PC waveguide mirror to change the direction of light by 135º

Cun-Zheng Ning and Natalia Malkova at NASA Ames Research Center (Moffett Field, CA) have used a computer simulation to design 2-D photonic-crystal waveguides that change the direction of light by 135º (resulting in an acute angle of 45º between the incoming and outgoing beams). The waveguides are formed by coupled defect cavities in which reflectionless transmission is achieved through an acute angle by forming the defect cavities in the bends and by designing a “control cell” with a specific symmetry for a desired angle. Simulation results indicate that loss-free transmission can be achieved through the bend.

The authors intend to use the same method to bend light at other angles by varying the symmetry of the control cell. They also hope that by using electro-optical materials for the control cell, they will be able to vary the direction of light propagation dynamically and at ultrafast switching speeds. Such light-bending waveguides are expected to play an important role in nanoscale photonic integrated circuits or chip-based photonics systems, as a nanometer scale mirror that can change the direction of light propagation as desired over a range of angles. Contact Cun-Zheng Ning at [email protected].