New single laser devices that are the size of a virus particle can also operate at room temperature. These plasmonic nanolasers could be readily integrated into silicon-based photonic devices, all-optical circuits and nanoscale biosensors. 

We're going to need ultra-fast data processing and ultra-dense information storage by the time Halo 8 comes to a holodeck near you, so reducing the size of photonic and electronic elements is critical.

"Coherent light sources at the nanometer scale are important not only for exploring phenomena in small dimensions but also for realizing optical devices with sizes that can beat the diffraction limit of light," said Teri Odom of Northwestern University, who led the research. "The reason we can fabricate nano-lasers with sizes smaller than that allowed by diffraction is because we made the lasing cavity out of metal nanoparticle dimers -- structures with a 3-D 'bowtie' shape." 

These metal nanostructures support localized surface plasmons, collective oscillations of electrons, that have no fundamental size limits when it comes to confining light. 

The use of the bowtie geometry has two significant benefits over previous work on plasmon lasers: the bowtie structure provides a well-defined, electromagnetic hot spot in a nano-sized volume because of an antenna effect, and the individual structure has only minimal metal "losses" because of its discrete geometry. 

"Surprisingly, we also found that when arranged in an array, the 3-D bowtie resonators could emit light at specific angles according to the lattice parameters," Odom said.

Published in Nano Letters.