Source: IT Home  3^rd Aug 2026

Researchers from École Polytechnique in France, Collège de France, and Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have achieved a breakthrough by creating the world’s first all-photonic time crystal (PTC) capable of rapidly and repeatedly changing its optical properties over time.

According to IT Home, the work was published in Nature on July 29. The study used the TELBE superradiant terahertz source at HZDR to drive the system into a state of terahertz light–matter interaction, paving the way for ultrafast computers, adaptive communication systems, and a new generation of terahertz lasers.

The photonic crystals involved in this research are nanostructured materials with periodic optical structures that control how photons propagate. By adjusting the refractive index and structural shape of different materials, scientists can block, guide, or enhance light at specific wavelengths—much as semiconductors control electrons.

The team had previously shown that the light-trapping ability of photonic crystals could be tuned by temperature or magnetic fields. However, such control remained static and could not vary over time. In this new study, the researchers achieved the first photonic time crystal whose optical properties can change dynamically on picosecond timescales—trillionths of a second—comparable to the oscillation period of light itself.

To make photon properties vary over time, the researchers created a plasmonic metamaterial with help from the Thales Group’s Albert Fert Laboratory and the Laboratory of Interface Physics at École Polytechnique. The material consists of micron-scale gold groove structures, beneath which lie an insulating layer and a semiconductor made from a mixture of indium and antimony.

These metal grooves act as microcavities that trap photons between the metal and semiconductor layers. When the semiconductor surface is stimulated, it generates surface plasmons—collective oscillations of electrons—that trap light and sustain the oscillation.

Using the TELBE terahertz source at HZDR’s ELBE accelerator, the team fired high-intensity, frequency-tunable terahertz laser pulses at the device. The results showed that the material’s optical properties and its ability to reflect light changed dramatically over extremely short timescales.

Looking ahead, the scientists will explore ways to further reduce photon losses through the crystal and increase the number of photons inside the device. once light amplification reaches a sufficient level, the technology could transform how terahertz light technologies are developed.

Reference: Plasmonic metamaterial time crystal | Nature