University of Glasgow-led Team Achieves Quantum Light Breakthrough to Enhance Time-Domain Spectroscopy for Advanced Diagnostics and Security

University of Glasgow-led Team Achieves Quantum Light Breakthrough to Enhance Time-Domain Spectroscopy for Advanced Diagnostics and Security

(IN BRIEF) An international team of engineers and physicists has made a significant breakthrough in time-domain spectroscopy by using quantum light to enhance sensitivity. Their new approach enables measurements of infrared electric fields with double the sensitivity of previous methods, which could open doors to new applications in security and medical diagnostics. This technique involves pairs of laser pulses entangled through quantum mechanics to counter the limitations of classical light sources, such as shot noise. With these improvements, the team has successfully achieved more precise measurements, revealing hidden signals that were previously obstructed by noise. The research, published in Science Advances, was supported by several prestigious organizations and universities, including the University of Glasgow and the University of Insubria, among others.

(PRESS RELEASE) GLASGOW, 3-Feb-2025 — /EuropaWire/ — An international collaboration of engineers and physicists has introduced an innovative approach to enhancing the performance of advanced spectroscopy by leveraging quantum light. Their breakthrough allows for infrared electric field measurements with twice the sensitivity of previous methods in time-domain spectroscopy.

This development could lead to significant advancements in areas such as security and medical diagnostics, say the researchers behind the work. Currently, time-domain spectroscopy relies on ultra-short laser pulses to measure the molecular composition of materials by observing how light interacts with them over time. This technique has proven essential in various fields, including detecting early disease indicators in blood samples, as demonstrated by the research team of 2023 Nobel laureate Ferenc Krausz.

However, the method’s dependence on classical light sources has posed a limitation. A phenomenon known as ‘shot noise’—which arises from the properties of laser light—reduces the resolution of the technique. Beyond a certain point, noise overwhelms the signal, obscuring valuable data about the material’s composition.

The newly developed method, outlined in a paper published in Science Advances, uses quantum light to overcome this limitation. By employing pairs of laser pulses linked through quantum mechanics, the team was able to probe the infrared field in a way that mitigates the shot noise effect. Though both pulses are affected by shot noise, the noise is mirrored in both beams. By subtracting the measurements from one beam to the other, hidden signals are uncovered, allowing for more precise measurements. This innovation improves sensitivity, making it approximately twice as effective as time-domain spectroscopy that relies on classical light sources.

Professor Matteo Clerici, from the University of Glasgow’s James Watt School of Engineering and the University of Insubria, who led the research, explained that while the technology is still in development, it holds promise for various future applications. “This technique could eventually help us better understand material compositions, detect harmful substances like explosives in the environment, or monitor disease markers in patient blood samples,” he said.

He added, “For several years, we’ve focused on applying quantum measurement methods to time-domain spectroscopy, and this paper shows how quantum radiation can enhance the sensitivity of the technique. Glasgow PhD students Dionysis Adamou and Lennart Hirsch were integral to this success, and we now plan to refine the method further, possibly incorporating interferometry techniques used in gravitational wave detectors to boost sensitivity.”

Contributing to this cutting-edge work were researchers from Loughborough University and the University of Strathclyde. The research, titled “Quantum-enhanced time-domain spectroscopy,” was published in Science Advances.

The project received support from a range of funding bodies, including Innovate UK, UK Research and Innovation (UKRI), the Engineering and Physical Sciences Research Council (EPSRC), the University of Glasgow Impact Acceleration Account, the Defence Science and Technology Laboratory (DStl), the Royal Academy of Engineering, the Leverhulme Trust, the devcOM US Army Research Office, and the European Commission.

Media Contact:

media@glasgow.ac.uk

SOURCE: University of Glasgow