 |
| Schematic of the tunable terahertz laser, which is built upon a semiconductor substrate (thick grey slab). The salmon-pink region is the waveguide that is topped by a layer of gold and then graphene. The slits in the gold are shown as a red glow. The graphene is topped with an electrolyte (also shown in gold). (Courtesy: University of Manchester) |
Topics: Graphene, Laser, Optical Physics, Quantum Mechanics, Semiconductor Technology
A new type of semiconductor laser has been created using the unique electronic properties of graphene. Designed in the UK by researchers at the University of Manchester, the prototype operates in the terahertz band and can be easily tuned to output radiation at specific wavelengths. The team says that its research could lead to the development of compact devices for a variety of different applications, from security scanning to medical imaging.
Coherent terahertz radiation can be created using quantum-cascade lasers, which were invented in 1994. These devices contain multiple quantum wells with energy bands that are split into subbands and minibands. When a bias voltage is applied to the laser, a periodic cascade of intersubband transitions is established. The population inversion necessary for terahertz lasing is then achieved through electrical injection.
Physics World: Plasmons call the tune in new graphene-based terahertz laser
Tim Wogan
Comments