Light may quicken computer

Extremely fast computer circuitry that runs on far-infrared light instead of electricity is the object of research the University of Utah is promoting in news announcements and in a study published in the online journal Optics Express.

Ajay Nahata, an associate professor of electrical and computer engineering, is leading the research and projects the far-infrared technology, known as terahertz radiation, will allow the development of "superfast circuits, computers and communications" in a minimum of 10 years.

In layman's terms, "It's a speed issue. People want to be able to transfer data at higher speeds. People would like to download a movie in a few seconds," Nahata said.

Nahata and doctoral students Wenqi Zhu and Amit Agrawal report they designed perforated stainless steel foil sheets that function as waveguides to transmit, bend, split or combine terahertz radiation. "A waveguide is something that allows you to transport electromagnetic radiation from one point to another point, or distribute it across a circuit," Nahata said.

For terahertz radiation to be used in computing and communication, it not only must be transmitted from one device to another, "but you have to process it," Nahata said. "This is where terahertz circuits are important. The long-term goal is to develop capabilities to create circuits that run faster than modern-day electronic circuits so we can have faster computers and faster data transfer via the Internet."

Fiber-optic phone and data lines now use near-infrared light and some visible light. The only part of the spectrum not now used for communications or other practical purposes is terahertz-frequency or far-infrared radiation — also nicknamed T-rays — located on the spectrum between mid-infrared and microwaves, according to a summary of the technology compiled by the university.

With so much of the spectrum clogged by existing communications, engineers would like to harness terahertz frequencies for communication, much faster computing and even for anti-terrorism scanners and sensors able to detect biological, chemical or other weapons. Nahata said the new study is relevant mainly to computers that would use terahertz radiation to run at speeds much faster than current computers.

In March 2007, Nahata, Agrawal and others published a study in the journal Nature showing it was possible to control a signal of terahertz radiation using thin, stainless-steel foils perforated with round holes arranged in semi-regular patterns.

Being able to manipulate the direction the t-rays move, such as by bending or splitting the radiation, is key to harnessing far-infrared light into circuitry devices that now rely on wires.

"Electronic circuits today work at gigahertz frequencies — billions of cycles per second. Electronic devices like a computer chip can operate at gigahertz," Nahata said. "What people would like to do is develop capabilities to transport and manipulate data at terahertz frequencies (trillions of hertz.)"

"In this study, we've demonstrated the first step toward making circuits that use terahertz radiation and ultimately might work at terahertz speeds," or a thousand times faster than today's gigahertz-speed computers, Nahata said.

---

E-mail: sfidel@desnews.com