(Image: Supplied)
A glass chip just a few centimetres wide has been used to combine light from multiple telescopes during astronomical observations, in a development led by scientists at Heriot-Watt University.
The photonic chip was tested at the CHARA Array in California, where it formed part of an instrument designed to explore how light-based technology could improve the performance of astronomical equipment.
Heriot-Watt University. (Image: Supplied)
The technology allows light collected by separate telescopes to be combined, enabling them to operate together as an instrument with the resolving power of a much larger telescope.
Conventional systems for combining telescope light rely on complex arrangements of mirrors and lenses. The chip uses miniature optical channels created in glass to carry out some of these functions in a more compact system.
The chip was used in on-sky observations during campaigns in 2024 and 2025 as part of an instrument called CHARIOT. Researchers reported that it successfully combined light from the CHARA Array’s telescopes and detected signals from stars fainter than those reached by the system it replaced.
The project builds on more than 15 years of research at Heriot-Watt University.
The technology uses an ultrafast-laser inscription technique to create tiny channels inside glass. These guide and combine incoming light from separate telescopes.
Chara-web-labeled. (Image: Supplied)
Researchers say the approach could eventually help astronomers investigate planetary systems in greater detail, including how planets form and evolve around stars beyond our solar system.
The project involved teams from the UK, Germany and the US. Its findings have been published in the Monthly Notices of the Royal Astronomical Society.
The CHARIOT instrument is also designed to allow researchers to test different photonic components. Its chips can be replaced in a matter of hours, making it easier to evaluate new designs under observing conditions.
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Professor Robert Thomson, from Heriot-Watt University’s Institute of Photonics and Quantum Sciences, said: “This is a significant milestone for a research programme that began more than 15 years ago.
“Astronomers can achieve much sharper views of the universe by combining observations from several telescopes at the same time.
“Doing this allows the telescopes to work together as though they were one much larger telescope.
“Traditionally, combining the light from multiple telescopes requires bulky instruments with complex arrangements of mirrors and lenses.
“We have shown that much of that work can instead be carried out by a glass chip only a couple of centimetres in size.”
Dr Aurélien Benoît, from Heriot-Watt University, said: “There is something very special about seeing a device that we conceived, designed, fabricated and characterised in the laboratory being used to efficiently collect and analyse light from real stars at one of the world’s leading astronomical interferometers.
“The great advantage of our approach is that we can integrate complex optical functions into a remarkably small and stable glass chip.”
Dr Aline Dinkelaker, lead author of the study from the Leibniz Institute for Astrophysics Potsdam, said: “Demonstrating this technology under real observing conditions is an important step forward.
“These first observations show that photonic technologies can deliver the performance needed for frontline astronomical research.”