Engineers Discover Avalanches in Nanoparticles for the First Time in Groundbreaking Study
Avalanching can be loosely described as a process where even a small disturbance can cause a cascade of changes. Just like an avalanche on a snowy mountain or a nuclear reaction, or even most of the world's financial crises -- each begins with a very minor perturbance.
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In a groundbreaking new study, nanomaterials with unmatched photon avalanching have been developed. This can help in revolutionising the field with its unparalleled extreme nonlinear optical behaviour and efficiency.
The study conducted at Columbia Engineering can have massive impacts on sought-after applications. James Schuck, lead author of the study, informed, “Nobody has seen avalanching behaviour like this in nanomaterials before.” The study has been published in the journalNature.
Avalanching can be loosely described as a process where even a small disturbance can cause a cascade of changes. Just like an avalanche on a snowy mountain or a nuclear reaction, or even most of the world’s financial crises – each begins with a very minor perturbance. So far, large materials have been used to study avalanching but photons, on account of their small size, have largely not been a part of such processes.
Schuck said the ability of nanoparticles to avalanche and the sensitivity is transformative. It would be like the ability to sense chemical changes around our body, for example, detect diseases like the coronavirus around us.
In the world of optics, photon avalanching is when a single photon absorption in a crystal can result in a large number of photon emissions. Now they suggest that it’s not just the number of photons that increase, but it also gets “upconverted” as in gets higher in energy. Applying this knowledge to avalanching nanoparticles, they can revolutionise physical and medical sciences. For example, shoot high photon into deep-seated cancer cells with avalanching nanoparticles for targeted therapy.
In this study, the team observed that nonlinear optical response in these nanoparticles is unmatched. Even a 10% change in incident light (incoming photon) causes more than a 1000% change in the emitted light.
Formerly, most of photon nonlinear research has been carried out in elements of the Lanthanide (Ln) of the periodic table. However, none of them showed such avalanching behaviour like this new study.
“The extreme nonlinearity in a single Avalanching Nanoparticles transforms a conventional confocal microscope into the newest super-resolution imaging system,” said Changhwan Lee from the study.
The team is now focused on analysing how this nonlinear behaviour can be applied for sensing changes in the environment. For example, temperature fluctuations or pressure or humidity and so on. So far, they haven’t had success in that area.
Though Schuck maintains that they are very excited by their findings. It will have positive application in imaging, sensing, and light detection in the near future. He thinks this study might be critical in the future of “optical information processing chips”.