idw – Informationsdienst Wissenschaft

Nachrichten, Termine, Experten

Grafik: idw-Logo
Grafik: idw-Logo

idw - Informationsdienst
Wissenschaft

Science Video Project
idw-Abo

idw-News App:

AppStore

Google Play Store



Instance:
Share on: 
05/12/2022 20:00

Fractal Drive – A Lack of Bulk Gives Photons an Edge

Sissy Gudat Presse- und Kommunikationsstelle
Universität Rostock

    Researchers from the University of Rostock have developed a novel type of micro-structured material that enhances the speed of light signals while keeping them protected from scattering. Their discovery will be published online by the renowned journal “Science” on Thursday, 12 May, 2022.

    Photonic topological insulators (PTIs) are artificial materials that conduct light along their edges, yet block it from traversing their interior. These “superconductors for photons” have fascinated Prof. Alexander Szameit of the University of Rostock for a long time. “Ever since our first implementation of a topological insulator for light, we have explored how these peculiar systems can be best utilized,” the head of the solid-state optics group remembers. Yet, while photonic topological insulators can ‘protect’ light propagating along precisely defined paths from scattering, their excellent resistance towards imperfections or external perturbations typically comes at a cost. “The periodic structures that we typically use to construct PTIs tend to slow down the light which they are supposed to transport,” first author Tobias Biesenthal outlines the motivation behind his experiments, “In trying to protect them, we are loading the signals with unwanted ballast.”

    The solution that the team of researchers came up with draws on the strange and beautiful world of so-called fractals. First formalized as a mathematical concept by Benoit Mandelbrot in 1967 in trying to understand why the measured length of the British coast gains hundreds of kilometers seemingly out of nowhere when more detailed maps are being used, these structures abound in nature. For example, the arrangement of twigs statistically resembles the way in which the larger boughs branch out from the trunk of a tree. Self-similarity across scales therefore lies at the heart of fractals, meaning that any section of a system reproduces the characteristics of the whole. In turn, “exact” fractals identically repeat their structure ad infinitum. A well-known example is the Sierpinski triangle that can be readily obtained by nesting ever-smaller replicas of an equilateral triangle into one another. Paradoxically, even if it is sketched on a sheet of paper, this structure does not actually cover any area: Rather, each of its points can be shown mathematically to belong to one of the manifold edges.

    In close collaboration with partners from the Israel Institute of Technology Technion in Haifa and Zhejiang University in China, the Rostock scientists resolved the long-standing question whether topological insulators can be constructed without bulk material, and leveraged self-similarity to relieve light signals of their burden. “Like a stone skipping across the waves of the Baltic Sea, light beams can race along the edges of our fractal material without seeing much of its interior,” explains Dr. Matthias Heinrich, lead author of the work. “The crucial difference is that, while such a stone loses its energy with every bounce and eventually sinks, light in such a material is protected from scattering: In principle, it could keep going indefinitely.”

    The successful international collaboration has substantially advanced fundamental research on topological photonics. While several formidable challenges remain until these insights will find their way into consumer products, the physicists’ newest discovery has great potential for a wide range of innovative applications such as topologically protected high-speed photonic circuitry and entirely new class of versatile synthetic materials.

    This research was funded by Deutsche Forschungsgemeinschaft and the Alfried Krupp von Bohlen und Halbach-Foundation.


    More information:

    http://Contact:
    http://Dr. Matthias Heinrich
    http://Experimental Solid-State Optics Group
    http://Institute for Physics
    http://University of Rostock
    http://Tel.: +49 381 498-6796
    http://E-Mail: matthias.heinrich@uni-rostock.de


    Images

    Fractal topological insulator: The synthetic photonic material composed of a self-similar arrangement of waveguides protects and speeds up light signals traveling along its edges
    Fractal topological insulator: The synthetic photonic material composed of a self-similar arrangemen ...
    Tobias Biesenthal
    Universität Rostock


    Criteria of this press release:
    Journalists, Scientists and scholars, Students
    Energy, Physics / astronomy
    transregional, national
    Research results, Transfer of Science or Research
    English


     

    Help

    Search / advanced search of the idw archives
    Combination of search terms

    You can combine search terms with and, or and/or not, e.g. Philo not logy.

    Brackets

    You can use brackets to separate combinations from each other, e.g. (Philo not logy) or (Psycho and logy).

    Phrases

    Coherent groups of words will be located as complete phrases if you put them into quotation marks, e.g. “Federal Republic of Germany”.

    Selection criteria

    You can also use the advanced search without entering search terms. It will then follow the criteria you have selected (e.g. country or subject area).

    If you have not selected any criteria in a given category, the entire category will be searched (e.g. all subject areas or all countries).