How to Light a Nanoscopic Christmas Tree

Plasmonics is the study of the interaction between light and free electrons inside metals to form waves called plasmons on the surface of these materials. There is a great deal of interest in plasmons because they can carry information at high speed across computer chips, act as sensors because they are highly sensitive to the properties of the materials they travel across and might even be useful for high resolution lithography because of their extremely small wavelength.

So finding ways to improve the interaction between light fields and metal surfaces is an important goal. That’s why materials scientists have begun to play around with zapping nanostructures with laser pulses to see what happens.

The goal is to find how arrangements of edges and the addition of extra materials can enhance this interaction. It’s even possible to simulate accurately how this interaction takes place using advanced computer modeling techniques

Today, we see a festive example of this kind of simulation by Arkady Gonoskov and pals at Chalmers University of Technology in Sweden. These guys have simulated the way a laser pulse interacts with a gold nanoscopic Christmas tree decorated with glass baubles and a glass star on top.

The results make a merry tale. The light pulse is absorbed and reflected by the tree as it passes. But after this, strong electric field gradients along the edges cause the tree and, in particular, the glass decorations to glow. “After the laser pulse has passed, we clearly see that the Christmas tree has been lit—edge fields provide a warm fireside glow,” say Gonoskov and co.

That’s not just some holiday season tomfoolery. The team point out that these fields are strong enough to accelerate charged particles. So this kind of Christmas tree effect could have a practical application.

That seems a fitting way for this blog to end its coverage of Emerging Technology from the arXiv for 2014. We’ll be running “Best of 2014” posts from now until January 5. Until then, have a peaceful holiday and a happy new year.

Ref: http://arxiv.org/abs/1412.5998 : Lighting Up The Christmas Tree: High-Intensity Laser Interactions With A Nano-Structured Target