Assistant Professor of Physics Jerome Fung and Ithaca College students Wyatt Vigilante ’20 and Oscar Lopez ’22 recently published a paper entitled “Brownian dynamics simulations of sphere clusters in optical tweezers” in the journal Optics Express.
The team used computer simulations to study the detailed behavior of clusters of micrometer-sized spheres in a focused laser beam (known as optical tweezers) for the first time. The laser beam exerts forces and torques on the spheres, but predicting a priori how the spheres respond is highly challenging. One surprising finding was that under certain conditions, the laser beam can cause the clusters to rotate continuously.
“What we found is somewhat akin to shining a spotlight on a football and having it start to spin,” said Fung. “Obviously, that doesn’t happen with actual footballs. But that something similar does happen with particles about 10,000 times smaller shows how light can have beautiful effects on the micro- or nanoscale.”
This research could guide scientists using light to manipulate or assemble microscopic objects.
Vigilante’s award-winning senior thesis project involved developing a key portion of the computer code that made these simulations possible. Last summer, Lopez helped test the code and run simulations as an Ithaca College School of Humanities & Sciences Summer Scholar.
The paper may be downloaded here: https://doi.org/10.1364/OE.409078
https://www.ithaca.edu/intercom/article.php/20201116060231209