Making Optical Vortices in Silicon

Guest_Jim_* - October 19, 2012 12:38PM in Science & Technology

Typically light travels in a straight line, which is very useful for laser pointers, levels, and more, but really it is not so limited to one-dimensional movement. With the right optics, it is possible to give a photon orbital angular momentum such that it will seem to orbit around an axis. A team led by researchers at the University of Bristol has successfully recreated these optics in silicon at a small enough scale to possibly be integrated into chips.

Optical vortices have multiple uses including optical spanners and tweezers which can manipulate small particles or droplets. They can also be used to transmit information more efficiently than a straight beam of light. If two beams of light travel the same path, it is possible for them to interfere with each other and corrupt whatever data are contained by both. By changing the degree the photons are rotating around a common axis though, the data can be preserved with multiple streams travelling the same path.

The devices the researchers invented are just micrometers wide and can be made with conventional silicon fabrication methods. Together this should allow for thousands of the emitters to be created on a single chip at very low cost. Potentially though this technology could reach the single photon level, which would be extremely useful for quantum computing and communication.