Communications of the ACM
Solid-State Terahertz Devices Could Scan for Cancer
Electron microscope image of a prototype chip using a ring of coupled oscillators to generate terahertz radiation.
Credit: Ehsan Afshari / Cornell University
Cornell University researchers have developed a method of generating terahertz signals on an inexpensive silicon chip. The method uses mainstream CMOS (complementary metal-oxide semiconductor) technology, generating power levels high enough for some medical imaging and scanning applications. Terahertz scanning, for example, can identify skin cancers too small to see with the naked eye. With further research, it will be possible to generate higher power, enabling such devices as handheld scanners for law enforcement, says Cornell professor Ehsan Afshari.
The prototype device shifts the phase of the signals being received, canceling out the peaks and valleys of the frequency waves at several harmonic levels and focusing them on the fourth harmonic. During testing, the researchers developed chips that generated signals with about 10,000 times the power level previously obtained at terahertz frequencies on a silicon chip. The power could be increased further by adding more oscillators to the ring or using multiple rings.
"The goal is to make a complete device on one CMOS chip," Afshari says. "I can envision a tiny thing you could put in a cell phone."
From Cornell Chronicle
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