A researcher from the University of Bristol has designed a new type of ultra-sensitive quantum sensor.

The new family of devices uses an array of tiny nanoantennas that detect fluorescence of chemicals using quantum properties and are being used in an innovative new ultrasensitive sensor to monitor water quality.

“This would allow for early warning of pollution or continuous monitoring of water quality in sensitive environments”


The arrays were designed and tested by Dr Neciah Dorh during his PhD at the University of Bristol while working with the University of Bedfordshire and multinational company ABB. They are made from aluminium nanorods fabricated using the same electron beam lithography that is used for commercial silicon chip prototypes by Kelvin Nanotechnologies in Glasgow.

The nanorods are just 50nm wide and 158nm long and enhance the fluorescence emission from a range of contaminants in water such as diesel or tryptophan.

The work shows a six-fold increase in measured fluorescence emission from a dye. The research also shows that by correctly designing the array element spacing, strongly directional fluorescent emission can be obtained which would allow for highly integrated multi-wavelength sensors to be designed.

The work was carried out in Professor Martin Cryan’s research group, which is part of the Photonics Research group in the Department of Electrical and Electronic Engineering.

The project was a collaboration with Dr Andrei Sarua from the School of Physics at Bristol and Dr Tahmina Ajmal from the University of Bedfordshire, who had previously worked on the Aquatest project at Bristol.

Low-cost sensing in hard to get to places

Together they developed a prototype low-cost, LED-based sensor system, which they plan to develop further into a hand-held field deployable system for performing water quality monitoring.

“The nanoantenna arrays, which can be fabricated by lower cost production techniques such as nanoimprint lithography, can bring significant sensitivity enhancement so that laboratory quality measurements could be carried out in the field,” said Cryan, Professor of Applied Electromagnetics and Photonics in the Department of Electrical and Electronic Engineering. “This would allow for deployment of remote wireless sensor networks for early warning of pollution or continuous monitoring of water quality in sensitive environments.”

Dr Dorh is now a Fellow within Bristol’s QTEC programme and has co-founded a start-up, FluoretiQ, developing quantum enhanced fluorescence sensors which will help identify bacteria within minutes rather than days.

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