May 11, 2016
UW researchers secure prestigious MURI grants for self-cooling lasers and fluid mechanics
University of Washington scientists are participating in three of these endeavors, known as Multidisciplinary University Research Initiative (MURI) grants. One, an effort to develop novel defenses against cyberattacks, is a collaboration among five universities led by UW electrical engineering professor Radha Poovendran. UW professors Peter Pauzauskie and Alberto Aliseda are part of two other MURI-funded efforts to develop innovative approaches to cutting-edge fields of engineering.
Cool ideas for lasers
In the Department of Materials Science & Engineering, assistant professor Peter Pauzauskie and his team have their eyes focused on laser innovations. Last year they unveiled an approach to cooling liquids using laser light. Now, as part of a MURI grant led by Mansoor Sheik-Bahae at the University of New Mexico, Pauzauskie’s research group is joining a larger collaboration to develop self-cooling lasers. Their efforts would address a major limitation in today’s laser technology.
“Because of the heat they generate, every laser based on optical fibers will melt down at high operating powers,” said Pauzauskie. “As a result, today we have to either limit the power at which lasers operate or accept that they’ll eventually burn out.”
But new laser designs using self-cooling materials could operate at a much higher powers. UW is one of four universities collaborating on this MURI grant, and they hope to create a prototype self-cooling laser that is significantly more powerful than what’s possible today.
In a laser pointer, a battery generates an electric current, which is converted into laser light through a semiconductor crystal. Researchers have also shown it is possible to amplify the power of conventional lasers by “stretching” laser materials into long optical fibers.
But even these devices are limited by the heat they generate. The MURI team will investigate materials that could both protect the fibers from mechanical damage and actively cool them as they operate. That, Pauzauskie says, could unlock a number of new applications for laser technologies, such as cutting and processing industrial materials or launching micro-satellites to remote parts of the solar system using the “radiation pressure” of light.
Out of the $7.5 million MURI grant to be shared among the five participating institutions, Pauzauskie’s group will receive $1.3 million over five years for experiments, equipment and personnel.
“I was over the moon to hear that we got the MURI grant,” said Pauzauskie. “This support will make it possible to bring at least three new graduate students or post-docs to our materials-science team to work specifically on this project.”
Over in the Department of Mechanical Engineering, associate professor Alberto Aliseda expressed similar elation. He and his team are part of a separate $7.5 million MURI collaboration among scientists at five universities to control the tiny liquid droplets that make up sprays.
“We want to take concepts from different approaches and disciplines and bring them together to address fundamental problems in controlling sprays,” said Aliseda. “Sprays form in many fast-moving liquids, and we want to control the droplets when they form and keep them from causing disruptions.”
While the sprays from ocean waves and spray bottles are generally harmless, sprays disrupt mechanical systems that depend on the reliable, predictable flow of liquids. Jet engines can stall if liquid fuel is injected improperly.
Led by Olivier Desjardins at Cornell University, the team wants to build upon past research in spray formation and apply that knowledge toward practical devices that can control the size and distribution of droplets in sprays.
One practical route for controlling sprays is the atomizer, the device that a liquid passes through to form a spray. Researchers can manipulate droplet size and concentration by modifying the atomizer’s design, such as the size of the injection needles. But the MURI team wants to explore other avenues to control the spray.
“We also want to take existing designs and modify their control, such as varying the pressure of the liquid or using acoustics or electrostatic forces to control spray droplets once they’re generated,” said Aliseda.
The team’s approaches will also include new sensors to monitor droplets and computational simulations of different sprays. The microscopic scale of manipulation they seek could increase control of liquid systems in a variety of settings, from diesel engines to ship wakes. Aliseda and his UW team will receive $2.2 million over five years. Like Pauzauskie, he plans to recruit and hire several researchers to work on this project.
“People have been thinking about these ideas for over 50 years,” said Aliseda. “What we’re trying to do is to advance the state of the science and technology so we can reach manufacturers soon through better and more practical scientific practices.”
And that is precisely what the MURI grants are designed to do.