An illustration of how a 2D photonic time crystal can boost light waves. Credit: Xuchen Wang / Aalto UniversityScientists have created two-dimensional photonic time crystals that amplify light, with potential applications in improving wireless communications and laser technology.
Time crystals were first conceived by Nobel laureate Frank Wilczek in 2012. Mundane, familiar crystals have a structural pattern that repeats in space, but in a time crystal, the pattern repeats in time instead. While some physicists were initially skeptical that time crystals could exist, recent experiments have succeeded in creating them.
“We found that reducing the dimensionality from a 3D to a 2D structure made the implementation significantly easier, which made it possible to realize photonic time crystals in reality,” says Xuchen Wang, the study’s lead author, who was a doctoral student at Aalto and is currently at KIT. “In a photonic time crystal, the photons are arranged in a pattern that repeats over time. This means that the photons in the crystal are synchronized and coherent, which can lead to constructive interference and amplification of the light,” explains Wang. The periodic arrangement of the photons means they can also interact in ways that boost the amplification.