The tool is also commonly used for "stand-off" detection in such harsh or potentially dangerous environments as blast furnaces, nuclear reactors and biohazard sites and on unmanned planetary probes like the Mars rovers.
Information provided by LIBS, however, is sometimes clouded by interfering signals caught by the spectroscope -- and eliminating the background can be expensive. But a group of chemists at the University of Illinois at Chicago reports that equipping LIBS with a polarizing filter can do the job at a lower cost and probably with equal or greater sensitivity than the tools presently in use.
Robert Gordon, professor and head of chemistry at UIC, became interested in polarized light after reading books by cosmologist Brian Greene that described a slight polarization of the cosmic microwave background left over from the Big Bang. Out of curiosity, Gordon had his lab group zap a crystal of silicon by firing pairs of near-infrared laser pulses at 80 femtoseconds -- or 80 millionths of a billionth of a second. This "mini-Big Bang-like" laser ablation caused a brief spark, or plasma, that gave off ultraviolet light, which the group checked for polarization.
"We thought we'd see maybe a few percent polarization," said Gordon. "But when we saw 100 percent, we were totally astonished."
The spectrum of light they studied, similar to the rainbow a prism creates when held up to sunlight, includes a series of lines that are the hidden signatures of chemical elements. To get rid of the background spectrum and focus just on the element lines, current LIBS use a time-resolved method that works like a camera shutter by snapping at nanosecond speeds. Gordon's group discovered that by eliminating the shutter and instead using a rotating polarizer, they could filter out the background and focus on the lines.
"The polarizer costs just pennies, whereas a time-shutter is a very expensive component," Gordon said. "By simply putting a polarizer in a detector and rotating it to get maximum signal-to-noise ratio, you can improve the quality of the signal effortlessly and fairly cheaply."
Gordon said there is still basic work that needs to be done to answer why the light gets polarized. He said that varying the angle and the intensity of the laser pulses used to ablate the sample material may provide additional ways to enhance LIBS.
Gordon and his coworkers first reported their findings in the Feb. 15 issue of Optics Letters and will present their results at the Conference on Lasers and Electro-Optics May 31-June 5 in Baltimore.
Gordon's coworkers include postdoctoral research associates Youbo Zhao and Yaoming Liu, doctoral student Sima Singha, and former undergraduate Tama Witt.
Funding came from the National Science Foundation and the U.S. Air Force Research Laboratory Materials and Manufacturing Directorate.
Paul Francuch | Newswise Science News
Further reports about: > Big Bang > Chemical Detection > Detection > LIBS > Mars rovers > Polarizers > biohazard sites > blast furnaces > cosmic microwave background > laser pulses > laser-induced breakdown spectroscopy > nuclear reactors > potentially dangerous environments > spectroscope > unmanned planetary probes
New insights into the information processing of motor neurons
22.02.2017 | Max Planck Florida Institute for Neuroscience
Wintering ducks connect isolated wetlands by dispersing plant seeds
22.02.2017 | Utrecht University
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
22.02.2017 | Power and Electrical Engineering
22.02.2017 | Life Sciences
22.02.2017 | Innovative Products