Producing optical images at resolutions as low as one nanometer is the goal of Virginia Tech College of Engineering researcher Yong Xu, who has received a National Science Foundation (NSF) Faculty Early Career Development Program (CAREER) Award.
Xu, an assistant professor of electrical and computer engineering, secured the five-year CAREER grant, which is worth $400,000 and is NSF's most prestigious award for creative junior faculty who are considered likely to become academic leaders of the future.
“The resolution of most optical microscopes is restricted by the so-called ‘diffraction limit,' which means we cannot produce optical images with resolutions higher than a few hundred nanometers,” Xu said. “Currently, the most advanced optical microscope can achieve a resolution only as low as 50 nanometers.”
In the field of nanotechnology, researchers are discovering ways to arrange atoms into unique structures on the molecular scale. Xu is attempting to produce an optical microscope that can observe nanostructures at a resolution of one nanometer — which is equal in size to approximately one-billionth of a meter, or the diameter of four atoms.
In addition to achieving a breakthrough in arranging nanostructures, Xu hopes that his research will lead to observation of the “vacuum field” at a resolution of one nanometer.
“Vacuum field refers to the tiny amount of electric field fluctuations that can exist in the absence of any sources such as electrons or atoms,” Xu explained. “Even though vacuum field cannot be directly measured, without it no light source can emit light. Observing the vacuum field at one nanometer resolution would help scientists solve one of the few remaining mysteries of quantum electrodynamics.”
All of this, Xu believes, can ultimately lead to chip-scale quantum information processing and can help boost the pace of discovery in nanophotonics research and engineering.
Every CAREER project includes an educational component, and Xu will help develop a nanophotonics education program at Virginia Tech. He also plans to mentor female and African American students at the university and in local high schools, with the aim of encouraging their participation in nanophotonics research and engineering.
Xu, who is affiliated with Virginia Tech's Center for Photonics Technology, is investigating a number of related areas, including the development of nanoscale optical sensors for chemical and biological applications. He holds a patent on semiconductor surface lenses and shaped structures and has a patent pending in the area of efficient electro-optical modulation.
Before coming to Virginia Tech in 2004, Xu was a postdoctoral scholar at the California Institute of Technology, where he completed his Ph.D. in physics in 2001. He earned his bachelor's degree in applied physics with a minor in mathematics at Tsinghia University in Beijing, China.