Advances in Terahertz Technology

This week the BBC reported on a Milestone for wi-fi with 'T-rays'. I previously reported on ROHM's demonstration of a 1.5 Gbps transfer rate at 300 GHz. Researchers from the Tokyo Institute of Technology doubled that to 3 Gbps using a frequency of 542 GHz by generating the signal in resonant tunneling diode (RTD). The article did not mention the length of the link, although at terahertz frequencies it would have to be limited. The Tokyo Institute of Technology team is now working to improve the proof-of-concept device, increase power and extend its frequency range deeper into the terahertz region.

In other terahertz technology news, researchers at the Agency for Science Technology and Research's (A*STAR) Institute of Materials Research and Engineering generated radiation 100 times stronger than that created by conventional techniques.

The procedure is detailed in the A*STAR release T-rays technology could help develop Star Trek-style handheld medical scanners. "In the new technique, researchers demonstrated that it is possible to produce a strong beam of T-rays by shining light of differing wavelengths on a pair of electrodes – two pointed strips of metal separated by a 100 nanometre gap on top of a semiconductor wafer. The unique tip-to-tip nano-sized gap electrode structure greatly enhances the THz field and acts like a nano-antenna that amplifies the THz wave generated. The waves are produced by an interaction between the electromagnetic waves of the light pulses and a powerful current passing between the semiconductor electrodes from the carriers generated in the underlying semiconductor. The scientists are able to tune the wavelength of the T-rays to create a beam that is useable in the scanning technology."

Dr. Jing Hua Teng, from A*STAR's IMRE, explained, "The secret behind the innovation lies in the new nano-antenna that we had developed and integrated into the semiconductor chip." Scientists said that the T-ray scanner and detector could provide part of the functionality of Star Trek's medical "tricorder" because THz waves are capable of detecting biological phenomena such as increased blood flow around tumorous growths. The devices could then use THz waves to transmit the results of the measurement at high speeds.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.