Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

’Frequency comb’ spectroscopy proves to be powerful chemical analysis tool

17.03.2006


Physicists at JILA have designed and demonstrated a highly sensitive new tool for real-time analysis of the quantity, structure and dynamics of a variety of atoms and molecules simultaneously, even in minuscule gas samples. The technology could provide unprecedented capabilities in many settings, such as chemistry laboratories, environmental monitoring stations, security sites screening for explosives or biochemical weapons, and medical offices where patients’ breath is analyzed to monitor disease.


The new JILA technique uses infrared laser light in many different colors, or frequencies, to identify trace levels of different molecules at the same time. For example, water molecules (blue) and ammonia molecules (green) absorb light at very specific characteristic frequencies. The pattern of frequencies absorbed forms a "signature" for identifying the molecules and their concentrations.



Described in the March 17 issue of Science,* the new technology is an adaptation of a conventional technique, cavity ring-down spectroscopy, for identifying chemicals based on their interactions with light. The JILA system uses an ultrafast laser-based "optical frequency comb" as both the light source and as a ruler for precisely measuring the many different colors of light after the interactions. The technology offers a novel combination of a broad range of frequencies (or bandwidth), high sensitivity, precision and speed. A provisional patent application has been filed.

JILA is a joint institute of the National Institute of Standards and Technology (NIST), a non-regulatory agency of the U.S. Department of Commerce, and the University of Colorado at Boulder.


"What a frequency comb can do beautifully is offer a powerful combination of broad spectral range and fine resolution," says NIST Fellow Jun Ye, who led the work described in the paper. "The amount of information gathered with this approach was previously unimaginable. It’s like being able to see every single tree of an entire forest. This is something that could have tremendous industrial and commercial value."

Frequency combs are an emerging technology designed and used at JILA, NIST and other laboratories for frequency metrology and optical atomic clocks, and are being demonstrated in additional applications. NIST/JILA physicist John (Jan) Hall shared the 2005 Nobel Prize in physics in part for his contributions to the development of frequency combs [www.nist.gov/public_affairs/newsfromnist_frequency_combs.htm]. In the application described in Science, the frequency comb is used to precisely measure and identify the light absorption signatures of many different atoms and molecules.

The JILA system described in Science offers exceptional performance for all four of the primary characteristics desired in a cutting-edge spectroscopic system:

  • The system currently spans 125,000 frequency components of light, or 100 nanometers (750-850 nm) in the visible and near-infrared wavelength range, enabling scientists to observe all the energy levels of a variety of different atoms and molecules simultaneously.
  • High resolution or precision allows scientists to separate and identify signals that are very brief or close together, such as individual rotations out of hundreds of thousands in a water molecule. The resolution can be tweaked to reach below the limit set by the thermal motion of gaseous atoms or molecules at room temperature.
  • High sensitivity--currently 1 molecule out of 100 million--enables the detection of trace amounts of chemicals or weak signals. With additional work, the JILA team foresees building a portable tool providing detection capability at the 1 part per billion level. Such a device might be used, for example, to analyze a patient’s breath to monitor diseases such as renal failure and cystic fibrosis.
  • A fast data-acquisition time of about 1 millisecond per 15 nm of bandwidth enables scientists to observe what happens under changing environmental conditions, and to study molecular vibrations, chemical reactions and other dynamics.

By comparison, conventional cavity ring-down spectroscopy offers comparable sensitivity but a narrow bandwidth of about 1 nanometer. A more sensitive "optical nose" technique developed at NIST can identify one molecule among 1 trillion others, but can analyze only one frequency of light at a time. Other methods, such as Fourier transform infrared spectroscopy, provide large bandwidths and high speed but are not sensitive enough to detect trace gases.

Laura Ost | EurekAlert!
Further information:
http://www.nist.gov

More articles from Physics and Astronomy:

nachricht Breaking the optical bandwidth record of stable pulsed lasers
24.01.2017 | Institut national de la recherche scientifique - INRS

nachricht European XFEL prepares for user operation: Researchers can hand in first proposals for experiments
24.01.2017 | European XFEL GmbH

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists spin artificial silk from whey protein

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Breaking the optical bandwidth record of stable pulsed lasers

24.01.2017 | Physics and Astronomy

Choreographing the microRNA-target dance

24.01.2017 | Life Sciences

Spanish scientists create a 3-D bioprinter to print human skin

24.01.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>