IEEE Spectrum August 6, 2018
To combine the advantages of ultrafast femtosecond nano-optics with an on-chip communication scheme, optical signals with a frequency of several hundreds of THz need to be down-converted to coherent electronic signals propagating on-chip. Researchers in Germany have demonstrated that 14 fs optical pulses in the near-infrared can drive electronic on-chip circuits with a prospective bandwidth up to 10 THz. The corresponding electronic pulses propagate in macroscopic striplines on a millimeter scale. They exploit femtosecond photoswitches based on asymmetric, nanoscale metal junctions to drive the pulses. The non-linear ultrafast response is based on a plasmonically enhanced, multiphoton absorption resulting in a field emission of ballistic hot electrons propagating across the nanoscale junctions. The results pave the way towards femtosecond electronics integrated in wafer-scale THz circuits… read more. Open Access TECHNICAL ARTICLEÂ
A laser (left) generates on-chip electric pulses in the terahertz frequency range. A second laser (right) reads the information transmitted by the first laser. Illustration: Christoph Hohmann/TUM