Miniature single-laser devices operate at room temperature

According to a statement, the so-called plasmonic nanolasers could be integrated into silicon-based photonic devices, all-optical circuits and nanoscale biosensors.

The results are published in the journal Nano Letters.

‘Coherent light sources at the nanometer scale are important not only for exploring phenomena in small dimensions but also for realising optical devices with sizes that can beat the diffraction limit of light,’ said Teri Odom, a nanotechnology expert who led the research.

‘The reason we can fabricate nanolasers with sizes smaller than that allowed by diffraction is because we made the lasing cavity out of metal nanoparticle dimers — structures with a 3D bowtie shape.’

These metal nanostructures are said to support localised surface plasmons — collective oscillations of electrons — that have no fundamental size limits when confining light.

The use of the bowtie geometry is claimed to have 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 3D bowtie resonators could emit light at specific angles according to the lattice parameters,’ Odom said.