Reviewed by Lexie CornerNov 13 2024
For the first time, an international research team has designed realistic photonic time crystals—exotic materials that exponentially amplify light—according to a study published in Nature Photonics. By creating the framework for faster and more compact lasers, sensors, and other optical devices, the discovery creates exciting opportunities in a variety of fields, including communication, imaging, and sensing.
“This work could lead to the first experimental realization of photonic time crystals, propelling them into practical applications and potentially transforming industries," says Professor Viktar Asadchy from Aalto University, Finland. Image Credit: Xuchen Wang / Aalto University
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.
Viktar Asadchy, Assistant Professor, Aalto University
Photonic time crystals are a special class of optical materials. Unlike conventional crystals, which have structures that repeat spatially, photonic time crystals oscillate periodically in time while remaining uniform in space. This unique property creates "momentum band gaps," where light pauses within the crystal, and its intensity increases exponentially over time.
To grasp the unusual interaction of light within a photonic time crystal, imagine light traveling through a medium that alternates between air and water quadrillions of times per second. This phenomenon defies traditional optical principles and represents a remarkable breakthrough in our understanding of light.
One potential application for photonic time crystals is in nanosensing.
Asadchy added, “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 long been a challenge because they require large amplitude variations in material properties at extremely fast rates. While members of the same research team have achieved the most advanced experimental demonstration of photonic time crystals to date, it has been limited to much lower frequencies, such as microwaves.
In their latest study, through theoretical models and electromagnetic simulations, the team has proposed the first workable method for creating "truly optical" photonic time crystals. They believe that by using a series of small silicon spheres, it will be possible to apply established optical techniques to create the unique conditions needed to amplify light—conditions that were previously unattainable in the laboratory.
The research team comprises scientists from Karlsruhe Institute of Technology, Harbin Engineering University, the University of Eastern Finland, and Aalto University. The study was published in Nature Photonics on November 12th, 2024.
Journal Reference:
Wang, X. et. al. (2024) Expanding momentum bandgaps in photonic time crystals through resonances. Nature Photonics. doi.org/10.1038/s41566-024-01563-3