Optical devices lose their sensitive side
Truly useful optical devices built onto microchips are a step closer to becoming a reality, thanks to the work of Tymon Barwicz and colleagues. In the inaugural issue of Nature Photonics, the team describes a way of producing tiny optical devices that process incoming light correctly even if it has a randomly-oriented electric field. They achieve this despite the fact that the individual components making up the device are very picky about the field orientation.Most devices that control light inside microscopic spaces are, unfortunately, extremely sensitive to the orientation of the light. This limits the usefulness of the technology. Barwicz and co-workers overcome this sensitivity with the aid of a clever miniature photonic circuit. Their circuit splits a light beam into its two constituent perpendicular orientations, rotates one orientation, and recombines the beams after forcing them to pass through identical optical devices. Essentially by aligning the orientation of both beams within the circuit, the initial direction of the field becomes irrelevant and the sensitivity no longer matters.For the trick to work, Barwicz and co-workers had to design intricate splitters and rotator components and make use of advance manufacturing techniques. By overcoming this barrier, they move us along the path to optical devices that can be integrated onto tiny chips in a big way.
Author contact:Tymon Barwicz (IBM Thomas J Watson Research Center, Yorktown Heights, NY, USA)Tel: +1 914 945 3454; E-mail: tymon@alum.mit.edu