Signal World's First All-Optical Photonic Time Crystal Cuts Terahertz Losses by Half

Summary

An international team from École Polytechnique, Collège de France, and Germany's Helmholtz-Zentrum Dresden-Rossendorf has demonstrated the world's first all-optical photonic time crystal, published in Nature on July 31, 2026. Unlike conventional photonic crystals that modulate light through spatial atomic arrangements, this plasmonic metamaterial—built from micrometer-scale gold structures over an indium antimonide semiconductor—periodically varies its optical properties in time instead. Using HZDR's TELBE superradiant terahertz source, the researchers achieved a new regime of light-matter interaction that cuts terahertz photon losses by more than 50%. The result opens a concrete path toward compact, tunable terahertz lasers, a device class that has eluded practical engineering despite a terahertz technology market projected to reach $2.12 billion by 2029. Lead author Tingwen Guo said the work extends photonic crystals "from space to time," creating a new dimension for light control and amplification. Potential applications include ultrafast optical computing, next-generation telecommunications, and medical imaging.