Optical interconnect prospects boosted by development of ‘needle beam’
1 min read
An international team led by researchers from Harvard University has demonstrated a light beam that propagates without spreading outwards. This 'needle beam', as the team calls it, could greatly reduce signal loss for on chip optical systems and may eventually assist the development of a more powerful microprocessors.
The needle beam is generated using surface plasmons, which travel in tight confinement with a metal surface. The team says the metallic stripes that carry these surface plasmons have the potential to replace standard copper electrical interconnects in microprocessors, enabling ultrafast on chip communications.
One of the problems that has hindered the development of optical interconnects is the fact that all waves naturally spread laterally during propagation, a phenomenon known as diffraction. This reduces the portion of the signal that can be detected.
"We have made a major step toward solving this problem by discovering and confirming experimentally the existence of a previously overlooked solution of Maxwell's equations that govern all light phenomena," says principal investigator Federico Capasso, Professor of Applied Physics at Harvard's School of Engineering and Applied Sciences. "The solution is a highly localised surface plasmon wave that propagates for approximately 80µm in our experiments in a straight line without any diffraction."
