Featured Research

from universities, journals, and other organizations

Swell new sensors developed to detect trace gas

Date:
June 17, 2014
Source:
American Institute of Physics (AIP)
Summary:
Using microscopic polymer light resonators that expand in the presence of specific gases, researchers have developed new optical sensors with predicted detection levels in the parts-per-billion range. Optical sensors are ideal for detecting trace gas concentrations due to their high signal-to-noise ratio, compact, lightweight nature and immunity to electromagnetic interference.

High-sensitivity detection of dilute gases is demonstrated by monitoring the resonance of a suspended polymer nanocavity. The inset shows the target gas molecules (darker) interacting with the polymer material (lighter). This interaction causes the nanocavity to swell, resulting in a shift of its resonance.
Credit: H. Clevenson/MIT

Using microscopic polymer light resonators that expand in the presence of specific gases, researchers at MIT's Quantum Photonics Laboratory have developed new optical sensors with predicted detection levels in the parts-per-billion range. Optical sensors are ideal for detecting trace gas concentrations due to their high signal-to-noise ratio, compact, lightweight nature and immunity to electromagnetic interference.

Related Articles


Although other optical gas sensors had been developed before, the MIT team has conceived an extremely sensitive, compact way to detect vanishingly small amounts of target molecules. They describe their new approach in the journal Applied Physics Letters, from AIP Publishing.

The researchers fabricated wavelength-scale photonic crystal cavities from PMMA, an inexpensive and flexible polymer that swells when it comes into contact with a target gas. The polymer is infused with fluorescent dye, which emits selectively at the resonant wavelength of the cavity through a process called the Purcell effect. At this resonance, a specific color of light reflects back and forth a few thousand times before eventually leaking out. A spectral filter detects this small color shift, which can occur at even sub-nanometer level swelling of the cavity, and in turn reveals the gas concentration.

"These polymers are often used as coatings on other materials, so they're abundant and safe to handle. Because of their deformation in response to biochemical substances, cavity sensors made entirely of this polymer lead to a sensor with faster response and much higher sensitivity," said Hannah Clevenson. Clevenson is a PhD student in the electrical engineering and computer science department at MIT, who led the experimental effort in the lab of principal investigator Dirk Englund.

PMMA can be treated to interact specifically with a wide range of different target chemicals, making the MIT team's sensor design highly versatile. There's a wide range of potential applications for the sensor, said Clevenson, "from industrial sensing in large chemical plants for safety applications, to environmental sensing out in the field, to homeland security applications for detecting toxic gases, to medical settings, where the polymer could be treated for specific antibodies."

The thin PMMA polymer films, which are 400 nanometers thick, are patterned with structures that are 8-10 micrometers long by 600 nanometers wide and suspended in the air. In one experiment, the films were embedded on tissue paper, which allowed 80 percent of the sensors to be suspended over the air gaps in the paper. Surrounding the PMMA film with air is important, Clevenson said, both because it allows the device to swell when exposed to the target gas, and because the optical properties of air allow the device to be designed to trap light travelling in the polymer film.

The team found that these sensors are easily reusable since the polymer shrinks back to its original length once the targeted gas has been removed.

The current experimental sensitivity of the devices is 10 parts per million, but the team predicts that with further refinement, they could detect gases with part-per-billion concentration levels.


Story Source:

The above story is based on materials provided by American Institute of Physics (AIP). The original article was written by John Arnst. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. Clevenson, P. Desjardins, X. Gan, D. Englund. High sensitivity gas sensor based on high-Q suspended polymer photonic crystal nanocavity. Applied Physics Letters, June 2014 DOI: 104/24/10.1063/1.4879735

Cite This Page:

American Institute of Physics (AIP). "Swell new sensors developed to detect trace gas." ScienceDaily. ScienceDaily, 17 June 2014. <www.sciencedaily.com/releases/2014/06/140617111816.htm>.
American Institute of Physics (AIP). (2014, June 17). Swell new sensors developed to detect trace gas. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/2014/06/140617111816.htm
American Institute of Physics (AIP). "Swell new sensors developed to detect trace gas." ScienceDaily. www.sciencedaily.com/releases/2014/06/140617111816.htm (accessed October 30, 2014).

Share This



More Matter & Energy News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Reuters - Innovations Video Online (Oct. 29, 2014) A Swedish amputee who became the first person to ever receive a brain controlled prosthetic arm is able to manipulate and handle delicate objects with an unprecedented level of dexterity. The device is connected directly to his bone, nerves and muscles, giving him the ability to control it with his thoughts. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Robots Get Funky on the Dance Floor

Robots Get Funky on the Dance Floor

AP (Oct. 29, 2014) Dancing, spinning and fighting robots are showing off their agility at "Robocomp" in Krakow. (Oct. 29) Video provided by AP
Powered by NewsLook.com
Saharan Solar Project to Power Europe

Saharan Solar Project to Power Europe

Reuters - Business Video Online (Oct. 29, 2014) A solar energy project in the Tunisian Sahara aims to generate enough clean energy by 2018 to power two million European homes. Matt Stock reports. Video provided by Reuters
Powered by NewsLook.com
Lowe's Testing Robot Sales Assistants in California Store

Lowe's Testing Robot Sales Assistants in California Store

Buzz60 (Oct. 29, 2014) Lowe’s is testing out what it’s describing as a robotic shopping assistant in one of its Orchard Supply Hardware Stores in California. Jen Markham explains. Video provided by Buzz60
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