Photonic time crystals are a novel class of optical materials that differ from traditional crystals by exhibiting periodic oscillations in time rather than spatial repetition. While they remain uniform in space, these materials create “momentum band gaps,” where light can temporarily pause within the crystal while its intensity increases exponentially.
This behavior is akin to light moving through a medium that alternates rapidly between air and water, a phenomenon that challenges traditional optical principles.
An international research team has successfully designed realistic photonic time crystals, exotic materials that can exponentially amplify light. This breakthrough paves the way for communication, imaging, and sensing advancements, offering the potential for faster, more compact lasers, sensors, and other optical devices.
The team included researchers from Aalto University, the University of Eastern Finland, Karlsruhe Institute of Technology, and Harbin Engineering University.
Assistant Professor Viktar Asadchy from Aalto University, Finland, said, “This work could lead to the first experimental realization of photonic time crystals, propelling them into practical applications and potentially transforming industries. From high-efficiency light amplifiers and advanced sensors to innovative laser technologies, this research challenges the boundaries of how we can control the light-matter interaction.”
“Imagine we want to detect the presence of a small particle, such as a virus, pollutant, or biomarker for diseases like cancer. When excited, the particle would emit a tiny amount of light at a specific wavelength. A photonic time crystal can capture this light and automatically amplify it, enabling more efficient detection with existing equipment.”
Creating photonic time crystals for visible light has been difficult due to the need for rapid and large amplitude changes in material properties. While previous experimental work by the same research team demonstrated photonic time crystals at lower frequencies like microwaves, their latest research proposes a practical approach for achieving “truly optical” photonic time crystals.
Through theoretical models and electromagnetic simulations, they suggest that using an array of tiny silicon spheres could enable the necessary conditions for light amplification, making this breakthrough achievable in the lab using existing optical techniques.
Journal Reference:
- Wang, X., Garg, P., Mirmoosa, M.S. et al. Expanding momentum bandgaps in photonic time crystals through resonances. Nat. Photon. (2024). DOI: 10.1038/s41566-024-01563-3
