Daniel Shahar is Bending Light and Breaking Boundaries in the Ramachandran Lab
By Jack Osmond
Reading about the latest cutting-edge scientific discoveries, it’s easy to forget about some of the people behind the experiments, crunched numbers, and written reports: the graduate students.
Daniel Shahar is one such student, now in his PhD program’s fifth year at Boston University. He first heard about the Photonics Center when his wife came to Boston University for law school. Having completed his B.S. in Physics, Math, and Electrical Engineering at the University of Florida, Daniel was fascinated by the prospect of studying photonics, especially given its potential as a relatively new field.
“I realized photonics had a lot of potential. A lot of people right now are starting to recognize even more the potential in photonics, especially given the recent Nobel Prizes. Boston University has a fantastic Photonics Center, and the university is definitely deciding to lean towards photonics.”
Shahar’s own work is at the forefront of photonics research as an NSF GRFP fellow in Siddharth Ramachandran’s High Dimensional Photonics Lab. The lab uses quantum physics to improve microscopes, biomedical imaging, and communications technology.
While quantum physics is often associated with science fiction concepts like time-travel and teleportation, the Ramachandran lab uses it for a much more tangible goal: communications. Currently, the lab is developing a speciality optical fiber to transmit information more efficiently by twisting light itself.
Light typically travels in a straight line, but certain types of light can travel in helical twists – like a spring. Such light has a property called orbital angular momentum, also known as OAM. The Ramachandran lab seeks to take advantage of this property by encoding information onto the very twists of the waveform, or modes.
“We leverage OAM by designing a specialty optical fiber to carry these modes more stably,” Shahar explains. “You can twist these modes together and expect that they [will] preserve the information, which is not a trivial thing. Essentially, it’s a way to increase information capacity.”
Shahar works directly with orbital angular momentum, discovering novel methods to encode even more information onto each photon, or particle of light. This research relies on quantum entanglement: when two photons are entangled with each other, their charges can remain connected across billions of light-years. If you measure one photon, the other one collapses to the opposite charge. The most commonly used method for entangling photons and encoding information is polarization. But it’s by no means perfect.
“The problem with polarization,” Shahar explains, “is that it’s only restricted to two dimensions. You can only have a horizontal or vertical polarization. With a two-dimensional property, it can only encode so much information, and it is only so robust to noise.”
Instead of polarization, Shahar works to entangle photons using orbital angular momentum. Unlike polarization, OAM is not restricted to two dimensions: light can twist a theoretically infinite number of times. This allows him to encode more information per photon, which also makes the system less prone to interference between channels and loss of information.
“The goal of what I’m trying to pursue in my project is to generate orbital angular momentum entanglement between two photons, using the fibers we have designed in our lab.”
If Shahar’s research seems complicated, and even a bit abstract, that’s because it is. His research in quantum physics, an inherently counter-intuitive field, is invariably more involved than some other fields. To Shahar, however, this ambiguity is at the heart of what it means to pursue a PhD. “It’s like exploring uncharted territory.”
“It’s not like a structured lab in a physics class, where you have to drop a ball from a certain height and see how long it takes to land. PhDs are about things we’ve never done before, so we don’t know what to expect. You can’t open up a textbook and see the solution. A lot of things are going to be a mystery, so you have to be ready to encounter these situations.”
Outside of the lab, Shahar is the president of the BU Photonics Student Society (BUPSS), formerly known as the SPIE/Optica/IEEE student chapter. Shahar is the chapter’s second president since its post-Covid revival, and is passionate about strengthening the graduate student community. He believes there’s plenty of room for fostering stronger connections between graduate researchers.
“You typically know people from your lab, but you might not know the people outside of it: personally as friends, but also in their research.”
To this end, the chapter has hosted a multitude of events to bring graduate students together. Recently, the chapter held a “Research on Tap” event, where graduate students had the opportunity to give “lightening” talks to practice presenting their research, and learn about each other’s lab work. The three winners of the event had the opportunity to present at the Photonics symposium on November 21, 2024.
Last semester, the chapter also held Boston Photonics Day to give Photonics graduate students the opportunity to learn more about career paths from industry professionals, as well as to present their research.
“It was a whole day event to bring the Boston photonics community together. And now, we’re focusing on bringing the graduate students together specifically.”
In the coming months, the student chapter plans to host more student-led and student-focused activities to provide graduate students with more opportunities to socialize and network.
To get involved in BUPSS, graduate students can email osaspie@bu.edu or reach out to Shahar directly at dshahar@bu.edu.