VIPER students George Popov, Andy Eskenazi, and Ji Won (Avery) Bang Publish in Science Advances

Congratulations to George Popov (VIPER '21), Andy Eskenazi (VIPER '22), and Ji Won (Avery) Bang (VIPER '19) for their recent publication with Professor Igor Bargatin's group in Science Advances! You can find their research article, Controlled levitation of nanostructured thin films for sun-powered near-space flight hereKeep reading below to learn more about this work from the perspective of our current students! 


Andy Eskenazi (on left), Avery Bang (second from right), and George Popov (on right)

By Andy Eskenazi 

My journey at the Bargatin Group began exactly two years ago, in March of 2019. At the time, I was just a first year student, with a limited research and academic background, so there was not much I could understand from what Sam (one of the group's PhD students) and John (a graduated PhD student) explained to me when I first toured the lab. However, it didn't require much to realize that what I was looking at was the future: devices that could levitate only using sunlight! At that moment, I knew I had to be part of the research that made these a reality, otherwise I would have lost one of the best opportunities of my life. And I was not wrong, because in the last two years, my experiences at Prof. Igor's group have been invaluable, learning from the work of Sam, Leo (the PhD student I work most closely with), George, Chris (a Viper student who was a junior when I joined), Avery, Tom (PhD Student), Wujoon (PhD student), and Matt (the group's Post Doc). Undoubtedly, doing research requires time, effort and imagination. However, in most of the cases, we lack the first one of these three, because we want to see our results immediately and continue innovating. Nonetheless, when one looks back and contemplates all of the work each one of us have done, it definitely took a long time, but it was worth every second of it! 


By George Popov

I started working with the Bargatin Group on the levitation project in Spring 2018 as a freshman. It was, and still is, a super exciting project for me for its elegance, diversity, and ingenuity. The main idea of the project is that we can levitate centimeter sized mylar disks using only light. When the disks used are illuminated, the carbon nanotubes on their bottom absorb the incoming light and heat up. As the temperature increases, so does the accommodation coefficient force. This force can be thought of as something that occurs from the difference in momentum transfer on the top and bottom of the disk. The rough carbon nanotubes tend to interact more with the surrounding air, resulting in a net collision force that keeps the disk floating. This technology paves the way for an innovative use of solar power, with broad applications in aerospace. The pressure regime that the mylar disks levitate in bridges the gap between where the atmosphere is too thin for airplanes to fly, but still too thick for satellites to stay in orbit. 

Throughout this project, I was able to learn and utilize all of my skills in mechanical engineering and physics. I’ve programmed, designed, calculated, simulated, soldered, and assembled along this journey. I was fortunate enough to be involved in the numerical, analytical, and empirical approaches to solving fluids, mechanics, and thermodynamics challenges that came up along the way with my fellow lab members. It was incredibly refreshing to focus on an advanced problem from many different angles, and with people from so many different backgrounds, including fellow VIPER students Andy and Avery. In particular, Professor Bargatin and Mohsen Azadi—a PhD student who leads the project—always set forth examples of great research and mentorship, which continue to inspire me as I prepare to become a PhD student next Fall. All of the members of the Bargatin Group and the VIPER program created an amazing research experience for me, and I am very excited to see this research develop further!