This Plug-and-Play "Exceptional Point" Tuning Platform Can Boost Optical Sensors' Sensitivity
A sixfold improvement in sensitivity from off-the-shelf sensors is proven in the lab, and could one day lead to bedside MRI capabilities.
Researchers from Washington University in St. Louis have developed a novel sensing platform that, they say, can unlock ultra-high sensitivities in existing off-the-shelf optical sensors — and it's as simple to use as plug-and-play.
"We've implemented a novel platform that can impart EP [Exceptional Point] enhancement to conventional optical sensors," claims Lan Yang, professor in the McKelvey School of Engineering and senior author on the team's paper.
"This system represents a revolutionary extension of EP-enhanced sensing, significantly expanding its applicability and universality. Any phase-sensitive sensor can acquire improved sensitivity and reduced detection limit by connecting to this configuration. Simply by tuning the control unit, this EP configuration can adapt to various sensing scenarios, such as environmental detection, health monitoring and biomedical imaging."
While enhancing optical sensors using exceptional points — the name given to specific conditions in which extraordinary optical phenomena can take place — isn't a new concept, it has previously required that the sensors themselves are modified. Yang and colleagues, though, have developed a new approach that separates the control hardware from the sensing hardware — offering the ability to tune EPs purely through adjustments to the control hardware, using unmodified off-the-shelf sensors.
To prove the concept the team took an existing sensor system and ran it through the EP-tuning control system, delivering a sixfold lowering of the sensor's detection limit for weak perturbations — without touching the sensor hardware itself. The same approach, the team says, could be applied to a range of sensor types, including ring resonators, thermal sensors, magnetic sensors, and biomarker vibration sensors.
"With this work, we’ve shown that we can significantly enhance our ability to detect perturbations that have weak signals," says first author Wenbo Mao. "We're now focused on bringing that theory to broad applications. I'm specifically focused on medical applications, especially working to enhance magnetic sensing, which could be used to improve MRI [Magnetic Resonance Imaging] technology.
"Currently, MRIs require a whole room with careful temperature control. Our EP platform could be used to enhance magnetic sensing to enable portable, bedside MRI."
The team's work has been published in the journal Science Advances under open-access terms.