November 6, 2012
Researchers Create Nano-Scale Laser
Michael Harper for redOrbit.com — Your Universe Online
It´s a familiar theme: As research and technology evolve, the components involved become more reliable, more advanced and, ultimately, smaller. The first computers, used mostly to churn through calculations, were housed in giant rooms. Now, we carry computers with the same amount of power in our pockets. The same can be said of lasers. What once took up a good amount of space on a table can now be carried around on a key chain.Building on these advancements, a research team from Northwestern University has found a way to make an even smaller laser device, around the size of a virus particle. With such a nano scaled laser, researchers would be able to observe the universe on an even smaller scale, as well as implement this tech into optical drives.
These new, super small lasers operate at room temperature and, according to the team, are ready to be used along with silicon-based photonics devices as well as optical-circuits and nanoscale biosensors. These nanolasers will help to not only reduce the size of existing technologies, such as the optical drive, but will also allow for the ultra-fast processing and reading of data, something which is becoming increasingly important as our world collects tons and tons of data every day.
“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,” explained lead author Teri Odom, a nanotechnology expert at Northwestern, in a press release.
According to Odom, the key to creating these nanolasers lies in the casing used to build them. With the right materials in place, albeit it very tiny materials, Odom and her team were able to create these forward-looking nanolasers.
“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,” explained Odom in the release.
The metal nanostructures used in the nanolasers allow for such a small implementation because they support surface plasmons. Surface plasmons are a collection of oscillating electrons which aren´t biased when it comes to confining light in a particular area.
According to Odom, using these nanoparticle metals and a bow tie shape create a laser which is better than all the other plasmon lasers in 2 ways. First, the 3D bow tie shape allows the laser to be much more focused than other plasmon lasers, creating a well-defined, electromagnetic hotspot in the beam. Secondly, Odom´s nanolaser doesn´t experience the same sort of metal “loss” when it´s being used as other plasmon lasers. The discrete shape of the bowtie shape makes these lasers ultimately more durable and able to work for longer periods of time.
Additionally, says Odom, these lasers are even more accurate than other lasers that had come before it.
“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,” said Odom.
The results of Odom's research into nanolasers will be published in the journal Nano Letters.