Unfortunately, silicon which is a key material in chips and electronic circuits has a high dielectric constant. “Because the dielectric constant of silicon is much higher than that of air, most terahertz waves are reflected at the silicon-air boundary rather than being cleanly transmitted out the back,” the study authors said.
A common approach to improve THz wave transmission is to use silicon lenses, which focus and enhance wave power. These lenses not only generate terahertz waves but also boost their radiating power allowing them to cover long distances.
However, there’s a catch. Due to their size and cost, silicon lenses can’t be integrated with electronic chips. Therefore one can’t use terahertz waves generated by these lenses for data transfer or any other electronic purpose.
“Such (silicon) lenses, which are often larger than the chip itself, make it hard to integrate the terahertz source into an electronic device,” the study authors said.