Phys.org April 5, 2023
The synthesis of photonic time crystals materials and experimental observation of their physics remain very challenging because of the stringent requirement for uniform modulation of material properties in volumetric samples. An international team of researchers (Finland, Germany, USA – Stanford University) has extended the concept of photonic time crystals to two-dimensional metasurfaces. They demonstrated that time-varying metasurfaces not only preserve key physical properties of volumetric photonic time crystals despite their simpler topology but also host common momentum bandgaps shared by both surface and free-space electromagnetic waves. Based on a microwave metasurface design, they experimentally confirmed the exponential wave amplification inside a momentum bandgap and the possibility to probe bandgap physics by external (free space) excitations. According to the researchers the metasurface proposed by them serves as a straightforward material platform for realizing emerging photonic space-time crystals and as a realistic system for the amplification of surface-wave signals in future wireless communications… read more. Open Access TECHNICAL ARTICLEÂ
Theoretical and numerical results. Credit: SCIENCE ADVANCES, 5 Apr 2023, Vol 9, Issue 14