Optical Wireless Communications Receiver using Nanostructure Devices
Ongoing research at the University of Duke partnering with facebook produced an optical receiver that is capable of collecting fast modulating light with a 3dB bandwidth of 14 GHz. The promising end goal of this research is to advance optical communications in the NIR region. The metamaterial structure is created on a glass slab with a 75 nm silver substrate on top, then it is coated with dye molecules and polymers and plasmonic silver nanocubes on top of that. The cubic structure of the silver film allows for the detection of light from various incident angles, refer to the image .
A current issue with optical wireless communications is the need for a near-normal incidence of light onto the receiver to capture the entire signal with minimal losses. The silver nanocube structure allows the receiver to capture light from different incident angles. The individual cubes act as a net to trap any reflected light from the receiver, therefore, if the incoming beam of light is off-angle the silver nanocubes will minimize the losses by allowing extra reflections into the receiver. When performing measurements in the lab, the structure was able to intercept light at angles up to 120 degrees from the normal.
This research demonstrates a receiver that can minimize losses from high-speed, high-power signals on a centimeter scale. This research is paving the way for the field of ultrafast optoelectronics .