The multiplexer device with one input and two outputs. (Source: IBS)
The computers of the future could work almost at the speed of light. Nanophotonics could indeed bring the speed of our technology to a completely different level. The Center for Integrated Nanostructure Physics CINAP within theInstitute for Basic Science have developed three key components of a circuit that works with light. These devices combine the advantages of photonics and electronics on the same platform.
While we are slowing approaching the end point of Moore’s Law, the future of big data processing requires high performance computers with higher speed operations. Researchers reckon that if we build computers that process information through light, instead of electrons, computers will be able to work faster. However, at nanometer dimensions, the wavelength of light is larger than the diameter of the silicon fiber and for this reason some light can be lost. A solution to control the propagation of light in matter can come from surface plasmons. These electromagnetic waves propagate along the surface of some conductive materials like silver, gold, aluminum and copper. Using surface plasmons, optical information can be transmitted nearly at the speed of light and in extremely miniature volumes.
Using surface plasmons in silver nanowires and 2D semiconductors like molybdenum disulphide (MoS2), IBS scientists built three key components for optical communication: optical transistors, optical multiplexers and optical signal detectors. These devices work thanks to plasmon-exciton-plasmon interconversion. IBS scientists constructed the optical transistor by interconnecting the silver nanowire to a flake of MoS2. Light shone on the device is converted to surface plasmon, than to exciton, back to surface plasmon and eventually emitted as light with a shorter wavelength compared to the initial input. For example, if the input light is green, the output light can be red.
Wavelength multiplexing devices were realized in a similar way, but instead of having only a flake of MoS2, the researchers used an array of three different 2D semiconductor materials emitting light at different wavelengths. In this structure, for example, a single input light (violet) generates three output lights (blue, green and red). The propagating optical signals along the silver nanowire can be also transformed and detected as electrical signals by an optical signal detector.
“The originality of this approach arises from the exciton-plasmon interconversion. We reported before about the conversion of exciton to plasmon, and from plasmon to exciton using silver nanowire/2D semiconductor hybrids, but this is the first time that we can complete the circle going from plasmons to excitons and back to plasmons. Using this concept, we created optical transistors and multiplexers,” explains Hyun Seok Lee. (Source: IBS)
Link: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon, Korea
Speak Your Mind