Getting wired for terahertz computing

Close-up of a waveguide device that "couples " terahertz radiation, moving it from one wire-like waveguide to another. The device is fabricated on a piece of stainless steel foil. Terahertz radiation... Click here for more information.

Nahata conducted the study with two doctoral students in electrical and computer engineering: Wenqi Zhu and Amit Agrawal.

Developing Terahertz Technology

The electromagnetic spectrum, which ranges from high to low frequencies (or short to long wavelengths), includes: gamma rays, X-rays, ultraviolet light, visible light (violet, blue, green, yellow, orange and red), infrared light (including radiant heat and terahertz radiation), microwaves, FM radio waves, television, short wave and AM radio.

Fiberoptic 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.

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 says 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.

This February, British researchers reported they used computer simulations and some experiments to show that indentations punched across an entire sheet of copper-clad polymer could hold terahertz radiation close to the sheet’s surface. That led them to conclude the far-infrared light could be guided along such a material’s surface.

But the London researchers did not actually manipulate the direction the terahertz radiation moved, such as by bending or splitting it.