Reviewed by Lexie CornerMar 18 2025
Researchers at Heriot-Watt University have made a breakthrough in photonic technology. The team’s work focuses on transparent conducting oxides (TCOs), a type of nanomaterial that can change the way light travels through it at high speeds.
L-R: Dr. Wallace Jaffray, a post-doctoral research associate, Dr. Marcello Ferrera, associate professor of nano-photonics; and Sven Stengel, Ph.D. candidate. Image Credit: Heriot-Watt University
For years, researchers have speculated that introducing time as a variable could alter the optical properties of light. This idea has now been realized by nanophotonics experts from Edinburgh's School of Engineering and Physical Sciences.
The materials, which can form ultra-thin films as thin as 250 nm (0.00025 mm), are widely used in solar panels and touchscreens.
Using ultra-fast light pulses, the Heriot-Watt research team, led by Dr. Marcello Ferrera, Associate Professor of Nanophotonics, and in collaboration with Purdue University, successfully "sculpted" the reaction of transparent conducting oxides (TCOs).
The resulting temporally constructed layer could modify both the energy and direction of individual photons. This capability, previously unattainable, opens up new possibilities.
The discovery holds significant potential for processing data at much higher volumes and speeds than currently possible. It is expected to have a transformative impact on areas like integrated quantum technologies, ultra-fast physics, optical computing, and artificial intelligence.
It is difficult to grasp the advances we will experience in our daily lives as a result of this breakthrough.
Dr. Marcello Ferrera, Associate Professor, Nanophotonics, Heriot-Watt University
“By using a nonlinear material to fully exploit optical bandwidth, companies and major organizations can process so much more information. This will hold huge benefits to the likes of data centers and advancing AI technology, among others, and will underpin exciting new technologies we cannot fully understand at this time,” continued Dr. Ferrera.
Dr. Ferrera commented on the potential future applications of this research, stating: “Society is thirsty for bandwidth. If we are aiming at making a virtual meeting a fully immersive 3D experience, this would demand enormous computational power and processing speed, which only ultra-fast all-optical components can provide. The material properties we are investigating here could increase computational speed by several orders of magnitude, enabling handling much greater volumes of information at a fraction of current energy expenditure.”
What science and technology is trying to do is emulate the human brain but by using electronic hardware. The materials we are working on are the ingredients towards this goal that can lower the energy consumption of these computational units, reducing costs and increasing processing power.
Dr. Marcello Ferrera, Associate Professor, Nanophotonics, Heriot-Watt University
Dr. Ferrera has been working with Sven Stengel, a Doctoral Researcher, and Dr. Wallace Jaffray, a Postdoctoral Research Associate, on this advanced research at Heriot-Watt University.
The core of their breakthrough lies in the ability to control TCOs to regulate photon velocity. This capability enables remarkable light transformations, including amplification, the production of quantum states, and new types of light control, effectively adding a "fourth dimension" to the process.
Dr. Ferrera continued: “Searching for a material that can drastically change under low-energy illumination in an ultra-fast manner has been the quest for the Holy Grail in all-optical technologies since the invention of laser.”
“This new class of time-varying media is the biggest leap forward towards the perfect optically controllable material in decades, enabling a large variety of novel and exciting effects that scientists all over the world are rushing to attempt. This is a new age in nonlinear optics which targets full light-control without the need of slow electric signals,” said Dr. Ferrera.
These low-index transparent conductors have brought a real revolution within the field of integrated nonlinear optics, allowing for the effective and energy-efficient manipulation of optical signals on unprecedentedly short time scales.
Vladimir M. Shalaev, Distinguished Professor and Research Assistant, Electrical and Computer Engineering, Purdue University
Alexandra Boltasseva, a Distinguished Professor of Electrical and Computer Engineering at Purdue University, noted: “Our common research effort demonstrates that with these materials, we can finally use the variable of time for engineering the optical properties of compounds beyond what is currently possible by using standard fabrication processes.”
The UK-Canada Quantum for Science Research Collaboration has given Dr. Ferrera a £6.5 million share to further study over the following two years.
Journal Reference:
Jaffray, W., et al. (2025) Spatio-spectral optical fission in time-varying subwavelength layers. Nature Photonics. doi.org/10.1038/s41566-025-01640-1