Cadet Researches Polarization Using Thin Films
By Mary Price
VMI 1st classman Nick Potter is conducting graduate-level work in physics – while still an undergraduate.
In the thin films lab in the basement of Mallory Hall, Potter is creating Janus particles – so named because they have one side different from the other – out of polystyrene spheres. Polystyrene is a type of plastic. The size of these Janus particles, 20 microns, is so small as to be almost unimaginable, as a micron is one-millionth of a meter.
To make the spheres into Janus particles, Potter coats one half of them with a metallic layer that is currently made out of aluminum, although he hopes to use gold eventually. With the Janus spheres created, Potter puts them on a microscope slide and uses an electrical field to control their orientation in space.
“If all of the spheres are oriented in the correct direction, … that will cause polarization of the light that’s being reflected off of it,” Potter explained. “Basically, what we are trying to do is coat optics in these Janus particles so we can easily control their orientation and ultimately their polarization by just using an electric field.”
Potter said that these particles could be used for the front optics of telescopes, to make the analysis of polarized starlight much easier. Another cadet, fellow physics major Philip Wulfken ’13 – who just happens to be Potter’s roommate – is currently conducting research on the analysis of polarized starlight.
Potter’s faculty adviser, Lt. Col. Daniela Topasna, added that using ultra-small dimensions for the Janus particles delivers a key advantage when dealing with optical applications.
“By using these particles, you can reduce the size and create novel gratings so then the wavelength that can be used goes down into the visible, ultraviolet [spectrum],” she noted.
Topasna continued, “Our goal is to create grating with the metals by orienting them with an electric field. More of a broad goal is to combine that type of grating with a filter.” Combining a filter and polarizer into one unit can save space on devices such as cameras and telescopes, she explained.
Potter, meanwhile, came to VMI with a strong interest in physics. He’d discovered the subject while in an accelerated science and math program at Mills Godwin High School in his native Henrico County. By the time he was a senior in high school, he knew he’d be majoring in physics in college – so when he came to VMI as a prospective cadet, he took a tour of the physics lab and liked what he saw.
During the summer of 2011, Potter worked with Col. John Thompson, head of the physics department, on a project having to do with optics. He began his current work on thin films with Topasna and her husband, Lt. Col. Gregory Topasna, last summer.
“We are always looking [for cadets to do research] because it’s such a small pool of students,” said Lt. Col. Daniela Topasna. Potter is one of only three physics majors graduating this year.
Topasna was quick to add that the kind of research Potter is doing would not be possible had it not been for a state-funded renovation of Mallory Hall in 2006-07. During that renovation, the study carrels which once filled the basement of Mallory were replaced by the thin films lab. Some of the equipment for the thin films lab was purchased with money from the Jackson-Hope Fund.
“This is unique,” Topasna commented. “The equipment we have here is typical for a graduate school … The renovation really helped us a lot.”