Time-asymmetric metamaterials for a new degree of wave control
Event details
| Date | 03.03.2015 |
| Hour | 15:00 |
| Speaker | Dr. Romain Fleury, University of Texas |
| Location | |
| Category | Conferences - Seminars |
Metamaterials are artificially structured materials that are engineered to interact with waves in extraordinary ways, leading to unconventional physical phenomena not found in natural materials, such as negative refraction and cloaking. They have been so far exclusively based on structures that are inherently symmetric upon time-reversal. In this talk, I will explore the largely uncharted properties of electromagnetic and acoustic metamaterials that are designed to purposely break time-reversal symmetry. First, I will show how time-reversal symmetry breaking can be exploited to build a novel class of non-reciprocal acoustic devices, such as isolators and circulators. I will then use them as building blocks to construct the acoustic equivalent of topological insulators, a metamaterial that supports one-way phononic transport on its edges with strong topological protection against defects and disorder. Second, I will study the exceptional properties of time-asymmetric systems that fulfill a special kind of space-time symmetry, consisting in taking their mirror image and running time backwards. Known as Parity-Time (PT) symmetry, this property leads to anomalous scattering behaviors such as unidirectional invisibility and phase compensation. I will demonstrate theoretically and experimentally how PT-symmetric metasurface pairs can replicate electromagnetic phenomena usually associated with bulk metamaterials, like negative refraction, planar focusing and cloaking, with the clear advantage of being completely loss-immune and potentially broadband.
Bio: Romain Fleury is currently a Ph.D. candidate in the department of Electrical and Computer Engineering at The University of Texas at Austin, where he is working with Professor Andrea Alù on new interdisciplinary concepts in wave physics and engineering, with an emphasis on metamaterials devices and metasurfaces. He received the M.S. in Engineering from Ecole Centrale de Lille, France, and the M.S. in Micro and Nanotechnologies from the University of Lille, France, in 2010. During his Ph.D., he has published over 20 articles in peer-reviewed scientific journals, including 15 first-author papers in journals such as Science, Physical Review Letters, and Nature Communications. His work on Non-Reciprocal Acoustics was featured on the cover of Science, and attracted the attention of the general public, with appearances in various media including NBC News, Daily Mail, and Scientific American. In 2014, he received the Best Student Paper award in Engineering Acoustics as well as the Young Presenter Award in Noise from the Acoustical Society of America. His research on Parity-Time symmetric metasurfaces has been awarded Best Student Paper at the International Congress Metamaterials 2014 in Copenhagen, Denmark.
Bio: Romain Fleury is currently a Ph.D. candidate in the department of Electrical and Computer Engineering at The University of Texas at Austin, where he is working with Professor Andrea Alù on new interdisciplinary concepts in wave physics and engineering, with an emphasis on metamaterials devices and metasurfaces. He received the M.S. in Engineering from Ecole Centrale de Lille, France, and the M.S. in Micro and Nanotechnologies from the University of Lille, France, in 2010. During his Ph.D., he has published over 20 articles in peer-reviewed scientific journals, including 15 first-author papers in journals such as Science, Physical Review Letters, and Nature Communications. His work on Non-Reciprocal Acoustics was featured on the cover of Science, and attracted the attention of the general public, with appearances in various media including NBC News, Daily Mail, and Scientific American. In 2014, he received the Best Student Paper award in Engineering Acoustics as well as the Young Presenter Award in Noise from the Acoustical Society of America. His research on Parity-Time symmetric metasurfaces has been awarded Best Student Paper at the International Congress Metamaterials 2014 in Copenhagen, Denmark.
Practical information
- General public
- Free
Organizer
- Suzanne Buffat
Contact
- Suzanne Buffat