Aswirl in Optical Vortices
Normally, light flows like waves on the ocean. Spectroscopic devices use regular light to examine the interaction of matter and radiation (think of a humble glass prism turning a shaft of sunlight into a rainbow). But extraordinary things occur when light assumes a complex form called an optical vortex, which is a corkscrew instead of a wave.
“Optical vortices are just like tornados. As they corkscrew through space, they contain angular momentum [which imparts force], exactly like the moon going around the Earth, but in this case it’s a photon going around the beam,” says Giovanni Milione (City College, M.A., 2011), who won a three-year, $40,500-per-year National Science Foundation grant for doctoral study at the CUNY Graduate Center and CCNY.
His research involves applying optical vortices to spectroscopy. “By using light with the twist, with both color and angular momentum, we’ll be able to access atomic structure with a degree of freedom that’s unavailable with regular, plain light,” he says.
Imagine a familiar white fluorescent light, which actually emits light in a variety of colors according to the inherent “selection rules” governing the electrical excitement of the molecules inside the tube. An optical vortex may excite those molecules differently, breaking the selection rules “in a way that could open doors to quantum computing or quantum communications, or maybe allow us to see something new in the atomic system,” Milione says.
The son of working class immigrants from Sicily and Bolivia (“They pushed the value of education on me”), Milione started college at the University of Arizona. In 2003, when he was a 21-year-old junior and in the Army reserve, he volunteered for the invasion of Iraq. “It was a valuable experience and gave me a lot of the skills I use now – a lot of patience, a great work ethic. I don’t mind 12 hours in the lab, six days a week.”
Back home, he opted to finish his undergraduate degree at SUNY Stony Brook because, as a veteran, there was no tuition. There, he read some papers about complex light written by CCNY Distinguished Professor Robert R. Alfano, director of the CUNY Institute for Ultrafast Spectroscopy and Lasers. After an exchange of e-mails, Alfano offered a summer internship. He remained for his master’s degree. “I wanted to stay in the CUNY system because they have great benefits for vets, too.” Alfano, who will mentor Milione during his doctoral research, noted that Milione received one of just 23 physics awards of the 281 NSF grants nationally, and that this was the first for CUNY in physics in at least 10 years. He quoted from one NSF reviewer, who had evaluated Milione’s anonymously submitted application: “At first I was astounded by the quality of research of this applicant after looking at his/her transcript. It is probably the most impressive publication/talk record I've seen in being on this panel several times.”
That record includes accolades rare for a graduate student, including giving a talk at a prestigious conference on singular optics in Trieste, Italy; being invited to attend a fully funded NSF Foundation workshop on optical imaging in Bogotá, Colombia; and collaborating with New York University researchers on the application of optical vortices to make particles move. “Professor Alfano is the pioneer and I hope we can bring together some new ideas in the next few years,” Milione says.