Featured Research

from universities, journals, and other organizations

Compact, Wavelength-on-demand Quantum Cascade Laser Chip Offers Ultra-sensitive Chemical Sensing

Date:
December 6, 2007
Source:
Harvard University
Summary:
Engineers have demonstrated a highly versatile, compact and portable Quantum Cascade Laser sensor for the fast detection of a large number of chemicals, ranging from infinitesimal traces of gases to liquids, by broad tuning of the emission wavelength. The potential range of applications is huge, including homeland security, medical diagnostics such as breadth analysis, pollution monitoring, and environmental sensing of the greenhouse gases responsible for global warming.

Engineers from Harvard University have demonstrated a highly versatile, compact and portable Quantum Cascade Laser sensor for the fast detection of a large number of chemicals, ranging from infinitesimal traces of gases to liquids, by broad tuning of the emission wavelength. The potential range of applications is huge, including homeland security, medical diagnostics such as breadth analysis, pollution monitoring, and environmental sensing of the greenhouse gases responsible for global warming.

Related Articles


The team is headed by Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, and includes graduate student Benjamin Lee, researchers Mikhail Belkin and Jim MacArthur, and undergraduate Ross Audet, all of Harvard's School of Engineering and Applied Sciences.

The broad emission spectrum of the Quantum Cascade Laser material, grown by a commercial reactor used for the mass production of semiconductor lasers, is designed using state-of-the-art nanotechnology by controlling the size of nanometric thin quantum wells in the active region. An array of 32 lasers, each designed to emit at a specific wavelength, is then fabricated on a single chip by standard semiconductor processing techniques to have a size of less than one-fourth of a dime. A microcomputer individually fires up and tunes each laser in the array in any desired sequence. This generates a broad and continuously tunable wavelength spectrum that can be used to detect a large number of chemical compounds.

"Our versatile laser spectrometer currently emits any wavelengths between 8.7 and 9.4 microns, in the so-called 'molecular fingerprint region' where most molecules have their telltale absorption features which uniquely identify them," Belkin says. "This ability to design a broad laser spectrum anywhere in the fingerprint region holds the promise of replacing the bulky and large infrared spectrometers currently used for chemical analysis and sensing."

The tunability of the laser chip can be extended up to 10-fold and several widely spaced absorption features can be targeted with the same chip, which will enable the detection in parallel of an extremely large number of trace gases in concentrations of parts per billion in volume. A portable compact spectrometer with this capability would revolutionize chemical sensing.

"These millimeter-size laser chips exploit the inherent enormous wavelength agility of state-of-the-art Quantum Cascade Lasers," says Capasso, who co-invented them in 1994 at Bell Labs. "As a first application we have shown that these widely tunable and extremely compact sensors can measure the spectrum of liquids with the same accuracy and reproducibility of state-of-the-art infrared spectrometers, but with inherently greater spectral resolution."

This research is published in the Dec. 3 issue of Applied Physics Letters.

The team's co-authors are research associates Laurent Diehl and Christian Pflügl of Harvard's School of Engineering and Applied Sciences; Doug Oakley, David Chapman, and Antonio Napoleone of MIT Lincoln Laboratory; David Bour, Scott Corzine, and Gloria Höfler, all formerly with Agilent Technologies; and Jérôme Faist of ETH Zurich. The research was supported by DARPA's Optofluidics Center. The authors also acknowledge the support of Harvard's Center for Nanoscale Systems, a member of the National Nanotechnology Infrastructure Network.

The researchers have filed for U.S. patents covering this new class of laser chips.


Story Source:

The above story is based on materials provided by Harvard University. Note: Materials may be edited for content and length.


Cite This Page:

Harvard University. "Compact, Wavelength-on-demand Quantum Cascade Laser Chip Offers Ultra-sensitive Chemical Sensing." ScienceDaily. ScienceDaily, 6 December 2007. <www.sciencedaily.com/releases/2007/12/071203111254.htm>.
Harvard University. (2007, December 6). Compact, Wavelength-on-demand Quantum Cascade Laser Chip Offers Ultra-sensitive Chemical Sensing. ScienceDaily. Retrieved April 25, 2015 from www.sciencedaily.com/releases/2007/12/071203111254.htm
Harvard University. "Compact, Wavelength-on-demand Quantum Cascade Laser Chip Offers Ultra-sensitive Chemical Sensing." ScienceDaily. www.sciencedaily.com/releases/2007/12/071203111254.htm (accessed April 25, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, April 25, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MINI Shows Off Augmented Reality Glasses

MINI Shows Off Augmented Reality Glasses

AP (Apr. 24, 2015) — MINI showcased its new augmented reality glasses at the Shanghai Auto Show this week, which designers say will make roads safer and allow the driver to see through opaque parts of the car. (April 24) Video provided by AP
Powered by NewsLook.com
3D Food Printing: The Meal of the Future?

3D Food Printing: The Meal of the Future?

AP (Apr. 23, 2015) — Developers of 3D food printing hope the culinary technology will revolutionize the way we cook and eat. (April 23) Video provided by AP
Powered by NewsLook.com
'Safest Bike Ever' Devised by British Entrepreneur

'Safest Bike Ever' Devised by British Entrepreneur

Reuters - Innovations Video Online (Apr. 23, 2015) — A British inventor says his Babel bike is the safest bicycle ever produced. Crispin Sinclair - son of famous British inventor Sir Clive Sinclair - hopes the bike&apos;s safety cage, double seatbelt, and host of other measures will inspire non-cyclists to get in the saddle. Jim Drury went to see it in action. Video provided by Reuters
Powered by NewsLook.com
First Successful Aerial Refueling of a Drone

First Successful Aerial Refueling of a Drone

Reuters - Innovations Video Online (Apr. 23, 2015) — The bat-wing U.S. Navy drone that became the first autonomous airplane to take off and land on an aircraft carrier accomplished yet another milestone on Wednesday, becoming the first unmanned aircraft to undergo aerial refueling. Ben Gruber reports. Video provided by Reuters
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