Researchers pioneer fluid-based laser scanning for brain imaging

Quiroz with the laser scanning microscope used for the optical scanning research project.听
Darwin Quiroz is exploring new frontiers in miniature lasers with major biomedical applications.
When Quiroz first started working with optics as an undergraduate, he was developing atomic magnetometers. That experience sparked a growing curiosity about how light interacts with matter, an interest that has now led him to a new technique in optical imaging.
Quiroz, a physics PhD student in the lab of听Professor Juliet Gopinath in the Department of Electrical, Computer and Energy Engineering, and also co-advised by听Professor Victor Bright from Paul M. Rady in Mechanical Engineering, is co-first author of a new study that demonstrates how a fluid-based optical device known as an electrowetting prism can be used to steer lasers at high speeds for advanced imaging applications.听
The work published in听, conducted along with mechanical engineering PhD graduate Eduardo Miscles and Mo Zohrabi, senior research associate, opens the door to new technologies in microscopy, LiDAR, optical communications and even brain imaging.
鈥淢ost laser scanners today use mechanical mirrors to steer beams of light,鈥 Quiroz said. 鈥淥ur approach replaces that with a transmissive, non-mechanical device that鈥檚 smaller, lower-power and potentially easier to scale down into miniature imaging systems.鈥
Traditional laser scanning microscopy works by directing a focused beam of light across a sample like a grid one line at a time. This method provides powerful, high-resolution images of cells and neurons, but it requires fast, precise steering of the laser beam.
That鈥檚 where the electrowetting prism comes in. Unlike solid mirrors, the prism uses a thin layer of fluid whose surface can be precisely controlled with voltage. By altering the liquid鈥檚 shape, researchers can bend and steer light beams without moving mechanical parts.
Previous work with electrowetting prisms was limited to slow scanning speeds or one-dimensional beam steering.听
Quiroz and Miscles pushed the technology further, demonstrating two-dimensional scanning at speeds from 25-75 hz, a milestone toward making the devices practical for real-world imaging.
鈥淎 big challenge was learning how to drive the device in a way that produces linear, predictable scanning without distortion,鈥 Quiroz said. 鈥淲e discovered that the prism has resonant modes like standing waves that we could actually leverage for scanning at higher speeds.鈥
The promise of this technology extends far beyond the lab. Since electrowetting prisms are compact and energy efficient, they could be integrated into miniature microscopes small enough to sit on top of a mouse鈥檚 head.
鈥淚magine being able to watch brain activity in real-time while an animal runs through a maze,鈥 said Quiroz. 鈥淭hat鈥檚 the kind of in-vivo imaging this technology could enable and it could transform how we study neurological conditions like PTSD or Alzheimer鈥檚 disease.鈥
The project builds on earlier work in the Gopinath and Bright labs, where former PhD student Omkar Supekar first integrated an electrowetting prism into a microscope system for one-dimensional scanning.听
By extending the technique into two dimensions and higher speeds, Quiroz and Miscles established a framework for calibrating and characterizing electrowetting scanners for a wide range of applications.
Looking ahead, Quiroz hopes this research not only improves imaging systems but also inspires future collaborations across fields.
鈥淭his work shows what鈥檚 possible when you combine physics and engineering approaches,鈥 Quiroz said. 鈥淭he ultimate goal is to build tools that help us see and understand the brain in ways we couldn鈥檛 before.鈥