Featured Research

from universities, journals, and other organizations

Redefining electrical current law with the transistor laser

Date:
May 17, 2010
Source:
University of Illinois at Urbana-Champaign
Summary:
A major current law has been rewritten thanks to the three-port transistor laser. Data the transistor laser generated did not fit neatly within established circuit laws governing electrical currents, so the pair created a new model to account for the transistor laser having both electrical and optical output.

A major current law has been rewritten thanks to the three-port transistor laser, developed by Milton Feng and Nick Holonyak Jr. at the University of Illinois.
Credit: Photo by L. Brian Stauffer

While the laws of physics weren't made to be broken, sometimes they need revision. A major current law has been rewritten thanks to the three-port transistor laser, developed by Milton Feng and Nick Holonyak Jr. at the University of Illinois.

Related Articles


With the transistor laser, researchers can explore the behavior of photons, electrons and semiconductors. The device could shape the future of high-speed signal processing, integrated circuits, optical communications, supercomputing and other applications. However, harnessing these capabilities hinges on a clear understanding of the physics of the device, and data the transistor laser generated did not fit neatly within established circuit laws governing electrical currents.

"We were puzzled," said Feng, the Holonyak Chair Professor of Electrical and Computer Engineering. "How did that work? Is it violating Kirchhoff's law? How can the law accommodate a further output signal, a photon or optical signal?"

Kirchhoff's current law, described by Gustav Kirchhoff in 1845, states charge input at a node is equal to the charge output. In other words, all the electrical energy going in must go out again. On a basic bipolar transistor, with ports for electrical input and output, the law applies straightforwardly. The transistor laser adds a third port for optical output, emitting light.

This posed a conundrum for researchers working with the laser: How were they to apply the laws of conservation of charge and conservation of energy with two forms of energy output?

"The optical signal is connected and related to the electrical signals, but until now it's been dismissed in a transistor," said Holonyak, the John Bardeen Chair Professor of Electrical and Computer Engineering and Physics at the U. of I. "Kirchhoff's law takes care of balancing the charge, but it doesn't take care of balancing the energies. The question is, how do you put it all together, and represent it in circuit language?"

The unique properties of the transistor laser required Holonyak, Feng and graduate student Han Wui Then to re-examine and modify the law to account for photon particles as well as electrons, effectively expanding it from a current law to a current-energy law. They published their model and supporting data in the Journal of Applied Physics, available online May 10.

"The previous law had to do with the particles -- electrons coming out at a given point. But it was never about energy conservation as it was normally known and used," Feng said. "This is the first time we see how energy is involved in the conservation process."

Simulations based on the modified law fit data collected from the transistor laser, allowing researchers to predict the bandwidth, speed and other properties for integrated circuits, according to Feng. With accurate simulations, the team can continue exploring applications in integrated circuits and supercomputing.

"This fits so well, it's amazing," Feng said. "The microwave transistor laser model is very accurate for predicting frequency-dependent electrical and optical properties. The experimental data are very convincing."

The Army Research Office supported this work.


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Journal Reference:

  1. h. W. Then, M. Feng, N. Holonyak. Microwave circuit model of the three-port transistor laser. Journal of Applied Physics, 2010; DOI: 10.1063/1.3371802

Cite This Page:

University of Illinois at Urbana-Champaign. "Redefining electrical current law with the transistor laser." ScienceDaily. ScienceDaily, 17 May 2010. <www.sciencedaily.com/releases/2010/05/100512164335.htm>.
University of Illinois at Urbana-Champaign. (2010, May 17). Redefining electrical current law with the transistor laser. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2010/05/100512164335.htm
University of Illinois at Urbana-Champaign. "Redefining electrical current law with the transistor laser." ScienceDaily. www.sciencedaily.com/releases/2010/05/100512164335.htm (accessed October 24, 2014).

Share This



More Matter & Energy News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Printed Instruments Make Sweet Music in Sweden

3D Printed Instruments Make Sweet Music in Sweden

Reuters - Innovations Video Online (Oct. 23, 2014) Students from Lund University's Malmo Academy of Music are believed to be the world's first band to all use 3D printed instruments. The guitar, bass guitar, keyboard and drums were built by Olaf Diegel, professor of product development, who says 3D printing allows musicians to design an instrument to their exact specifications. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins