2021 Slam Top 12 Finalists

Yoseob's Interview with Brian Malow

"Lightsabers At The Nanoscale"

Yoseob Yoon

Energy Sciences

Have you ever imagined having a real lightsaber?

Ever since I watched the Star Wars lightsaber duel by Obi-Wan and Darth Maul, I fell in love with those amazing weapons and wondered how to make one. Well, a powerful laser beam can already cut through steel. Those laser beams propagate forever, but we can use mirrors at the two ends to trap light. But there’s a key feature that is missing from conventional lasers, and this one is tricky. Lightsabers, they clash, they repel each other, but normally light beams don’t do this. In fact, it is extremely difficult to make light beams repel.

However, we can solve this problem. Let me show you how. I use a special cloudy gas called Rydberg atoms, which are highly excited atoms with a lot of energy. And I trap these atoms between two mirrors, and fine tune the laser wavelength, then this light beam mixes with the Rydberg atoms and become hybrid particles that are half light and half matter. They still have properties of light, so they can propagate and shine, but they also have properties of atoms, so there is a strong repulsion between them. Now, I can effectively make a lightsaber in a lab, but the Lawrence Berkeley Lab’s mission is not to battle our enemies.

Instead, lightsabers can potentially replace those millions of transistors in computers. Transistors are basically switches, where you can turn the electric current on or off. A computer processes everything in terms of 1’s and 0’s, where the presence and absence of electric current represent 1’s and 0’s. But the problem is that they are very inefficient. When electrons flow through wires, they tend to bump into each other and generate heat, and that’s why our computers and smartphones get hot. On the other hand, if we have two lightsabers, and turn on one of them first, then the second lightsaber cannot be turned on because they repel each other. If we turn this one off, then the second one can be turned on. This is a switching operation done by two lightsabers! These lightsaber switches are much faster and much cooler than conventional computer chips because they are made of light.

I am working to improve the lightsaber efficiency so that they can work even at the very dim light level. To make them more efficient, we need smaller lightsabers. But Rydberg gases tend to spread out and take a large volume. We need to find a special gas that lives inside a small solid-state material, and we’re still hunting for the right one. That’s why I’m trying to make lightsabers at the nanometer scale, for fast and efficient computing devices.