The first ever spaser to be made completely of carbon has been modelled by researchers from Monash University. The technology could lead to mobile phones becoming so small, efficient, and flexible they could be printed on clothing.
A spaser (an acronym for Surface Plasmon Amplification by Stimulated Emission of Radiation) is essentially a nanoscale laser or nanolaser. It emits a beam of light through the vibration of free electrons, instead of the space-consuming electromagnetic wave emission process of a traditional laser.
“Other spasers designed to date are made of gold or silver nanoparticles and semiconductor quantum dots while our device would be comprised of a graphene resonator and a carbon nanotube gain element,” said lead researcher Chanaka Rupasinghe. “The use of carbon means our spaser would be more robust and flexible, would operate at high temperatures, and be eco-friendly. Because of these properties, there is the possibility that in the future an extremely thin mobile phone could be printed on clothing.”
Graphene and Carbon Nanotubes
Spaser-based devices are able be used as a substitute for current transistor-based devices like microprocessors, memory, and displays in order to surmount current miniaturisation and bandwidth limitations.
The researchers opted to develop their spaser using graphene and carbon nanotubes. These materials are more than a hundred times stronger than steel and can conduct heat and electricity much better than copper. They can also withstand higher temperatures.
The research demonstrated for the first time that graphene and carbon nanotubes can interact and transfer energy to each other through light. These optical interactions are very fast and energy-efficient, and so are suitable for applications such as computer chips.
“Graphene and carbon nanotubes can be used in applications where you need strong, lightweight, conducting, and thermally stable materials due to their outstanding mechanical, electrical and optical properties. They have been tested as nanoscale antennas, electric conductors and waveguides,” Chanaka said.
Spasers generate high-intensity electric fields, concentrated into a nanoscale space. The fields are much stronger than those generated by illuminating metal nanoparticles by a laser in applications such as cancer therapy.
“Scientists have already found ways to guide nanoparticles close to cancer cells. We can move graphene and carbon nanotubes following those techniques and use the high concentrate fields generated through the spasing phenomena to destroy individual cancer cells without harming the healthy cells in the body,” Chanaka said.
Spaser Made of Graphene and Carbon Nanotubes.
Chanaka Rupasinghe, Ivan D. Rukhlenko, and Malin Premaratne.
ACS Nano 2014 8 (3), 2431-2438. DOI: 10.1021/nn406015d