future ultra-high-speed optical computing units. According to the research, led by Dr. Tal Ellenbogen and conducted by group members Nadav Segal, Shay Keren-Zur, and Netta Hendler, all of the Department of Physical Electronics at TAU’s School of Electrical Engineering and TAU’s Center for Nanoscience and Nanotechnology, these “nonlinear metamaterials,” which possess physical capabilities not found in nature, may be the building blocks that allow major companies like IBM and Intel to move from electronic to optical computing.

Nature Photonics – Nonlinear optics: Metamaterial quasi-phase matching The introduction of periodic inversion in the geometry of a plasmonic metasurface markedly boosts the efficiency of nonlinear processes in ultracompact structures.

Nature Photonics – Controlling light with metamaterial-based nonlinear photonic crystals

Light and matter

In natural materials, the interaction between light and the material is governed by the chemical composition of the material. In the new optical materials, however, through the creation of fine nanostructures, the interaction can be controlled and new optical phenomena can be observed. When the strength of the interaction is not directly proportional to the strength of the light field, nonlinear optical effects kick in. These effects can be used to make active optical devices.

These artificial optical materials are sometimes referred to as optical metamaterials and their nanoscale building blocks are sometimes referred to as “optical meta-atoms.” “Future on-chip communications systems are expected to change from relying solely on electronics to relying on photonics — that is, the qualities and mechanics of light — or hybrid electronic-photonic systems,” said Dr. Ellenbogen. “These photonic on-chip communications systems will consist of active nonlinear nanoscale optical elements. Our research opens the door to consider nonlinear metamaterials as the active nanoscale components in future on-chip communications.

“By merging two disciplines in optics — metamaterials and nonlinear photonic crystals — we are opening the door to constructing novel active nonlinear devices based on metamaterials and to new fundamental studies altogether,” said Dr. Ellenbogen. The researchers are currently exploring how to make the nonlinear interaction more efficient by using multilayered metamaterial structures and by examining different metamaterial building blocks.

Abstract

Since the seminal paper by Bloembergen and colleagues on nonlinear optical interactions1, this field has supplied some of the most important contributions to optics-related science and applications, including the exceptional ability to generate coherent light throughout the optical spectrum. Recently, a new family of nanostructured optical materials, so called metamaterials, with artificial effective nonlinearities has been demonstrated. Controlling their nonlinear output has the potential to open up a whole new area of fundamental research and lead to the development of efficient, active, integrated and ultra-compact nonlinear optical devices. Here, we experimentally demonstrate unprecedented control over the nonlinear emission from metamaterials by constructing the first nonlinear metamaterial-based photonic crystals. We specifically demonstrate engineered nonlinear diffraction and all-optical scanning, enabling ultra-wide angular scanning of the nonlinear output from the metamaterial. We also demonstrate intense focusing of the nonlinear signal directly from the metamaterial, resulting in an intensity enhanced by nearly two orders of magnitude.

17 pages of supplemental material

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