A researcher from Aston University has developed a novel technique harnessing Orbital Angular Momentum (OAM) light, which could transform non-invasive medical diagnostics and enhance optical communication capabilities at the same time.
The research, led by Professor Igor Meglinski, and published in Light Science & Applications, demonstrates how OAM light could unlock transformative applications in both secure optical communication through biological tissues and other optically dense media, as well as non-invasive advanced biomedical imaging and diagnosis.
What potential does the use of OAM light hold?
OAM light, characterised by its structured beam profiles, has previously found applications in various fields, such as astronomy, microscopy, and optical communications. Now, this new study has revealed that OAM light maintains its phase characteristics even when traversing highly scattering media, unlike conventional light signals.
Professor Meglinski, based at the Aston Institute of Photonic Technologies, said: “By showing that OAM light can travel through turbid or cloudy and scattering media, the study opens up new possibilities for advanced biomedical applications.For example, this technology could lead to more accurate and non-invasive ways to monitor blood glucose levels, providing an easier and less painful method for people with diabetes.”
How did the research team assess the potential of OAM light?
The research team conducted a series of controlled experiments to assess the transmission of OAM beams through various scattering media. Employing advanced detection methods, including interferometry and digital holography, they analysed the behaviour of the light, finding strong alignment between experimental results and theoretical models.
The results showed that it is possible to detect extremely small changes with an accuracy of up to 0.000001 on the refractive index, far surpassing the capabilities of many current diagnostic technologies.
By manipulating the wavefront shaping of OAM beams, it’s possible to customise penetration depth and focal precision within tissues in biomedical imaging, allowing for selective imaging at varying depths without the necessity of physically adjusting the imaging equipment.
Additionally, the modulation of OAM modes can alter the light-tissue interaction dynamics, significantly improving the contrast in images, and aiding in distinguishing between normal and pathological tissue structures.
“The potential for precise, non-invasive transcutaneous glucose monitoring represents a significant leap forward in medical diagnostics,” Professor Meglinski added. “My team’s methodological framework and experimental validations provide a comprehensive understanding of how OAM light interacts with complex scattering environments, reinforcing its potential as a versatile technology for future optical sensing and imaging challenges.”
The research paper states: “[The] findings bridge a crucial gap for the biophotonics and OAM communities by demonstrating how OAM light, even in environments characterised by a high optical depth, retains its helical phase structure. This behaviour underscores the potential of OAM light for probing biological tissues in the multiple scattering regime."
The ability to structure and tune OAM light in complex ways not only enhances its application in diagnostic imaging of living tissues, such as in optical coherence tomography and microscopy, but also extends its utility to therapeutic uses, including targeted photodynamic therapy. The non-invasive nature of the OAM approach is also hoped to be particularly beneficial for continuous monitoring and medical diagnostics in vulnerable populations, including paediatric, elderly, or immunocompromised patients, where traditional invasive procedures are less feasible.
