Featured Research

from universities, journals, and other organizations

'Nanotubes on a chip' may simplify optical power measurements

Date:
January 25, 2013
Source:
National Institute of Standards and Technology (NIST)
Summary:
A novel chip-scale instrument made of carbon nanotubes may simplify absolute measurements of laser power, especially the light signals transmitted by optical fibers in telecommunications networks.

The circular patch of carbon nanotubes on a pink silicon backing is one component of NIST’s new cryogenic radiometer, shown with a quarter for scale. Gold coating and metal wiring has yet to be added to the chip. The radiometer will simplify and lower the cost of disseminating measurements of laser power.
Credit: Tomlin/NIST

The National Institute of Standards and Technology (NIST) has demonstrated a novel chip-scale instrument made of carbon nanotubes that may simplify absolute measurements of laser power, especially the light signals transmitted by optical fibers in telecommunications networks.

The prototype device, a miniature version of an instrument called a cryogenic radiometer, is a silicon chip topped with circular mats of carbon nanotubes standing on end. The mini-radiometer builds on NIST's previous work using nanotubes, the world's darkest known substance, to make an ultraefficient, highly accurate optical power detector, and advances NIST's ability to measure laser power delivered through fiber for calibration customers.

"This is our play for leadership in laser power measurements," project leader John Lehman says. "This is arguably the coolest thing we've done with carbon nanotubes. They're not just black, but they also have the temperature properties needed to make components like electrical heaters truly multifunctional."

NIST and other national metrology institutes around the world measure laser power by tracing it to fundamental electrical units. Radiometers absorb energy from light and convert it to heat. Then the electrical power needed to cause the same temperature increase is measured. NIST researchers found that the mini-radiometer accurately measures both laser power (brought to it by an optical fiber) and the equivalent electrical power within the limitations of the imperfect experimental setup. The tests were performed at a temperature of 3.9 K, using light at the telecom wavelength of 1550 nanometers.

The tiny circular forests of tall, thin nanotubes called VANTAs ("vertically aligned nanotube arrays") have several desirable properties. Most importantly, they uniformly absorb light over a broad range of wavelengths and their electrical resistance depends on temperature. The versatile nanotubes perform three different functions in the radiometer. One VANTA mat serves as both a light absorber and an electrical heater, and a second VANTA mat serves as a thermistor (a component whose electrical resistance varies with temperature). The VANTA mats are grown on the micro-machined silicon chip, an instrument design that is easy to modify and duplicate. In this application, the individual nanotubes are about 10 nanometers in diameter and 150 micrometers long.

By contrast, ordinary cryogenic radiometers use more types of materials and are more difficult to make. They are typically hand assembled using a cavity painted with carbon as the light absorber, an electrical wire as the heater, and a semiconductor as the thermistor. Furthermore, these instruments need to be modeled and characterized extensively to adjust their sensitivity, whereas the equivalent capability in NIST's mini-radiometer is easily patterned in the silicon.

NIST plans to apply for a patent on the chip-scale radiometer. Simple changes such as improved temperature stability are expected to greatly improve device performance. Future research may also address extending the laser power range into the far infrared, and integration of the radiometer into a potential multipurpose "NIST on a chip" device.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. N. A. Tomlin, J. H. Lehman. Carbon nanotube electrical-substitution cryogenic radiometer: initial results. Optics Letters, 2013; 38 (2): 175 DOI: 10.1364/OL.38.000175

Cite This Page:

National Institute of Standards and Technology (NIST). "'Nanotubes on a chip' may simplify optical power measurements." ScienceDaily. ScienceDaily, 25 January 2013. <www.sciencedaily.com/releases/2013/01/130125111337.htm>.
National Institute of Standards and Technology (NIST). (2013, January 25). 'Nanotubes on a chip' may simplify optical power measurements. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2013/01/130125111337.htm
National Institute of Standards and Technology (NIST). "'Nanotubes on a chip' may simplify optical power measurements." ScienceDaily. www.sciencedaily.com/releases/2013/01/130125111337.htm (accessed April 23, 2014).

Share This



More Matter & Energy News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Is North Korea Planning Nuclear Test #4?

Is North Korea Planning Nuclear Test #4?

Newsy (Apr. 22, 2014) South Korean officials say North Korea is preparing to conduct another nuclear test, but is Pyongyang just bluffing this time? Video provided by Newsy
Powered by NewsLook.com
China Falls for 4x4s at Beijing Auto Show

China Falls for 4x4s at Beijing Auto Show

AFP (Apr. 22, 2014) The urban 4x4 is the latest must-have for Chinese drivers, whose conversion to the cult of the SUV is the talking point of this year's Beijing auto show. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com
Hagel Gets Preview of New High-Tech Projects

Hagel Gets Preview of New High-Tech Projects

AP (Apr. 22, 2014) Defense Secretary Chuck Hagel is given hands-on demonstrations Tuesday of some of the newest research from DARPA _ the military's Defense Advanced Research Projects Agency program. (April 22) Video provided by AP
Powered by NewsLook.com
Lytro Introduces 'Illum,' A Professional Light-Field Camera

Lytro Introduces 'Illum,' A Professional Light-Field Camera

Newsy (Apr. 22, 2014) The light-field photography engineers at Lytro unveiled their next innovation: a professional DSLR-like camera called "Illum." Video provided by Newsy
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:
from the past week

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