Photonic Time Crystals Could Control Light
“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. Credit: Xuchen Wang / Aalto University

Scientists created photonic time crystals, unique materials that amplify light and could enhance lasers, sensors, and communication technologies.

These crystals exhibit time-based oscillations, allowing for the exponential amplification of light, with potential applications ranging from advanced sensing to communication.

Photonic Time Crystals

Scientists have successfully designed realistic photonic time crystals—exotic materials capable of exponentially amplifying light. This breakthrough, an international team of researchers, opens up transformative possibilities in fields like communication, imaging, and sensing, laying the groundwork for faster, more compact lasers, sensors, and other optical technologies.

“This work could lead to the first experimental realization of photonic time crystals, propelling them into practical applications and potentially transforming industries,” says Assistant Professor Viktar Asadchy from Aalto University, Finland. “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.”

Understanding and Applications of Time Crystals

Photonic time crystals are a unique type of optical material. Unlike traditional crystals, which have repeating structures in space, these crystals remain spatially uniform but oscillate periodically in time. This property creates “momentum band gaps,” unusual states where light effectively pauses inside the crystal while its intensity grows exponentially. To illustrate this extraordinary interaction, imagine light traveling through a medium that alternates between air and water quadrillions of times per second—a phenomenon that challenges the conventional understanding of optics and reveals new possibilities.

One potential application for the photonic time crystals is in nanosensing.

“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,” says Asadchy.

Overcoming Technical Challenges

Creating photonic time crystals for visible light has long been challenging due to the need for an extremely rapid yet simultaneously large amplitude variation of material properties. To date, the most advanced experimental demonstration of photonic time crystals – developed by members of the same research team – has been limited to much lower frequencies, such as microwaves. In their latest work, the team proposes, through theoretical models and electromagnetic simulations, the first practical approach to achieving “truly optical” photonic time crystals. By using an array of tiny silicon spheres, they predict that the special conditions needed to amplify light that were previously out of reach can finally be achieved in the lab using known optical techniques.

The team consisted of researchers from Aalto University, the University of Eastern Finland, Karlsruhe Institute of Technology, and Harbin Engineering University. 

The research was published in Nature Photonics on November 12.


Reference: “Expanding momentum bandgaps in photonic time crystals through resonances” by X. Wang, P. Garg, M. S. Mirmoosa, A. G. Lamprianidis, C. Rockstuhl and V. S. Asadchy, 12 November 2024, Nature Photonics.
DOI: 10.1038/s41566-024-01563-3 


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