From lectures to explosives detection: Laser pointer identifies dangerous chemicals in real-time

Oct 10, 2012
This is a schematic drawing of the Raman spectrometer, including a laser pointer, dichroic mirror, prism, objective, x,y motorized translational stage, long wavepass edge filter, lens and a detector (spectrometer/intensified charge-coupled device). Credit: Ilana Bar, Ben Gurion University of the Negev

By using an ordinary green laser pointer, the kind commonly found in offices and college lecture halls, an Israeli research team has developed a new and highly portable Raman spectrometer that can detect extremely minute traces of hazardous chemicals in real time. The new sensor's compact design makes it an excellent candidate for rapid field deployment to disaster zones and areas with security concerns.

The researchers will present their findings at Laser Science XXVIII—the American Physical Society Division of Laser Science's Annual Meeting—collocated with the Optical Society's (OSA) Annual Meeting, Frontier in Optics (FiO), taking place in Rochester, N.Y. next week.

Raman spectrometers rely on highly focused at precise wavelengths to illuminate small samples of materials. Very sensitive detectors then study the spectra of light that has been re-emitted, or scattered, by the sample. Most of this retains its original frequency or color, but a very small percentage of that light is shifted ever so slightly to higher or lower wavelengths, depending on the unique vibrational modes of the sample being studied. By comparing the shifted and the original wavelengths, it's possible to determine the precise chemicals present in the sample.

The researchers brought this capability down to size by constructing their using a low-power and low-cost commercial green laser pointer. The green laser's relatively short helped to improve the detection of the inherently weak Raman signal. The spectrometer also has the capability to first scan the entire sample optically, sweeping from side to side, to locate individual particles of interest – a task usually performed by large and cumbersome Raman microscopes.

"Since the overall system is modular, compact, and can be readily made portable, it can be easily applied to the detection of different compounds and for of objects that are contaminated with drugs, explosives, and particularly explosive residues on latent fingerprints," said Ilana Bar, a researcher with the Department of Physics at Ben-Gurion University of the Negev in Israel. "With proper investment this system could be deployed quite quickly as a consumer product." Other members of the research team include Itamar Malka, Alona Petrushansky, and Salman Rosenwaks.

Explore further: Physicists develop miniature Raman laser sensors for single nanoparticle detection

More information: Presentation LTh3I.3, "Detection of Explosives and Latent Fingerprint Residues Utilizing Laser Pointer Based Raman Spectroscopy," takes place Thursday, Oct. 18 at 2:30 p.m. EDT at the Rochester Riverside Convention Center in Rochester, N.Y.

Related Stories

Finding explosives with laser beams

Feb 27, 2012

Scientists at Vienna University of Technology have found a way to detect chemicals over long distances, even if they are enclosed in containers.

NRL Develops Technique To Speed Detection Process

Feb 15, 2010

(PhysOrg.com) -- Researchers at the Naval Research Laboratory are developing a device to enable rapid detection and identification of bacteria, chemicals, and explosives in the environment or on the battlefield.

Taking a closer look at plaque

Oct 26, 2010

A team of University of Rochester scientists is using the technique of Raman spectroscopy to study two common dental plaque bacteria, Streptococcus sanguis and mutans. The relative balance of the two may be an indicator of ...

Laser Goes Tubing for Faster Body-Fluid Tests

Apr 02, 2007

University of Rochester researchers announce in the current issue of Applied Optics a technique that in 60 seconds or less measures multiple chemicals in body fluids, using a laser, white light, and a reflective tube. The te ...

Identifying gems and minerals on Earth and on Mars

Mar 10, 2006

It'll be a snap to identify gemstones once Robert Downs finishes his library of spectral fingerprints for all the Earth's minerals. Downs is almost halfway there. So far, the associate professor of geosciences ...

ORNL nanoprobe creates world of new possibilities

Jul 15, 2004

A technology with proven environmental, forensics and medical applications has received a shot in the arm because of an invention by researchers at the Department of Energy's Oak Ridge National Laboratory. ORNL's nanoprobe, which ...

Recommended for you

Researchers develop powerful, silicon-based laser

Sep 29, 2014

A silicon-based laser that lases up to a record 111°C, with a threshold current density of 200 A/cm2 and an output power exceeding 100 mW at room temperature, has been demonstrated by collaborating researcher ...

Predicting landslides with light

Sep 29, 2014

Optical fiber sensors are used around the world to monitor the condition of difficult-to-access segments of infrastructure—such as the underbellies of bridges, the exterior walls of tunnels, the feet of dams, long pipelines ...

Studies in laser physics help understand rogue waves

Sep 29, 2014

(Phys.org) —University of Auckland physicist Dr Miro Erkintalo is part of an international team investigating how lasers and optical fibres can be used to understand freakishly large waves on the ocean.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Griffiti
not rated yet Oct 11, 2012
This is an older technology, and has been done well by American coumpanies like Delta Nu and Ahura for years now