Photonic Time Crystals - A Thought Experiment From Francis Tuffy

Researchers in France and Germany have demonstrated what they describe as the first all-optical photonic time crystal, using a plasmonic metamaterial whose optical properties can be varied at terahertz frequencies. The work provides a new way of controlling light in time rather than simply through the spatial structures traditionally used in photonic crystals, metasurfaces and holographic devices.

Led by Yannis Laplace at École Polytechnique in France, the team developed a surface-plasmon cavity metamaterial comprising micrometre-scale gold structures, an insulating layer and an indium-antimony-based semiconductor. Powerful multi-cycle terahertz pulses supplied by the TELBE source at Helmholtz-Zentrum Dresden-Rossendorf in Germany were used to change the optical characteristics of the material on picosecond timescales. The results have been published in Nature [1].

How does it work?