Observing avalanches in nanoparticles

Researchers say they have developed the first ‘photon avalanching’ nanomaterial, which could be used to develop new applications in sensing, imaging and light detection.

‘Nobody has seen avalanching behaviour like this in nanomaterials before,’ says James Schuck, Associate Professor at Columbia University, USA. ‘We studied these new nanoparticles at the single-nanoparticle level, allowing us to prove that avalanching behaviour can occur in nanomaterials.

'This exquisite sensitivity could be incredibly transformative. For instance, imagine if we could sense changes in our chemical surroundings, like variations in or the actual presence of molecular species. We might even be able to detect coronavirus and other diseases.’

The researchers suggests that the photon avalanching has a combination of extreme nonlinear optical behaviour and efficiency. Triggered by a series of small perturbations, the avalanching processes can change in input or excitation leads to a disproportionate – often disproportionately large – change in output signal. 

The team implemented some key nanoparticle design innovations such as select lanthanide contents and species, resulting in successfully synthesising 20nm nanocrystals that demonstrate photon avalanching and its extreme nonlinearity.