Published by the Students of Johns Hopkins since 1896
July 8, 2020

Terahertz opens the door to a novel technology for data storage

By WILL EDMONDS | November 29, 2018



Researchers developed a new mechanism to control storage circuits.

There’s a principle in the field of computer science known as Moore’s law. Put simply, this law states that the potential storage capacity on a circuit will grow exponentially every two years. In recent years, however, the promise of Moore’s law has been subjugated to the harsh realities of physics. Transistors are small enough now, at atomic sizes, that there may no longer be a future for conventional circuit design. This seemingly will not, however, put a damper on progress.

Storage in computers currently takes one of two forms: hard disk storage or solid state storage. Hard disk storage consists of a platter and a read-write head. As the platter spins at speeds of up to around 15,000 rotations per minute, the read-write head can magnetize and demagnetize billions of individual sectors on the platter. These magnetizations and demagnetizations can then be read as series of zeros and ones — encoded data. Solid state drives have taken on more market share as of late due to their faster speed, enhanced durability and other benefits that come with requiring no moving parts. These drives store their data in electrical charges, with sectors either being charged or not charged. 

Researchers at Kyoto University in Japan have created a new mechanism to control storage circuits. The technique discussed in their recent research paper published in Physical Review Letters is a new way to encode data through tiny changes to underlying data storage material, similar to the idea behind CD technology.

The leader of this research team, Hideki Hirori, spoke about the promise of their research. “We identified a phenomenon which should assist in the design of new devices and ultimately realize the fast and stable digital information handling potential that this material promises,” Hirori said in a press release.

Compact disks, despite having fallen out of favor in recent years, provided much of the inspiration for the novel research. CD technology relied on light pulses to make atomic changes to the substrate. These microscopic physical bumps could then be read by shining a laser onto the surface and measuring the amount of reflected laser light on each bump, converting it into a series of ones and zeros. Rather than light, the new mechanism uses electromagnetic pulses in the terahertz range to enact these changes. Subnanosecond electrical pulses are able to act on certain substrates to form crystal growth in a very narrow region, within a few nanometers per pulse.

Hirori explained the broader implications of their research. 

“Terahertz technologies have matured to the point where we can use short pulses to generate strong electric fields while suppressing heating effects,” he said. 

Operating technology in the terahertz region of the electromagnetic spectrum has not proved viable for consumer technology. This region of radiation produces submillimeter waves. This feature is the primary reason that Hirori and his team have found success. Rather than heating a substrate indiscriminately as microwaves would, terahertz pulses are short enough to allow local selectivity that would not otherwise be possible.

Future research into terahertz technology may potentially spark changes in the medical imaging industry as well as the wireless communications industry. Terahertz rays (known as T-rays) are harmless, unlike X-rays, and are able to provide further structural details into soft tissue, giving medical practitioners a chance to stop cancer before it metastasizes. 

Hopkins freshman and premed hopeful Sohan Shah made a bold prediction. 

“Terahertz technology may well prove revolutionary in discovering tumors and lead to quicker diagnoses and better patient outcomes,” Shah wrote in an email to The News-Letter.

Alan Davy, a leader of an industry think tank, spoke to Silicon Republic about the potential for terahertz cellular technology. 

“This is beyond 5G and it could even be 8G or 10G, and could serve demands that are 10 or 20 years down the road,” Davy said. 

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